Blown Head Gasket-Torched Head/block

Hey guys I went out over the weekend and had a little problem right at about 60ft. I pulled everything apart and have blown the gasket out on number 6 & 8 up on the intakes, it blew out torching the head and the deck surface it went past the pushrods burning half of it on both cyl and spraying melt aluminum on the lifters. I pulled the other head and found that the gasket which is a cometic MLS by the way was blue and a little burnt up on the intake side of every cylinder.

This is a 526 BBC twin turbo with a pro mag 44. Running 45 psi boost and about 27 28 deg timing, egts where 950-1100 comp is 12.5 :1. I have run the set up at 30-32 psi with out issues just stepped up the boost and bam first run it torches it. So I am now thinking o ring and reciever grove with copper gaskets. what do you guys think? I was thinking more torque also has we have 1/2 studs and they were torqued to 90 lb/ft

 

Did the same thing with blown 588 BBC 30lbs of boost with cometic gaskets. Went to o-ring and receivers; one of the best values in racing. You can also change compression ratio by swapping out gasket thickness.

 

Thanks thats what im going to do.

 

O ring it, without doubt

 

Mike,

I was around or at the 60ft cone when the car layed over/stopped pulling. I could see the car accelerating through first gear/rpm climbing then the rpm just rolled right over and headed down and the TPS was still 100%, I then realized it wasnt pulling and lifted. I can tell you the plugs had about 3/4 of the cad burnt off with no real heat in the threads yet. I do not know what you mean by frosty but they didnt appear to be white in color, the porclin was brownish all cylinder being pretty even some showing almost all the car burnt but still no heat in the threads. I am going to have a look at the rods and mains now and see if we can learn anything else. I run a coating on the piston tops and they all look brand new with a little carbon on them.

Thanks for the replys

 

I just got done tearing the whole motor down. I run coated bearings and the tops show the usual signs of slight wear/looks as little shinny on the top rod bearings, lower bearings look brand new. The coatind looks like it just started to rub off the tops but no real smashing/pitting or flaking.

I have to inspect the plugs better I dont have them in front of me they got left in the trailer and the car came back to the shop so i will check later but pretty sure they are just like new minus some burnt cad.

 

Certainly detonation will blow anything out...

I run o-rings and most of my stuff does not have recieving grooves. When I ran 14's and high 30's worth of boost I couldn't keep copper head gaskets in. I finally added the inside bolt holes and that made a huge difference.
Also when you go to copper you want a very smooth deck surface finish.
Some people are afraid to run thick amounts of copper, but actually thicker is better.

Good Luck!

I've run the gammet on keeping head gaskets in BBC's and feel like I've won, so let me know if you have more questions.

 

I know bearing smash to be the center of the upper bearing being smaller when you measure the bearing thickness. Am i wrong?

 

What thickness gasket would you recomend, I just want this thing to be bullet proof.

 

Mike, the valves did not go blue around the edges. I have the head all disassembled and welded already, looks like i am going to have 1 new seat put in as i had to get the weld very close to it.

My question for you Mike is what egts are too cold? around 700-800 and the car does want to rpm during the run but to be honest I dont know if it was much better at 1000. I think I may be blowing spark .018 gap pro mag 44 as my rpm trace has been pretty hashed up from day 1 with the mag.

 

ProMod83,

Bearing smash is the center of the bearing being thinner that the rest but most measure it by measuring the width of the bearing shell that is if the bearing is .856" wide at the ends it should be close to .856 wide in the middle you will often find them to be .07 or more wider after detonation.

Richard Gavle

PS I agree with you on the two grooves and copper, MLS is for small block Fords with F2s. Mike this is not meant to be a shot at Fords by any means its just that a lot of people with small block Fords and ProChargers have good luck with them for some reason.

 

Promod83

Like Mike said 062-081 thick and make the other adj. as needed (pushrods, etc)

Do you have inside head bolts?

What heads are you running?

I'm surprised it wasn't cyl #'s 2 or 7

 

We do have inside head studs, this is a sonnys hemi.

 

Oh, I had normal BBC stuck in my head.