Thread: popping through carb

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Its a head gasket.....if it was a hole in the block, smoke would be everywhere.....not to mention, all kinds of weird noises.

Head gasket probably blowen between them That does happen used to happen a lot "BACK IN THE DAY"

Check to make sure the block isn't eaten away or the head in that area if that is the problem. If you cought it soon enough you'll be OK

This is starting to sound more loke the valve clearances were set to tight. If you had a hole in the piston the engine would be pumping smoke out the exhaust and breathers, but you have not mentioned that.
Can you get your hands on a cylinder leakdown tester ? Rotate the engine untill you close both valves on the bad cylinder, than hook up the leakdown tester to the plug hole, pressure it up and listen, If it hisses at the carb = bad intake valve, if it hisses out the exhaust = bad exhaust valve, if it hisses out the breather = bad rings or hole in piston.

BLAST ! Went back and read the query properly, two middle cylinders on pass side of block, I agree with everybody else, probably a blown head gasket.

Hey Rich, If you have an aluminum coated exhaust system it could have a partly blocked exhaust. If it's not flowing good,it will run fine at idle and fall on it's face as you open up the gas. Tommy

I just got the passenger side head off and sure enough, you guys were right. The head gasket is blown right between the two middle cylinders! Man you guys are good. That is a cheap fix. Lots of labor, but a cheap fix.

Check your block real good at the leak.

The block looks good. I only drove it about 1 mile after it happened and that was at 30 mph. What type of head gasket should I get to stop this from happening again. I have a 4" cylinder, should I get a 4" gasket or should I get one a little bigger? How much difference does the thikness make?

Originally Posted by richmondb

What type of head gasket should I get to stop this from happening again?

Cometic. That is the name brand and they can be reused and you can order any thickness you like. They will cost you $200. Edelbrock and Felpro make regular ones and if your heads are true, you can use them. Cometic can handle nitrous, blowers and turbos.

Originally Posted by richmondb

How much difference does the thickness make?

I would reccommend .040. Thickness matters in the area of compression, but not durability, hopefully that helps.

I have a 350 bored 30 over. The cylinders measure 4" exactly. World products S/R Torquer 67 cc heads, Comp cams XE268, edelbrock performer intake, I just ordered some Thorley tri Y headers. The head gasket that blew out was part of a $30 summit engine rebuild gasket set. I guess I need a more durable one. What other info is needed to determine size and thinkness of head gasket needed? Any recommendations?