Shimming main and rod bearings?? Am i crazy?

[twentyover]

Building a quasi hot-rod European Ford motor, a Cologne V6. Known in the US by displacemenst of 2.6, 2.8, 2.9, 4.0, and 4.0 SOHC.

I'm going to use a word not often heard in Pro-Touring- Budget. I'm using Clevite Michigan 77 bearings, and am finding clearance with standard mains is just a skosh on the high side- it's coming on about .003, 5 tenths over specification limit. Looked for .001 oversize mains to close it down to .002, but they appear to be unavailable.

I'd rather not cut the crank. I seem to remember hearing somewhere that people have shimmed the back side of a bearing shell to get correct clearance.

So am i nuts? (although that doesn't really have any relevance to the question presented.) Anybody done this, or have any recommendation how to close the clearance down a little, or should i just blow off the deal since I'm only out 5 tenths. All input appreciated, and will be considered, even if in the end i ignore it.


greg fast

[Vegas69]

I'd run it .0005 off before I'd backwoods it. It will cost you oil pressure but you can likely make it up with a thicker viscosity. If you plan to beat the snot out of it, it may not be the end of the world to build it a hair loose.


Brought back a funny memory. I once knew a guy that built a small block chevy and needed to tighten things up a bit. He used a hammer and a hard surface to "adjust" the bearing shells. Needless to say, it ran for a while. A short while.

[Che70velle]

Journal to bearing clearance is 0.001-0.0026 service limit 0.006
Mian bearing to crankshaft is desired:0.0008-0.0015 allowed 0.0005-0.0019

So, are you consistent with your numbers across the board, on all journals? You using plastiguage, or real tools?
Are you gonna run boost?

Biggest problems we have in America with the 4.0 sohc, is the rear timing chain giving up. That's the weak link on this engine platform. Make sure you purchase Melling timing components.

[twentyover]

Clearance is about the same on all of the mains. Used plastigage. The engine is the 2.9L variant. No boost.

[358Mustang]

.0005" isnt much, I don't use plastigauge much so I cant speak for its accuracy. .003" isnt too bad though, I would run it. That is pretty much what my motors are anyways. .0025"-.003" is about right for a race motor. What is the journal diameter?

[twentyover]

Nominal? 2.25 main, 2.125 rod