Head Sealing & O-Ringing

[cribbj]

A number of us who have run > 20psi of boost through our motors have had issues with head sealing, even with upgraded head studs, Cometic MLS, etc.

On the last teardown, my #1 motor still showed evidence of coolant leakage into one of the cylinders, even with 12mm ARP head studs and the Cometic MLS. So I wonder if we don't have a distortion issue, rather than a fastener or head gasket problem?

Has anyone taken the next step and o-ringed their head/block?

Let's hear about it!

 

[Speeedy]

Cometic MLS Phuzion

Hello community,

today I emailed John with the head gasket sealing problem and after that he started this thread.

I did a little research and found out that it seems Cometic know the sealing problem. It's a little bit funny because John told me something about Helicoflex gas filled O-rings (http://www.helicoflex.com/ViewProduct?product=514). And tharaaa... Cometic combined their MLS gaskets with this Helicoflex O-Rings. John, did you told Cometic your idea?? .
Take a look at this article and the Cometic info and let us know what you are thinking about it...

http://www.hotrod.com/techarticles/engine/hrdp_0603_cometic_cylinder_head_gaskets/index.html

http://www.cometic.com/files/CometicPhuzion.pdf

Best regards from Germany
Alex

 

[cribbj]

What a great idea! Wish I could take credit for it, but no, it wasn't me who put Cometic and Helicoflex together

On the surface this looks like one of those magical silver bullet solutions, but I'd be curious to know what they propose for people who need thicker gaskets than normal, either for decompression of an engine, or to make up for lost material on the heads/block?

It would seem to me that the ratio of compression between the MLS and the o-ring would have to be tightly controlled for each to do its job correctly.

 

[CarlosR347]

oh man and all along i thought i would be able to boost 20-22 psi with just ARP std studs and MLS.. do we have to special order these from Cometic??? how much boost do you guys think these will hold?? im planning to use the basic 10mm ARP studs sold here on lextreme

 

[Speeedy]

Yes John, you are right. I'm curious too if there is a way for those who need thicker gaskets. It looks like there is only one thickness of .051" (1.3mm) available...
My last blown gasket was a Cometic MLS .051". But after machining the heads and blocks surface I would prefer a thicker gasket about 1.5-1.9mm to get the same compression ratio.

Here is an article about O-ringing a Pontiac block. I think O-ringing the heads is possible too. It's an alternative...expensive alternative...

http://www.highperformancepontiac.com/tech/hpp0307_head_gaskets_upgrade/index.html

 

[cribbj]

Carlos, some have little or no problems with the standard Cometic MLS, but others (like me) have had some leakage regardless what we've done.

In my case, I have a hunch that if I'd retorqued the heads after the engine had heated up, and after the first couple of high boost runs, we would've been OK.

Still, I think anyone venturing above 20 psi with these motors needs to know that many of us HAVE had leakage issues.

These hybrid o-ring head gasket sets look like a great solution; I'm tempted to see if Cometic have a set available for our 1UZ, as we're going to be back on the dyno soon with the #2 motor.

 

[Speeedy]

oh man and all along i thought i would be able to boost 20-22 psi with just ARP std studs and MLS.. do we have to special order these from Cometic??? how much boost do you guys think these will hold?? im planning to use the basic 10mm ARP studs sold here on lextreme

I used the 10mm ARP2000 stuts and boosted the engine up to 1.3bar and had gasket problems (compression gases in the cooling system). I torqued the stuts to 60 ft lb so I think a little bit more torque (70-75 ft lb) would help a little bit. But I think it's not safe.
John use the 12mm stuts and had head gasket sealing problems too. So in my opinion the head gaskets are the critical part...

 

[CarlosR347]

Carlos, some have little or no problems with the standard Cometic MLS, but others (like me) have had some leakage regardless what we've done.

In my case, I have a hunch that if I'd retorqued the heads after the engine had heated up, and after the first couple of high boost runs, we would've been OK.

Still, I think anyone venturing above 20 psi with these motors needs to know that many of us HAVE had leakage issues.

These hybrid o-ring head gasket sets look like a great solution; I'm tempted to see if Cometic have a set available for our 1UZ, as we're going to be back on the dyno soon with the #2 motor.

I actually called up cometic after school and they said that they do carry it but only .051" and only 90mm bore nd the 1uz Is 87.5mm tech rep said it would work just fine.. the set will run you $600!! So Ima just stick to the MLS for now lol.. how much did you torque ures to? And what's the max allowable torque the 10mm studs can handle? I want it sealed for good but i don't plan on pulling the block out since im doing it in my front yard.. im getting the heads resurfaced tho

 

[Turbo4L]

Yes i have used o-ringed heads on a turbo 1uz.
Worked fine.
stock graphite gaskets with the heads o-ringed.

 

[cribbj]

Ben, did you use something like the Helicoflex gas filled stainless o-rings, copper wire, or ??

