Moparts
Blowing head gaskets question
Posted By: KY Charger
Blowing head gaskets question - 10/27/11 01:41 AM
I have a 360 with two 450 Holley's tunnel ram setup and compression of 11.2:1 I first blew the driver side head gasket, replaced it with a different type gasket and as soon as I fired it up to make sure nothing was leaking it blew the passenger side. The gaskets that blew was the Fel Pro 1008 Ihad a set of Mr Gasket that I put one on the driver side but plan on putting Cometic on both sides. Does anyone have any clue what could have caused the problem; they blew almost straight across from each other. The driver side was leaking about at the #5 cylinder and the passenger is around the #4 cylinder. I had tooling at my work check the driver side head on their flat stone with dykem paste and everything was good with it. I had 93 octane in it at the time the heads are ported J heads.
Posted By: stumpy
Re: Blowing head gaskets question - 10/27/11 02:02 AM
Are you using pistons with a quench dome?
Posted By: RapidRobert
Re: Blowing head gaskets question - 10/27/11 02:08 AM
The blowing out straight across was a coincidence. possibilities: warped head or block, block threads not clean giving an improper torque reading, bolts bottoming out, defective gasket, improper torque sequence/amt, bolt threads dirty/nicked giving improper torque reading (as above not enough clamping force but the torque wrench shows enough), block/head surfaces not clean (debris)
Posted By: KY Charger
Re: Blowing head gaskets question - 10/27/11 02:15 AM
Yes they are the Keith Black 190-030
050" solid dome, centered pin. Quench dome elevated .050". Machining required to achieve optimum quench.
Posted By: stumpy
Re: Blowing head gaskets question - 10/27/11 02:24 AM
I had the same problem with my 360-410 stroker. I finally ended up milling .030 off the top of the quench pad to get it to stop blowing gaskets. They blew into the valley area. It didn't matter what head gasket I used it didn't help including cometic. It was getting expensive and very agravating. Milled the pad and haven't had another gasket bolw in 3 years of racing.
Posted By: KY Charger
Re: Blowing head gaskets question - 10/27/11 02:25 AM
It has ARP studs and was torqued 30,60,then 90 ft. lbs.
the block was surfaced .010" and the heads checked good.
Posted By: stumpy
Re: Blowing head gaskets question - 10/27/11 02:31 AM
So were mine.
Posted By: RapidRobert
Re: Blowing head gaskets question - 10/27/11 02:38 AM
Stump how much quench clearance did you have (before the milling took care of it)
Posted By: stumpy
Re: Blowing head gaskets question - 10/27/11 03:05 AM
I believe it was right at .025 which was too tight.
Posted By: RapidRobert
Re: Blowing head gaskets question - 10/27/11 04:21 AM
Quote:
It has ARP studs and was torqued 30,60,then 90 ft. lbs.
the block was surfaced .010" and the heads checked good.
Sounds good there. Thanks Stumpy for answering my Q
Posted By: dodgeboy11
Re: Blowing head gaskets question - 10/27/11 04:36 AM
Never seen it on a small block, but on big blocks the factory chamfered the bores so much that the fire ring sticks into the bores with the standard fel pro head gaskets. I doubt that's your problem, but it's something to check.
Also, if it's improper quench, you can always try thicker head gaskets. Unless it's the corner of the quench pad hitting the chamber...
Posted By: KY Charger
Re: Blowing head gaskets question - 10/27/11 07:41 AM
We got to feeling the gasket where the metal is around the cylinders and it feels like it's been warped or hit by something the bore on the gasket is 4.180 if i recall right. It's on the same cylinders where I am having the problem.
Posted By: babarracuda
Re: Blowing head gaskets question - 10/27/11 01:25 PM
I have the KB pistons with a quench pad in my 410. I clayed it to check the clearance. I have .045 to the head. No problems and it runs hard. At 4000', it ran 12.80 and 103 with full exhaust. Drove it to the strip. If you didn't check the quench clearance, you are asking for problems.
Posted By: KY Charger
Re: Blowing head gaskets question - 10/28/11 05:18 AM
What is the process of checking the quench area. I'm not very familiar with how to properly check it.
Posted By: KY Charger
Re: Blowing head gaskets question - 10/28/11 05:23 AM
Could the problem maybe be with the Flowkooler high volume water pump and and the combination of March Performance pulleys causing too much flow and pressure building up.
Posted By: stumpy
Re: Blowing head gaskets question - 10/28/11 05:19 PM
You can't build up enough water pressure to blow a head gasket. The cooling system won't be the cause. To check the quench you put a small chunk of clay on the top of the quench dome of the piston and set the head back on the engine with the gasket. Bolt it down to squeeze the gasket.Manually turn the engine over at least one full rotation to make sure the piston has reached to TDC. Pull the head back off and measure the thickness to the clay. Use feeler gauges on top of the quench dome next to the clay to equal the height of the flattened clay. That's the amount of quench space you have. I use a drop of oil on top of the clay to keep it from sticking to the head and ruining your measurement.
Posted By: KY Charger
Re: Blowing head gaskets question - 10/28/11 09:34 PM
Thanks Stumpy for the info, I've already put on a thicker but will definately will try it if they blow again.
Posted By: WheelsUp73
Re: Blowing head gaskets question - 10/28/11 11:51 PM
Quote:
I believe it was right at .025 which was too tight.
If you ran your motor with that little clearence the piston would have been tagging the head hard. Quinch has nothing to do with your head gasket problem. By milling the top off the piston you would be lowering your compression and that is what may be saving your gasket but that is a crutch.I run .038 piston to head and that is pushing the limit, most engine builders like to see .040 piston to head. I use cometic gaskets and so does every body racing in NASCAR with no problems. A cometic gasket is made of stainless steel so if you hurt a cometic gasket the block and head would have been torched.
http://youtu.be/N6v55H0vriw
http://youtu.be/1HtN08OzO0s
Posted By: stumpy
Re: Blowing head gaskets question - 10/29/11 04:26 AM
Why do you think I had the pistons milled? It was causing detonation which is what was blowing the gaskets. Piston never touched the head. Cometics are good but any head gasket can go bad.