Delanoso's 2.9L Build

[ForcedFirebird]

not sure that is correct

http://www.new-part.com/product/bmw-...kshaft-1432277

is the pan off?

That site is pretty obscure for reference.

Adam (skifree) has measured and cataloged a lot of crank casting numbers, I would trust him over "new-part.com"...

https://adamsautosport.com/information/tutorials/bmw-m20-ultimate-street-stroker-engine-checklist/

Also these list them as "x28i":

http://www.athousakis.gr/en/product/crankshaft-bmw-1432277-9165/

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2322090.m570.l1313&_nkw=Crankshaft+%2F+1432277&_sacat=0

EDIT: ...and just realized I have one sitting here at the shop with the same casting #:

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/9934671-the-things-you-find-2-8l-cranks

Top row in the pic, the modified crank is definitely 84mm.

I also have a 1748751 and 2242898 sitting here.

[digger]

Yes we have, 1432277 was on the crank and it's very definitely blue, which makes it forged as opposed to cast. My research shows that the the m50 cranks were cast so it would have to be the M52B28 or an M54 bizzarro. Correct me if I'm wrong - obviously, I seem to be wrong more often than not with this motor.

not sure that is correct

http://www.new-part.com/product/bmw-...kshaft-1432277

is the pan off?

[Delanoso]

Have we confirmed that it is an 84 mm crank? The balancing pads on those rods look huge compared to the M 42 world from which I come.

Yes we have, 1432277 was on the crank and it's very definitely blue, which makes it forged as opposed to cast. My research shows that the the m50 cranks were cast so it would have to be the M52B28 or an M54 bizzarro. Correct me if I'm wrong - obviously, I seem to be wrong more often than not with this motor.

Now that is concerning if they told you they used m52 rods - the m52 rods are significantly lighter, not that there would be a power difference, just would help the rev up speed.

I *was* sold the M52 rods and I've busted his chops about the M20 rods that show in the picture - he agrees that they are after looking at them again.

Also, Just sent you an e-mail.

[ForcedFirebird]

Ah, after being here at work with rods all over the place, yes, those appear to be m20 rods, but have wide shoulder for the bolts, and rounded edges? I have some early m50tu rods here that have a small square pad, then some s50 rods that have almost no pad on them.

Now that is concerning if they told you they used m52 rods - the m52 rods are significantly lighter, not that there would be a power difference, just would help the rev up speed.

[digger]

I am aware of that. I'm referring to the physical size of the balancing pad. The 2.8 Tu rod has a much smaller balancing pad when you Google up a pic. That pad looks like your normal M20 or early M50 on the photos I've found. Just trying to confirm it has the correct parts.

apologies, yes those look to be m20 rods. its not clear if the OP was sold 24V rods or whether he assumed as such.

while the pan is off he can measure the stroke fairly easily (or atleast the distance from the bottom of rod when at BDC to the oil pan flange or some other datum and i can measure the same on a known 84 mm crank here)

at BDC the very bottom of rod should be 22 mm below the block where oil pan gasket fits if it is a 84 mm stroke

i.e. crank throw + cap height - crank C/L to pan flange

= 42 + 40 - 60 = 22 mm for 84 mm stroke

or

= 37.5 + 40 - 60 = 17.5 mm for 75 mm stroke

[e30sh]

the balance pads having nothing to do with the crank or its balance. the rods are balanced against each other and nothing else so you can chuck a set of matched rods and not need to rebalance anything. its an inline 6 with balanced primary and secondary forces

I am aware of that. I'm referring to the physical size of the balancing pad. The 2.8 Tu rod has a much smaller balancing pad when you Google up a pic. That pad looks like your normal M20 or early M50 on the photos I've found. Just trying to confirm it has the correct parts.

[digger]

Have we confirmed that it is an 84 mm crank? The balancing pads on those rods look huge compared to the M 42 world from which I come.

the balance pads having nothing to do with the crank or its balance. the rods are balanced against each other and nothing else so you can chuck a set of matched rods and not need to rebalance anything. its an inline 6 with balanced primary and secondary forces

[digger]

I'd disagree though, that there's nothing to suggest I didn't get the parts I requested. 160whp is significantly below anyone's estimate based on the parts we used so I didn't get something I paid for, which means it was worth it to verify.

i guess what i mean is that with a better tune lets say it makes 170 whp that's about what i expect. My metric mechanic based stroker (11:1 286/272 Rally cam ,ported head, 3.1L made 185-190 whp on stock manifolds and motronic first dyno iirc)

a true proper port job is worth a lot but the average head guy is mostly prettying things up and little else except in the case where the head is just garbage e.g. old pushrod cast iron job from 80's/90's which is not the case with the stock m20 885 head.

[ForcedFirebird]

...ForcedFirebird, what's the best way for me to get in contact with you? I'm willing to pay for the tune and time you can offer so that I'm certain I've got the right set up...

Missed this. Email is in signature: John@m20guru.com. Can call the office, but I am usually out in the shop hands-on (check voicemail daily): 954-786-3100

[ForcedFirebird]

Have we confirmed that it is an 84 mm crank? The balancing pads on those rods look huge compared to the M 42 world from which I come.

Rods look like any other m5x rods I have come across (aside from s54, they are quite tear-drop-shaped), and that crank appears to be a forging with it's blue tint. If you think those rods look beefy, check out m20/m50nv ;)

[e30sh]

Have we confirmed that it is an 84 mm crank? The balancing pads on those rods look huge compared to the M 42 world from which I come.

[ForcedFirebird]

The stock ECU with the 2.7 made something like 164whp and went up to 172 with a custom chip. So, the stock ECU with stock injectors should run your car at minimum, and probably won't be far off from adding a custom chip. As digger said, doubt the tune will be the magic bullet, unless the chip you have is really botched. Before spending any money, put the stock stuff in and see if any changes.

[Delanoso]

OK, so now just feel dumb because I can't make sense out of your the stock ECU suggestion. 8whp down from modified mapping meaning a remapped Motronic? Which would mean I'd see an increase from what I have now?

[ForcedFirebird]

Look for an "84" stroke mark on the crank. M20's have 75 or 81 on them...I assume the 2.8's have them as well. Someone chime in if they know for sure.

84mm and more do not. Easy way to spot a 75/81mm, though. For the larger cranks, you must use the casting numbers for identification:

https://www.r3vlimited.com/board/for...nd-2-8l-cranks

[ForcedFirebird]

If you think it's the tune, just stick a stock ECU and injectors in it and note any changes. The stock ECU ran our car no problem, it was just down about 8whp from modified mapping. If the stock ECU is still lacking, then there may be a mechanical issue.