Squish Band Clearance on a 260

**hoop235** · 01-26-2018, 08:30 AM

I'm building my first 260 with C4 heads that have been cut to run on pump gas. I'm using ProMarine thin gaskets and when I checked my squish clearance, I'm somewhere between .035 - .038. (Play Dough is hard to measure! Lol)
Is this ok? Just checking while its still on the bench.

**patchesII** · 01-26-2018, 09:39 AM

That's pretty good. I wouldn't go any tighter. Using two pieces of soft solder opposing each other inserted through the plug hole is the better way to measure squish

**hoop235** · 01-26-2018, 09:55 AM

Thanks for the reply. That's a great idea! (I'm an old man, old school I guess. Lol)

**patchesII** · 01-26-2018, 03:35 PM

You can put them at 12 o' clock and 6 o' clock. Cut the pieces long enough that you can bend them over on the outside of the head and use a piece of masking tape to hold them in place while you use a breaker bar to rotate the engine over.

What gasket were you using when you measured it? On a lake engine I'd rather see .038"-.040" so you might consider a slightly thicker gasket

**hoop235** · 01-26-2018, 03:51 PM

Thanks for the info, that sounds like a much better way to check it and I really appreciate your reply.
I'm using Pro Marine thin gaskets.
At .038 the "putty" was very snug. At .035 it began to stretch so I figured that was the smallest it could be.
Motor will be on a small, lightweight bass boat. Looking to turn 7k-8k if I can figure out how all of this fuel injection stuff goes together! LOL!!! (Remeber, old man, old school)

**KIRCHNER** · 07-16-2018, 03:54 PM

I ALWAYS used kids clay 2 small balls perpendicular to wrist pin turn engine over slice clay with razor knife measure clay thickness with mic. i dont know if how merc measures advertised or compressed thickness. gm uses compressed thickness advertised.. i ran 0 deck w/ .032 gasket to 7200, steel rods .050 for aluminum.