Valve sizing question

T

Tim

Senior Member
I finally tore apart the A motor in my Phaeton last night. All the valves were pitted on top and the reason it popped and had minimal power was not a burned valve but a pit that finally made it outside the seat. That whole finding process alone made alot more hair turn gray. But I digress. So today I ran over to All Ford and bought 8 shiny new stainless valves, springs, all the gaskets, one guide and one retainer as one was questionable but the rest were primo. I set the valves in tonight to see if and or how much I needed to grind the stems and they are all too short. Has anybody else run into this? I am curious if the new ones are made for adjustables only. They are alot short like .025-.045. I don't think lapping them will close the gap that much. Am I destined to have to cut new seats in this? It's still in the car and the seats look good, so that would be a bummer.

Thanks,

Tim
 
I would try another source for longer valves. I too would hate to cut good seats, or grind good valve heads.

Also, are you using a reground cam? That will add to the clearance.
 
Tim said:
I finally tore apart the A motor in my Phaeton last night. All the valves were pitted on top and the reason it popped and had minimal power was not a burned valve but a pit that finally made it outside the seat. That whole finding process alone made alot more hair turn gray. But I digress. So today I ran over to All Ford and bought 8 shiny new stainless valves, springs, all the gaskets, one guide and one retainer as one was questionable but the rest were primo. I set the valves in tonight to see if and or how much I needed to grind the stems and they are all too short. Has anybody else run into this? I am curious if the new ones are made for adjustables only. They are alot short like .025-.045. I don't think lapping them will close the gap that much. Am I destined to have to cut new seats in this? It's still in the car and the seats look good, so that would be a bummer.

Thanks,

Tim
Click to expand...


Tim, Never, never drop seats to set clearance, you will have all negative out comes. The new valves should be of the correct length, unless other wise stated. Not that they can't be made wrong. The valves should be sitting all on top of the block anyway, as when you take the valve lower, and lower, you will have each cylinder getting, and getting rid, an uneaven amounts, of gas, and or exhaust. on the exhaust side, it is especially bad as any exhaust left in the cylinder will dilute the new fuel charge, and that gives an out of balance effect also. If a motor is over heating, and all the normal things have been tried, and not worked, many times it can be traced to exhaust valves ground to low in the block. A guy will bore a motor .125 over, and its over heats, they will blame the boring, and it will be the exhaust seats ground down in to much, seen it many times. If you have solid lifters, they most likely have been reground, and that could be the length problem. The only thing left, is a reground cam, with to much taken off?? Thanks Herm.
 
Tim said:
I finally tore apart the A motor in my Phaeton last night. All the valves were pitted on top and the reason it popped and had minimal power was not a burned valve but a pit that finally made it outside the seat. That whole finding process alone made alot more hair turn gray. But I digress. So today I ran over to All Ford and bought 8 shiny new stainless valves, springs, all the gaskets, one guide and one retainer as one was questionable but the rest were primo. I set the valves in tonight to see if and or how much I needed to grind the stems and they are all too short. Has anybody else run into this? I am curious if the new ones are made for adjustables only. They are alot short like .025-.045. I don't think lapping them will close the gap that much. Am I destined to have to cut new seats in this? It's still in the car and the seats look good, so that would be a bummer.

Thanks,

Tim
Click to expand...


Tim, A N.O.S. Model A Ford valve is 5" 725 thousands, give, or take .010. Herm.
 
Thank you Gents,

I'll probably check with All Ford to see if they have some Ford Valves. If that doesn't pan out I'll drop the pan and put some adjustables in there. I don't know if the cam is reground but I suspect not due to the fiber gear. Like most things this little valve job will lead to a much bigger job, but that's how I learn. Good thing I have a B cam on the shelf, now the question of fitting a cam? Should the B cam slide in there, or is it going to be a bigger can of worms than it seems?

Herm is the 5" .725 equal to 5 5/8 +/- .010? or did I read that wrong. I have a surface plate and height stand to check them, so I want to be darn sure.

Thank you,
Tim
 
.750 is 3/4, so it is 750, minus .025 thousands, or .025 thousands under three quarters of an inch. .625 thousands would be five eights of an inch. Herm.
 
Tim, You did not say if you have adjustable valve lifters. The modern valves (no flair on stem end) must be used with adjustable lifters to adjust the correct valve/lifter clearance.
If you need the adjustable lifters, e-mail me as I have a new set ...reasonable.
 
Mikeinnj said:
Tim, You did not say if you have adjustable valve lifters. The modern valves (no flair on stem end) must be used with adjustable lifters to adjust the correct valve/lifter clearance.
If you need the adjustable lifters, e-mail me as I have a new set ...reasonable.
Click to expand...

??? This is the first time I've heard that. Just wondering why original big foot valves can't be used with adjustable lifters?
 
Thank you guys,

I got it apart today, camshaft out and lifters. It was time and the thought of chasing valves down, grinding them, and not putting a cam in it just didn't make sense. Nothing major ugly inside just some grit and grime. But I'll feel better about the whole operation after I set the lash and have a B cam in it.

