How much is too much
 

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?

Re: How much is too much
 

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"

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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?

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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

Re: How much is too much
 

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).

Re: How much is too much
 

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.

Re: How much is too much
 

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]

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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. :eek:

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 :o)

Re: How much is too much
 

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

Re: How much is too much
 

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.

Re: How much is too much
 

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.

Re: How much is too much
 

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".

Re: How much is too much
 

Not so. The base circle (heal) is reduced in order to have enough "new" material on the other end to grind the stock profile. Here's a good thread on that...

http://www.jalopyjournal.com/forum/t...am-work.36558/

You do have to make up the difference in the slightly shorter total cam lobe. Usually done with adjustable lifters/rockers. With a stock model a valve train you would need new valves so that you have long enough stems to obtain the proper clearance.

I have owned many Studebaker V8s and agree they are quiet engines when the valves are adjusted correctly. It is a function of the "ramp" on the cam from the lobe to the heal letting the valve down gently to it's seat. Contrast with a high performance Chevy V8 solid lifter cam that has so much duration that it has to literally "dump" the valve on to the seat. They make a pretty neat hot rod clatter :D.

Re: How much is too much
 

"You do have to make up the difference in the slightly shorter total cam lobe."

And that's why I still stand by my statement that the original specs can't be in a reground cam.
Either the lift or duration will have to be changed.
Actually I need to add a third parameter to this to be accurate, and that is valve opening to piston position. So, if you have a reground cam you can't have the same degree for engine cam timing and the same lift and dwell as original factory specs.

Re: How much is too much
 

Agree with Toms post #22

The reground cam will not spec out as original unless you add metal and machine it.:)

Of course youll need an adjustable valve train to compensate....

Most of us will never notice the difference on our stock 40 horse machines

Re: How much is too much
 

Yea, I said that wrong. The total cam height would be the same (nose to heal). You would still have the same lift, the same duration, the same cam profile. The lobe heal is just closer to the cam shaft base circle which would make the valve clearances greater. This is usually easily made up with adjustable lifters/rockers.

Re: How much is too much
 

I think it was Marco who posted a good overlay picture showing how you can't grind an original cam and have it spec out the same. Anyway he did a good post showing why it can't be done, but I don't have time to find it now.

Re: How much is too much
 

X2.
Valve clearances are measured when the cam follower is on the heel of the cam. That is, when the valve is closed. The cam follower is only on the lobe when the valve is open.
To the OP, too much clearance will only cause noise and reduce the amount the valve opens. It will have a MINOR effect on the engine's breathing but not so much you need to worry. IF your clearances were set correctly when the motor was assembled, I'd guess it has done lots of miles by now for them to be that big. I think I'd let it run till it needs a rebuild and be confident your clerances are not going to cause a burnt valve.:D

Re: How much is too much
 

I agree with Tom. There is no free lunch. Something has to give.

Re: How much is too much
 

Here's just a few cam regrinders that say that they will grind the stock cam profile on your stock cam...

http://www.elgincams.com/

If your camshaft is pitted, chipped, or worn, send it to us and we will grind it to either stock specifications or to a performance grind that meets your requirements.



http://www.oregoncamshaft.com/regrinding.html

we perform custom camshaft grinding to factory or performance profiles.



http://deltacam.com/

Custom camshaft grinding to factory or performance profiles.


Here's a diagram that may help. In this case, the grinder has actually increased the lift and duration of a stock cam. Notice that it is done by reducing the base circle. The same principal is applied when grinding a stock profile back on a stock cam.

http://i819.photobucket.com/albums/z...groundlobe.jpg

One more...

http://img.photobucket.com/albums/v6...pscrnnd3yf.jpg

It's tough to debate opinions or theories. If there are cam grinders that say it's impossible to put a stock grind back on a stock cam, or a profile with even MORE lift and duration onto a stock cam, please post links.

Re: How much is too much
 

I think Tom and George are the only guys on this thread who understands the facts and is correct.

You cannot regrind the cam and get the original lift and duration back back. People make the mistake of thinking it is a simple lift geometry problem. It is not, and it has nothing to do with making the push rods longer.

The cam profile plot of lift versus angle duration represents the time and opening of the valve, which affects the amount of air fuel mixture entering the cylinder. This is directly related to the power capable of being produced. If you integrate the area under the curve, it is profoundly different (less) for a reground cam.

Depending on the regrind, you can bias the torque and power a little, but overall you are at a loss compared to stock.

Many people here seem incapable of grasping this, or unwilling to believe it.

and so it goes...

Re: How much is too much
 

I respect and admire all you have done for the hobby and have often used the information you have spent a lot of time putting together. Thanks. I'm sure you have forgotten more about Model A's than I'll ever know.

