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Old March 12th, 2014, 07:04 AM
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Default Re: Blown head gasket vs. cracked block

Quote:
Originally Posted by Vern View Post
Ok, folks when I got my '66 (inline 250) there was lots of white smoke coming out of the tailpipe that I chalked up to bad gas and a messy carb. However, after only 20 mi on it, I found the crankcase is down a couple quarts and the rad is dry. Is there a good way to determine if I just need to replace the head gasket or if the engine is toast (cracked block)? The compression is pretty good and reasonably uniform across the cylinders. Ideas? Thanks!
In either circumstance you have to pull the head off for repairs. If you are going to do a head gasket and there is no obvious deterioration of the old head gasket when you take it apart then you will automatically get a mag test and or pressure test done on the head to look for cracks. I think the white smoke does point more to the head than the block.

There is always a risk that a bad gasket could fill up a cylinder with coolant after you shut off the engine and possibly cause severe breakage the next time you turn the engine over and it can't compress the fluid. If the engine still runs and starts okay you can guess that the leak could be going into the exhaust port as suggested already.

A head gasket leak on the compression side could also put a puddle on the ground and pressurize your radiator blowing coolant out the cap, possibly blowing a weak hose and or cause the water pump shaft to start leaking.

Depending on what you know about the engine history you could just have the head gasket/head replacement done but in my experience it makes sense to at least do rings and bearings along with that if not an even more complete rebuild.

Or maybe you have access to another good dropin engine.

Last edited by quest; March 12th, 2014 at 07:32 AM. Reason: missed word
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