2F rebuild. Where do I go from here?

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Sep 8, 2020
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Well, all parts back from various machine shops. Block bored .030, crank turned 0.010.

Problems im having that I dont know what to do are:

Crank oil clearances are 0.004" manual calls should be 0.0014/0.0018 in. Seems sloppy and im scratching my head as far as next steps.

Ring gap seems large as well at the service limits in the 2F manual.

Any thoughts, input? A V8 would have been easier and cheaper.
 
Joined
Sep 8, 2020
Messages
296
Location
WA
Well, all parts back from various machine shops. Block bored .030, crank turned 0.010.

Problems im having that I dont know what to do are:

Crank oil clearances are 0.004" manual calls should be 0.0014/0.0018 in. Seems sloppy and im scratching my head as far as next steps.

Ring gap seems large as well at the service limits in the 2F manual.

Any thoughts, input? A V8 would have been easier and cheaper.
Took a break and rechecked. I'm at 0.0025" to .003" on all mains. Am I splitting hairs here? Figured out of spec is no bueno.
 
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Oct 7, 2011
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.002 to .003 are fine clearances for these engines. Your oil pressure may be a little less than 60 psi, but I doubt it. Don't run the new low viscosity oils in the engine. The engines weren't designed for that weight of oil. Be sure to add a bottle of ZDDP oil additive to the oil before startup. Our gas today is missing the zinc and phosphorus that used to coat and protect the internals. What clearances do you have between your pistons and the cylinder walls?
 
Joined
Sep 8, 2020
Messages
296
Location
WA
.002 to .003 are fine clearances for these engines. Your oil pressure may be a little less than 60 psi, but I doubt it. Don't run the new low viscosity oils in the engine. The engines weren't designed for that weight of oil. Be sure to add a bottle of ZDDP oil additive to the oil before startup. Our gas today is missing the zinc and phosphorus that used to coat and protect the internals. What clearances do you have between your pistons and the cylinder walls?
I gave the machinist the FSM numbers : 0012"-.0020". Id assume they're going to be on the large end. This entire process has been weird. 3 different shops working on engine components, crank, cam, and engine were in different shops.

My ring gap is coming in on the large end as well. Think they're 0.022" which is on or over the FSM specs.

I understand this isn't a drag engine, i just want to do it right the first time.
 
Joined
Sep 8, 2020
Messages
296
Location
WA
I gave the machinist the FSM numbers : 0012"-.0020". Id assume they're going to be on the large end. This entire process has been weird. 3 different shops working on engine components, crank, cam, and engine were in different shops.

My ring gap is coming in on the large end as well. Think they're 0.022" which is on or over the FSM specs.

I understand this isn't a drag engine, i just want to do it right the first time.
Not that its related but the builder of a previous vortec SBC we built for a boat said don't run anything other than Kendall 20/50 high zinc conventional in it. Thinking this will be similar. Or run Brad Penn 20/50.
 
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Joined
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WA
Well, update, 0.030 rings are like hens teeth stateside. I was able to locate sets of 030 Nippon Piston Rings. Hoping they show up and fit. They actually have a lot of literature and info on the rings/clearances and install so thats promising since ITM has zero info. Crossing my fingers.
 
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