Valve length

[Jim Yergin]

Yesterday, I tried to turn my newly re-assembled engine over. Turned about a quarter of a turn then stopped. Would not turn any further. Put a socket on the crankshaft nut and tried to turn it by hand. Would not move. Pulled the head and it would turn. Placed the head back on top and saw the head move up and down while I rotated the engine. It appears that I have an interference problem with the valves. In my prior re-build I had the head shaved and there was no problem with the valves hitting the head. In this re-build I had to re-place two valves. This is a P24 block and head and the valves were from that engine. The two replacement valves came out of the D24 engine that also donated its 230 crank and connecting rods. I did not check the length of the D24 valves. I just assumed they would be the same length as the P24 ones. Did the two different engines use different length valves? The difference appears to be very slight. With two head gaskets in place there is no interference. Can anyone shed some light on this? Need less to say I am some what frustrated. I was working hard to get the car to the Sully show today. I made it but the car stayed home. Did get to see Rodney and his Studebaker but had to leave before Chet arrived.

Jim Yergin

Edited June 21, 2010 by Jim Yergin

[greg g]

Jim, I can't reliably talk about different valve lengths sourced rom different engines, but I think you can grind a bit off the lifter end to address this. This was done in the old days after a valve job and or after a block decking. If the extra gasket relieves the interference, a bit of work on the ends of the offenders should take care of the problem.

As always it is best to wait to get a second opiion before doing any machine work. Do you have a local machine shop you could get some info from??

[HalfdollarMayflower]

My parts book shows 42-54 Plym/Dodge intake 1109911

Exhaust 42-54 Plym/Dodge 954302

Hmm...my 1950 MoPar passenger car parts list shows;

P19/20, D33/34 Intake 868886

P19/20, D33/34 Exhaust 954302

Edit: p/n 868886 is the same part as 1109911 - 42-53 Ply/Dodge

Edited June 20, 2010 by HalfdollarMayflower

[Jim Yergin]

Thanks for the info on the parts numbers. Looks like they should be the same. Greg, I thought about the possibility of grinding the ends. Do you think the metal will lose any needed hardness if I do so?

I am not really looking forward to removing the valves with the engine in the car but I definitely don't want to take it out again.

Jim Yergin

[james curl]

What is the shape of the valve head? Is it convex with a slot for a screw driver? My old original valves were convex but had a knife edge and I was afraid to surface them for fear of burning the thin edges so I used 235 Chevy stainless valves and they have a concave head with an edge that is a good .063 thick. I cut my head .090 and had the block surfaced .010. The valves touched the head on the cam side of the head in the radius. I used a smaller diameter bur and tightened up the radii to clear the valve in that area only, have about 10,000 miles on the engine mostly in the 60 to 70 mph range without any problems. If I had used the original thin edged valves I would not have had an interference fit problem.

[Merle Coggins]

Hold on here... even if a valve was slightly longer than another one it wouldn't make it lift up higher. The amount of valve lift is determined by the camshaft. If 2 valves are lifting up higher than the rest you need to look at your adjustments. Are those two very tight? Are they returning fully into the valve seats, not hung open slightly? Bottom line... they would have to start out higher than the rest to end up higher than the rest. And if those 2 are hitting the head, how close are the others? Maybe you need to test the clearance of all of your valves.

Merle

[Niel Hoback]

You could do a quick tappet adjustment with the head off so you can actually see if each valve is fully seated. Don't be too quick to remove metal that you can't put back.

[Jim Yergin]

Actually I did triple check the valve clearance but you guys are right, I can lower the lift height by increasing the gap. I will play with that and see what happens.

I am glad I decided to take a break from it when I did and seek advice here.

Thanks.

Jim Yergin

[Joe Flanagan]

What, and not plunge heedlessly into the abyss and make everything worse? Where's your sense of adventure? All kidding aside, knowing when to step away is one of the important things my own project has taught me. I don't always remember it, but I'm getting better.

[Don Coatney]

As has been mentioned valve lift is a function of the camshafttotal lift MINUS the valve lash adjustment.

The advertised lift of my re-ground camshaft was .410" My actual lift was .396". (.410" minus the lash adjustment of .014" equals .396") I verified this using a dial indicator as I wanted to insure I did not have a valve to head clearance issue.

[Jim Yergin]

Here is where I stand now. On the two intake valves that are hitting the head, I backed off the tappet adjustments as far as I could and they still hit. I tried a different head and they still hit. I removed those two valves and also two of the intake valves that do not hit. I measured and compared. The two that hit are 0.025" longer than the two that do not hit. Next I plan to try the longer valves in the cylinders where there was no interference and vice versa for the valves that do not hit to see if that makes any difference.

