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Micke's Tecumseh Hh120 Build

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#31 KennyP ONLINE  

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Posted November 27, 2014 - 08:17 AM

Thanks for sharing the info with folks! Someone else will find this valuable.


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#32 MountainMichael OFFLINE  

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Posted November 27, 2014 - 10:31 PM

Thanks for sharing the info with folks! Someone else will find this valuable.

Thank you, I really appreciate it!

 

Question for anyone who can help:  I found the full governor speed RPM setting I think; appears it is 3600.  Does anyone know the preferred speed setting for HH120? 

 

Thanks!

 

Micke



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Posted November 27, 2014 - 10:57 PM

Thank you, I really appreciate it!
 
Question for anyone who can help:  I found the full governor speed RPM setting I think; appears it is 3600.  Does anyone know the preferred speed setting for HH120? 
 
Thanks!
 
Micke


This screen shot confirms your #'s. keep in mind, that's on brand new parts with no fatigue. I might drop the high end a scosh to be safe... If I was at all concerned.
image.jpg

Last page of this manual: http://gardentractor...hh120-overhaul/
There are also many Teccy manuals here:http://gardentractor...ry/73-tecumseh/
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#34 MountainMichael OFFLINE  

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Posted November 28, 2014 - 02:05 PM

This screen shot confirms your #'s. keep in mind, that's on brand new parts with no fatigue. I might drop the high end a scosh to be safe... If I was at all concerned.
attachicon.gifimage.jpg

Last page of this manual: http://gardentractor...hh120-overhaul/
There are also many Teccy manuals here:http://gardentractor...ry/73-tecumseh/

Thank you very much!  It's appreciated.

 

I put in an NOS rod with polished beam and deburred/radiused/polished high stress points (in autos, the worst/most dangerous are usually the sharp square cornered broach cut near where the rod bolt head seats), but the crank and piston are used so I think that is excellent advice.

 

I have several hours of organizing left - "...every tool in the garage..." kind of thing.  But I might get to try kicking the old girl over today!  Hurray!  ??  We'll see.

 

My Dad and brother are coming out here to the sticks from Pueblo (if they can find the goat trail I live on once again - GPS maps tell people to turn into deer pastures and such) in a few hours to help with all the startup logistics and the insane checklist I've made.  Well, my brother may help me with some heavy lifting, too, like removing the mower deck and installing the dozer blade. 

 

Hopefully cheery updates in the next day or two.

 

I hope everyone had a great Thanksgiving; my own was very good.  I visited my Dad in Pueblo and we barbecued a smallish turkey.  It was 68 degrees outside where he lives.    

 

mm


Edited by MountainMichael, November 28, 2014 - 02:17 PM.


#35 MountainMichael OFFLINE  

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Posted November 28, 2014 - 08:40 PM

Start up:  SUCCESS!  So far.

 

I sure do appreciate everyone's input; especially MH81!  Looks like this one is going to be a Goodie. 

 

It was a really nice visit with my dad Ed from Pueblo and brother Tom from Colorado Springs here today for the start up.  For changing implements and during final work and prep and the 15 minute run in, it was sure helpful to have extra hands and knowledge here.

 

Before the run in, we got the mower deck out from under it and stowed and installed the dozer blade.

 

Although we were working with the garage doors open, I ran my big radiant propane heater aimed at the engine for a few hours because I don't like to start a newly rebuilt engine cold.  The engine was at 65 degrees on start up on the side away from the heater.  We made certain to turn the heater off and let it cool before filling the tractor's gas tank.   Checked thoroughly for gas leaks; thankfully, none.

 

The start up went without a hitch.  It was our collective impression that Dale Colvert's ignition must put out some good power because the engine fired on the first revolution and fully started on the 3rd revolution.  I know that sounds unbelievable; I can hardly believe it and I was there.  A later restart after a hydro trans check and top us was stubborn taking maybe 20 revolutions.  I then noticed that I still had some choke in.  Opened the choke all the way and the start up stubbornness didn't happen again.  By the way, the start up was with a conventional new Autolite spark plug - no fast start iridium plug just yet.

 

My Dad commented that oil smoke on startup was almost zero.  I was surprised by that because I had oiled the cylinder, piston and rings before assembly.  Go figure.  I'm wondering if a lot of the cylinder oil had run down to the sump in the week or two before start up?  

 

The head temp was low suggesting the timing is certainly not retarded.  The main mixture was easily adjustable by sound and very responsive.  Best setting thus far actually came out very close to 1-1/2 turns.   

