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Case 448 -- Can't get to run right... no matter what I try!


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#46 Case448 OFFLINE  

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Posted December 02, 2015 - 02:43 PM

I've very likely just found my problem.

 

Valve lash wasn't that far off. I had previously measured at the largest available gap (going by sight), rather than at TDC, according to the "TC" mark on the flywheel, and the row of marks on the housing.

 

So, I set the valve lash, and just for grins, thought I would check when the points were opening, since the timing marks are now right there in plain sight.

 

I think I just found the problem...

 

The points are only opening once every two revolutions of the crankshaft, and when the points do open, it is at about 120 degress past TDC (where the TC mark on the flywheel lines up with the 0 mark on the engine case.)

 

The 120 degress is definately wrong, the once per two revolutions is definately wrong.

 

What could be causing this, and how serious is it?



#47 Case448 OFFLINE  

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Posted December 02, 2015 - 03:08 PM

ANOTHER CORRECTION:

 

HUGE MISTAKE:  

We did not set point gap at TDC, but rather on sight, when the points started opening, we went for the max. .021 gap, thinking all was well.

 

So the points never opened until about 120 degrees.

 

I just set the points at TDC to the .021 gap. Now points open every revolution at 21 degrees before TDC. Points stay open for a long time, until it gets to (around) the 120 degree mark, where there is a quick "increase" in point gap, just before shutting the points. Not sure why, but there appears to be some kind of a "bumper" at around the 120 degree mark.

 

I'll bet I put the motor back together, and it will run like a watch.

 

I'll get it back together today (I have to now, I'm very curious), and we'll see what happens...


Edited by Case448, December 02, 2015 - 03:09 PM.


#48 gopher OFFLINE  

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Posted December 02, 2015 - 03:53 PM

Someone told me that if the points are run from crank every revolution if from cam every second revolution. All you need  TDC is for valve setting. Your point gap sets your timing.



#49 Case448 OFFLINE  

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Posted December 02, 2015 - 09:13 PM

Someone told me that if the points are run from crank every revolution if from cam every second revolution. All you need  TDC is for valve setting. Your point gap sets your timing.

 

Yes, but you missed exactly what I meant.

 

Actually, I looked this up in the service manual, and the service manual is wrong. It says nothing about using TDC to set the point gap. Only that you should go for the maximum gap specified (which in this case, is .021).

 

THAT is where the point timing issue got messed up. What we did, was find the high spot 120 degrees past TDC, just because "thats where we were on the rotation of the motor" when we "started checking" for the high spot. Problem is, it was the "bump" spot at 120 degrees that we set the points to, and NOT based on TDC. So, the points would never open until that bump was reached at 120 degrees.

 

My friend suggested the above scenario. And suggested that I go set the points to .021 AT TDC.  ---- SUCCESS --- the points now opened .021 starting at 21 degrees before TDC. They then stayed open for a long time, until the "BUMP" was reached, when they went open further, just before they shut completely.

 

I know this might sound confusing, but I've tried to describe this as accuratly as possible.

 

The short version is:  We set the points based on the "second bump" RATHER than using TDC.

 

Don't know if anyone else ever ran into this. Was rather bizarre, I though....



#50 Case448 OFFLINE  

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Posted December 02, 2015 - 09:26 PM

* - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* -   V I C T O R Y  ! ! ! ! ! !   * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * - * -* - * -

 

As predicted above, I set the points at .021 BASED ON the motor being at TDC.

 

Earlier today I fixed the valve lash situation.

 

Actuals on valve lash (now previous settings) - for those who were following this thread, and wondering what the actuals where on valve lash (since like a bonehead I took the measurents wrong.) . . .

 

 

Drivers side - Exhaust (actual at time of trouble):             .010

Drivers side - Intake (actual at time of trouble):                .001

 

Passengers side - Exhaust (actual at time of trouble):      .012 

Passengers side - Intake (actual at time of trouble):         .003

 

Notice the two tight intake valves - likely means they were never shutting all the way.

 

 

SO -- as predicted, I finished the above, turned the key, and it fired right up.

 

Just ran it for an hour in the yard. Has a serious growl (in a good way) -- like it wants to GO TO WORK!

 

I think overall, this was a combination of a lot of different problems, all compounding on top of each other.

 

Have a few small issues remaning, but this things got BITE !!!

 

I can hear it --- it's MEAN !!

 

Will put a load on it Saturday, see how it does.  I figure I'll go till the garden (toss those leaves one more time) before (hopefully) snow hits.

 

THANKS  TO ALL who helped me like you did.

 

 

MERRY CHRISTMAS and HAPPY NEW YEAR to YOU ALL !!

 

Dave


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#51 KennyP ONLINE  

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Posted December 03, 2015 - 05:30 AM

Glad you got it figured out, Dave!



#52 Alc ONLINE  

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Posted December 03, 2015 - 08:44 AM

THAT"S GREAT NEWS !!!!       I think all of us  have either got the wrong manual  for the job   or misunderstood what the manual was trying to explain  



#53 Rick OFFLINE  

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Posted December 17, 2015 - 11:03 PM

My 446 was doing the same thing. Drove me crazy,I tried an electric fuel pump and a pressure regulator set to 1 1/2 pounds. It runs real good and strong. I mow grass,blow snow,and plow the garden with no problem. Hope this helps.




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