Small Block & Big Block Chevy Specific - Need an opinion SBC

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THIS PLUG HAS ABOUT 30 MILES ON IT!

350 SBC
I have had trouble with cylinders #2 & #4, they fire but not all the time. I can glass bead the plugs, reinstall and they work better. I looked at the intake gasket and it looked good. I do have molly rings and may have not treated the cylinder walls correctly before installing. The engine has about 8k miles.

What do you guys think?

Same problem i had with mine, turned out to be the valve stem seal was bad causing oil to leak into the cylinder. Looks that same as mine did when i tore my heads off.

yea i agree with him^^, i wouldnt think it would be the rings since none of the other cylinders are having any problems, did this just start happening all of a sudden or had it been goin on since you got it running?? i think its eatheir worn out guides or your valve stem seals are not sealing, what heads are you running???? you didnt by chance do a compression check before you pulled the heads off did ya?? that will tell ya if its rings or not, and usually if its rings the cylinder walls will look scored up compaired to the others.

If you have screw in studs you should also use some thread sealer for the studs going into the intake ports. They can suck oil through there as well.

If you have screw in studs you should also use some thread sealer for the studs going into the intake ports. They can suck oil through there as well.


+1 :judge:

If you use Felpro MLS intake gaskets nothing getting past those, the thread sealent is mainly used to keep oil from coming out top of the bolts and setteling in the manifold.

..and it looks like youve burned a little coolant in the 4th cylinder, what head gaskets did you use?

I did get the valve springs off and didn't find a problem, the seals were tight and soft. I think the intake was sealing fine and the valve seals were good as well. The fact I used molly rings may have been the biggest problem, well maybe not. I took a look at the bearings and they are not doing well. The engine is second hand and has had bearing issues prior to today. I have a pull type clutch and dusted a set of thrust bearings about 10K ago.
I think I will have the heads inspected / reground and look into a short block built by a pro. I haven't removed the pistons yet but might tomorrow.