Adamant1971

I'm rebuilding an 89, tolerance group 1 block.

Cylinders were re-coated (paste & felt), original pistons and rods.

I know the factory specs for the piston gap range. But my question is how tight should I go. Would .25 for the compression rings and .50 for the oil ring be ok?

I'm using Goetz 951 rings.

Thanks in advance.

Factory specs:

Top 0.20 to 0.40mm
Middle 0.20 to 0.40mm
Bottom 0.40 to 1.40mm

85euro928

Adam,
That seems to be on the low end of the spec but still within spec. The only advice I can give is after I finished doing my rings I read an article that explained the benefits of either smaller gap on the top ring or second ring to reduce blow by. I can't remember which it was, hopefully someone will chime in and clarify.

85euro928

Also rings will wear in quickly and the gap will increase.

Adamant1971

That was my plan, to gap them on the lower end of the range. So far the rings I have test fitted and measured are on the very tight side (with no adjustment) 0.15 to 0.20.

I'm also going to put all rings in one bore to find the respective sizes of each ring set, so hopefully I don't have to grind too much.

85euro928

Also if you're not familiar with start up procedures do a search. GB gave a detailed how to regarding rings, oil changes, etc.