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Working on Valves


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#1 bbuckler OFFLINE  

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Posted October 03, 2016 - 11:56 AM

The intake with the spring on shows 0.10 now and the exhaust shows 0.20 on my SS15 I guess time to lap some more I think it slowing getting there.



#2 EricFromPa ONLINE  

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Posted October 03, 2016 - 02:13 PM

Intake .007 / .009

Exhaust .017 / .019

 

Your getting real close..002 on both valves should lap out pretty quick.I absolutely love the sound of a big cubic inch Briggs but there a huge pain in the butt to figure out if there not running correctly.

 

I was going to put a newer electronic ignition Coil on mine but my flywheel magnet needed re-polerized for it to work.Ended up borrowing an old Dwell meter and got my points set up.It's the only way to get the coil and points timed perfectly.I had to retard the Coil timing slightly from where it was and then gap the points to .020.

 

My problem all along was the Coil bracket must of moved a bit.Might have something to do with the huge mouse Hotel in the blower housing.Thinking it jammed up the flywheel against the coil and moved it when the Previous Owner ran it last.   

 

After that fiasco I pulled the head and both valves and lapped them.Had to grind a bit off of the exhaust valve stem after lapping.There was no gap.I think I took around .006 off of it a little bit at a time till it was in spec.

 

She runs beautifully now.Mission accomplished another one saved.Now it's time to send it down the road lol.Don't feel like spending $200+ to rebuild the deck spindles and put fresh blades on it.It mows good but 2 spindles are noisy.They took greese and tightened up good just pretty darn noisy.All of the seals are worn out so I just pumped it full till I seen fresh grease come out.From the rusty grease that came out I'm Betting the races have some pitting on them.They might quiet down a bit if I use it more.They are alot quieter now than what they were.There running warm but not Hot like they were.


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#3 bbuckler OFFLINE  

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Posted October 04, 2016 - 03:21 PM

I been lapping for a hour and still at 0.10. I don't know what I'm doing wrong.



#4 Bruce Dorsi OFFLINE  

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Posted October 04, 2016 - 04:25 PM

I been lapping for a hour and still at 0.10. I don't know what I'm doing wrong.

 

Hopefully, you're mis-reading the feeler gauges, or you have the wrong feelers.

 

You should be using the .010" feeler gauge, which is 10/1000".

 

0.10 that you keep writing is 1/10 of an inch, which is slightly less than 1/8".

 

Somebody on GTT was using metric feelers one time, which produced some odd numbers.



#5 bbuckler OFFLINE  

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Posted October 04, 2016 - 05:59 PM

Hopefully, you're mis-reading the feeler gauges, or you have the wrong feelers.

You should be using the .010" feeler gauge, which is 10/1000".

0.10 that you keep writing is 1/10 of an inch, which is slightly less than 1/8".

Somebody on GTT was using metric feelers one time, which produced some odd numbers.

it was me but I'm using the right one now

#6 bbuckler OFFLINE  

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Posted October 10, 2016 - 01:48 PM

Got it back together and did a leak down test and can hear it leaking air from the intake

#7 Bruce Dorsi OFFLINE  

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Posted October 12, 2016 - 08:14 AM

Got it back together and did a leak down test and can hear it leaking air from the intake

 

Piston at TDC with both valves closed?

 

Is it possible compression release is bleeding air?

 

What engine model?



#8 bbuckler OFFLINE  

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Posted October 12, 2016 - 09:25 AM

It at tdc and I don't know if it the compression release. Briggs And Stratton 325431-0139-99



#9 Bruce Dorsi OFFLINE  

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Posted October 12, 2016 - 02:07 PM

If it is at TDC of the compression stroke, then both valves should be completely seated.

 

If it is at TDC between the exhaust stroke and intake stroke, then the intake valve may be partly open due to valve timing.

 

The compression release on your engine actuates the exhaust valve, so the leakage you are experiencing is not due to a compression release.

 

So, if you are  on the correct TDC, there is a problem with the intake valve or valve seat.  .....The valve may be bent slightly, or the valve face may need to be ground.   ......The valve seat is part of the cast-iron block, so if the seat is not good, the block needs to have the valve seat reground. 

 

The contact area of the valve & seat should only be approx. 1/16" to 3/32" wide.  .....Too much contact area (too wide)  does not help valve sealing, and my actually promote leakage.

 

This assumes there is clearance between the intake tappet and valve stem.


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#10 KCJAX6810 OFFLINE  

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Posted October 12, 2016 - 07:56 PM

Idk if it's Been mentioned but is it the true tdc because some of the I/c Briggs compression release does engage when you hit the top one of the strokes.
Correction it was mentioned. Ditto what he said lol.

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Edited by KCJAX6810, October 12, 2016 - 08:00 PM.





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