Thank you for the advice that sounds a good idea. Problem is I live in a Antigua a small island in the Caribbean. Nothing like that here I would presume.

I noticed in your sig it says "BR700" on it... may I ask then... do you have your coolant reservoir getting filled on full chat race fuel driving?

 

How much is the overfill going up?

I think 2 - 3 inches should be normal when comparing to when engine is cold and hot.

Remember, water takes on a larger volume when hot, and the sysem is mostly air tight. The overflow is a place to dump the extra volume and pull it back in as it cools.

As long as it's the same level every time it's cold and it doesn't go any higher than 2-3 inches I would say don't worry

 

Haven't used race fuel since the mapping. During the mapping when got back it was near full to the brim.

 

If you are pushing coolant from the water jackets then that is bad.

If you are simply overheating the coolant that is bad too but easily fixed.

 

Originally Posted by U2SLO View Post
Ok do this drive your car hard make reservoir full, go to a shop/station with a gas analyzer probe and stick it in the tank but don't submerge it in the coolant let it sniff it and see if you get H/C C/O readings while it's still idleing if so then yes your head gasket,time to o-ring your head.
I have done this test several times and it's a no brainer.If there is no gases there then your overheating.

That is called a block test you can buy the block tester at napa and it will have a liquid in a tube that you can attach to the radiator and while its idling you can test to see whether or not you have combustion gases in the cooling system. I was pushing coolant and the block test did not tell me anything because when I was pushing coolant it was when I was under boost. Thats the only time that the head gasket would allow coolant to push. This is w/head studs installed. Swapped the HG everything is normal

 

U2SLO... by the above I'm inferring your BR700 pushes coolant to the reservoir too?

 

I lifted the head with the stock turbo, and it wasn't from detonation.

 

Why is it that none of the gurus here can comment on whether, when your cylinder pressures are really high (eg lots of torque and boost and ign advance)... you will get the head lifting a bit. No not a blown head gasket, but the head physically lifting a bit.

 

This is a problem we are seeing on the 3000GT platform once you get around 30+ psi... We have added bracing to the weak area in the head where it was flexing and allowing the HG to "lift." You can also O-ring the block/head as another line of defense.

Basically the cylinder pressure flexes the head and pushes itsself into the coolant galleries and pushes the coolant into the overflow. My car has actually pushed it totally out of the overflow as well so i had to add more. When this happens, it will start to burn the HG so the HG will eventually fail.

This is soemthing that the big turbo deisel guys have been dealing with for a while as well as a few people on supraforums. APR head studs are a great fix but eventually with more boost, you MAY need to find something else.

If you are mixing oil and coolant you will not blow white smoke... Your oil will look like a milkshake! This is extremely bed and you need to switch your bearings after you get it all cleaned out.

 

Physical lifting of the head is a known issue on high HP 4g63s, more common with the older DSM versions, as their heads were "thinner" on the mating surface with the block. The newer Evo heads have more meat and a smaller spark plug hole.

Felpro has measured that head lift at as much as 0.03 without any detonation. The solution is to use studs that do not stretch so much, and a "stopper" head gasket that will "spring" enough to maintain a seal when these events occur.

Overtorqueing the head studs is not the solution, as it creates deformation of the head, not greater resistance to stretch.

 

Forgot about that part, very true!

 

Yes it did fill the reservoir before I o-ringed the head on full race gas 40 psi, on my old setup.
Now on full race gas 40 psi with o-rings in head no problems at all.

 

Absolutely agree except we seem to get it less on the DSM motor and more on the Evo type new generation motor.

The last 3 cars we built back to back lifted its head irregardless what we did only if we were pushing the cars over 35 psi of boost on race gas. Tried AMS/TMS head studs, all sorts of metal head gaskets but particularly lifted more on the EVO 6 which was a 2.3 litre stroker running a T04Z at 38 psi of boost. MAde the power at just under 750 WHP but the lifting was bad enough to a point that the radiator endtanks bulged at the end of a drag event. Went back pulled the motor apart, everything was ok except signs of combustion gases pushing through the head gasket. Doesn't matter if its HKS, Cometic or SCE Titan , they all lift. DOESN' T LIFT only if we're running below 30 psi of boost.

Am contemplating running 12 mm studs from the 1G DSM but that means having to rebore the stud holes.

O ringing is the last resort but anyone here knows where I can get more info to purchase a kit or something?

 

Ok I'm definitely not an expert, but I'd put forward the observation that anyone running race fuel, pushing 30+ psi of boost, a bunch of ignition advance... making around 600 or so ft/lb of torque will be filling their coolant reservoir.

And the reason the coolant reservoir fills is because the head is physically lifting.

And that this is not necessarily that bad of a thing to happen depending on the severity.

Now regarding o-ringing... I don't know anything about it except I do know my friends Buschur motor was o-ringed. He is only on a stock 9 turbo so I cannot comment. But U2SLO's experience seems to show perhaps this is the answer.

Me personally, I only run race gas for that odd visit to the track. So a bit of head lifting does not seem to me to be something serious, but it would be great if it was avoidable I guess.

 

I would strongly recommend you try the Felpro gasket before you start with the 12mm stud mods. O-ringing is not needed, either.

Correspond with Marco at Magnus Motorsports (marco@magnusmotorsports.com) He has done a lot of testing with very high HP 4g63s and various head gaskets, and can point you in the right direction. The Felpro has worked better than any other gasket under high PSI applications. Your PSIs are no worries, compared to what they are running on Brent Rau's 1400HP motors...