How much is too much

[bwaii64]

I've read several threads on valve lash. I've got way too much but they're not adjustable. Ours vary between 17 and 25 thou. At what point must I pull the head and remove the valves and try to close the gap?

[160B]

Ford service Bulletin March 1928 page 231, changed the clearance gap from ".013 - .015" to ".011 - .014".

Les Andrews Model A Ford Handbook, A Complete Guide For Service and Maintenance page 2-21

Exhaust valves : No's 1, 4, 5, 8 - set at .015"

Intake valves : No's 2, 3, 6, 7 - set at .013"

[SeaSlugs]

yea thats the specs. now how much is too much? i cant tell you. What i can tell you is the wider the gap gets the faster its going to expand. (think hammer blows - 1" between hammer head and nail isn't going to move the nail if at all per blow, increase the gap to 6" and it starts to move - increase it to a foot its really gonna move per blow)

Hows the compression? any oil consumption? Ideally it would be best to install the adjustable tappets but that involves pulling the engine out and just about getting it down to bare block (cam has to come out) then would be the time to check clearances on mains and rods - replace rings/check bore etc.

how much do you drive? if you just putter around town on nice days then i would just remove the valves (can be done with engine in car - not ideal though) weld up the ends and grind em back to size. - if you like to be adventurous or drive as much as possible id say pull the engine as above...

dont forget to keep all the valves in the correct order once you remove them and the valve guides. The valves will bend amazingly easy to be very careful.

[Tom Wesenberg]

I would weld and grind to the stems, or buy new valves with longer stems. Does it appear the old valves have had the stems ground? The other possibility for excess clearance is worn cam and/or tappets.

[Dick Steinkamp]

I've had a couple of engines with wide valve clearances also. How does this happen? I would think the only change in valve clearance would be to a lesser clearance as the valve recedes into the seat. What am I missing?

[Patrick L.]

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Is there a problem ? How noisy are they ? If they not too bad then I'd keep running it. I'm thinking its either had this clearance since the last valve job because the mechanic didn't know how to adjust the lash,or, the camshaft and or lifters are wearing. But I don't think these cams or lifters have a wear issue.

Mine have been at .017" for the 40 years I've owned it.

If the engine has a B camshaft then maybe the lash is OK. If I remember correctly Ford changed the B lash after a few years to .022" for the exhaust.

[H. L. Chauvin]

FWIW:

Set INT. @ 0.011" and EX. @ 0.013" and never have a problem with either original A cams and/or original B cams; and I even used same recently, (maybe 8 years ago), for my new Bill Stipe 330 cam.

These magic numbers can always take a licking, and you will never hear ticking.

They were given to me as a teenager in 1958, by my professional mechanic Uncle, born 1905; and after 59 years, would much prefer to fight rather than switch.

At a 45 degree valve seat angle, it would not take much valve lapping with good course and fine valve compound to close the gaps to 0.011" and 0.013" if you have original tappets.

[forever4]

Originally Posted by Dick Steinkamp

I've had a couple of engines with wide valve clearances also. How does this happen? I would think the only change in valve clearance would be to a lesser clearance as the valve recedes into the seat. What am I missing?

The nose of the camshaft gets wiped off.
Typical, maybe more so on reground cams.

http://www.fordgarage.com/pages/ruleofnine.htm

http://www.fordgarage.com/pages/stipecamshaftspecs.htm

The links above show the original design gaps for various original and Stipe camshafts.

[Kevin in NJ]

Valve clearance depends on the material of the valves. The stainless exhaust valves expand more with heat and needed more clearance.

[bwaii64]

The engine runs fine, I just decided to check it while the cover was off. I ran my fingers over the cam lobes (mostly to see if I was off the lobe) and didn't feel wear which I would expect to be a rough surface, really sharp edges and sudden contour changes) and they felt ok.

Except for end-play, the bottom end is really tight. Cranks (starts) easily by hand (warm).

[H. L. Chauvin]

FWIW:

In addition to above reply no. 7:

My 1930 Briggs Town Sedan's newly installed, (10 years ago) valves, are "stainless steel".

Whether valves are "original" steel, or "stainless" steel; and whether the cam is an "original new" cam, or a "used" A cam, B cam, or 330 Stipe cam, the old reliable setting of INT @ 0.011"; and EX @ 0.013" works every time for both cars and marine racing boat engines.

