Head Gasket Issues

[Lukas 33]

Hey,

I just found out that Ive blown a head gasket

The block has been o-ringed and used a copper gasket.

I was wondering if I could simply remove the old gasket and use a cometic mls head gasket and still keep the o-rings there? Or would I have to get the block shaved to remove the recess for the o-rings and use a thicker head gasket or what?

I was told the pistons were 20thou oversize. If I used a head gasket for 40thou oversize pistons am I able to continue to use the o-rings or is that just silly?

I really dont want to buy anything that isnt going to work.

Thanks,

Lukas

[Adriano]

90% of the time it wil be fine, you just need to check the diameter of the o-ring vs the recess in the head gasket to ensure they dont overlap each other.

[Lukas 33]

90% of the time it wil be fine, you just need to check the diameter of the o-ring vs the recess in the head gasket to ensure they dont overlap each other.

I guess I will pull the head off and measure the o-rings to check the size of it. I guess I just get a head gasket which has a bore that matches the outer diameter of the o-ring?

Sorry to sound so dumb, I just want to put any basic question out there

[Lukas 33]

Hello? Anyone?

Can somebody unblock Paul so I can get some help around here!

[Lukas 33]

Tried bleeding the coolant for about half an air. Still getting bubbles into that coolant after that long.

Pulled off the cam covers and retorqued/checked the torque on all the head bolts and still getting bubbles in the coolant.

Looks like it is definitely in the bum.

[r33_racer]

You running copper o rings?

[Lukas 33]

You running copper o rings?

No i think the o-rings are stainless, but the gasket was copper.

[r33_racer]

You did goop up around the water and oil holes? Or perhaps used some hylomar?

If you are using a MLS with the O rings, you need to use copper O rings, stainless wont work. In that setup, either the gasket or O rings need to give when crushed, stainless rings with MLS head gasket, neither will give. Also do the ends of the rings actually butt up to eachother nicely? Do you know what the protrusion height is from the deck?

Ill put this up just incase.

Edited July 22, 2010 by r33_racer

[discopotato03]

If you are sure the gasket is leaking you should pull the head off and make any determinations based on what you find .

Its pointless guessing what has happened when you can't see anything .

People I know are not big fans of Cometic head gaskets and for normal use they often use a genuine gasket or if the manufacturer has a competition gasket gasket available one of those .

Always remember that an inline six the block and head are long so the surfaces must be flat and square or things will leak . If the engines doing super duty studs and nuts are always the best fastening option .

From what I hear RB engines don't have HG issues std but if you screw a lot of boost into them then its the same as any half decent OE engine . I believe the wire rings work because they sit in a groove in either the had or the block and attempt to form a mechanical lock just outside the headgaskets fire rings to help prevent them moving and breaking their seal .

I know many won't agree but I think copper gaskets were a means of having a cheap reusable item which could better stand up to high cylinder pressures than the cereal box gaskets cars had back in the 1970's .

Their problem as I see it is that its asking a lot for a non ferrous material that sees uneven heating to remain a uniform thickness after lots of heating cycles and being annealed to go again .

Also its not at all uncommon to see them leak water or oil via small machining marks on the head or block .

Your call , for road I think an OE gasket with stainless rings are fine if done properly . The next stage is to cut the fire rings from a good new conventional gasket , machine same depth steps in the tops of the bores and use parallel wall rings to physically lock the block to the heads deck face . The conventional gasket minus fire rings seals water and oil like they are designed to . The crush seal is critical and the compressed thickness of the rings and gasket has to be carefully worked out . I think Alex at Plazmaman was the first person I'd seen do this on his 700+ Hp FJ20's . Thats three and a half times the factory FJ20 output BTW .

Your call .

[BoostdR]

I have a spare gasket left over from my build. Cometic 88mm 1.3. will do you trade price if you need it. new in box

Matt

[Lukas 33]

I have a spare gasket left over from my build. Cometic 88mm 1.3. will do you trade price if you need it. new in box

Matt

After speaking with Paul from Red R Racing about the gasket issues i was told that you can NOT use a cometic or nitto gasket if it is O-ringed. I have chosen to use an ACL copper gasket and see how that goes.

