My Pete rebuild

[Rawze]

(07-07-2018 )Nostalgic Wrote:  If I'm pulling the main bearings to wash out the passages, I might as well lift the crank out of the way, and if I need to do that, I might as well pull my new crank before any more machining. If apex wasn't sold out, I would have already purchased the tool at this point. It's NOT going back to the place that did this, and at the least, I better get a refund + cost of wasted shims.

When I dropped the first liner in (#6 as I was working backwards), I ran the gauge on a couple spots, and it was .013-.014. When it was compressed, then everything went to hell. Granted, my homemade press is not equal to the one you use - I can side load pretty easily if I'm not careful lining up my plate, but even in that case, I should see discrepancies showing high readings in spots and the lowest reading I should see would be .014 if it was cut correctly, right?

your liner compression tool looks to be as good as any cummins tool would be. Be sure to use a torque wrench and torque the compression tool to 100 ft/lbs. You should be getting a consistent measurements to 0.0005" variance or less. That is if whoever cut it is worth their salt and as long as the top of the engine block + all other surfaces are very clean and washed with acetone. Don't know about after-market kits but I have never seen any variation in liners themselves from cummins, nor a variation in shim thickness. BTW: the brass shims from cummins are "hardened" brass shims. I was not so sure about apex or others, so I go with OEM when helping someone here.

If I had had gotten a shim that was 0.021", I would have taken it back and demanded a new one. You should NEVER have to cut the block for varying length shims or incorrect liner sizes, it is bad practice. Assume the shim could have been defective (incorrect hardness, etc. -- I.E.> something went wrong during the manufacturing process). I would not trust it.

Start by pulling the liners out and measuring the consistency of the step in the block itself. Same thing, there should be less than 0.0005" if you want them consistent.

(These numbers should be valid for the CM870, CM871, CM2250, Cm2350-X101 engines) ...

A depth of 4.724" results in 0.011" with the new OEM anti-carbon liners (no added shims). - THIS Is TOO LOW!- and NOT recommended!.

An OEM shim of 0.020" and a depth of 4.741" results in 0.014" height. <- Acceptable.
An OEM shim of 0.020" and a depth of 4.740" results in 0.015" height. <- OPTIMAL HEIGHT!.
An OEM shim of 0.020" and a depth of 4.739" results in 0.016" height. <- Max height safely possible.

An OEM shim of 0.032" and a depth of 4.753" results in 0.014" height. <- Acceptable.
An OEM shim of 0.032" and a depth of 4.752" results in 0.015" height. <- OPTIMAL HEIGHT!.
An OEM shim of 0.032" and a depth of 4.751" results in 0.016" height. <- Max height safely possible.

-- This all assumes your measuring tools are calibrated and measuring practices are accurate + consistent. At 4+ inches depths, I have been bitten by digital depth gauges, so I use only trust a mechanical gauge when doing the counter-bore depth measurement itself. - Ask if whoever counter-bored it used a digital depth gauge on it when checking it.

Tags:

counter-bore depths, liner height, 0.015", 0.014", 4.724", 0.020 shim, 0.032 shim