Why did you decide to o-ring the heads and not the block - liner flange interference?

How much boost was that engine running?

What was the approximate cost?

 

[Turbo4L]

stock gaskets, normal o-rings(piano wire) about $500AU, it spiked up to 25psi with an 1100hp turbo strapped to it.

 

[CarlosR347]

stock gaskets, normal o-rings(piano wire) about $500AU, it spiked up to 25psi with an 1100hp turbo strapped to it.

I've never really seen an o ringed engine in real life.. do you have to machine a recess onto the head or around the bore? And is it expensive?

 

[Turbo4L]

(about $500AU) , just around the bore

 

[Speeedy]

I've never really seen an o ringed engine in real life.. do you have to machine a recess onto the head or around the bore? And is it expensive?

Hey Carlos,

check this links about O-ringing:

http://www.highperformancepontiac.co...ade/index.html

http://www.hotrod.com/techarticles/e...ets/index.html

 

[CarlosR347]

Hey Carlos,

check this links about O-ringing:

http://www.highperformancepontiac.co...ade/index.html

http://www.hotrod.com/techarticles/e...ets/index.html

BTW speedy tight work with the Supra! i just read through your build.. I wish I had half the machining tools you got! it would've made my life a hell of alot easier ..

The O ringing is a bit out of my reach at the moment but I think if i had the coin id go with the Cometic Phuzion HG, Im going to go the MLS route and torque the studs to 75ish ft/lbs.. im hoping this will hold 20psi, which by then my Clutch will slip so I have other things to worry about lol.. is there any type of sealing agent that can be used like they do on copper HG to help the Sealing of water passages?

 

[Speeedy]

Calros, I'm a little bit confused that you have got a positive feedback from Cometic about our 1UZ head gasket. I charge a friend in the USA to ask Cometic for the Phuzion HG for the 1UZ and they told him they can not offer the Phuzion for this engine.

Yes, you are right it's very nice to have the machining tools. I thought I could spend 2500-3000 bucks for this machines first and can do a lot of work myself before I have to pay for every part that I need.

Alex

 

[Speeedy]

I called Garlock here in Germany and asked for the gas filled O-rings. I'm still waiting for an answer but the chance to get the O-rings is very good. They can do every diameter (cylinder bore) we need. Thickness of the O-rings are available in:
0,9 [mm]
1,6
2,4
3,2
4,0
etc

So it seems Cometic use the 1,6mm thick O-rings for their 1,29mm (.051") Phuzion HG. If you want to use thicker HG's (for example 1,9mm) you have to use the 2,4mm thick O-ring + grooving the block or head to get about 0,3mm preload.



Another option (that's what they use here in Germany) is to use the Helicoflex O-rings filled with a spring wire instead of the gas-filled O-rings. That's what Formula 1 teams use here. If I'm right we can get the spring-wire types in other thicknesses than the gas-filled types. So it would be possible to use a 1.9mm HG with a sw-type O-ring without grooving the block/head.
So the European use the spring-wire types and the USA guys use the gas-filled O-rings. That's what the Garlock man told me. It's historical grown in each country...

Alex

 

[cribbj]

Nice research Alex.

Here in the US Cometic are probably offering the Phuzion solutions for the most popular (chebbie, Ford, etc.) bores first.

As you've discovered, that doesn't limit us from designing our own solution. Did Garlock quote you any costs, yet?

 

[Speeedy]

Hey John,

yes...it seems that we have to go our own way. I don't want to pay $600 for that Phuzion HG like Carlos said. My old .051" MLS HG laying around and I will take a look how I can modify it to the needed diameter of about 92mm for the O-ring.

I didn't get an answer from Garlock yet but I will post it when I hear something...

Alex

 

[BigKriss]

Some of you may know that I have been playing with Alfa Romeo engines most of my life..Turbo`s have presents their fair share of problems .
The following is my bullet proof solution to the leaky and blown head gasket saga.
I progressed from stainless rings with three grooves biting into the head , two grooves and ultimately this setup.It is bullet proof.

This is obviously for a four banger turbo.. Copper gasket in conjunction with my sealing rings which I machine at home utilizing a jig for accuracy.



The rings are "L" shaped for a reason. Firstly a largish surface is required on top of the sleeve or block. No recesses here.



The upright portion of the "L" is machined with a taper upwards so that it can bite into the ally head. The protrusion is 3/10 ths of a mm.This easily goes into the ally head when torqued down. It also fits through the gasket bore opening.



These are used items but the pics are still good for description. Now the rings seal TWO FOLD ! The sharo "spike" biting into the head and the flat portion sealing against the copper gasket as per conventional sealing methods !



I have used a copper main gasket here but also utilized the brilliant "Reinz" gaskets from Germany. The only hassle is having to carefully cut the "fire ring" out of the Reinz gasket for the "spike" to go through.

]

Totally bullet proof.