[Terry, NJ]

Are you sure that's a Ford engine in there? I cannot imagine how you can even touch the camshaft in a Mod. A engine unless you have the oil pan off. Is this the case?. If you are that far into the engine, then why not take the radiator off and remove the cam, replace the old lifters and put a set of adjustables in the engine.
You'll be much happier in the long run!
Terry



[QUOTE=bwaii64;
I ran my fingers over the cam lobes (mostly to see if I was off the lobe) and didn't feel wear which I would expect to be a rough surface, ).[/QUOTE]

[Dick Steinkamp]

Originally Posted by forever4

The nose of the camshaft gets wiped off.
Typical, maybe more so on reground cams.

In order for the valve clearance to INCREASE with wear, it would have to be that the HEAL of the cam (not the nose) wore faster than the valve receded into the seat.

Having the NOSE of the cam wear would reduce valve lift but would not affect valve stem to lifter clearance.

I think it is unlikely that the heal of the cam wears to the point of affecting clearance in these low valve spring pressure engines.

[Mike V. Florida]

Originally Posted by bwaii64

I've read several threads on valve lash. I've got way too much but they're not adjustable. Ours vary between 17 and 25 thou. At what point must I pull the head and remove the valves and try to close the gap?

Must? when the engine won't run any more.

Seriously, if the engine is making noise, then there are problems, and problems should be fixed. Do you HAVE to fix them, no. keep driving the car and it could "run" for years ( not run well but will move the car).

Sure you can wait and drive the engine until it stops but if you are looking for an absolute drop dead measurement there is none.

[Tom Wesenberg]

I wonder if you have excess clearance due to having a reground cam?

Since there is no pressure on the heal, I can't see that wearing. I can see the tappets wearing, or someone grinding the stems to give excess clearance.

[Dick Steinkamp]

Originally Posted by Tom Wesenberg

I wonder if you have excess clearance due to having a reground cam?

That would account for it IF the clearances were not reset after the new cam was installed. Possible, but I would think that if someone went to the trouble of installing a new cam that they would also replace the rest of the valve train. Stranger things have happened, however.

Since there is no pressure on the heal, I can't see that wearing. I can see the tappets wearing, or someone grinding the stems to give excess clearance.

I can't imagine the tappets/valve stems wearing more to increase clearance than the head of the valve receding into the valve seat to reduce clearance.

Someone grinding too much off the stems seems to be the most logical answer. It's not an easy process to set clearance on the original valve train. It's time consuming and easy to take shortcuts that would result in over size clearances (don't ask me how I know )

[Mitch//pa]

Originally Posted by bwaii64

The engine runs fine, I just decided to check it while the cover was off. I ran my fingers over the cam lobes (mostly to see if I was off the lobe) and didn't feel wear which I would expect to be a rough surface, really sharp edges and sudden contour changes) and they felt ok.

Except for end-play, the bottom end is really tight. Cranks (starts) easily by hand (warm).

Leave it alone,,, eventually youll need an engine job once the bottom end gives completely out from the excess end play

[H. L. Chauvin]

FWIW: One (1) experience:

Without a thorough examination, one never knows just by word of mouth what one will experience on the hidden inside of an engine when one buys a Model A or a Model A engine.

For example: I had one of my best of several original Model A cams re-ground about (20) years ago by a "highly recommended" young guy in a "highly recommended" mechanic shop, where this young guy said his precise computerized grinder could render an exact duplication of the function of a B cam.

Fortunately, I had measured all cam lobes "before" re-grinding with a dial micrometer and compared same to precise drawings mailed to me by Mr. Marco and Mr. Yapp.

Results: After re-measuring afterwards, so bad with unequal measurements from lobe to lobe, I later bought and installed a new 330 cam from Mr. Stipe which was "Right-On" on every lobe.

If anyone is interested in reading further about re-ground cams, the Ahooga Forum has many interesting discussions and experiences shared from a few years back in regards to A & B cams.

[Tom Wesenberg]

NO cam can be reground and match original specs. Either the lift or duration has to change.

I agree with Mitch to leave it alone since it runs fine now.
BTW, I have a Studebaker V8 and the spec calls for .024" valve clearance. I thought this would make the engine sound like a rear bumper dragging tin cans at a wedding ceremony, but it's quiet.

[H. L. Chauvin]

Regrinds not all that great:

"Either the lift or duration has to change in a reground cam."

Took a long time many years ago on the other Forum for this Horse to be beaten to death.

Some even later exhumed this Dead Horse years ago, and beat him unmercifully until he was mere dust and could no longer be recognized ..... new cams were "IN".