[gilby246]

First of all forgive me if Im posting in the wrong section. The original thread I started was posted under valve noise but it’s kinda moved off that subject.

I just finished restoring my 70 chevelle but hadn’t yet built an engine for it. I had a known running 350 sitting in my garage left over from a previous engine swap. Has roughly 120k miles on it and figured I would give it a cam and throw it in the chevelle till I built the 400 I have just the way I wanted it.

The 350 ran great for about 200 miles till I switched from the stock 76cc heads to a set of 62cc camel humps. The combustion chambers of the camels have been ground out a bit so exact CC is no longer known.
Roughly 50-70 miles on the head swap it started fouling plugs due to excess oil in the cylinders. First only a few now all of them. The heads were checked out by the machine shop and were fine. It has a new intake, gaskets, bolts and was torqued to spec
My theory is that due to the increased compression I toasted the oil rings, there is now blow by and pressurizing the oil pan, then sending oil back up into the cylinders….A compression test on 4 random cylinders yielded 160 psi. seven new plugs completely dripping with oil within 15 minutes of idling...

Question one - Does this theory sound logical?

Question two - Do you think swapping back to my old 76 cc heads would eliminate this blow by just enough (if that’s the case) for another month or two till I can build the other engine… I would like to drive the thing and am willing to change heads.

Question three - should I just cut my losses with this 350 and go straight to building the 400. The condition of the 400 is unknown…it’s complete but has not been cracked open yet

[Henry Highrise]

Your theory is probably right. Only way to fix it is to put a set of rings in it.

[gilby246]

And that’s my dilemma..if this theory is correct

That is, to take the time to yank it out, and re-ring an engine I only planned on keeping for the summer.
Pulling it means new gaskets, bearings, bolts, and time.
Now Im not looking for someone to tell me what to do but am hoping to get some suggestions on the smartest way to go about this.

[red65mustang]

????? you don't need to pull the motor to do a re-ring

350 re-ring kit (bearings/gaskets/rings/etc) typical $100-120? at Autozone etc...look up your motor on their site and NAPA

[oldschoolrods]

you can probably re-ring the motor in the car, heavy truck engines are done like this all the time its called an inframe. Just pull the heads, drop the pan and go to work.