 

One thing that failed was the cheap ebay tachometer.  It would read but at a guestimated RPM of 2400, readings would fluctuate wildly from 1200 to 3800 with the actual engine rpm not fluctuating a bit.  Because we couldn't know the true RPM, we limited it to what we collectively agreed was about 2400.  So I will need to touch up the main mixture when I have it at a proper known full governor RPM - whatever that will be.  We are uncertain whether the tach is just no good or whether maybe this ignition is sending out a signal that the tach just can't deal with.  This just brought to mind:  If the tach is seeing too much signal, maybe reduce from 4 wraps around the plug wire to 2?

 

Can anyone suggest a tach that works reliably with small engines with electronic ignitions?  A permanently installed tach or a temporary diagnostic tach - either one would be good.    

 

I had changed the hydro fluid out long ago before I knew the crate motor was shot, so we had to bleed the hydro unit a few times after startup which meant stopping the engine to check and top up the hydro.  Wasn't exactly happy about that, but it had to be done.  

 

The engine's internal sounds are minimal.  Thankfully, much quieter than my relatively new Tecumseh 9 hp snow thrower engine.  The hydro transmission is, to my ears, noisy when in forward.  But then, that's another can of worms.  From what I've read, noisy hydros can run 5 minutes or 20 years.  Only one way to find out.  There was no metal visible in the hydro oil when I drained it.  (Note; I complied with the manual's warnings and was scrupulously careful to not introduce dirt into the hydro when draining and refilling).  I'm wondering if I maybe need to adjust the rear belt guide weldment?  Is it maybe chattering against the back of the new belt when running forward?  Need to give that a look. 

 

Using an IR temp gun towards the end of the 15 minute run, the head temp was 258 (hotter near the exhaust port), the block temp near the cylinder was 160 and the exhaust pipe temp at the hottest location (about in the middle of the pipe) was 660.  The block temp down low in the oil sump was 148.  I consider all of these except the exhaust pipe temp to be on the cool side of nominal.  The exhaust pipe temp I consider about nominal; open to input if anyone thinks that is off.  Regarding the 3 obviously low temps, it was a very cool day, a short run and a very low friction oil.

 

We dumped the oil immediately after the 15 minute shutdown and really tried to get it down to the last drop as best as possible.  I looked obsessively but didn't see anything of concern in the oil at all, but then at a measily 15 minutes, I'd have been horrified if I had.  Similarly, not a drop of seepage yet, but there had better not be this early on! 

 

Refilled with oil and carefully topped up to just below the full line, so it is ready to go after the head re-torque tomorrow.

 

My Dad and brother are both experienced mechanics in their own right.  Both think the engine really sounds excellent and were tickled that everything went by the numbers.  I think it sounds like a sweetheart of a mill, too.  I feel fortunate that things went so easily. 

 

The clutch pedal works fine and the new idlers track the belt like a champ.

 

In conclusion of the initial start up:  So far, so good! 

 

Tomorrow:  Minor disassembly for access for head bolt re-torque number 1.  Then run the tractor up and down some deer trails I've opened up in my back yard to put an hour on it... followed by another oil change, full cooling cycle and 2nd head bolt re-torque...

 

mm


Edited by MountainMichael, November 28, 2014 - 10:54 PM.

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#36 MountainMichael OFFLINE  

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Posted November 28, 2014 - 11:32 PM

For Dale Colvert - Overnight Solutions HET Ignitions:

 

Here is an excerpt from an email exchange.  These are my brother's impressions regarding what he thinks of the ignition:

 

"Michael,

I'm glad we were able to help.  That is an impressive ignition system you put on that engine.  The engine started easier than any rebuilt engine I've ever seen.

Tom"


Edited by MountainMichael, November 28, 2014 - 11:45 PM.


#37 MH81 ONLINE  

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Posted November 28, 2014 - 11:45 PM

:dancingbanana:
Really glad to hear she fired up like she was supposed to. The fact that she is running cool and starting easy is a very promising first step.
Sorry to hear you're fighting the tach, I haven't looked for a good one in forever. I will probably have to soon as my access to the harmonic one has passed away with its owner and guessing is kinda difficult.

Thanks for the follow up. Happy trail riding.
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#38 MountainMichael OFFLINE  

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Posted November 28, 2014 - 11:46 PM

Thank you very much.  I appreciate it!

 

For a tachometer, I found the below linked thread that has a link to a photo-optical laser tach for 17 bucks plus shipping in Amazon.  One places a small piece of reflective tape on something that spins.  On an HH120, I would place the reflective tape on the PTO pulley.  Point the tach at it and pull the trigger.  Presto.  RPM. 

