Blown head gasket, bent valve kissed piston. W/pictures

[robztheman]

I had my engine over heat I checked all of the standard stuff. After a leak down test I discovered number 6 was leaking into the coolant. I had RJC bullet proof head gaskets. I think the accidental 30 pounds was to much for it.

The number 5 exhaust valve was leaking 50% leak down after pulling the head I noticed the valve hit the piston. My question is why did the valve hit the piston could this be from valve float? If so what springs should I buy? Anything else I should get while its apart? Where can I buy a new exhaust valve? The valves are currently Manley but I don't care what brand. Not sure what else would cause this other than valve float. Also I noticed the Teflon has popped out of several of the seals can I do something about this or not worry about it?

Most of the time I find all the answers just searching old threads so I don't post much but this time I need some input from you guys. I was getting ready to buy a ball bearing turbo but my car had a different idea. She must like the turbo she has now.

 

[turbofabricator]

New exhaust valve and valve job. Re-assemble and let her eat. Oh ya, upgrade your valave springs, too. Detonation will also bend a push rod, too. Roll every pushrod on a known flat plate (Like a mirror or piece of glass) to verify they are not bent. Head gaskets on these cars are a fuze. Better to R&R a head gasket than a lower end. I use to change head gaskets like most people change oil.

 

[robztheman]

New exhaust valve and valve job. Re-assemble and let her eat. Oh ya, upgrade your valave springs, too. Detonation will also bend a push rod, too. Roll every pushrod on a known flat plate (Like a mirror or piece of glass) to verify they are not bent. Head gaskets on these cars are a fuze. Better to R&R a head gasket than a lower end. I use to change head gaskets like most people change oil.

Thanks that's what I was thinking. What about spring's? What spring's do you think I should buy pretty sure I need to replace them.

 

[fastblackracing]

I had my engine over heat I checked all of the standard stuff. After a leak down test I discovered number 6 was leaking into the coolant. I had RJC bullet proof head gaskets. I think the accidental 30 pounds was to much for it.

The number 5 exhaust valve was leaking 50% leak down after pulling the head I noticed the valve hit the piston. My question is why did the valve hit the piston could this be from valve float? If so what springs should I buy? Anything else I should get while its apart? Where can I buy a new exhaust valve? The valves are currently Manley but I don't care what brand. Not sure what else would cause this other than valve float. Also I noticed the Teflon has popped out of several of the seals can I do something about this or not worry about it?

Most of the time I find all the answers just searching old threads so I don't post much but this time I need some input from you guys. I was getting ready to buy a ball bearing turbo but my car had a different idea. She must like the turbo she has now.

Something else to think about is I have seen exhaust valves in our turbo motors "stick" in the valve guides from not enough stem to guide clearance and then the piston meets the valve....... This was from a new sets of heads from well known turbo head vendor........ Turbo heads need a bit more clearance on the exhaust guide than a n/a motor due to the heat the valve sees, the higher the boost the more heat is generated and the valve runs hotter and grows from the heat......... IMO you would have to float the valves big time to kiss a valve, we typically have a lot of piston to valve clearance on these engines, I am not convinced this is your issue.....Dig deeper to find your problem....I would have all of the guide clearances, and spring pressures checked...... I leave nothing to chance anymore, everything is taken apart measured and fixed if needed and reassembled.......I have seen issues from all of the vendors I deal with at one time or another and learned the hard way s..t happens ......Do you know what springs and cam/lobe numbers you have now? The lift and lobe intensity will dictate what springs you need...... I like to use the rubber type seals if possible.

 

[Nick Micale]

Something else to think about is I have seen exhaust valves in our turbo motors "stick" in the valve guides from not enough stem to guide clearance and then the piston meets the valve....... This was from a new sets of heads from well known turbo head vendor....................

Over the years I have replaced over 1000 blown head gaskets, and if coolant escapes it can, and will, many times seize a valve due to the guide shrinking.

It is best to then install bronze guides in the heads and be sure there is enough clearance as most production shops do not allow for the extra HP of a turbo engine.

