It's my understanding that once you are in the 550-600+ ft/lb area of torque, let us say for example a stroked GT35R on race fuel... that the head lifting at peak cylinder pressure is to some extent common. Symptoms or signs of this occuring would be coolant appearing in the overflow reservoir.

True or False?

 

I would say false. Bad tunes cause bad things to happen.

You could kill head gaskets and stretch bolts on the stock turbo if your tune is crap.

 

Yes I agree with the above about bad tunes. Let's assume in my examle the tune is spot on. I'm of the opinion that you still will be lifting the head to some extent. Take for example AMS head studs... why do they exist? I would suppose perhaps because they know the head lifts on the bigger power cars and they are trying to minimize this effect. And I think it's possible a stoker and GT35R might make similar torque to a 2 litre GT4X turbo... so this head lifting issue might apply to more people than you think?

 

you'll see white smoke out of the exhaust too as the coolant will mix with oil

 

But I'm wondering if this is common. For example, if Buschur or AMS build you a 700 hp GT35 car... is it normal to have coolant pushed to the overflow reservoir when running race gas and beating on the car?

What say you David Buschur and other top builders?

 

Our tuner has a very good rep for tuning cars and for the most part on the conservative side.....and has yet to "blow" a motor :knocks on wood:

He has many cases of cars in that power level lifting heads and pushing coolant into reservoirs and most recently spraying the windshield of our shops 2G DSM.

I should say many of these are 4g63's from DSMs.

Matter a fact i posted in another thread about this same car as we tried to use a fairly think SCE HG w/ no luck and popped it at about 580 HP on a Mustang that has a 2.3 stroker.

That was with Magnus studs.

That was also after another failed attempt months back w/ another SCE gasket i believe.

The owner ended up sending the head to Buschur for o-ringing.

It's on now w/ the Magnus studs and oem HG.

On my own car we run an O-ringed block, AMS studs, and oem HG, and so far so good at 527 HP on our dyno.

We also have a couple other Evos that run 35rs on stock blocks but w/ arp studs and they are about 430-475 HP on our dyno as well and so far so good!

One last car we just finished was another 2G 2.3L o-ringed block, Magnus studs, and oem HG.

It put down 450HP on 91 pump and 560 on ERC 118......no probs w/ pushing coolant.

 

There are many people with stock head bolts running 500+ hp that don't have leaky head gaskets.

Most OEM bolts are very very good. On big HP motors people often rework the heads. Many folks prefer prefer studs over bolts and therefore upgrade to aftermarket goodies. This doesn't mean that stock hardware is junk. Stock bolts probably cost more than arp replacements.

Most of the high rollers like AMS have completely built motors. I dont think anyone should EXPECT the stock hardware to last after you double the stock HP rating. I wouldn't. I would rather pay and have a built motor made out of my perfectly good stock one rather than pay for a new block, head, and valves because I was too cheap to upgrade before going for big power.

 

But is it fair to say there is a distinction between lifting the head enough to pressurize the coolant system under race fuel big power conditions, which therefore fills the reservoir. Versus actually blowing a head gasket?

In the first case I believe this is not inherently damaging anything and it is ok.

In the latter that is a problem which needs to be resolved because you even in low boost situations have coolant leaking into the combustion chamber or vice versa.

 

my brother 4 wheel slide is making 438/444 on stock head studs and has been making that power for over 15k and beats the living hell out of his car.... goes out racing every other night

 

my buddy is 537/460 stock block, gasket etc.... no arp's. His car runs perfectly fine. I am about to hit the good ole 50k mark and as of next weekend will be on a 35 and meth so i will be doing my head gasket then and will go to head studs at that point. If you dont run your car on the raggedest of edges, you should be fine. In the end, i think it has a lot to do with boost and how much you throw at it. My buddy is on meth at only 27 psi.... i think the stock bolts are fine there. Its when you start doing stuff like 30 psi or more on a daily basis and drive the car that way all the time that you need to actually upgrade

 

If you are pushing coolant from big power it dosnt matter its the same as pushing coolant with any blown headgasket. I have blown 2 head gaskets so far. One was from an overboost symptom and stretched the stock head bolts. The other was when my meth pump failed on me running 28 psi and then I started pushing coolant. When I took the head gasket off you could see a small area that was bad. Since I have replaced the headgasket again (using the stock gasket) and fixed my meth problems I have no had any "coolant pushing" problems. I can see that the more boost you throw at the motor the higher the chances of the head lifting. Studs offer alot more clamping force and are much better than the stock bolts for higher boost applications but the head definitely can still lift on you. Even with smaller detonation levels in a high boost scenario can put effect on the head lifting. Anyways thats my 2 cents.

*When I say high boost applications I mean 35 psi + When I blew the hg the 2nd time I was running 30 psi with ARP's and the meth pump failed so obviously you can see the detonation levels were by far good enough to damage things.

 

Lets say you have a built motor. You throw in some race fuel. Tune it to close to 600 ft/lbs of torue. No detonation. You go for several blasts of hard driving. You pull in to the garage, and lo and behold your coolant reservoir is full.

Is there a problem with this motor?

 

'
not necessarily, your coolant system may not be able to keep up with the increased duty it sees due to the elevated heat/power levels. A high hp, highly tuned car is going to put more stress on the coolant system than a stockish car. It could just be as simple as boiling the water in your coolant system and nothing is wrong with the motor.

 

That is an interesting explanation. I've been told it was because the head is lifting slightly... but maybe you are right.

 

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.