 

Some guys here in the GT forum said they have one and it works very well.  RF noise is no longer a consideration.

 

mm

 

http://gardentractor...?hl= tachometer


Edited by MountainMichael, November 29, 2014 - 12:32 AM.


#39 MountainMichael OFFLINE  

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Posted November 29, 2014 - 08:09 PM

The bottom line of this ramble is:  Head bolt re-torque followed by 1 hour run in went normally; no surprises.  This re-upped HH120 acts very strong.   :rocker2:  The eerily fast start up happened once again today. 

 

Details follow along with some "deer trailing" pictures if'n you're interested.

 

Busy work completed: 

 

Finished dozer blade installation; easy peasy.  Wheels and weights on with no smashed fingers.  Adjusted the aft hydro belt guide weldment.  It wasn't making any noise but I improved the position by maybe a bit more than 1/8". 

 

Head bolt re-torque:

 

Tear-down for access was easier than expected.  I originally torqued these bolts to 210 inch pounds using high temp nickel anti-seize on the bolt threads. 

 

Torque spec:  I recently noticed that although the torque specs page says 180 to 240 inch pounds, the page with the tightening pattern on it says 200 inch pounds, period.  So that is what I went with today.

 

Breakaway torque for various bolts ranged from 125 inch pounds to 150 inch pounds.  The most settling had occurred hear the exhaust port.  Because of where the breakaway torque was, I first took the bolts to 175 and then to 200 inch pounds with an antique calibrated gauge type Proto torque wrench.  I personally prefer the gauge type because when I reach the number, I note that the bolt continues to turn for awhile at that torque.  I hold the number persistently for maybe 10 seconds. 

 

No bolts broke thank goodness and reassembly of parts removed for access was as easy as teardown.

 

With that much torque loss from 15 minutes, I can see why I have read of so many HH120's losing head gaskets when re-torquing is not done timely.  Furthermore, as easy as it is to do, I believe MH81's advice to do another heating/cooling cycle and re-torque at 1 hour is very apt advice indeed.  

 

Driving impressions:   

 

Roll on torque was a little lethargic at first so I added just shy of a quarter turn richer to the main.  I'll 'read' the plug tomorrow as best I can and probably end up taking half of that back out because it smelled fat at times.  OTOH, 1 hour of working the ol' tractor pretty hard didn't move the gas gauge needle nearly as far as I had expected.  

 

After richening the mixture, the power was good and transient response was surprising for an engine with no accelerator pump.  My loop gravel driveway is on a hillside, so it acted about perfect at first for varying load; good power going up, trailing throttle going down.  When hotrodding the hydro lever like an idiot shoving it full forward pretty quickly, the tractor either chucks gravel and dirt or squawks the belt.   

 

When I thought the neighbors had probably had enough, I first took the tractor out on the dirt road here and up what I call "Cardiac Hill" when I'm out walking.  It's about a half mile long and maybe 9% grade.  Even with the dozer blade, wheel weights, 3 point hitch and mountain sized driver, it pulled the hill with the hydro shifter set full forward. 

 

Power was more than adequate deer trailing.  The dozer blade has low ground clearance even when up, so that limited me from fully traversing either of the 2 entire circuits of trails I've opened up for hiking on my land.  For this 1 hour run in, I had not installed chains.  Nevertheless, the tractor hauled through the snowy and muddy areas of the trails just fine.  Had I needed to do work with the blade, obviously that would have been different.

 

About the hydro noise:

 

Yesterday during the 15 minute run in on jack stands, I noted that the hydro sounded noisy when in forward, quiet in neutral and reverse.  While I adjusted it to better centering, that belt guide I'd speculated about was not hitting.

 

Today when driving, the hydro acted totally predictable, smooth and able to transmit full power bursts just fine.  Furthermore, the gravelly rattling kind of noise that was present when on jack stands was not audible when driving.  I could hear some hydraulic whine when under heavy loads but I have read that this is fairly normal - no panic necessary.  I had some serious doubts yesterday but my Dad said "don't sweat it".  Appears he was right.

 

I suspect sitting on the harsh surface of jack stands on concrete was inducing some harmonics between metal parts of the tractor.  Whereas, sitting on nice mushy tires tends to dampen such racket.  

 

Oil draining aid:

 

I tested with and without this.  Tilting the tractor to the right definitely drains more oil than just leaving it sit flat.  So this lame trick is to screw a 1/2NC by 3" bolt into the bottom of the trailer hitch with washers and 2 nuts - one above the hitch, one below.  Tighten snugly but nowhere full torque for this size of bolt.  Then I jack the tractor up on the bolt head that is sticking down with a floor jack,  This allows the tractor to tilt sharply to the right.