 

[robztheman]

The head gasket that was blown was the #6 cylinder. The valve that kissed the piston was #5 the head gasket on #5 side was not blown. When removing the exhaust valve it was not as free as I thought it should have been but I think that was due to the bent valve. I installed one of the other exhaust valves into that guide and it seemed ok. If i need to change the guides I will if it needs to be brass, what ever it takes to make it right. honestly I cant remember what the lift is on the cam it is an old grind. I think it was a 218 duration cam. I will go look in my files I think I still have a cam card. I will do that and post back.
What should the guide clearance be on our motors?

 

[robztheman]

The cam. Precision Turbo cam
duration at .050 .210 x .210
lift .317 x .317 lobe sepration 110 deg.
seat duration at .006 .259 x .259
gross valve lift .475 x .475 degree intake lobe 110 deg ATDC seat timing int. .050 lift BTDC 5- ABDC 35 seat timing exh. BBDC 35 ATDC 5-

I know this is more than needed but just put exactly what the cam card read. looks like time for a new cam also it must be 15 yrs old.

I was thinking of just getting a complete cam kit from full throttle with cam springs lifters and all. l. also was going to buy the valves from TA performance.but there is no Buy button on the parts I emailed them.I guess they just want you to call. I couldn't find these part on any other vendors web site.

 

[gunzandgearz]

Doubt you got into valve float, unless you wrapped engine way to high.sounds more like the boost getting that high probably caused this. with boost comes heat and with that much boost the exhaust valve gets super hot,and it probably was enough to grow the valve, heat causes expansion, and hang the valve in guide and hello piston. You can stick the valve in guide, and with a dial indicator, move itback and forth and check clearance.

 

[robztheman]

Doubt you got into valve float, unless you wrapped engine way to high.sounds more like the boost getting that high probably caused this. with boost comes heat and with that much boost the exhaust valve gets super hot,and it probably was enough to grow the valve, heat causes expansion, and hang the valve in guide and hello piston. You can stick the valve in guide, and with a dial indicator, move itback and forth and check clearance.

Thanks i will measure the valve clearance this weekend. I found some specs. on a site that say the clearance should be .0015" to .0032" I will let you know what I find.

I don't know about you guys but every time I look at fixing parts I look at upgrading them. I cant help it. I have been eyeballing the aluminum GN1's even though I don't need them.

 

[robztheman]

I measured .0018" I guess on the tighter end of what I read is acceptable clearance. Jason at RJC was a big help he got my head gaskets out the same day and gave me a great deal on some other parts. I replaced the exhaust valve and lapped all the seats and started putting it all back together. I hope it was just a backfire or boost temp but what if i wanted to run these boost numbers I hope the problem doesn't come back up. I have no plans on running 30 psi in my car as it already scares the hell out of me but who knows in the future.
I have a double roller chain so I don't think there is a problem there.

 

[JimP]

Does RJC recommend a retorque when using their head gasket kit? Can you let me know what their instructions say about that?

 

[robztheman]

yes the instructions say to re torque 85 lbs after a few heat cycles.

 

[gunzandgearz]

It would scare me too, I probably would have checked all of the guide clearances and had a REPUTABLE machine shop ream the guides just a tidge.It seems harder and harder to find a good machine shop nowdays, any way good luck you will probably be alright.

 

[Mike Licht]

give me a call you might just need springs, they could be worn out, there is better cams than what you have but what you have is not that bad either
Mike

 

[robztheman]

give me a call you might just need springs, they could be worn out, there is better cams than what you have but what you have is not that bad either
Mike

I will give you call tomorrow. I will try the number on your website (586) 294-4404.
Thank you

 

[robztheman]

It would scare me too, I probably would have checked all of the guide clearances and had a REPUTABLE machine shop ream the guides just a tidge.It seems harder and harder to find a good machine shop nowdays, any way good luck you will probably be alright.

I have never seen heads with a ream job but it sounds like a good idea. I am not sure what that would cost. I was thinking of just buying the GN1s because if I bought all new valves, keepers, retainers, springs, brass guides and now if I add in the ream job sorry I couldn't help myself I am close enough to the price of some GN1's.

 

[gunzandgearz]

Mike and Marianne are good people, they can definatley hook you up on some new heads at a reasonable price too, and your right if your going to spend that much money might as well get some ported heads.