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So searching for BMW M30 mains, I find that it isn’t common to fix them domestically.
Oddly for cheap aluminum bearings I get a hit from Israel made “King” main bearings that seem to offer the dimensions needed. I also see Glycols offered that I suspect are more tradition steel backed design.

Neither would drop in especially the thrust, but the non-thrust (6 sets!) show some promise of fitting the air cooled case bore and water cooled crankshaft.

I realize that this maybe clip art or a brand (or reboxer) I have never heard of but I think this is it;
https://www.rockauto.com/en/moreinfo.php?pk=4806156

Not sure what to make of the oiling groove, is it normal for cranks held by caps to only oil from the block side?

Yeah

...They want the higher loaded side fully supported by oil film/max surface area.

Hi, I came across this thread by accident.

I had a Laurie Pettit wasser crank/t1 case conversion.
It was very mild so after a while I rebuilt it. It had the later thrust bearings and notches to stop them spinning. I don't remember exactly which were which but to replace the mains I needed one set of type-1 bearings, 1 set of type-4 bearings and the wasser thrust plates. There was also 1 extra thick shim as described above. No BMW bearings. Hope this helps someone.

It's a great conversion, eliminating thrust case wear and providing the best VW flat four crank and a type-4 flywheel. Mine revved smoothly off my 7,000rpm clock without being dynamically balanced.

Annoyingly, this is the only photo I have of the crank in the case.

Ignore the crazy case clearancing, Laurie wasn't at his best and retired shortly after.

Found another, even worse!

Thanks Zed for insight, it is great to hear from someone that has figured it out.
I don’t know what use a type-4 #1 main could be used with the late wasser thrust plates, as both provide the thrust surface
Looking at your first picture, that sort of looks like the later wasser #1, I am now wondering if the solution is to by a set late wasser mains and adjust it down width wise.


Well I got a set if ITM BMW bearing, they sort of look like the clip art, but both sides have a groove on the crank side. To my surprise they don’t feel like cheap aluminum backed, more like old elephant k&S, and a magnet sticks.

sideshow wrote: ↑Wed Sep 26, 2018 5:06 pm Thanks Zed for insight, it is great to hear from someone that has figured it out.
I don’t know what use a type-4 #1 main could be used with the late wasser thrust plates, as both provide the thrust surface
Looking at your first picture, that sort of looks like the later wasser #1, I am now wondering if the solution is to by a set late wasser mains and adjust it down width wise.


Well I got a set if ITM BMW bearing, they sort of look like the clip art, but both sides have a groove on the crank side. To my surprise they don’t feel like cheap aluminum backed, more like old elephant k&S, and a magnet sticks.

I've been hunting for more info bit no joy. I can tell you that I didn't adjust any bearings when I replaced them, I'd remember that. Would it make sense if one of the other type-4 bearings was used between the thrust plates? I have a vague memory that all the machining was on just that one? If the sides were cut for the thrust plates the width would have been adjusted to suit whatever bearing it was he used. I also remember he'd cut a fairly long wide channel around the bearing saddle to get oil to the bearing as the holes didn't line up antwhere near. Probably 120° out of line.

I hate to be the one to revive an old thread, but this concept intrigues me. Can anyone itemize the definitive bottom line? Bruce provided the p/n for the crank seal SKF CR75x90x10HMS5V. Can anyone give a 100% for the number 1 main bearing? I know 2,3,&4 are typical T1

Thx
H2OSB

I wish somebody would update this also, as after I scored the bmw mains I looked around and discovered the only std case I had was turned into an engine (w/standard one screw crank)...So I have a new case on order.

Tells me about the mains and what's needed to make them work.

H2OSB

I suppose you could have the case cut for the t4 main... would probably need a split thrust shim as IIRC the t1 case is thinner.

I personally wouldn't bother on a mag case, but it might be a ~reasonable way to save one with a jacked up thrust.
(for some definitions of "reasonable")

It would be well worth paying // having it done by someone who knows wtf they are doing.
Cases aren't free these days. Nor is machine work.

Sorry for bringing back an old thread, but as I move slowly forward on my T4 build, and lament the cost, I always drift back mentally to just building a T1.

Something occurred to me, and there MUST be a reason this isn't done, but for installing a 1.9 or 2.1 WBX crank into a T1 case, why not have the no. 1 main machined from the 60mm T4 size to the 55mm T1 size? Then simply use all T1 main bearings? Do I have something backwards there?

H2OSB

The five screw flywheel holes are in the same area a T1 as crank journal expects an oil film. Well that and bore spacing

As you lament the cost, figure how much adding 30% more cooling area, greatly improved oiling, and a pressure die cast aluminum case to your t1... 2 of those 3 really desirable features are not actually things with a T1..

If you had simply stuck the 1700 back together you would have been driving it for a couple years....