engine and drivetrain Trans mounts for a 5 speed conversion

[algon]

I am getting close to installing the engine and trans in my 71 and I'm unsure about the trans mounts that I have for the install. (see pics) They are new BMW parts (I removed the BMW stickers myself ) but I was wondering if they are missing something. My stock location 4 speed mounts have a captured plate and stud for attaching the cross member but these new ones don't. Do I just put a bolt in before mounting to the tunnel? Is that little pushed in tab to keep the bolt I'd use from pushing up?

I got these mounts with a parts car along with all the other parts for the 5 speed conversion so maybe the mounting studs like the stock ones got lost at some point? I am also running a Stahl header which is going to make cross member access a real P.I.T.A! Maybe I should just go with the 2002Haus horseshoe type conversion adapter - just hate to spend that much on the mount if I already have the means to use the stock type mounts. Also planned on leaving the stock mounts in place....thoughts?

algon

[couttsdesign]

Would you mind providing the part number for those mounts (if you still have it). I'm working on a crazy diesel conversion that uses a Toyota W58 transmission that I will need to make a custom crossmember/mount and your parts look perfect for my application.

But to answer your original question, IMO it looks pretty straight forward...the two small holes bolt to the transmission tunnel and the larger hole with the adjustable slot is where you mount the transmission crossmember. I would probably put piece of plate steel on the inside of the car if you in fact plan on bolting the mount to the transmission tunnel. Best case would be to weld the mounts to the tranny tunnel.

If you plan on buying the 2002haus mount I would be interested in buying your mounts. Thanks and please post a pic when you get it figured out.

[jimk]

The cross member hangs from the mounts with the bolt to the crossmember pointing down. I cut a small square plate for the bolt head to rest on to increase he bearing area of the bolt head on the mount.

[algon]

No I understand how they mount and all.

What I'm asking is if anyone here knows if these over the counter BMW trans mounting tabs are complete or is something missing? Were they supposed to come with a special cross member mount bolt (like a"T" bolt) or do you just use a regular grade 8.8 M8 ? Also wondering if anyone here has left their stock 4 speed mounts in place or do they need to come off for clearance?

By the way the part number on the bracket was 41 121 808 830

algon

[M3M3]

they are complete. just use regular bolt.

i cut my original mounts off. they made getting tranny in and out more difficult.

[jerry]

there's no need to remove the original mounts. i leave mine intact.

[algon]

Think I'll make a set of "T" bolts to do the job. Looks like it will be a little tight with the exhaust there and all. I don't like the idea of having to fight getting a wrench up in there to hold the bolt while tightening the nut. A "T" bolt will also be able to slide front and back in the slotted hole making lining things up easier. I'll post pics later. Thanks all for the input.

algon

[M3M3]

no need to get a wrench up there to hold the top of the bolt. there is not much space in there...all you have to do is jam a big screw driver between the bolt head and the bracket and it keeps it from turning. ez.

[allbim]

You can leave the original mounts in place. I just did the same thing a week ago. I don't know about the tabs, I made my own mounts. I think the u-shaped cantilevered cross member is a bad idea as the original mounts are not designed for the bending load it causes.

[algon]

So I made up a couple of M8 T bolts and bent the retaining tabs over to hold them in place. Also drilled out the holes for M8 mounting hardware....

[algon]

(nt)

[M3M3]

nice.

noticed the mounts are same height as stock ones. did you measure the location height or put the tranny in and mark where they need to be? that stock height did not work in several of the 5spd conversions i have done. all had to be higher than stock.

[algon]

nice.

noticed the mounts are same height as stock ones. did you measure the location height or put the tranny in and mark where they need to be? that stock height did not work in several of the 5spd conversions i have done. all had to be higher than stock.

Actually I clamped a straight edge to the bottom of the stock mount and placed the new mount on top of that 3.5" further back as was outlined in a 5 speed conversion manual I have been following. This made sense to me as the added OD section of the 5 speed is 3.5" and using a straight edge would keep the slight downward angle that engine and transmission had stock. But in answer to your question no I have not yet test fit. Plan to soon as I can get some time off. If its wrong I'll either move them or use shims as necessary. I have also built a drive shaft alignment tool like ones that have been used by folks here in the past. You've done a few then I take it?

[eurotrash]

After having watched these conversations for years, and watched the various methods and trans mounts used, as well as having used this type of mount in my own conversion (measuring down the proper mm from the frame rails), here is what I am thinking..

Has anyone who has used the method of running rails from the stock mounts to the center bearing mounts had guibo issues?? Will someone ring in with an honest answer? I like this concept, if the end product is actually spot on when it comes to guibo alignment. We all know the ins and outs of this 5 speed conversion, most eating guibos, or having clearance issues with the shifter mechanism... we just don't like to brag about the issues as much as we rave about the 'awesomeness'. The fact of the matter is, for most, its an imperfect 'upgrade', and we live with the drawbacks.. silently.

SO, If the answer to the above question comes back, or were to come back as it being a sound technique (mechanically. - although less than sexy), then it suggests that one could use the method of running a rail between the mounts and using this rail to properly locate the bolt-in tabs that the OP is using.

Considering that the end goal is to have the centerline of the trans output shaft and the center of the carrier bearing in line with one another, essentially making the driveshaft an extension of the output shaft.. this seems to quite possibly be the best boiled down method of installing the BMW or MASSIVE bolt-in mounts.

This all in theory of course... as brain exercise and conversation. But it makes sense.

nice.

noticed the mounts are same height as stock ones. did you measure the location height or put the tranny in and mark where they need to be? that stock height did not work in several of the 5spd conversions i have done. all had to be higher than stock.

Actually I clamped a straight edge to the bottom of the stock mount and placed the new mount on top of that 3.5" further back as was outlined in a 5 speed conversion manual I have been following. This made sense to me as the added OD section of the 5 speed is 3.5" and using a straight edge would keep the slight downward angle that engine and transmission had stock. But in answer to your question no I have not yet test fit. Plan to soon as I can get some time off. If its wrong I'll either move them or use shims as necessary. I have also built a drive shaft alignment tool like ones that have been used by folks here in the past. You've done a few then I take it?

[algon]

I agree - bottom line is that the Guibo alignment has to be correct. That will be my determining factor. I did not use the carrier bearing mounts as my guide but the original 4 speed mounts. I will take a longer straight edge to it and see if the trans mounts align with the carrier bearing mounts. Good idea euro!

algon