I am interested in a 37 LaS. sedan located in another state. I plan to see car next week. The owner mentioned that the (original) engine had been rebuilt by an engine shop but has a "valve knock". They mentioned that the noise appears after the engine is warmed up. My question to you experts is what might be the problem? Owner mentioned they thought a valve had been ground down excessively. I never heard of this problem. Could it be associated with the lifters or is it more serious? Thanks for any comments. John (CLC)
Hello John
I found this thread for the LaSalle engine for the valve lenth setup. Can you tell me where I can find the tool. We are building a cadillac 1939 346 v8 for a customer and we have discovered that this tool is required. you can contact me at 1800-201-4776 ask for Marteen or myself and any help you can give would be great.
Brad
No surprise, but this tool hasnt been available for a mighty long time. If you know what it liiks like, its like a little hammer. The "head" part of it is made EXACTLY 3 inches long, with the ends rounded spherically, and the handle part welded to it. You measure the valve stem length without the springs; just the valve seated in place. If, after a grinding, the stem is too long, you simply put it back in the grinder such that you can take off the little bit necessary to make the fit proper.
The other thing to watch out for is if you have the early style lifters (Wilcox-Rich), be sure that the plunger and spring work freely in their bores. Never mis-mate them! This should be covered in the shop manual.
Brad:
I agree with Doug about the length of the tool. You can get one easily by getting an inside bore measuring T gage from any good tool supply store. These T gages are adjustable, and you simply set the gage to 3.0 inches and have at it.
My experience is that the 3 in dimension is pretty conservative i.e., the clearance can be a bit less (say, 2.98 or so) and the valves will still work OK. The idea is to make sure that a fully compressed valve lifter will be short enough to allow the valve to close completely.
If you dont have enough clearance, it is very difficult to get the lifter bodies back into the engine -- thats another sign that you have not removed enough material from the valve stems.
Good luck!
Bill.
One more thing, the factory tool assumes new factory parts. If the lifter has been faced (the surface that touches the cam)a correction has to be made for that. I find it more sure to take an old lifter and remove the little spring, then measure the actual clearance with a feeler gauge. Specified clearance is 0.030 to 0.070.
The cam follower surface refaced? Thats interesting. While Ive never heard of it being done, and have never seen anything about this in a shop manual, I suppose it has been done, and an error in length would be introduced.(Where is the original length of the outer lifter body specified?) While were probably thinking of the Wilcox-Rich (Early) style lifter, a similar measurement would be necessary with the AC (late) lifter.
Normally in days past, the lifter was simply replaced. They werent very expensive, and surface grinding of them wouldnt have been cost effective. I also inderstand that that "foot" of the lifter wasnt a flat surface, but very slightly dished (source?). While it hasnt been said here, the main purpose of the space check between the valve stem and the camshaft is to provide the correct operating range of the lifter in operation.