Piston Problem

I'm new here so maybe you folks can help me. I pulled the heads off my 1970 Renegade with the 225 V6 and noticed that all the Pistons on the passenger side of the engine are .020 over and the ones on the left side are stock. Has anybody ever seen this before? and when I put the new head gaskets on is it going to be a problem driving it? I've driven it for about 10 years like that but.... just asking...
Thanks

 

reman assembly line work. Be sure to measure to be sure, not all pistons are marked. Ron

 

The right side of your jeep will be faster than the left side.

I knew a guy who had a brand new Dodge Hemi back in the 70's. He couldn't get it to run well until they discovered it had a hi-compression head on one side, regular on the other.

In your case, I doubt it will matter. But I'm no expert.

 

If you hold the throttle just right it will help balance out the tendency of Jeeps to lean to the left.

 

Looking at the firing order for the 225 Odd Fire you will see it fires one side then the other. That being the case I doubt you will notice any diff.

Oh and welcome to the forum from Ga.

 

Reminds me of the old nascar trick to fool the rules the first two pistons were stock size because thats the ones they check and the rest were over bored.

 

We can get an idea of how different this is...

bore x stroke = 3.75 x 3.4 = 37.5518 cid per cylinder, 0-over
3.77 x 3.44 = 37.9534 cid per cylinder, 20-over
(37.9534 / 37.5518 - 1) * 100% = 1.07% displacement difference.

It's definitely different. Power is roughly proportional to displacement, so the over-bored cylinders are making about 1% more power than the standard cylinders.

I would guess this is less than the difference between the center and end cylinders, which are a different distance from the carburetor. The end cylinders are typically a little leaner than the center... that's just the way it was before MPI.

If compression were good on both banks, I'd run it.

Welcome from Boston.

 

In the FSM section D-1.1 the engine code number on the side of the block can tell you what oversized pistons were used when original. It only shows up to .010 over. If you have larger, someone may have bored that side. Why? Seems if you are boring one side, you would have done both sides, unless someone overheated it and galled a cylinder and did a bore to just one side. Just a thought.