What is the risk of boosting hard on BHG motor?

[mk3ukr]

Few days ago during quarter mile run my motor detonated and blew coolant from overflow bottle. Checked compression – all cylinders pressure close to equal, between 145 and 150psi. This is with closed TB, I forgot to block it open :nono:
Today after driving around 40-50 miles, occasional boosting (not really hard) I found first signs of BHG – air in the radiator, gases push coolant into the overflow bottle.
What is the risk of damage to motor when running it hard with BHG? Here will be drag day next Saturday, want to see what my car is capable of with 61mm turbo before rebuilding motor and going bigger turbo.
Head gasket is Cometic 1.3mm. My biggest concern is not to warp cylinder head, I invested a lot into it.

 

[Big Wang Bandit]

You could destroy your bearings. You are in process of doing that now, so I would recommend draining your fluids and ripping it apart.

 

[ForcedTorque]

Are you considering dyno'ing with BHG?????????

I wouldn't advise it. Coolant on bearings doesn't really do any good. You may cost yourself extra machining, and head warpage if you let it heat up enough. The dyno is very rough on a good car.

 

[bountykilla0118]

Hhmmm ...... wow did you really ask that sounds like you are willing to blow something up for just one night. Those who fight and run away(when losing) live to fight again another day.

The material that head is made out of is very very soft, as in you can use a screw driver and your human strength to damage the head pretty bad, but the aluminum does not handle heat very well and can warp beyond repair and you would have to find another head.

I would park the damn car ........ but to answer your question hmmm the list of possibilities are really to long but here is a start ........

1) The motor can be blown to shit beyond repair with that size turbo meaning you would have to start from scratch

2) You could be lucky and not have any damage for that one night because many people have had a slight BHG and either they did not know or just said fuck it if it blows it blows and they drove it for a good while before any major damage. However you coolant story didn’t sound like a slight BHG …..

Russian Roulette

 

[TurboFreak]

I LOL'd before I even clicked on the thread...

Now its Roflcopter-status.

 

[Rennat]

rofl at the roflcopter! i havent seen that in a long time..

BHG = water in oil

what does a turbo LIVE off of..? oh.... OIL.
dont ruin your turbo. park the car and take care of it NOW. otherwise its going to get COSTLY.

 

[TurboFreak]

BTW guys its not a dyno... its DRAG day. LOL

 

[Facime]

As long as you dont severely overheat, your head "should" be fine, but why risk it. The rest of the motor...not so much. You have very high odds of killing the bearings and ending up with rod knock bad enough to require a new crank when rebuilding. If the rods go knocking at high rpm and cylinder pressure you could end up throwing a rod through the block. After all that, there is certainly the possibility of warping the head.

Is it worth the risk? I guess it depends on what kind of money you are willing to throw at it if you guess wrong.

 

[Poodles]

We've seen our fair share of people with more money than brains (or lacking both leading to even more disaster). Don't fall into that category.

First off, confirm the BHG, it might not even be a BHG but a pinhole leak releasing pressure in the cooling system (pressure raises the boiling point). Driving hard on a car that MIGHT be broke is just wishing to be BROKE financially.

 

[Rennat]

but pinhole leaks dont push coolant out of the res. they just make the birdcage light come on.

check your rad cap. if thats bad, it wont hold the pressure either...

 

[Facime]

pinhole leakes cause pressure loss in the system causing spontaneous boil which DOES push coolant out the overflow. Leaks can be small enough that once the pressure is released they close back up again and the process recycles.

either way, one symptom of BHG isnt enough reason to cry wolf just yet. A block test would go a long way here as a diagnostic tool.

 

[Doward]

The stupid is so thick in this thread. Jdub, I'll try to throw a life preserver into the BS to help you out :3d_frown:

1) Do not drag race when you know your car is less than 100%. Seriously. Do you have ANY idea how pissed off it makes everyone behind you, when you spread shit down the track and stop everyone else? I assure you, if you blew up your car on the track, you would get a serious ass beating for wasting everyone else's time. By the track clean-up crew, if no one else.

2) You will kill your turbo, and throw a rod out the side of the block, while warping the head. That's the damage you can cause.

3) Any depressurization of the coolant system (ANY) can cause a boil-over condition.

 

[NewWestSupras]

It'll be fine. Turn up the boost and mash it. 7m's never get bhg's. That's a big fat lie put out by people who want you to buy these new fangled "metal" head gaskets. Who ever heard of such a thing....M series motors love milkshakes. Hey, so do I! mmmmm.... milkshakes.

 

[IJ.]

Park it..... :nono:

 

[Rennat]

i just logically thought about #3 doward... and it does make sense now... forgot if theres no pressure on the coolant system the mixture will boil at a lower temp (180)

damn chemistry... lol

 

[Wills7MGTE]

No don't park it......SELL IT!!!!! honestly if you dared ask this question you have no business driving the car, much less tuning it yourself. This could have been answered by either searching on here or god forbid the half ass encyclopedia known as wikipedia.

 

[Who]

I broke my leg, how far should I run?
My parachute has a tear in it how high should I jump from?
I keep coughing up bloody sputum should I see a doctor?
:sarcasm:

 

[Rennat]

wikipedia has diagnosis of a BHG????

 

[Who]

wikipedia has diagnosis of a BHG????

Look it up under Supra

 

[Poodles]

Ibwos