My Pete rebuild

[Rawze]

(12-25-2021 )Nostalgic Wrote:  

(12-25-2021 )tree98 Wrote:  I don't remember seeing Rawze weigh all his parts when he did his rebuild. What am I missing?

I think Rawze reused his rods. I've never had a set of original assembled rods to use, they are not available new through Cummins, and buying RX's get you rebuilt rods that could have been manufactured over a 20+ year span.

The new block kit - the only way I could find to get a virgin block, comes with liners pre-installed, oil cooling nozzles & bolts, and dowels. The only advantage of buying a kit is that pistons would most likely all have the same date code and possibly vary a little less in weights. It would cost more because I would be buying new liners that I don't need.

And - I would still be faced with wide ranging rod weights.

Cummins is still producing new CM570's for export, but aside from snagging one of those on it's way out of the country, it's been pretty challenging to source all of the parts needed to make a brand new 14 year old model engine without going aftermarket.

well... at least if you precision balance it.. and get it right, then you could run it down the roads at its full 2700-RPM rating all day and not blink an eye about it. Of course, the bearing clearances for the rods/mains, would also need to be plasti-gauged too, (and all verified to be at 0.002" - 0.003") to ensure there is no variance in clearances, to help prevent any harmonics from setting in.

All the wrist pins bushings would have to be on the underside of the acceptance range too. Most already come this way from cummins when they are new if I remember right. matter of fact, the wrist pin bushing clearance it actually the absolute most precision, and critical measurement in the whole engine. The longevity of the engine depends on this very heavily, right along with raising of the liner heights above factory settings on an engine that has a lot of miles and is being rebuilt.

As far as machining some of the weight differences out of the rods, the outer shoulder (intake side) would be the best place for that. No way would you want to remove material form the center or any other part of it as it needs to hold up to 2,000 foot-lbs of torque without deflection otherwise.

just some random blabbering thought while enjoying my 3rd' beer, nothing more. I have never had to precision balance an engine myself, so its all just beer speculation.