Something Let Go !!

[Twil]

Last night (and all week) I was able to do 4 runs with everything set for the street. Good O2, no KR, FP 70 at WOT, etc.

23# boost
26* Timing
Alky
93-Oct
773 -O2 & 0KR

I went to the track tonight and it doesn't look good.

On my 1st run, the car blew up about half way down the track.
1.8 60ft. (My best so far) I was on my way!

White/Gray (hint of blue - alittle) smoke everywhere!!

At the end of the run, track officals check under hood and it looked like oil blew out of the breathers. Lots of it.

NO smoke coming out of the exhaust.

I had my Turbo-Link running but it didn't record any data??????

Scanmaster had no readings - car was shut off (I thought I had the run recorded w/ TL)

In the pits, I was able to take a look myself.

Idles fine. (But lots of press coming from breather holes)

No power

Smokes out of the valve both covers when I hit the throttle.

Drove it home 15 Miles and it only smokes over 1800 rpm but has no power.

My guess:

1 Piston met a valve(s) Intake(s)

2 Cracked head (Not likely)

3 Blown Head or intake gasket (Probably not)


???????Any Better guesses??????


Gotta do a tear down this week :-(

This Sucks!!!

Welcome to Drag Racing I guess.

 

[grey1]

When my car was having blow-by out of both breathers it was a bad head gasket. Sound like it's running on 3 or 4 cyl.? Is there stuff floating in your radiator res.? Pull your oil plug and hopefully there will not be any water. Mine blew on the driver's side intake. My son took the car on a joy ride this past Mem. weekend. w/o my permission. He now knows what kind of work is involved with pulling and fixing the motor.

 

[Turbo 6 Justin]

My guess is also a head gasket, they have a funny way of really showing their problem the day after they get hurt. I would go further and say that it blew into the valley pan thus throwing pressure into the valve covers and pushing it out the breathers. I have seen it before, kind of looks like steam engine puffing away, runs like it is missing either 1 or 2 cylinders (depends exactly where it blew). the good news is it will not be mixing the oil and coolant so there should be no problems with the bearings even after driving it home. do a compression test and I'll bet 1 or 2 is way low pull the heads off and replace the gaskets and go try again.

good luck

 

[Joe 1320]

As long as there was no mechanical interferance (nasty noise), I'd bet head gasket too.

 

[Twil]

No coolant in the oil

I have checked the oil (dipstick) and it is clean. I will drain the oil tonight for a better look.

Overflow looks good also - no bubbling, no oil. I could drain it also. I will have to anyway to do a headgasket.

I will assume that I will need to replace them both since I am tearing it down.

Two questions:

1 How much time does it take to do the Headgaskets??

2 What type, brand, etc. should I use??
(I want something that will let go again but not very easily. I like having a relief - better than loosing a motor !!)

Thanks for any help,
Brandon

PS
I feel alittle better now that it looks like a HG blew.

 

[TRENT THOMPSON]

the gaskets are not cheap approx. $35-$45 a piece plus ~$20 for the intake valley pan tray. Arguably the best gaskets too use are the factory GM composite gaskets or the identical fel-pro's sorry don't know the number. Remember also you are going too need some new bolts.as far as time is concerned it depends on how fast you can wrench. I would say for both sides engine in the car at least ( probably more ) 6-10hrs. hope this helps

 

[Night Train]

When I bought a GN 4 years ago with a known sick motor, it had similar symptons to your car. Car would run, but a LOT of pressure to the breathers. When we took the motor out for the rebuild, it had several problems. There was a blown headgasket, but there was also a hole in one of the pistons. Hope yours is only head gaskets.

Bob

 

[Twil]

Is there anyway to check for a hole in the piston other than a tear down???

Brandon

 

[PsychoBuickBoy]

Headgasket!

Let this be a lesson for ya not to run pump gas at the track (even with alky). A couple of alky blasts on the street is alot different then a full blown quarter mile run. The only times I popped a head gasket is at the track running something other then race gas (Xylene mixes, alky and pump gas etc....). Usually didn't see any knock either! I only run the good leaded stuff now at the track.

 

[tazgn]

Hole in Piston

I would say you'll see the hole in the piston (if you have a hole) when you pull the heads for the head gasket replacement. No matter what, you have to pull the heads so I would just go for the head gaskets with the thought of piston hole in the back of your mind. I would bet it's just a headgasket into the valley area though.

Derrick

 

[Twil]

Back Running Again!!

I finally fixed my car!

Great news Guys, it WAS the Head Gasket!!!

***Not a Piston***

Numer 3 let go big time!!

Either 1 or 5 was getting ready to let loose also (I cannot remeber which way the gasket came off)

Checked out the Passenger side and it one cylinder was showing that it was ready to go next. Glad I was doing both sides!

In all pretty straight foward - just time consuming.

DO I need to retorque the ARP Head Bolts since I have driven the car three times??

Or is the 85 Ft lb with 30wt (and #2 permatex for sealant of the threads) for lub OK???

Thanks all,
Brandon

 

[Fred 86 GN]

Drive it around a couple times. Get it good and warmed up each time to thoroughly heat cycle everything. Make a couple low boost pulls on the street. Then retorque the headgasket bolts. I did one at a time, loosening it about 1/2 turn then retorquing to full torque. So far mine have held up...compared to not retorquing them!

The first time I replaced the headgaskets, I did not do this, and the driver side #3 let go again in short order with just a little abuse (20psi, cold morning, 110 race chip with not quite 110 octane in the tank).

 

[steve hughes]

It also is a very good idea to pull the oil pan to clean it out. That is if it was a stock 86-87 gm gasket or similar composition gasket. It will hurt the bearings and clog the oil pump pickup tube.