Different head gasket question??

[10drum]

Greetings,

Ok, The driver side head gasket has been leaking oil out the back for awhile now. I originally thought (hoped) it was the intake. I replaced the intake gasket and was able to clean the back real good and now I'm sure the it's the head gasket. The truck has a 307 with low milage but sat for many years. I've pulled the head on the drivers side and see where it was leaking out the back, probably did it since new. I bought a top end kit and it had both head gaskets and all the others because it was cheaper than just one head gasket and the intake kit. The kit has a fibre faced gasket which is thicker than the original steel gasket. The passenger side is fine I don't want to disturb it.

Here's my question:

Will the thicker replacement gasket affect the compression enough to cause a problem? the original is .0275" thick and the replacement is .045".

This may be a stupid question, but keep in mind I'm a British motorcycle guy and head gasket thickness on those critters is critical.

Thanks for all replies.

Phil

[davepl]

How would you get oil out of a head gasket?

I'd think it'd be valve cover or intake. Intakes are tricky and need to be done right, especially the china walls (end rails). You could prove it by adding blacklight dye and tracing it with a lamp. They sell it on Amazon, cheap like dirt.

That aside, you'll drop compression slightly yet increase the chances of detonation because you're opening up the quench area. Good thing is 307s could care less, they're low compression.

[10drum]

Dave that's exactly what I thought. The oil psi comes off right behind the intake, then just below that, under the top back corner of the head, in the block, that plug may be the source of the leak (I think) which shows up in the seem between the head and the block. I may try to get a photo of it posted. Thanks for the reply.

[10drum]

I hope this photo uploaded It may be the source of a leak that is coming from between the head and the block.

[davepl]

Can't hurt to pull and re-seal that plug. But you might still be chasing zebras instead of horses - intake leaks at the back can be pernicious. And everything goes everywhere; I thought I had a rear main seal leak but my local reputable shop showed me it was just an intake leak at the back.

Google around for how to lay down the bead of silicon and use no gaskets on the end rails, let it set for a day before putting it to the test.

Clean everything like your mom was going to make dinner on it, then add the dye, then run it for a couple of minutes and look for the dye. Problem is it can take time to show up but if you wait too long, you're back where you were at not being able to tell where it's from!

Before you use the dye, make sure it's really clean like I said - clean enough that you can wipe that whole area with a paper towel and have no oil come off. Then you can reassemble and let it run a bit and look for oil coming out. You might get lucky, maybe it'll just be fixed this time and you won't find anything!

[GRX]

Old hot rodder trick. After a good cleaning dust on some foot powder. Sticks better than baby powder, makes fresh leaks readily apparent, and is easy to wash off.