 

Although the forward tilt caused by raising the back of the tractor is not the best for full drainage, I confirmed that the above drains considerably more oil than just draining the tractor when sitting level.

 

Is it worth the time?  Probably not.  But on a newly rebuilt engine for the first few break in oil changes, I will probably do this.

 

There was some more noticeable swirl in the oil.  It was about the same as I've seen in new Tecumseh's after 1 hour of usage. 

 

Minor adjustments:

 

I had previously loosened the friction clutch nut and spring on the hydro shifter because I thought it was too tight.  I was wrong.  I need to put it back where it was.  The current effects of this problem:  When I pull the hydro lever back to slow for a sharp turn, if I don't keep a hand on the shifter, bumps will make it go full foward which can be interesting while in a sharp turn...  yikes.

 

Easily adjusted; it's just one of those "improvements" I will need to unimprove.   :rolling:   

 

Deer trailing pics:

 

My 2 trail circuits meander their way through the Cacti, Pinion, Juniper and Cedar to the back of my property where there is a shared "common area" that is a deep ravine.  That ravine is a game super highway.  The specific game is deer, rabbits, badgers (Badgers?  BADGERS??  We don' need no stinkin' badgers! [Cheech Marin - "UHF" (the movie)), rattle snakes, black bears (always tearing up people's garbage bins), coyotes and the ever elusive elk.  My family were elk hunters for decades.  My Dad and I have seen the largest elk tracks in that ravine of our lives.   

 

I was unable to make it all the way to the ravine today or I'd have some really gnarly pics. 

 

In Arizona, terrain like this is called "High Mountain Desert".  In Colorado, nobody seems to agree on what to call it.  Wish I could upload a video but I don't know how to work my editing software or how to upload vids.  I suppose I could figure it out, however, it is probably futile since our upload speed here is nearly as bad as dial up.  Anyhow, pics of some trailing:

 

NE up the valley side.jpg

 

Some old deer tracks.jpg

 

Back climb out SE of shed.jpg

 

Ok, I screwed up and lost a few.  There's 3 anyway.

 

It was another successful day and I'm beginning to develop some confidence that this engine is a keeper.  I'll obviously be able to give a more confident opinion after the first 100 hours. 

 

The laser tach should get here next week so I'll set the governor speed and revisit mixtures again then. 

 

mm


Edited by MountainMichael, November 30, 2014 - 02:34 AM.

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#40 MountainMichael OFFLINE  

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Posted November 30, 2014 - 04:07 PM

Today's head bolt re-torquing:

 

In a nutshell, everything went fine :thumbs: and it appears the head gasket has settled down.  This re-torque should hold things fine.  Added details if you are interested:

 

History:  Head gasket was sprayed with aerosol permatex hi temp copper head gasket spray - allowed to dry 1 hour before assembly.  Hi temp nickel anti-seize on head bolt threads.  Head bolts torqued in 50 inch pound steps up to 210 inch pounds at initial engine re-assembly.  Ran engine in for 15 minutes, then shut down and cooled overnight.  Re-torqued head bolts to 200 inch pounds in 2 steps.  Scary low breakaway torque on the head bolts in that sequence covered previously.  At minimum, first head bolt re-torque is absolutely essential IMHO.   

 

Ran the engine under varying loads yesterday for 1 hour continuously and immediately did another oil change.  Left it cool overnight.  Warmed the shop to 70 degrees with the radiant heater pointing away from tractor so I'm hopefully not skewing head bolt torque results. 

 

Today's torque sequence saw bolt breakaway torque ranging from 180 to 195 with breakaway still smooth and predictable; no indications of seizing.  The one at 195 was near the exhaust port - the opposite of yesterday.  2 bolts did not move so I tried 210 inch pounds to see if they were hiding anything - but no.  No movement.

 

Was today's sequence necessary?  One could argue maybe not, but maybe is not good enough for me.  So I believe it was good advice and I'm glad I did it.  I'm leaving the head shroud on top of the main shroud because I've decided it just makes the thing more serviceable.  I may do the head bolt torque sequence again after a lot of winter snow pushing during spring maintenance.  Probably not unless there are problems.

 

Oil leaks?  -  Admittedly, 1 hour is very little running time.  Still, I checked various areas where the old incarnation of the engine was leaking like a shotgunned sieve.  No oil leaks found so far.  The carb nuts accepted a little bit more at what I'm guessing is just shy of 50 inch pounds; can't get a torque wrench to it.  I'm staying below listed torque for these because I don't want to bend the throttle base again.  Used some Loctite 290 green penetrating grade thread locker on the nuts since I'm using lower than specced torque.    

