m20b28 rotating assy pics

[ForcedFirebird]

I'm bad at taking pics, worse at posting projects, but do my best to help the community. Snapped some pics for a mail-order client and figured why not share here.

[ForcedFirebird]

.5mm over 9.4:1 early Euro pistons on 130mm rods, 84mm crank, .5mm off the block. Will result in 10.4:1 with the added stroke.

[ForcedFirebird]

The pistons are early model, so long skirts need trimming.



Keep weights in check when taking so much off.

[ForcedFirebird]

A little off topic, but relevant since this is the first job it's used on. Never had my own rod balancing fixture, but my friend about a mile away does. Been meaning to purchase one, but they are pricey for what they are, so grabbed some scraps of aluminum from the neighbors bin, and some skateboard bearings I keep for the kids' skateboards - made my own. His uses chains and a hanging bearing, looked at other designs and went with pendulums. The chain system is kinda cumbersome. Once this one is set up for a rod length, takes minutes to weigh them, and the bearings are universal, so the rod can be flipped easily on the scale.

[RobE30]

Awesome man!

[digger]

dumb question, some of those slugs say 84.48 and some 83.98?

[ForcedFirebird]

dumb question, some of those slugs say 84.48 and some 83.98?

Yessir. Sorry, mix of builds. Some are over sized pistons.

[digger]

phew, whats the availability on the 9.4:1 slugs? i thought they were NLA like the 9.8's?

[ForcedFirebird]

phew, whats the availability on the 9.4:1 slugs? i thought they were NLA like the 9.8's?

NLA, but managed to get my hands on a few sets. Some are +.5mm.

Fired up the lathe today. Been meaning to make oil pump drive bearing installation drifts. This tool will install the rear bearings in a snap. O-Rings hold the bearing centered, and the shoulder makes setting the depth a sinch. Copied the o-ring idea from my Chevy cam installation tool. Also plan on making one to install the needle bearings.

Now to make a drift for the front bearings....

[ForcedFirebird]

Finished the other drift and fixture today.




Use the long drift to center the jig for the outer bearing, then tighten bolts.




Mount inner bearing on the drift.

[ForcedFirebird]

Tap it with a dead blow to seat.


Perfect.

[McGyver]

I was reading this thread on bimmerforums where they mentioned you by name:
https://www.bimmerforums.com/forum/s...-gear-bearings

Will hot tanking the block really destroy these bearings? If so, would you be willing to share your tooling design sketches?

[2mAn]

Awesome!

[ForcedFirebird]

Some chemicals are safe for aluminum, but honestly the ones I've been taking apart lately have the copper layer showing anyways. If you are spending money on an engine, replacing these bearings are small change in the big pic. I have been replacing them for years without issue, but have never taken the time to make a proper tool to turn a tedious job into a 10min gig (take several hours now to save an hour each time). Normally I would use a bearing press tool kit and take the time to square them before burnishing. These drifts and centering jig make it super easy.

If anyone is interested in a tool kit, PM me. Thought about making and selling them, but how many people would really use them on a regular basis? Also have a mind to think the people who would use this tool would also be capable of making their own. :/

[digger]

add locating marks so its easier to get the gallery hole aligned?