m20b28 rotating assy pics

[ForcedFirebird]

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

Yup. Figure just a center drill to mark 12 o'clock on the ends of the drifts, and a center drill mark in the side of the shaft to show oil passage location.

Again, modeled this after my Chevy cam bearing installation tool, o-rings and all. I've had that kit for at least 20yr and installed 100's of bearings, figure this bit of kit should last just as long. Made it from t6061 aluminum drops - this just doesn't look as nice lacking anodizing.

[ForcedFirebird]

These are used bearing getting pressed in and out to prove repeatability. Galley location wasn't paid attention.

[digger]

are you rough machining to size before pressing new ones?

[ForcedFirebird]

are you rough machining to size before pressing new ones?

Impossible. The shafts are what dictates the bearing size. I literally have at least a dozen m20 bottom ends, and the shafts DO NOT go from one motor to another. Not sure what process was done or changed in the factory, but have done dozens, if not hundreds of m20 intermediate bearings. For some reason, the bearings are burnish to fit, vs having a boundary layer like a cam in a V8 pushrod engine.

Not sure how to explain it, it just is what it is. Crazy too, because BMW did so well with colored bearings on the crankshaft, but left the oil drive to the wind.

[digger]

Peerless who did a write up on e30tech said he machined them on the lathe before install and then honed to size to the usual journal clearance after installed.

The factory reamed them iirc

[ForcedFirebird]

Everyone mentions Peerless/Robert. Good dude, we had many conversations, even after he left the automotive industry and went into the health field about 6-7yr ago. Yes, we all chatted behind scenes, just like tuners do. Honestly, he told me about his drift kit, got jealous, said "I can install these", but did it by hand and measuring tools. This makes it a no-brainer. Hats off to Robert, aka e30MotorWorks. Miss ya man.

[whodwho]

I like it!! How about a little line bore setup to go with it now 8^)

Was crazy(but great) to see him get all in fit shape! Miss going to his annual BBQs 8^(

[ForcedFirebird]

I like it!! How about a little line bore setup to go with it now 8^)

Was crazy(but great) to see him get all in fit shape! Miss going to his annual BBQs 8^(

Unlike caps (main, or rod) these should never need to be line bored. All the casting had to do is hold the bearing tight, the boring comes from the burnishing final process...unless you are referencing a line bore in the bearings after install? That's a great idea......more work.....

[digger]

yeah i think he means the two bores need to be concentric, iirc the factory reaming tool was a dual sized reamer done in one op.

[whodwho]

Sorry yes for finishing the bearings. Would be more accurate then hand reaming but I guess you could make fixtures to hold the reamers as well.

[ForcedFirebird]

Thanks for the ideas. Went ahead and picked up an adjustable reamer, 1.344"-1.5" ($$$) to see about "maybe" making a one-operation tool. Worst case, it will be two operations, and plan on making a squaring fixture to hold the reamer(s).

[whodwho]

Nice, I will be watching for updates 8^)

I have had one on my watch list for a while but haven't needed it yet

[ForcedFirebird]

Nice, I will be watching for updates 8^)

I have had one on my watch list for a while but haven't needed it yet

May be a bit. After a lot of thought, pretty sure a tool post grinder build will come before making a stepped reamer. Might be able to pull it off in the Toolmaker surface grinder, but would be stuck using a rotating collet. I feel it would be better suited on a lathe with a post grinder. Plus I can make valve guide pilots in house with a green wheel. Purchasing carbide valve guide pilots is very expensive compared to round carbide blanks (about 150x less).

Making up a plan to make a fixture to allow this process to be done in one's garage, and rent them out to fellow m20 enthusiasts. Think if the locating dowels for the front crank seal housing and/or oil pump mount holes, then a square jig can be bolted to the block and be really close to parallel of the crank mains. I am shopping for a block boring setup, so there will be tooling and a fixture setup to pop these out in-house, but it's not along the ultimate goal of this little side project. :)

[ForcedFirebird]

Left r3v for almost 2yr, and no-one wants to talk about the interesting/technical stuff. :(

I sold several installation tools, and am now making bearings from bronze since they have been NLA (outside NOS) for over a year. I really don't forsee BMW making any more, either. Such a small market. :(

https://www.r3vlimited.com/board/forum/e30-classified-forums/for-sale-wanted/parts-for-sale/10054997-m20-intermediate-bearings-upgraded#post10055001

[hasa]

I’m interested. Technical postings are best, and sharing knowledge!