Setting 8ba valve lash by grinding valve stems

Ken Henry

Ken Henry

Senior Member
I'm assembling a 276ci 8ba engine with new stock type valves and a reground camshaft with 0.350" lift. I'm about ready to set the valve lash by grinding the stems and want to run the procedure by the forum here first, to help avoid having to re-buy parts. I have a set of NOS Ford lifters and 0.085" thick lash caps (Crower 86121S) that I will use to make up the excess clearance due to the reground camshaft. Valves have already been lapped to the seats by my machinist and are marked as to what positions they go in. The lash caps are relatively shallow at 0.060" deep to avoid interfering with the locks.



I have done one valve so far, with the timing cover torqued down over the gasket I plan to use. I turn the crank clockwise until the lifter is on the heal of the cam and measured the clearance with the valve pushed firmly against the seat and the guide in place (no springs etc). Actually I have measured all 16 this way and they range from 0.040" to 0.060" clearance. Next I grind away the valve stem using a a fine stone on a bench grinder and a jig carefully set up on the bench to hold the valve perpendicular to the plane of the plane. So far so good?


I grind the valve until I get the required clearance, which according to the camshaft grinder (Schneider) is 0.010" intake and 0.012". This is a little tighter than the Ford specs for any 8ba style engine (even early 8ba without valve rotators) but I suppose I should follow the cam grinders recommendations?? If there is a reason to go with the looser Ford spec please someone let me know...


Thanks for any input! Ken


52120252085_72a1e0fb6f_b.jpg9F9F04F4-404D-4003-8E79-A137A9D986AB by kenhenry_06268, on Flickr


52119751901_3cc08c0bc7_b.jpg0C84101A-D424-4246-B557-10C897191B3E by kenhenry_06268, on Flickr
 
Follow the cam grinder's instructions.


Also be careful of how you have the engine mounted


https://www.fordbarn.com/forum/showthread.php?t=290412&highlight=engine+stand+cracked+block


421241
 
Holding the valve on the seat by pressing down is not going to give you and accurate reading. The clearance is going to change once the spring is on the assembly. Unless you add the spring and put the assembly in your measurement is not going to be accurate.
Ronnieroadster
 
If the cam is ground on an original core the amount of material removed from the heal to gain lift is easy to adjust for with adjustable lifters. Doing it like a stock engine with an aftermarket cam is going to be trouble eventually when there a need to adjust clearance for any reason.
 
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I must be misunderstanding something here and need to be corrected. Is not a lash cap like a cup, open end up, floating on the end of the valve stem? Could oil not get in this "cup" and cause the cap to go hydraulic, making lash clearance impossible to set? On a OHV engine I get it but when inverted in a flathead? Thanks for your patience.
 
You have a simple but good setup for adjusting your valves.
In the end this system will be FAR superior to adjustable lifters.
No there will be NO hydraulic action in the lash caps.

On a street engine or even a mild race engine, with stock STEEL lifters you should never have to re-set or adjust the clearance for the life of the engine.
Trial assembly is best done with a spring. If you use a "C" clamp type spring compressor the job goes quickly.

Actually, after you do a few valve jobs this way, you will find you can do them faster than adjustable lifters.
 
Its an 8ba , its generally okay to hang them this way . The problem arises when using an earlier motor with the half bell .
 
It is agreed that these engines originally did not use any lash cap or cup. Now Ken Henry indicates he is using lash caps, I understand his reason for using them but I am wondering if they could become oil filled when inverted on a flathead engine. That is my question. I also did not use adjustable lifters but used a combination of a stone on a grinder and emery cloth/wet fine grit paper rotating by hand to take off the last thou or so. Perhaps I am not understanding how the lash cap is attached to the valve stem (or is not attached). Thanks
 

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Sure, some oil may interpose itself between the valve cap and the bottom of the valve stem, but since there is no pressure feed to that area, it is of no consequence.

Do you remember the recent thread about the Lincoln hydraulic lifters in an 8BA? They didn't work and ended up ruining the engine.

When a cam is reground, the base circle is reduced; how else could the difference be made up?
 
Don T said:
It is agreed that these engines originally did not use any lash cap or cup. Now Ken Henry indicates he is using lash caps, I understand his reason for using them but I am wondering if they could become oil filled when inverted on a flathead engine. That is my question. I also did not use adjustable lifters but used a combination of a stone on a grinder and emery cloth/wet fine grit paper rotating by hand to take off the last thou or so. Perhaps I am not understanding how the lash cap is attached to the valve stem (or is not attached). Thanks
Click to expand...

Valve spring pressure holds it on.
 
Lash caps are used on a lot of Ford engines like 302/332 Y blocks. Also shims are available that go inside the caps. Watch John at 'Fiat Nuts' on Utube a Calf. engine builder. He has a jig that the valve goes in with an attached dial indicator. I always
wondered that we all know how long this takes with 16 valves. So how did the factory manage mega engines out the door daily??? Just my way, I always do valves without
the cam gear I turn cam manually with a little crank I made up.
 
Don, the depth of the cup is 0.060, which is greater than the valve lash spec, so there is nowhere for them to go. When running, I think oil film will cause them to adhere to the valve stem tips but really don’t know. Any excess gets squeezed out by valve spring force. It will be interesting to see how much the lash changes w valve spring force. I would think a thousand or two at most… I will try to check a few both ways this weekend. Thanks everyone! Ken
 
Not sure if I will get to the point where I will be employable by Ford LOL. I can do 6 per h after a little practice. Most don’t need further adjustment after installing the springs and guide retainers, though I did buzz an extra half thousandth off one so far because the feeler gauge got a little tight. Regarding turning the cam directly, I heard the front cover needs to be installed in 8bas because the cam rides against it on. Only six more to go…
 
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