 

Next up:  Mundane stuff not related to the engine build like control rods for the dozer blade, strap brace for the muffler, "Big Daddy Ed Roth"-esque :rolling: shifter extension/angle modifier so I can use the hydro shifter for a lot longer without aggravating my back like I did yesterday.  I may do a thread on that last just for grins if it turns out to be worth doing.  At least one mod for it is something most people won't appreciate and won't want to do...  it involves a heavy boot, aka, a "Brogan adjustment". 

 

After 1 hour and 15 minutes of run time, the existing conventional Autolite spark plug had a clean white insulator all the way up with no signs of detonation, damage or burning.  The bottom edge of the plug body has a partial ring of black on it - maybe some break in oil burning that wasn't visible at the muffler?  The old standard was a tan insulator but that went out the window with the advent of unleaded gas.  It will hopefully show at least some color eventually.  I'll read the plug at intervals and sample the exhaust pipe temp until I'm convinced that I'm not going to broil a valve or piston - or head gasket! 

 

If anything that I believe may be interesting pops up as pertains to the engine rebuild or if anything outright fails, I'll post it.  I'll probably post back about the laser tachometer and final tuning in a week or so.

 

Thank you again for input from all.  Special thanks to MH81 for knowledge shared.  Much appreciated! 


Edited by MountainMichael, November 30, 2014 - 04:27 PM.

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#41 DH1 ONLINE  

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Posted November 30, 2014 - 04:25 PM

Thanks for all the detailed info in this thread, maybe it should be made in to an article.

I have followed it from the start and found it to be very informative.

 

1 thing I still cant seem to get is the timing with the new ignition, I take it your engine had the SSI factory ignition on it which would mean there were 2 different timings that the engine would fire at.

1 near TDC during low RPMs during start up and a 2nd more advanced above 850RPM +/- after the engine fired and was running.

 

What is the timing on the new setup?

Does it work the same way or is it just at a single fixed point?

Where does it get the signal to fire?

Just trying to figure this out in my head.

 

BTW I would love to have an engine like that in my Massey 10 or 12.

Awesome job. :thumbs:  :thumbs:  :thumbs:


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#42 MountainMichael OFFLINE  

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Posted November 30, 2014 - 05:09 PM

Thanks for all the detailed info in this thread, maybe it should be made in to an article.

I have followed it from the start and found it to be very informative.

 

1 thing I still cant seem to get is the timing with the new ignition, I take it your engine had the SSI factory ignition on it which would mean there were 2 different timings that the engine would fire at.

1 near TDC during low RPMs during start up and a 2nd more advanced above 850RPM +/- after the engine fired and was running.

 

What is the timing on the new setup?

Does it work the same way or is it just at a single fixed point?

Where does it get the signal to fire?

Just trying to figure this out in my head.

 

BTW I would love to have an engine like that in my Massey 10 or 12.

Awesome job. :thumbs:  :thumbs:  :thumbs:

DH1,

 

Thank you very much for your input and kind comments.  I appreciate it.  :wave:

 

First off, my HH120 did in fact have the SSI OEM factory ignition with NO alternator under the flywheel, instead, with external starter/generator.  Under the flywheel, it looked exactly like the pre-replacement photo Dale has on his (previously linked) product page.  

 

I apologize for my bad memory, but from 4 months ago before the machine shop debacle until now, I have forgotten some things.  I do not remember if Dale mentioned anything about a retarded spark during startup.  I vaguely think he did say something about retarded timing at cranking rpm stepped to normal timing at running rpm.  Whether it does or doesn't, the engine starts super fast with no signs of backfire or starter difficulty - it cranks at normal speed easily each time whether cold or hot.

 

I personally chose to add a separate clean fused/switched circuit and ground from the battery for the HET ignition.  So if I were to go to some crazy compression ratio or aggressive static spark advance someday and IF I ever saw cranking difficulties, I could easily start the engine cranking and then flip on the ignition after it was already spinning.  However, that is absolutely not necessary with my engine at present.  That might be something a garden tractor pulling competitor could do with a highly modified engine?

 

It would be a good question for Dale.  If you learn anything, please do post back with the added info.  I have a couple of emails in for Dale to thank him for how well the ignition works but I haven't heard back so maybe he is off for the holiday's?  If I hear back from him, I will ask the question myself and post back to this thread.     

