Head gasket leaking? I dont want to pull heads unless I know.

[RabbitCTSV]

Hello all, I have a 1986 T-Type. love the car, Picked it up from a friend of a friend, "long story"

car has 48K miles and in very good condition, Car has has had a lot of motor work done to it and I have all the receipts to show the work, all done by Century automotive and transmission in Houston TX,

I replace a bad 6466 BB turbo with a 6766 BB , now im starting to play with data log and boost. Im currently at 22 psi and im noticing that im pushing air into my over flow tank. I have replaced the thermostat back to a 160. Ive also replace the 16psi cap a few times. I also did a pressure test on my coolant system to 30 psi. and over 8 hours lost 1 psi. I never over heat, im at 180 all day , when AC is on ill get up to 190 at lights.

i have topped of the system many times getting " air " out, but if i get into boost I piss water

 

[pacecarta]

you could try a retorque but you probably need to pull heads..
head gasket is damaged most likely by the #1 or #6 cylinder .
i see this often with cometics and steel shims (rjc),
only ocassionally on stock gasket as they usually will full blow and theres no doubt the gasket is toast

 

[RabbitCTSV]

you could try a retorque but you probably need to pull heads..
head gasket is damaged most likely by the #1 or #6 cylinder .
i see this often with cometics and steel shims (rjc),
only ocassionally on stock gasket as they usually will full blow and theres no doubt the gasket is toast

It has RJC gaskets with ARP studs,

 

[pacecarta]

It has RJC gaskets with ARP studs,

had ... time for new

 

[RabbitCTSV]

I guess so. whats the best head gasket to use? I was thinking about going with champion aluminum heads over my ported iron heads, any advice?

 

[bison]

If you're lifting the heads then the gasket used won't really matter. As Paul stated the stock gasket will fail rapidly from this. The steel ones won't. Fwiw I have a set of rjc steel gaskets on my slower car and they've been there for about 5 years. Low 10 or better power. Boost as high as mid 30's.


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[Flyin Brian]

Definitely sounds like a head gasket. If you have head studs as you stated you will have to pull the motor to replace the gaskets if you still have a/c on the car.

 

[pacecarta]

Definitely sounds like a head gasket. If you have head studs as you stated you will have to pull the motor to replace the gaskets if you still have a/c on the car.

you dont have to pull motor
ive done them in car many times , just need to spin out a couple studs on pass side

 

[RabbitCTSV]

If I'm lifting my heads at 20 -25 psi something else must be wrong .

 

[RabbitCTSV]

Yes I have factory A/c

 

[Flyin Brian]

You could be getting knock or the heads are not flat or the block is not flat or the heads were not installed correctly but something is definitely wrong.
If that water is getting into the motor you might want to check your bearings as well.
I did not know you could get the passenger side head off with studs and the motor in the car.

 

[bison]

If I'm lifting my heads at 20 -25 psi something else must be wrong .

Usually the cylinder pressure is the problem if the heads are lifting. Boost has a lot less of an effect on that compared to timing or things that are variable and not mechanically linked to the engine like the CR and cam and cam timing. There is a huge difference between 20 and 25psi especially on an engine with good heads and potentially higher CR than stock. What is the timing and was the baseline timing verified? In the last year I've seen at least 5 examples of timing error that could be trouble. One was off 2.5* positive. This will burn you really bad on the tune if you were fine on another application with similar combo and timing. Also with a chip that is burned for 20psi and the timing is perfect or even on the low side of the happy window it will be way too much at 25psi with the same fuel. With a regular chip you're limited to tuning to the highest boost you will be running at any time with it even if that's out the back of a full pass. Everything will be just fine till the boost creeps 2-3psi at 120+mph then it's like a grenade with the pin pulled. A 6766 is a mid 9 sec turbo at minimum. Boost control below 60lbs/min will be a challenge without a good wastegate strategy. Usually boost is ok down low but will take off in 3rd as rpm climbs from the increased exhaust pressure.


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[pacecarta]

have your alky pump tested..

 

[RmvBfrFlght]

I wonder if this is a set of the 'too long' studs? Where the nut bottoms before the stud is properly tensioned in place.

In this case I'd pull those nuts, add the washers, torque back down and see if the issue goes away. There is a thread here on the engine board about this stud issue.

RemoveBeforeFlight

 

[RmvBfrFlght]

Here it is:

http://www.turbobuick.com/forums/th...uter-studs-under-valve-cover-too-long.366491/

RemoveBeforeFlight

 

[LSTTYPE]

I have a very similar situation. Last year I had a vacuum line fall off at 22psi. Lifted a head and started pushing a little coolant into the overflow. I am running stock gm gaskets on a 40 over motor. It would usually fill the tank about a half an inch every pass. Never lost any coolant or had any temp variances. It would also suck the coolant back in after a little driving. I retorqued the heads and added gm coolant tablets which really helped. It hasn't come up at all this year for whatever reason but I'm sure it will again when I raise the boost. I'm gonna live with it till it's more of a problem. The motor is 16 years old anyways.

 

[Bobs rare 6]

Sounds like Plowman is ready to go Silkey!

 

[vacuum 6]

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