PM me the price of that cometic one however

[Lukas 33]

If you are sure the gasket is leaking you should pull the head off and make any determinations based on what you find .

Its pointless guessing what has happened when you can't see anything .

People I know are not big fans of Cometic head gaskets and for normal use they often use a genuine gasket or if the manufacturer has a competition gasket gasket available one of those .

Always remember that an inline six the block and head are long so the surfaces must be flat and square or things will leak . If the engines doing super duty studs and nuts are always the best fastening option .

From what I hear RB engines don't have HG issues std but if you screw a lot of boost into them then its the same as any half decent OE engine . I believe the wire rings work because they sit in a groove in either the had or the block and attempt to form a mechanical lock just outside the headgaskets fire rings to help prevent them moving and breaking their seal .

I know many won't agree but I think copper gaskets were a means of having a cheap reusable item which could better stand up to high cylinder pressures than the cereal box gaskets cars had back in the 1970's .

Their problem as I see it is that its asking a lot for a non ferrous material that sees uneven heating to remain a uniform thickness after lots of heating cycles and being annealed to go again .

Also its not at all uncommon to see them leak water or oil via small machining marks on the head or block .

Your call , for road I think an OE gasket with stainless rings are fine if done properly . The next stage is to cut the fire rings from a good new conventional gasket , machine same depth steps in the tops of the bores and use parallel wall rings to physically lock the block to the heads deck face . The conventional gasket minus fire rings seals water and oil like they are designed to . The crush seal is critical and the compressed thickness of the rings and gasket has to be carefully worked out . I think Alex at Plazmaman was the first person I'd seen do this on his 700+ Hp FJ20's . Thats three and a half times the factory FJ20 output BTW .

Your call .

Holy shit disco you've done it again!

I will have a look into answering this in more depth as Im tired at the moment. The head is off and the gasket was leaking on the block side of cylinder number 5.

I didnt think I could use a std gasket when it has been bored 20thou?

Sorry for the dumb shitness Been up for too many hours

Thanks heaps for the in depth info

[Lukas 33]

You did goop up around the water and oil holes? Or perhaps used some hylomar?

If you are using a MLS with the O rings, you need to use copper O rings, stainless wont work. In that setup, either the gasket or O rings need to give when crushed, stainless rings with MLS head gasket, neither will give. Also do the ends of the rings actually butt up to eachother nicely? Do you know what the protrusion height is from the deck?

Ill put this up just incase.

No the ends of the rings dont butt exactly to be honest. There is a slight gap in between the ends.

And no I don't know what the protrusion height is from the deck

Yeh it had enough good, but It was leaking so I can't confirm it was done right. I am going to be using hylomar when I put this next copper gasket on. If this doesn't seal it I think it is going to be time for ANOTHER rebuild!

[Lukas 33]

*had enough goop

[Lukas 33]

OK I picked up my new ACL copper gasket yesterday and I am slightly nervous.

The bore of the gasket is 88.25mm and the o-rings in the block are set at 91.5mm (roughly).

The gasket is also 1mm thick.

NOW THE QUESTION

Do you think I will have any issues with the o-ring biting into the gasket nicely or will the o-ring try to fold a lip around/along the bore of the gasket due to the minimal difference/distance between the o-ring and bore?

[Lukas 33]

OK I picked up my new ACL copper gasket yesterday and I am slightly nervous.

The bore of the gasket is 88.25mm and the o-rings in the block are set at 91.5mm (roughly).

The gasket is also 1mm thick.

NOW THE QUESTION

Do you think I will have any issues with the o-ring biting into the gasket nicely or will the o-ring try to fold a lip around/along the bore of the gasket due to the minimal difference/distance between the o-ring and bore?

NOTE the o-ring is about 1mm thick.

90.5mm is the inner diameter of the o-ring and 91.5 is the outer diameter.

[Lukas 33]

New gasket went on today and it looks like we have a winner!!!

I think I might need to get a higher temp thermostat though.

I was sitting around 70 degrees.

Max temp reached was 76 degrees.

Ambient temp was 20 degrees.

ANOTHER QUESTION!

If I had a CR of 7.9:1 with a 1.2mm gasket, what CR do you think a 1.0mm gasket will give me?

I am thinking about 8:1?

Thanks