Valve marks on pistons?

[Drew2010]

well as some of you may know, I am having a set of heads rebuilt for my truck. tonite I got one of the old heads pulled off the engine in preparation for when I get my heads back from the shop, and found something I am not sure about. There are marks on the pistons where the valves have been just touching... there is no damage, but the pistons are shined up, its on all 4 on that side, I havent got the other side apart yet.
I put new head gaskets in this engine before it went in. and there were no marks then?

What would cause this? my only thoughts would be:

1. Out of Spec Cam... doubtful, I have never heard of this being an issue.
2. Bad valve springs allowing the valves to float a little? Although I never over revved it?
3. Timing cant cause this could it, I am 99.9% sure all the gears stayed lined up, but if the TYP4 cam has no extra lift, but lift in different places, it couldn't do this right?

 

[rjjp]

Measure the height of the piston above the deck at TDC.

 

[FordGuy100]

Did the mill the surface of the head?

 

[typ4]

both good suggestions, especially only one side.

 

[Drew2010]

no this engine got no machine work, took the heads off, new VR gaskets, put em back on...

Valvesprings are about all I can come up with...

 

[typ4]

springs first

 

[Drew2010]

When I go to pick up my heads, Im going to bring a few of these springs and have them test them.

It had to be a pretty gentle touch for no damage to occur, Im gonna have comp 910's in the "new" heads, I havent heard anything from the shop, so hopefully they wont have to take any off the head surface.

Ill be sure to post up how the other side looks when I get it off, prolly tomorrow.

This shouldnt cause any issues with this engine should it?

 

[typ4]

you sure the cam isnt a tooth off. dont put the heads on and I will forward this to the cam grinder. I have never had a problem with their cams, Now is the oil relief stuck in the header?, this I have seen and it will pump up the lifters. till theoil warms.

 

[Drew2010]

I am 99.9% positive everything was lined up perfectly. Can I take a look without removing the front cover? even if it is off a tooth, if there is no more lift then stock, then is it even possible for it to push the valves into the piston?

well i guess it could be? since there is no combustion chamber or anything.

I would love not to pull the front cover. If I can get away with just the timing cover I would be fine with that. My buddy has a borescope, could that get down there and see the marks?

and how would I go about checking the oil relief?

 

[typ4]

I asume you ran this a while with the cam?
Oil relief is in the rear header, on the engine block face.

 

[Drew2010]

I asume you ran this a while with the cam?
Oil relief is in the rear header, on the engine block face.

Yeah, put about 2,000 miles on it, ran great, started great, just had rocker issues, that I thought we had narrowed down to bad guides.

I know where the relief is, do you just look at it and see if its stuck or what?

Oh and I just want to say, I love this forum, gettin replies in no time...

 

[typ4]

put a mechanical oil gauge on it . it will go to 100 if itss stuck. you dont rev this thing cold do you. did an engine for a guy that lit it and it was in gear and gone, in cold weather it would go about 100 feet before the lifters pumped up.then it would die.

 

[Drew2010]

I have a mechanical gauge, but I never hooked it up since I got this engine in... but its too late to run it now.

And no, every morning I would start it, and would never even move it until it came out of high idle. I've always been good about letting things warm up.

 

[typ4]

before yu pull the other head bring each piston up, stack the firing order and the one up on the open side will coincide with one on the other then rock the rocker and see if there is room to push the valves open further, watch for the lifters to top out, you kinda get what im sayin, the cam should not be bigger on both as the intake is the mostly ground side.
also try to dial indicate lifter travel.

 

[riotwarrior]

I'ld doubt but with banging going on it's possible to bend valves...make sure they are not bent...doubtfull since they are not canted at an angle but flush/parallel to the head surface.

If cam is out a tooth one way or another it won't change the amount of lift but it will change the location of the lift in relation to the location of the crank and its rotational position during the stroke...thus banging valves....

My guess....cam out a tooth!