B230 bellhousing bolt pattern.

[HenrikGM]

Hi All.

I have rewelded a M5 E39 gearbox with volvo flange, to fit it to a normal redblock, and discussed the clutch options with KL, and got the feedback tht these always explodes due to poor alignment. Apparently it goes so wrong in the welding process that the gearbox is massively offset.

My original plan was to remill it flat after welding, and reposition the guide pin holes in the mill. That would ensure parallel and concentric solutions.

Now, i took the measurements off an old bellhousing using the digital readout on the mill, and the stock one is certainly not running true it seems. I would EXPECT volvo to have put the bolt patterns on similar circles, but that is not the case.

The 2 top blts run on 169,2mm from center.
The next two(going down on either side of the blot, run on 166mm
The next two, one of which is sharing the starter motor runs on 168,86 and 168,87mm
Then the first guide pin comes at 166,07mm and the second one at 165,49mm. Apparently the guide pins are not on the same bolt circle or at least not as well as all the rest of the holes.

The lower two bolts runs on a 167,36mm and 167,48mm circle.

So the guide pins are actually the biggest discrepancy here.

I have all the coordinates, and can post it here if someone is interested, but im concerned the data are not exactly spoton, or the bellhousing i used to grab the measurements from, was not particular well machined...Hmmm

Anyone with a similar measurement i could compare with?

How much misaligment must a gearbox/clutch assembly be able to handle without problems?

[OlavT]

Earlier I used to work With marine engines for 25 years . When we fitted "damper plates" and gearboxes on hight rpm units the Maximum runout was 0.1mm. Hope this helps.

Found this link, more or less the same tolerance. http://www.hurst-drivelines.com/files/G ... 15-09A.pdf

[HenrikGM]

Okay...
But this will mean either the volvo bolt pattern is seriously strange or the oem bellhousing is quite distorted. Thanks for the information.
Maybe i should measure a few bellhousings.

[HenrikGM]

Hrmmh...

Maybe im overcomplicating this.

The volvo blocks have the guide pins at different lengths from the crank center, some 0,5mm or so.

I milled the bellhousing flat so flanges are parralell now. Check.

Upon lineup in the mill i took new centers for the guidepins, and one is shifted 0,46mm, second is shifted 0,2mm to one side, meaning the gearbox will be misalligned 0,3something.

Trying to hit the ideal alignment is quite a bit of a challenge, as it seems like the blocks are also not the same. Apparently the 3 bloks i have are measuring some 0,25mm apart, so either volvo was sloppy with the tolerances, or this ws just acceptable.
Its strange if it was acceptable given the quite tight fit on the guide pins though....

Anyone that have measured a volvo bellhousing so i can cross check it?