 

I am attaching Dale Colvert's HET (hall effect trigger) installation instructions.  I do not see any copyright warnings so I'm pretty sure Dale is ok with this being here since these instructions ONLY work with his unique ignition and don't seem to give any proprietary intellectual property away.  IOW, it could only help his sales.  Moderators/Admins:  If you disagree with having these instructions posted here, please let me know and I will take the attached files down.  Likewise, Dale:  If you want the instructions taken down, say the word and I'll do it.  

 

In addition to the instructions, my extensive email exchange with Dale indicated the following:

 

The signal to fire is from the main large flywheel magnet.  I believe the magnetic gauss of the leading edge of the big magnet is what tells the Hall Effect device to fire; like a magnetic crank trigger on a car.  Any startup retard would be done with electronics - IOW, something may be counting RPM in the module and switches advance up to normal running at some preset RPM.  I believe that may exist; I believe it is also NOT adjustable. 

 

During installation, I was instructed to remove the factory SSI coils under the flywheel (both trigger and ignition voltage generation coil) and the secondary spark voltage coil above the flywheel.  No marks from the under flywheel coils are necessary as how and where the aftermarket ignition fires is done differently.   

 

Dale decided that his aftermarket ignition would fire using the main flywheel magnet by the so called Hall Effect.  This means no finicky/dangerous close air gap is needed.  The magnet is not generating the primary voltage anymore, instead, it is only providing a firing or 'trigger' pulse.  The battery provides primary voltage with Dale's ignition.  

 

He said he used both a bench assembly jig (made from an HH120?) and testing on several running HH120's to establish where he would precision locate the firing coil before the electronics are final potted in epoxy.  He told me that this has turned out to be so accurate, there is almost never a need for setting timing.  He said that the mounting bolt hole would usually have some added clearance in case someone took the time to dial indicate .095" BTDC, make a mark and run the engine with a timing light for a precision check - and might need some small adjustment range.  Note that the instructions are specific about which way to push the module in and down during bolt tightening.  Dale said this is to make our installations as close as possible to how he bolts the thing up on the build jig before potting the electronics in place.  I put significant torque on the provided socket head screw since it is the sole mounting screw.  I was a bit jumpy about the pc board maybe cracking but that didn't happen.  The star washer plus maybe (I'm guessing here) 90 inch pounds of torque and I doubt the module will be moving.   

Not discussed with Dale, but I believe a good Woodruff Key is essential for any HH120 in order to avoid having the flywheel in slightly the wrong place as referenced to the crankshaft morse taper.  A worn key - or one that has had burs sanded off may be too loose and I speculate that could throw timing off.  The keys are still available for about a buck in ebay, so that might be a good thing to add for installation if the old key has been removed or disturbed.   

 

I'm not sure he bench tests every one for timing anymore; maybe he only did that during R&D?  Not sure.  Anyway, he said he has done enough installations checking timing and receiving feedback on same that he is confident one can install it as per instructions and things will be very, very close.  I personally forgot to dial indicate .095" BTDC while the head was off and make a mark on the flywheel and block, so I would now have to pull the head to make marks so I could then check with a timing light to definitively say whether it is spot on or not.

 

Dale's marketing doesn't really say the module is high energy, but I've gotta say:  The engine starts freaky fast.  Could any of that be due to the work I did in the head to de-shroud the spark plug?  I don't know; it just seems like a variable worth mentioning.     

 

I don't believe the module has any logic built in other than possibly some retard at starting rpm, so it is my guess that it fires at .095" BTDC on compression and on exhaust.  That's not anything that bothers me but it might be important for setting up a conventional tachometer.  

 

The above all seemed like a leap of faith to me but I'd read some things here and there that suggested Dale was a very knowledgeable guy and got the same impression in our email exchanges so I gave it a shot.  I'm glad I did.

 

Please let me know if there are any other questions I might answer.

 

mm 

 

edit:  I tried uploading the instructions with both basic and advanced in jpeg files.  No joy.  Let me try with pdf files:

 

Attached File  Overnight Solutions HET instructions page 1.pdf   263.87KB   38 downloads

 

Attached File  Overnight Solutions HET installation instructions page 2.pdf   135.56KB   33 downloads

 

Ok, trying to see if that works...  yup, looks like it went.


Edited by MountainMichael, November 30, 2014 - 05:44 PM.