Now about those adjustables please PM me.

Thank you,

Tim
 
Be sure the lifters you get have a foot 1.125 in diameter. The last time I saw any, the double lock lifters had a 1 inch foot. I hear they are now 1.125 too, but I do not know that fer certain.

If you have the money, Bill Stipe's .340 cam will bring you joy. Call him to discuss your engine, gearing and driving style and he'll recommend one.

http://specialtymotorcams.com/pages/camshafts.html
 
Tom Wesenberg said:
??? This is the first time I've heard that. Just wondering why original big foot valves can't be used with adjustable lifters?
Click to expand...

Tom he didn't say that.
This is one of those weird sentences which can imply 2 entirely different things.

*Here it is >> The modern valves (no flair on stem end) must be used with adjustable lifters to adjust the correct valve/lifter clearance.

I think he means... if you own valves with NO flare, you MUST buy adjustable lifters.
Punctuation might help...;)
 
Thanks Craig for clearing that up with Wessenberg..... What I meant to say to Tim is, if you are using modern straight stem valves and modern one piece guides, you want to use adjustable lifters.

I know Henry used non adjustable lifters ( I have a few sets of those too) with the two piece guides as original, but this did not allow for future adjustment. An original OEM replacement valve could have the stem ground to shorten it if the valve seat receded from wear.

The one inch adjustable lifters are fine for use with an original or reground A camshaft but the new cams made by Bill Stipe should use the newer 1.125 diameter lifters he and other supply houses carry.
 
Gottcha, now I see the double meaning of the statement.

BTW, Mike that is a nice looking Tudor in your avatar, and the black wheels and metal stems really add to the good looks.
 
Mikeinnj said:
Tim, You did not say if you have adjustable valve lifters. The modern valves (no flair on stem end) must be used with adjustable lifters to adjust the correct valve/lifter clearance.
If you need the adjustable lifters, e-mail me as I have a new set ...reasonable.
Click to expand...


This is incorrect and the following statement to this is also incorrect. The modern valves CAN be used with original pushrods if preferred. It may take some grinding to get the lash correct but, it can be done and in some cases be advantageous. I have done this myself many times, even though, I don't suggest it or even like to do it. Lots of work and much room for mistakes that cannot be redone at home.
 
Tim said:
I finally tore apart the A motor in my Phaeton last night. All the valves were pitted on top and the reason it popped and had minimal power was not a burned valve but a pit that finally made it outside the seat. That whole finding process alone made alot more hair turn gray. But I digress. So today I ran over to All Ford and bought 8 shiny new stainless valves, springs, all the gaskets, one guide and one retainer as one was questionable but the rest were primo. I set the valves in tonight to see if and or how much I needed to grind the stems and they are all too short. Has anybody else run into this? I am curious if the new ones are made for adjustables only. They are alot short like .025-.045. I don't think lapping them will close the gap that much. Am I destined to have to cut new seats in this? It's still in the car and the seats look good, so that would be a bummer.

Thanks,

Tim
Click to expand...

Without looking at your new valves there is no way to asses the problem and any reply would be speculation. However, there are some conditions that would cause this. Original valves had no kerf. This is the thickness of the valve at the edge of the large circle. Modern valves have a .030 to .050 kerf which, can cause the valve to sit higher in the seat. Anytime I install new valves, I cut the seats and lap the valves by hand to make sure the seats match. Lapping the valves is not always ( or probably ever) about lowering the valve in the seat pocket. The lapping is to make the seat and valve compatible and to make sure the seat hits the middle of the valve seat making for a more positive seal.

You are doing the right thing putting in the adjustables since, they will always be easier to adjust but, if you don't re-cut the seats and lap the valves, you may still have problems. I would lap the valves at the very least.
 
Rogers said "and to make sure the seat hits the middle of the valve seat "

Whatever does that mean....?

and he also said "The modern valves CAN be used with original pushrods if preferred. It may take some grinding to get the lash correct but, it can be done and in some cases be advantageous."
................................. How in ANY case could this tedious time wasting process be advantageous over using adjustable lifters?
 
Mikeinnj said:
Rogers said "and to make sure the seat hits the middle of the valve seat "

Whatever does that mean....?

and he also said "The modern valves CAN be used with original pushrods if preferred. It may take some grinding to get the lash correct but, it can be done and in some cases be advantageous."
................................. How in ANY case could this tedious time wasting process be advantageous over using adjustable lifters?
Click to expand...

The area where the seat touches the valve head should be near the center of the lip on the valve head. I make the contact area just a very tiny bit outside the center, so as the valve expands from heat it will be at the center.

Some lazy people cut the seat with a one angle cut and make the seats too wide. This can result in the seat touching the valve head in way too wide an area, which will result in very low loading pressure on the contact area. This allows for carbon to cause the valve to not completely close, and will cause the valve to burn. You need to check all 3 angles of the valve seat to make sure the contact area isn't too wide, nor too thin, and is centered on the valve lip.
 
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