Jim Yergin

[Don Coatney]

Here is where I stand now. On the two intake valves that are hitting the head, I backed off the tappet adjustments as far as I could and they still hit. I tried a different head and they still hit. I removed those two valves and also two of the intake valves that do not hit. I measured and compared. The two that hit are 0.025" longer than the two that do not hit. Next I plan to try the longer valves in the cylinders where there was no interference and vice versa for the valves that do not hit to see if that makes any difference.

Jim Yergin

Strange? Are these new valves? Reground valves? Something is out of the ordinary???

[Jim Yergin]

They are neither new nor reground. They are from the D24 motor that donated its crank and connecting rods to my P24 block to make my 230.

I agree that something is out of the ordinary. Just my luck.

Jim Yergin

[Dodgeb4ya]

If the valves come back down firmly against the factory installed valve seats and then come all the way back up and hit the head either the valve heads are way too thick-not likely, the cam lobes are too high on those problem cylinders-no way, the cam is bent-never seen that, tons of carbon build up and I mean 1/8" or more-doubt it, Block dect shaved too much or head shaved too much also- and or the MoPar devil is working against you! I measured some intakes, max length was 4.858" and the exhaust were at 4.879" . All valves were just old valves out of old misc. 218/230 motors I had parts from.

Bob

Edited June 27, 2010 by Dodgeb4ya

[Jim Yergin]

If the valves come back down firmly against the factory installed valve seats and then come all the way back up and hit the head either the valve heads are way too thick-not likely, the cam lobes are too high on those problem cylinders-no way, the cam is bent-never seen that, tons of carbon build up and I mean 1/8" or more-doubt it, Block dect shaved too much or head shaved too much also- and or the MoPar devil is working against you! I measured some intakes, max length was 4.858" and the exhaust were at 4.879" . All valves were just old valves out of old misc. 218/230 motors I had parts from.

Bob

Bob,

Thank you very much for your input.

It looks like I may be looking at a bent cam. I switched out the valves last night and no matter which valve I used, they hit when in those two particular cylinders. I also double checked my measurements and discovered I was incorrect. They are all the same length. So out of your list, I guess that leaves the bent or distorted cam. Last December when the #3 piston disintegrated, the "shrapnel" did a lot of damage. The stem of the #3 cylinder intake valve broke in half and the intake valve in cylinder #5 was bent. Do you think that indicates evidence of enough force to damage the cam shaft?

My plan now is to remove the cam shaft and see what it looks like.

Jim Yergin

[Don Coatney]

Bob,

Thank you very much for your input.

It looks like I may be looking at a bent cam. I switched out the valves last night and no matter which valve I used, they hit when in those two particular cylinders. I also double checked my measurements and discovered I was incorrect. They are all the same length. So out of your list, I guess that leaves the bent or distorted cam. Last December when the #3 piston disintegrated, the "shrapnel" did a lot of damage. The stem of the #3 cylinder intake valve broke in half and the intake valve in cylinder #5 was bent. Do you think that indicates evidence of enough force to damage the cam shaft?

My plan now is to remove the cam shaft and see what it looks like.

Jim Yergin

I have seen camshafts break but I have never seen one bend. Once your cam has been removed I recommend you replace the camshaft bearings.

[Dodgeb4ya]

Don,

I agree with you about cams not bending, they usually break. I have never seen a cam in a flathead get bent/broken ect. I don't know if in years past I have ever tried to break a worn out flathead cam. I have snapped old small block chevy cams-Only way for Jim to check the cam is with a dial indicator. This is a really odd situation!

[Dodgeb4ya]

Bob,

Thank you very much for your input.

It looks like I may be looking at a bent cam. I switched out the valves last night and no matter which valve I used, they hit when in those two particular cylinders. I also double checked my measurements and discovered I was incorrect. They are all the same length. So out of your list, I guess that leaves the bent or distorted cam. Last December when the #3 piston disintegrated, the "shrapnel" did a lot of damage. The stem of the #3 cylinder intake valve broke in half and the intake valve in cylinder #5 was bent. Do you think that indicates evidence of enough force to damage the cam shaft?

My plan now is to remove the cam shaft and see what it looks like.

Jim Yergin

Jim,

If you have a dial indicator you could check the camshaft for being damaged-seems like it is not a straight cam anymore.

Bob

[Jim Yergin]

I do not have the capability to measure valves to .025", but I have some valves from a 230 that you can have.

Shel,

The valves arrived in today's mail. Thank you very much.

Jim Yergin

[P-12 Tommy]

You need anymore valves? I still have the intake valve you gave me that wouldn't fit. If you need it let me know.

Tom