[zoomo]

Alright, here are some close up pictures of the valve. It's not as clear as i would like but it's the best i can get. since i really don't want to pull the motor again i'm going to do the work myself. I figure i can pull the one piston easily with it still in the block and order a new one. Also as far as the heads i really don't want to risk dropping another, so if i can't find any reason to why the valve is broke i'm eaither going to look into getting new valves or a new set of heads, depending on the price. I've put way to much money into building this to risk having a cheap part destroy it.

[cobalt327]

It broke right at the O-ring seal groove. Not a good omen for the rest of these valves to be any better, unfortunately. Maybe someone else has better news, but as I see it, the valves' quality/metallurgy/manufacturing are definitely suspect.

[ssmonty]

Aren't those stock rotator type retainers for exhaust valves? I gotta ask if you used the stock springs as well? Could things have gotten wound up a bit and maybe lofted a valve/retainer into a guide and maybe snapped the valve sideways? Check the top of the guide/seal for a witness mark. Might have to remove the seal.? Just a thought. If you had revved it up with stock springs and that cam from your earlier post???
ssmonty

[zoomo]

well thta's the news i was afraid of. smonty i'm not quite understanding your post. if i'm understanding correctly here's your answer. These are not the heads i had on my other motor, these are different heads and a different cam. They are stock springs on the other hand, i had plans of changing the springs after break in. I didn't want any problem with my cam going flat this time. As far as revving, i have only revved the motor to about 3800 rpm so far. I have decided like i said to just replace these, i'm just wondering what the cost of buying a set of good valves and springs i don't have to worry about versus just buying a set of aftermarket heads. I wanted to upgrade heads at a later point anyway, just didn't really have financial plans of doing it now lol.

[cobalt327]

Are the rotators on ALL the valves or just the exhaust?

If you used rotators and the cam has enough lift to coil bind the spring/retainer combination, that could break the valve. Was the valve spring installed height verified to be sufficient?

[zoomo]

no the rotators are only on the exhaust, as far as it being verified i figured it was but i don't really know.

[ssmonty]

What kind of engine/cam do you have now? The springs should be matched to the cam. The cam depends on your engine/heads and what you want to do with it.
ssmonty

[cobalt327]

Originally Posted by zoomo

no the rotators are only on the exhaust, as far as it being verified i figured it was but i don't really know.

Depending on the exact spring/retainer combo and the cam you're using, the lift can be excessive and cause the spring to stack solid, or coil bind.

If that happens, something has to give- sometimes it will bend a pushrod, that usually being the weakest link. But a weak or stock spring can allow the valve to loft over the nose of the cam (aka valve float) even if the spring isn't coil bound- and this can also break a valve.

I would recommend that you check the installed height of the spring and see if that will allow for the lift your cam has w/o coil bind. The rotators can "eat up" some of the installed height that would ordinarily be there w/a standard retainer.

If the installed height is close, but there's enough room to not coil bind the spring- suspect the possibility of valve float. If there's insufficient room for the lift w/o coil bind, then that's the likely answer.

And good catch, SS

[zoomo]

ok i will do some research on exactly how to check the installed height. I did notice that he installed some sort of spacers under the springs. I guess this gives you a little more spring height to allow for more lift? he did not installed the cam, i put everything together, though he did know what the lift on the cam was going to be. I got good reviews about this guy from a couple people, but it seems obvious to me that because i was just trading him some other heads to do these for me that he took every short cut possible. The short block itself looked to be put together good but who am i to say? oh well i'm done trusting these machine shops. from now on all i'm having them do is what i don't have the machines for. At least i know when i put something together it's not going to come back in pieces.

[ericnova72]

A spacer under the spring would reduce available valve lift before the spring coil binds. Shims or spacers under the spring are usually there to either correct installed height or add spring pressure.

[zoomo]

ok so ive been doing some research on coil binding and how to measure it. I will go out and do some measuring later tonight. I'm really scared to re use the valves no matter what i find though. So at this point i'm still looking into finding a new set of heads. It just sucks because i don't have the financial means to do this at the moment, but i'm not going to risk re using them to have it destroy my engine the next time one snaps. Oh well i'll keep you guys informed. As far as the piston. I have never really messed with installing one, so i suppose i can re use my rings? are the pistons pressed on the rod?

[cobalt327]

Before condemning the valves too quickly, see what the installed height measurements get you.

Basically, you will remove the spring (leaving the valve in the head and the shims in position that were under the spring), and reinstall the retainer and locks onto the valve.

Then using calipers w/a 'depth' function (the depth function of a caliper is the wire or blade that will protrude from the bottom of the caliper that gets longer the more you open them up), a valve spring height micrometer or a snap gauge/calipers- or even carefully use a machinist ruler- measure the distance from the shims on the spring pad to the retainer lip where the spring rides. This will be the installed height.

[zoomo]

ok now i'm completely lost. once i find the installed height where do i go from there? i was understand the i was supposed to turn and open one valve completely and measure the distance between the coils on the springs

[cobalt327]

Originally Posted by zoomo

ok now i'm completely lost. once i find the installed height where do i go from there? i was understand the i was supposed to turn and open one valve completely and measure the distance between the coils on the springs

That would be measuring for coil bind- coil bind is measured to be sure there's enough distance between the spring coils at full lift. You need to have 0.060" of space- total- when the spaces between the coils are added together. An example would be 5 coil 'gaps', each gap being at least 0.012" = 0.060" TL.

This is often misstated as being 0.060" between EACH of the coils, but after speaking to Comp Cams, they advised that it was, in fact, the total clearance- even though their web site says otherwise.

The installed height will show you if the spring is too short, also- but measuring for coil bind at max lift is perfectly acceptable, as well. It's usually harder to do, because the spring has to be compressed until the valve is open to the max lift, but as long as you can do this, no problem.

[zoomo]

So i'm still lost, what exactly do i need to do to figure out for sure what caused this?