engine and drivetrain How Much Adjustment Is Built Into The Engine Mounts?

[thehackmechanic]

In my 5-speed installation blog, I detail how my transmission is pretty far to the left, forcing me to move the center support bearing unnaturally far to the right to get the driveshaft aligned with the guibo. I did, and thought that was that, but my slave cylinder is hitting the tunnel. So I'm re-examining the root cause.

 

I was always under the impression that the engine mounts aren't really adjustable. The left mount is the one that slides into the vertical slot in the subframe (the one that cracks). That can't really be adjusted for left-right bias. The right mount has the J-shaped metal piece that can be adjusted to prevent the engine from rocking forward, but neither the bracket the mount attaches to at the top, nor the holes it sits in at the bottom, is oblong, so it doesn't seem like there's independent adjustability there.

 

Is this correct? Is the only adjustability of the twist of the engine obtained by moving the back of the transmission on its support bracket, and to have the engine slightly stretch the mounts in response?

 

--Rob

 

 

 

[M3M3]

correct.

 

did you beat on the tranny tunnel enough for the clutch slave?

 

your setup/alignment sounds exactly like mine

[jimk]

 

Is this correct? Is the only adjustability of the twist of the engine obtained by moving the back of the transmission on its support bracket, and to have the engine slightly stretch the mounts in response?

 

--Rob

You got it!

You gonna have to drive into a lamp post to tweak the chasis it you want to change the alignment!

Edited December 2, 2013 by jimk

[thehackmechanic]

Thanks guys.

 

Marshall, yes, I beat on it, but not enough, and not in exactly the right spot. Today I dropped the slave, levered the trani over to one side, and did some pinpoint beating with a sledge hitting a thick wooden dowel positioned on the offending spot. Then I jammed a 2x4 into the general area and levered it over. Both actions gained me a bit more clearance for the slave. 

[dbmw2002]

did this solve the alignment issue or just make it fit better? Any chance the left chassis part of motor mount was bent slightly on install, it dosent take much movement to show up as a inch at back of tranny, had a engine move and eat the raditor and still am pondering mounting issues 

[allbim]

There is always some clearance in between bolts and holes. If I were you, I would loosen all the engine mount fasteners, wedge the end of the transmission over and tighten all the fasteners while the wedge is in place. 

[Emyers]

Rob,

  When I rebuilt the current engine some two years ago, upon reinstallation, I too had some alignment issues.  I solved mine by loosening the mounts, motor and transmission, then gently rocking the motor by grabbing the cylinder head/intake manifold allowing the motor to "settle".  Then tightened up all the bolts.  Worked for me. 

Earl

74 02Lux

02 M Roadster

72 Volvo 1800ES

[TobyB]

I am a big fan of just levering against the transmission once it's in there.

 

Yes, you whallop it with the BFH first, but yes, never exactly right.

 

So then, once you find out what you REALLY need, wedge things against other things

and push.  With strategic intent.

 

Viola.

 

t

[thehackmechanic]

Good lord what a pain in the butt.

 

This post will serve as the coda to the epilogue in my 5-speed installation blog.

 

On my car, the guibo alignment is a worst-case scenario. Vertically, the back of the transmission needs to come up higher, but it can't because the car has a triple-core radiator and the extra width of the radiator is causing the fan to hit the top of the radiator if I raise the back of the trani up where it needs to be. So, instead, I have to drop the center support bearing. I now have four washers and a 13mm nut between the underside of the center support bearing and the body of the car. I haven't measured it, but it's got to be at least 3/8". Rather a lot.

 

Laterally, the back of my trani seems to want to be pretty far to the left. If I shove it to the right, that shoves the right side of the fan into the radiator. I knew when I bought it that the car had been smacked in the front; it's obvious looking at the welds on the nose. I previously had to hit the inside of the right side of the nose with a small sledge and a well-placed hockey puck in order to gain the 1/4" of clearance I needed to put the triple-core radiator in. It seems that I really need more than that.

 

But it's not that easy. Shoving the back of the transmission over to the right opens up a gap on the right side between the guibo and the driveshaft flange. I've already put a notch in the center support bearing and pushed it literally as far to the right as it can go. The body of the CSB -- the big round part that holds the bearing -- is now up against the body of the car. It cannot go any farther over. So even if I had the radiator clearance to push the back of the trani to the right, there's no more movement available in the CSB.

 

I put it all back together, shook it around, and the left side of the trani is so close to the U-shaped bracket that it hits it when the trani is rocked around. I loosened the rubber trani mount, shoved it over to the right just a tad (knowing that that puts pressure on the guibo), cut a piece of rubber hose, and slid it on the left between the U-shaped bracket and the body of the trani. I'll drive it around a few hundred miles then take another look at it.

 

None of the other 5-speeds I've done have been nearly this persnickety. 

[TobyB]

...the E21 radiator is nice and thin, and works just fine...

 

 

 

the coda to the epilogue

Would you please postscript this???

 

heh

 

Something sounds fishy, though.  That much misalignment isn't right.  Yes, the transmission corner will bump the tunnel when

it's close to right, and yes, getting the exhaust to miss everything is a trick. 

And a little bit of misalignment on the Guibo is ok- how much is really an open question, of course.

 

Could the nose be REALLY off? 

 

t

[thehackmechanic]

Toby, I know everyone has their preferred approaches, but the idea of introducing plastic into a 2002s cooling system... just... drives... me... nuts....

[Emyers]

Toby, I know everyone has their preferred approaches, but the idea of introducing plastic into a 2002s cooling system... just... drives... me... nuts....

Rob,

 Use the early 320i rad 1977-1979  all brass/copper like the OE in the 2002....I have been running one for years.

Earl

[Hans]

Dumb question, but what happens if the rt side mount is put in backwards?

Edited December 4, 2013 by Hans

[rms_sandiego]

it sounds like you are having exactly the issues I am with my ongoing 5 speed install on my '69.

 

From my perspective the real issue is that the case of the 5-speed is very assymetrical (with much more on the left side and in order to get a relatively straight line between the crankshaft, the actual centerline of the tranny, and the input of the differential (and therefore the center bearing), the back of the tranny really has to be shoved way over to the left and that leaves the assymmetrical case right up against the left side ot the tranny tunnel.

 

I took the approach of using new brackets bolted on rather than the "U-bracket" to support the back of the tranny and was glad (more or less) that I did. In order to get the tranny far enough over to line things up, I had to cut out the old left side bracket as the optimal position for the tranny had the case up against the bracket. I I started with a straight car and an engine and 4-speed that had all been in line and didn't remove the engine, so the alignment issues are really all involving the position of the new 5-speed tranny. I might have been able to use the U-brackets but I tend to think the bracket itself would have gotten in the way. 

 

And as you and Toby both imply, there needs to be a lot of walloping with the BFH to get the right clearance for the slave. I thought I had enough on three separate attempts but after finally getting everything lined up for what I thought was the last fitting and driving for a bit, I am getting a little hitting of the slave against the tunnel and am going to take the tranny out one more time for some more hammer blows where the very back edge of the slave is against the tunnel. I would love to just lever it over, but I don't want to push against the very back end of the slave cylinder.

 

Having said all that, I do really like overdrive in 5th, and once I get the IE exhaust fitted so that it doesn't bang into things (I am going to replace the center section with something thinner), I think it will be perfect.

 

That's my story and I'm sticking to it.

[M3M3]

Dumb question, but what happens if the rt side mount is put in backwards?

nothing...it is symmetrical.