#43 MountainMichael OFFLINE  

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Posted December 03, 2014 - 07:46 PM

FUEL USAGE REVISION:

 

The last run was the one hour run-in prior to the 2nd head bolt re-torque.  I had commented that I thought the engine was using very little fuel.  Not so.  Instead, the original gauge/cap has had its needle cut loose.  In the below pic, the needle should be reading E for empty since the float is all the way down.  Note where the needle is currently reading; about 5/8 tank.  Hence the confusion on my part:

 

DOA OEM gas gauge.jpg

 

Looking in the tank right now with no further run time, there is about 1/4" in the bottom of the tank.  I'm lucky I made it back to the garage.  To use that much fuel in 1 hour and 15 minutes total run time (3/4 tank), the engine must be running pig rich.  Optical tach supposedly arrives tomorrow.  If so, I'll do some more serious tuning.

 

I replaced the gas cap with one of these new ones for Simplicity?? from Briggs.  Arguably overpriced.  You can see that this gas cap gauge indicates the current fuel level is pretty much empty - which it is.  

 

New gas gauge cap on tank.jpg

 

It fits nicely although the float run is somewhat shorter so the empty reading will occur with maybe an inch more of reserve capacity.  I'm ok with that part - but there is the info in case you're not ok with it. 

 

This fits a 68 Super so I figure it will probably fit 'burbs of similar year range.  Below is a pic of the package:

 

New gas gauge package.jpg

 

What I don't like about the new gauge cap:  The internal screening of the letters and quadrants looks cheap and new whereas the old gauge cap looked quality and antique.  It's maybe just a bit offensive having a very expensive gauge cap look cheap. 

 

Still, there is something to be said for a gauge cap whose gauge works and that seals properly. 

 

Re:  Cranking and starting speed:

 

During a test of the hydro fan blade clearance, I cranked the engine with ignition off.  I note that it cranks considerably slower when it hasn't been warmed by the radiant heater.  That's expected but I suspect it will take more cranking to start on a cold morning without pre-heat due to slower rotation speed and less than optimal fuel atomization.

 

Hydro noise:

 

Mentioned earlier in this thread was rattling noise when running the hydro up on jack stands to bleed the fluid.

 

Having the mower deck out of the way has revealed a lot of things not previously easily visible. While under the tractor today, I saw that the lower surface of the parking brake linkage has been dragging against the back of the drive belt.  This would make a lot of racket and I'll do something about it.  It's not engine rebuild related per se, but since I'd mentioned it before in the thread, thought I should close the loop on it.

 

 

 

mm


Edited by MountainMichael, December 03, 2014 - 10:36 PM.

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#44 TAHOE OFFLINE  

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Posted December 04, 2014 - 09:19 AM

Thanks for the extensive write up!!!!

 

I had to go back and read up on Dale's page, I am learning that the early systems were CDI and his HET system converts it to a coil also. I know his system for the later OH motors is a direct bolt on, you do not convert to a battery igniton.

I guess I need to read up more on the early systems, I have no had a need to deal with them although if I ever get my SS12 worked on, I probably will need to know.

 

Dang, Dale's Bosch blue coil is about the most expesive on the market, glad I got mine much cheaper!

 

I did a conversion using a module from Midwest Super Cubs that is used on both single and twin high horsepower Kohler pulling motors. I had to remove the trigger pins and glue in a small magnet to trigger my micro switch to fire coil. Their kit has a reluctor rim w/magnets that mounts on the Kohler cranks, but since mine is a one off on a Tecumseh, I just had to glue the magnet in flywheel.  I have no TDC fire, only advance 25* and I have to spin motor as you stated, then flip switch to juice the coil and start or i can get kick back which can snap a rod. It looks like as Dale still used the pins, you really don't need to spin yours, but can juice coil right off the bat.

I also get backfire if I idle down too fast from WOT as timing cannot keep up with instant change as with SSI module.

 

I will be using Ed Stoller's instructions and using my old SSI module and converting it so I can use it as a pickup trigger and fire a coil, my hope is to do a complete conversion for under $60 :dancingbanana:

 

My ignition conversion is linked in my sig.


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#45 MountainMichael OFFLINE  

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Posted December 04, 2014 - 06:04 PM

Tahoe, YW and thank you for the input and the link to your excellent thread on Tecumseh SSI ignition conversion options.  Looks like a much more cost effective solution.  I had considered some of those options in advance due to Ed Stoller's excellent website.  I hadn't seen your conversion thread or I'd have probably gone with that.

 

I asked for the blue Bosch coil but Dale was out.  He substituted an American made coil that is less expensive and supposedly identical including epoxy potting.  It probably wasn't the best price but he seemed like a good guy so I figured 'salright.  

 

Updates: 

 

CyberTach arrived and works well.  It takes a moment to read so it is mostly for static measurements and that is fine - it is what I needed here.

 

Start up:

 

It was fully running by 3 cranking revolutions this time.  Although I didn't pre-heat the engine, it was 50 out there so it was not cold.  2 other partially and fully warmed up starts went about the same.  Fast start. 

