Delanoso's 2.9L Build

[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 ;)

[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

[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.

[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

[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]

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

[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.

[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.

[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?

[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.

[Delanoso]

I saw this post as well as a few others.

https://www.bimmerforums.com/forum/s...-Crank-casting

I feel pretty good about the number being correct.

[digger]

I don’t doubt the 84mm are those forging numbers but it maybe the case that the smaller cranks use the same forging but get machined differently. I don’t know if that is possible or correct but raising as a possibility. I have seen pics that suggest the m52b25 crank is actually cast so idk

[ForcedFirebird]

I don’t doubt the 84mm are those forging numbers but it maybe the case that the smaller cranks use the same forging but get machined differently. I don’t know if that is possible or correct but raising as a possibility. I have seen pics that suggest the m52b25 crank is actually cast so idk

All the 75 and 81mm cranks I have come across have "H75" or "H81" cast into them. The only way I have been able to identify (without measuring) the longer throw cranks is by the casting/forging numbers. It might be different in other countries?

[digger]

All the 75 and 81mm cranks I have come across have "H75" or "H81" cast into them. The only way I have been able to identify (without measuring) the longer throw cranks is by the casting/forging numbers. It might be different in other countries?

There are different 84mm versions but don’t know about others. I know the 75mm stroke were forged at some point it may be in the e90/92 only

[e30sh]

Did you verify bore? They didn't stick i pistons on e rods did they.? We know the rods are not the Tu rods you were supposed to get?