HG failure on the old motor....Is there such a thing as deleting the Oring groove?

V8Supercoupe

Registered User
Well, to try to summarize the situation, my old motor which now resides in Arizona has blown the Hg's after a few thousand miles.

I am curious as well as the gentleman who bought the motor, can the Orings be machined out of the heads safely and be reassembled as ususal? We are trying to get together a list of parts, and I suggeted that maybe eliminating the groove all together would simplify things.
Also.....
Would this screw with the compression ratio too much?

Both HG's will be getting done, and we were uncertain if this was a feasible option.


Skip
 
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You had oringed heads?..If so why not just put new gaskets in and call it a day?..What gaskets wehere there originally?
 
if you want to get rid of the o-ring in the head, you'll have to have the heads decked. It'll take a couple CC out of the chamber, but probably not enough to make much of a difference in compression. If you run a copper gasket, can just make up for it with a thicker gasket.
 
I guess what I am asking is:

  • Could you leave the grooves and just install new gaskets?
  • or, would shaving the heads be the most prudent thing to do and throw a set of Felpro's on and forget about it?
From what I gather, I am not so certain this gentleman would be up for filling in the grooves. I probably shouldn't speak for him, but I am just going by my gut. I know it's not an unusual thing to do, I think we are just trying to make it as easy as possible.
I thought I had read that people have shaved the groove out and eliminated it entirely, I guess I just needed you guys,"in the know" to hold my hand on this one.
I'd hate to give bad advice.

I appreciate the replies.
Skip
 
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The O-ring grooves can be machined out. If they are in the block, it's probably OK. Just check the deck height before you do. If they are in the heads, you can machine them out but it will raise your compression.

Why not leave the O-rings in?
 
Hey Dan,

When he and I were talking on the phone he had concerns over what he needed for material to replace the existing wire. I made the suggestion that perhaps it may just be easier to eliminate the orings all together and get it to the point where you could just put another set of gaskets in and be done with it.
What I didn't know is how safe it was to put new gaskets in and not touch the Orings. I was under the impression, from what I have read, that it was better to shave the heads and go from there.

Skip
 
They can be welded up and the head resurfaced. I had something similar done to the heads on my turbo car while getting them repaired.

David
 
So I'm assuming the o-ring grooves are in the heads. Normally the grooves are cut to use a .040" stainless steel wire. I have reused my wire a few times inspecting it for damage or leakage. If the grooves are cut for .040" wire, they are probably about .035" deep. That could be cut out of the heads if you just want to get away from the o-rings and go with conventional gaskets or MLS gaskets.
 
I would assume your right Dan, this just isn't my area. The company that did it had a pretty good rep, and if there was a, "rule of thumb", I would assume that's what they would use. I was just thinking the easiest thing to do, is get the heads off, get them checked out anyway, and while they are out getting checked, have them decked. (hrm, it ryhmes).

Anyhow, I'm thinking he will need to make a decision as to what he needs to do and what the easiest way to go about doing it. I would just hate to give bad advice, but that's what you guys are for!:D

Thanks,
Skip
 
Teh heads should have a stainless steel oring which can be reused without replacement..Unless heads are warped in which they would need to be resurfaced anyway. I would be under suspicion why they blew in teh first place though
 
Damon, apparently overheating could be an issue. That's really about all I know about what happened, and to what degree it was overheated I have no idea.
 
If he overheated bad he may just have to mill the heads. I'd get the deck surfaced checked first. If its fine I'd leave the orings and use soem standard felpro non mls gaskets with some ARP studs. If its bad then they have to be milled anyhow
 
Skip thanks for starting the thread. I'm a newbee to the SC world and appreciate all the help and expertice on this one. Oh, and I'm located near the Quad Cities area in Illinois (not sure where Arizona came from, but it might be a good place to go when Im ready to retire..)

The root cause was overheating from bad connection :mad: on the cooling fan. I was not driving the car when it happened, so don't know how hot it got. My son was driving the car when the cooling fan connection failed, so he got to fix the cooling fan connection. Only Dad gets to fix the fun stuff like HGs.:rolleyes:

Sadly, after fixing the cooling fan we had fluctuating engine temp gauge and steady bubbles in the coolant reservoir :eek: which are classic HG failure symptoms caused from compression leak into the coolant system. We "burped" the air out of the system probably 20 times over the next few days in hopes it was just trapped air, but turns out to be HG :mad: (or possible cracked head.. hope not).

Planning to do more diagnostic tests and try to determine which cylinder(s) is leaking. Will start with a coolant system pressure test. Might do a compression test too if needed to determine which cylinder is leaking. The leak is small compared to other non-SC engine HG leaks I've had, so I'm wanting to have a good idea where to look when inspecting the failed gasket. Since I don't know how hot the heads got, I'm planned to have the heads pressure tested to test for cracks while they are off. Hope they're not cracked, but better pressure test to be sure.