 

Speed and mixture tuning:

 

As mentioned earlier, my Dad, brother and I guestimated that we had the full speed limited to 2400 RPM during first start and first 1 hour and 15 minute run in.  The CyberTach measured that setting at 3040.  Still safe, but it goes to show how far off guestimates can be when mostly auto guys are listening to small engines.

 

I was unable to get more than 3280 rpm with the governor spring on the middle lower hole, so I moved it to the outer lower hole and dialed the adjustment screw back in a few turns for safety.  Glad I did that because it made a big difference.  The spring move allowed adjustment to wherever I want it.  The throttle lever may or may not have some friction clutch adjustment; I'll have to look it up.  The point is:  If I hold the throttle full forward, I now get 3550 rpm whereas if I don't hold it, the lever vibrates back on its own to where I get about 3480 rpm. 

 

The Tecumseh chart says about 10.7 hp at 3000 rpm at sea level so less here.  The difference in power between 3040 and 3480 is very noticeable. 

 

I dialed back main fuel mixture almost 1/4 turn so I had it far too rich.  It is roughly 1/8 turn leaner than the initial by the book 1.5 turn setting.  That setting should be considered meaningless unless you live at very high altitude like I do.  

 

The idle only likes the faster end of spec.  Sobeit.  Maybe that is due to port and valve mods?  Who knows. 

 

Warning about the low buck idlers (it may be the idlers; it may not be):

 

At first start up today, I got quite a bit of squeal.  It stopped with pushing the clutch pedal and diminishes with warmup.  I adjusted more clearance in the hydro pulley guide but that had no effect.  Pushing the parking brake lever around which was obviously rubbing at times made no difference.  It is difficult to isolate exactly where the squeal is coming from but I suspect the idlers since there is some wear on the back of the new belt.  I'll need to look at the flat idler's guide finger as well and see if maybe that is too close.

 

It is possible I damaged an idler the other day with my 'cowboy' driving of the hydro lever.  Hope I didn't damage the hydro but I've read they are fairly robust.  

 

Gas gauge update:

 

It takes a lot of fuel before it starts showing; over a quarter tank.  So it is probably too short for this tank.  Also, the needle dances like crazy when the engine is running so it is only accurately readable with engine off.  It dances with the median about where the actual level reading is, so I dunno; maybe it is readable.  That may be typical with all gauge caps, I don't know.

 

I need to loosen the tank straps and slide the tank a bit to the left for some clearance from the battery.  That could be the cause of this, too.

 

Shifter friction clutch adjustment:

 

I tightened this a lot yesterday afternoon.  It no longer moves on its own.  Much safer. 

 

Conclusions:

 

Today's run was maybe a half hour total.  The speed with the hydro lever full forward at 3480 rpm is arguably too fast for much of my property.  But that's fine; if I need to get a run at a snow drift with the dozer blade, it'll do it.

 

The tractor really resonates and rattles at 3550 but is much smoother at 3480 so I think I'll leave the throttle lever alone and call 3480 good.  I think vibes may be attenuated somewhat when I install the OEM angle bracket at the back of the head to the tractor chassis.  I figure it was there for a reason.  Didn't install it while I was doing the head bolt re-torquing sequences.   

 

I like the tractor and the engine.  Still not a drop of oil leakage, but it is very early.  

 

mm 

 

edit:

 

The noisy belt was bothering me so I went back out and put the back of the tractor way up on a motorcycle jack - the safe kind.

 

I found that the finger belt guide on the flat idler was in contact with the 'teeth' of the belt.  This leaves the question in my mind of why it didn't squeal from minute one?  Anyway, the guide and belt are amazingly (to me) both apparently pretty tough as they still look fine.

 

I took steps to keep my belt adjustment while loosening the flat idler nut until I could use a long screwdriver to slide the guide finger down and forward.  The guide went from contact to about 1/4" clearance.

 

This is probably partially caused by using improvised idlers so please count this as a warning about that if you decide to try those part numbers.

 

I didn't test run it since I don't want partial warmups right now.  If this isn't THE problem, it was definitely A problem and was undoubtedly causing a lot of unnecessary vibes.  After re-tightening the flat idler bolt and nut, I checked the clutch idler height above frame and it is still set a bit on the tight side where I had reset it after first belt stretch. 

 

Modified/improvised OEM angle bracket back in place on the back of the head.

 

Might be knocking down some vibes here.  "...that'd be alright...".    


Edited by MountainMichael, December 04, 2014 - 08:24 PM.

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