Valve clearances

fundytides

fundytides

Well-known member
My Model A was resurrected last year from about a 50 year hibernation. The motor had had new mains and rods poured and was bored .125 oversize. Before running it, I removed and cleaned the oil pan and changed all the fluids. The engine starts and performs well. I drove it enough last summer that everything should be well lubricated and working freely. My only issue is noisy valve train. As far as I remember the valve train did not receive a great deal of attention when the other work was done to the engine, maybe replaced a few broken guides or weak springs. All of the work on the motor was done 50-60 years ago. I checked valve clearances today and found that 4 of the valves are .014-.015 clearance while the other 4 run .018-022. Valves and seats look good. Considering my options and would like your opinions:
1) Leave it alone and put up with the clatter
2) Try to lessen the clearances by hand grinding the valves. (can I even do that?)
3) Buy 4 new valves and replace the 4 with the greatest clearances (Not sure if I have the capability to file/grind the new valves to the proper length to provide the specified clearances)
4) Buy a set of adjustable lifters. (I have these in my Model T but they are very difficult to adjust).
I would really appreciate your opinions or any other suggestions.
 
Unless you want to do the work to have something to do, I'd leave it alone. You didn't indicate that performance is affected. Maybe try to quiet valve train down. Run some high phosphorus/zinc motor oil??? Brad Penn 10W-40??
 
With basic tools, I think your options are either switch to adjustable lifters or leave it alone. Installing the lifters is doable but tedious, especially if you don't remove the engine. Gotta take the camshaft out.
 
if you are careful not to allow valve grind compound into the inside of the engine you could try to lap them down a bit with a hand suction cup. it may clean them up enough to tighten up the clearance.
and make sure you clean all the compound out real good.

other wise the next option is to pull out the cam and put adjustables in, the next cheapest step.
 
AS mentioned in post #5:

0.022 is the correct valve lash for Exhaust valves with an UNGROUND Model B camshaft, when using Model B lifters.

Model B lifters have a .070 larger heel and .032 longer lifters.

Many Model A engines had Original Model B camshsfts and lifters installed
 
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Wow! Nice catch guys. The valves that are .018-.022 are all exhaust. The intakes are all .014-.015. Any way to confirm it's a B cam without a lot of disassembly?
 
Lash beyond .017-.018" will make a little noise. I think a little noise is better than none.

Apparently you have original type non-adjustable lifters, so, changing the lash is a lot of work. I'm not a fan of lapping which means cutting the seats and facing the valves so the contact width and position are correct. Then if the lash is too tight the stem has to be cut.

Since your loosest is .022" like Ford recommended for the 'B' due to burnt exhausts, why not just run.
 
I do that too. I just turn down my hearing aids until the I get the correct balance between too loud and too quiet.
 
I had several noisy valve lifters on a Model A engine which didn't have adjustable lifters and agree that it is a lot of time and effort to grind valve stems to get the proper clearance. I even went out and bought an old (1939 vintage) Kwik-Way valve grinding machine to properly grind the end of the valve stems. The problem in your case is the clearance is already too large and there is no way to make the valve stems longer to reduce the clearance, so you would need to purchase new valves, lap them to the seats, and then start the valve stem adjustment process. This is time consuming work if you do it yourself and with today's labor rates quite expensive if you can find someone to do it for you.
 
Consensus seems to be drive it and enjoy it. Next fall, I may consider pulling the motor and going over the whole valve train-lifters, guides, etc. and replace/repair whatever is necessary. Maybe adjustable lifters as well. See how it goes by then. Thanks to everyone for the ideas and advice. Great knowledge base on this forum.
 
I had a model b block completely rebuilt with inserts etc. spent a lot of money. There was a lot of lifter noise and no matter how I tried. I found that if I closed the clearances I could make the noise go away(almost). Of corse now I started to have other problems with valve leaks. Found out the lifter bores we worn to the point the lifters rocked. This should have been caught by the machine shop.
 
Starting to suspect the lifter bores in mine as well. Is there any way to check this without taking everything apart? How much clearance should the lifters have in the bores? If the clearance is more than it should be, which tend to wear more, lifters or the bore? It would be simpler to just replace the lifters but maybe I would have to go to oversize lifters and machine the bores. This motor, before it was "rebuilt" came from a very tired 29 A. At that time, in the 1960's, all mains and rods were rebabbited, cylinders were bored and new .125 pistons fitted. I don't remember the valve train getting much attention other than a routine lapping of the valves.
 
fundytides said:
...At that time, in the 1960's, all mains and rods were rebabbited, cylinders were bored and new .125 pistons fitted. I don't remember the valve train getting much attention other than a routine lapping of the valves.
Click to expand...


Damn, my hat's off to you Fundy. You can remember the '60's! Some of us have trouble remembering last week.


JayJay
 
Benson said:
AS mentioned in post #5:

0.022 is the correct valve lash for Exhaust valves with an UNGROUND Model B camshaft, when using Model B lifters.

Model B lifters have a .070 larger heel and .070 longer lifters.

Many Model A engines had Original Model B camshsfts and lifters installed
Click to expand...

So an engine with an original B cam and standard Model A valves uses the same clearances as an A engine with a standard cam?
 
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