Regarding the O-rings, it appears there is an option to re-use them depending on condition of the o-rings and head surface. I would have thought the o-rings were made from a more malleable material that would "squish" when the heads were torqued down. Stainless is pretty hard stuff so probably is safe to re-use. :confused: Any futher thoughts on re-using???

One more concern... if we were to not re-use the o-rings and machine the grooves out, the big blue book states "do not plane or grind more than 0.010" from the original head surface". Sounds rather conservative to me but a lot less than the .035-.040 required to remove the o-ring grooves. :confused: Sounds much safer to either re-use the o-rings or get the grooves TIG welded and the heads re-surfaced??

I'll give another update after more testing and the engine is dis-assembled. Till then, I'll keep checking back for any further comments and advise.

Thanks to all.....
 
Geesh....I don't know where Arizona came from either ...lol! I guess I wasn't paying attention to what I was typing.
Well, I am not sure what else to add...I just hope it it's nothing more than a gasket issue . I kind of wish I was a little closer to at least lend you a hand Mike, when I think of what I spent to put that motor together back then, it's dissapointing to see this happen. Your probably the 2nd to the last person that needs to hear that though...(your son being 1st).

Tickler, I don't think he has the engine disassembled yet.
 
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walter89 said:
Skip thanks for starting the thread. I'm a newbee to the SC world and appreciate all the help and expertice on this one. Oh, and I'm located near the Quad Cities area in Illinois (not sure where Arizona came from, but it might be a good place to go when Im ready to retire..)

The root cause was overheating from bad connection :mad: on the cooling fan. I was not driving the car when it happened, so don't know how hot it got. My son was driving the car when the cooling fan connection failed, so he got to fix the cooling fan connection. Only Dad gets to fix the fun stuff like HGs.:rolleyes:

Sadly, after fixing the cooling fan we had fluctuating engine temp gauge and steady bubbles in the coolant reservoir :eek: which are classic HG failure symptoms caused from compression leak into the coolant system. We "burped" the air out of the system probably 20 times over the next few days in hopes it was just trapped air, but turns out to be HG :mad: (or possible cracked head.. hope not).

Planning to do more diagnostic tests and try to determine which cylinder(s) is leaking. Will start with a coolant system pressure test. Might do a compression test too if needed to determine which cylinder is leaking. The leak is small compared to other non-SC engine HG leaks I've had, so I'm wanting to have a good idea where to look when inspecting the failed gasket. Since I don't know how hot the heads got, I'm planned to have the heads pressure tested to test for cracks while they are off. Hope they're not cracked, but better pressure test to be sure.

Regarding the O-rings, it appears there is an option to re-use them depending on condition of the o-rings and head surface. I would have thought the o-rings were made from a more malleable material that would "squish" when the heads were torqued down. Stainless is pretty hard stuff so probably is safe to re-use. :confused: Any futher thoughts on re-using???

One more concern... if we were to not re-use the o-rings and machine the grooves out, the big blue book states "do not plane or grind more than 0.010" from the original head surface". Sounds rather conservative to me but a lot less than the .035-.040 required to remove the o-ring grooves. :confused: Sounds much safer to either re-use the o-rings or get the grooves TIG welded and the heads re-surfaced??

I'll give another update after more testing and the engine is dis-assembled. Till then, I'll keep checking back for any further comments and advise.

Thanks to all.....
Walter89 - Here is my advice on how I would handle the issue if it were my car. First of all, the o-rings are meant to maintain their round profile and to apply extra compression to the hg in the critical area surrounding the combustion chamber which I believe is a good thing.
My first choice would be to check the heads, and if they were free from cracks and could be made flat with a .010" cleanup cut, I would reuse them with the original o-ring. There is no way I would take a .040" cut on SC heads to remove the o-ring groove. This would raise the compression ratio to a level to guarantee detonation and compomise the strength of the heads.
I would not opt to tig weld the groove since the heat will surely distort the heads so that more than .010" clean-up would be needed. My choice would be to source a pair of used heads, I see them selling for $100 or less all the time and would probably be cheaper than tig welding the old heads. Good luck, John
edit: this goes without saying, but make sure if you opt for used heads that they are for SC and not the common na heads.
 
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Uh, John, I paid about $2300 for the heads on that engine.
:rolleyes:
I am thinking they might be worth saving.
 
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V8Supercoupe said:
Uh, John, I paid about $2300 for the heads on that engine.
:rolleyes:
I am thinking they might be worth saving.
Uh, V8Supercoupe---:rolleyes: Notice I recommended to keep the old heads first, not even knowing how much they were modified. But, if they are cracked in the wrong place they should find a nice home in the nearest trash can no matter how many dollars are invested.:eek: John
 
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