However, I try to deal with facts whenever possible. I supplied links to quality cam grinders who claim they can regrind a stock cam to the same stock profile...and that they can even grind a higher lift and longer duration than stock on a stock cam. I also provided illustrations of how this is done by reducing the base circle.

Is there anything you can link to that would substantiate your opinion that it can't be done?

Re: How much is too much
 

This conversation has been on fordbarn and ahooga 25 times over the years, and the facts are still unchanged.

Your illustrations from Marco / Bob Johnson are correct. Your understanding of them is not.

"OR", versus "AND" and the limits of the physics are key points. This is real life, not a theoretical abstraction.

Also what really matters is the integration of the area under the curve representing valve height and duration off seat, which is the real life breathing and the charge.

Based on the many discussions preceding on the boards, I don't expect to convince you of anything. That is your job. Or not.

As a practical matter, why do you suppose that new repro stock cams outperform all the 'stock/touring' regrinds available for the last 50 years, and that everyone wants to use and recommend a Stipe 330 or clone, when a regrind is a third the cost?

Re: How much is too much
 

I didn't think so.

Re: How much is too much
 

The total distance the lifter travels on a reground cam is less. So you have to change some thing. less lift,or less dwell or open and close the vales at a different time. You just can not get the same work done in a shorter distance.

Re: How much is too much
 

Hmmmm. The dead horse from years ago seems to have risen.

Sounds like we are beginning to lean on individual opinions in Soap Opera Style where :

Oh, I agree with Mrs. Pertunia and Mrs. Fanny; but Mrs. Appleskin is not far off.

But, only Mrs. Pooh really understands what is going on!

Then Mrs. Pooh has to brag on Mrs. Pfinella because she complimented Mrs. Appleskin and Mr. Fanny, plus told Mrs. Lollypop she is full of B. S.

Seems if one wants to dig deeply in any type of cam modification, why not just go online where there is enough mechanical cam engineering terminology and can technical information to study the function of varying cams to any depth desired.

Re: How much is too much
 

Post 31.
Also what really matters is the integration of the area under the curve representing valve height and duration off seat, which is the real life breathing and the charge.

This is the key and illustrates why you can't have the original lift and duration.

Re: How much is too much
 

Help me out here,

Re: How much is too much
 

With a regrind the width at the base of the lobe gets smaller.

You do not get something for nothing. There is always a trade off.

You end up with a more aggressive lift on the side as the ramp has to 'increase' due to the reduced base diameter. It is like moving a handicapped ramp closer to the house, the angle has to get higher. So you have to lose something.

You also have to trust the guy sets things up right.

Really the cam is the heart of the engine. You need to spend the $$$ if you want things to be right. I spent the $$$ for a NOS B cam.

Re: How much is too much
 

You can regrind for more lift, duration, different center line,etc. Thats what cam grinders do. But you won't end up with a profile exactly the same as original if thats what wanted.

Re: How much is too much
 

I realize that it is counter intuitive to think that you can put a stock profile on a stock cam by removing material. I also doubted that it could be done even though all cam makers say they can do it. I spent a lot of time doing research with the intent of proving the cam makers wrong. Something HAD to give.

What I found was that something DID give. Valve clearance had to be adjusted. Most commonly done with adjustable lifters on our flatheads and with adjustable rockers on overheads (sometimes with longer push rods and sometimes by machining down rocker stands if so equipped). That's it.

Here's one more try at an explanation...

In this image you can see the effects that a worn camshaft has on lift, if it is worn by 0.020" then it will have that much less total lift. To calculate the lift you measure the width of the lobe and subtract that from the height. By removing that same 0.020" from the entire perimeter of the lobe, keeping the same centerline, the entire lobe is smaller but the effective lift is restored to 0.400". That 0.020" now can be made up with the extra preload the factory gives hydraulic lifters, or on a solid lifter valve train you just reset your clearances.

http://www.coltcams.com/images/Image/techtips.gif

http://www.coltcams.com/html/tech_tips/

I think it's healthy to doubt. I do...all the time. I did on this subject. The bottom line, however, is your opinion must be supported by facts in order to be substantiated (well, at least on engineering subjects ;)). Making it true by saying it's true doesn't work. If you believe that a stock profile can not be ground on a stock cam (like I believed at one time), then do some research and link to some facts from credible sources that support your belief. Your opinions and thoughts are interesting, but won't win debates.

Re: How much is too much
 

Dick, true that you can grind back the same lift, but now lay a degree wheel over the blueprint of the reground cam and see if you can also maintain the same specs.

I never gave the subject much thought until about 10 years ago when a couple guys were debating the same subject. Marco had a nice drawing showing why it can't be done. Something has to change, just as Marco's drawing pointed out. I'll try searching for Marco's picture, but I don't always have luck finding old posts.