From Boost to Reliable. M62b44 Swap!

[RobertK]

You're the first person I've ever known say that.

Yes, this discussion HAS come up before, and there are people who accumulate miles with stock pans without spacers and don't tear guibos up as could be expected.

I've seen a few in person. Without notching the pan the mounts people have been using maxes out the inner control arm ball joint angle. Yes you can drive your car like that but its a matter of time before it causes premature failure.

Our shop prefers to keep the suspension geometry as close to stock as possible because we know that it holds up 20+ years safely in that configuration.

That said we consider notching the pan to be a better solution to getting the engine into the bay mounted with the correct drivetrain alignment.

[JGood]

I've seen a few in person. Without notching the pan the mounts people have been using maxes out the inner control arm ball joint angle. Yes you can drive your car like that but its a matter of time before it causes premature failure.

Well, that's not true. I had full suspension travel and plenty of ball joint articulation with 20mm subframe spacers installed, regardless of the ride height setting on my coilovers (which can go pretty damn low).

The main impact it will have is on bump steer, and nobody that I'm aware of has measured the bump steer curve before and after the spacers to know what that impact will be. I do know that I had no more *noticeable* bump steer with them, but this is obviously subjective, especially on a street car.

Our shop prefers to keep the suspension geometry as close to stock as possible because we know that it holds up 20+ years safely in that configuration.

That said we consider notching the pan to be a better solution to getting the engine into the bay mounted with the correct drivetrain alignment.

What Will is saying is that it's possible that neither the subframe spacers nor the oil pan notching are needed to get the correct drivetrain angle, since it seems that nobody has measured to find out.

I can't say for sure what the proper engine height is for correct alignment, but I do know that without the subframe spacers that I used to run, or the notched oil pan / lower engine mounts that I currently run, my trans tunnel would need cut out and rebuilt to clear the 420g. That's enough incentive for me to keep the engine lower, regardless of the drivetrain angle, especially since I now have 20k miles on this setup without any unusual drivetrain wear.

[The Dark Side of Will]

Without notching the pan the mounts people have been using maxes out the inner control arm ball joint angle.

That's a bad side-effect of spacing the subframe.

Our shop prefers to keep the suspension geometry as close to stock as possible because we know that it holds up 20+ years safely in that configuration.

Yep, BMW did their homework.

That said we consider notching the pan to be a better solution to getting the engine into the bay mounted with the correct drivetrain alignment.

I'm not saying it should or should not be done.
I am saying that I have NEVER seen any numbers related to driveline alignment.

For example:
"Center of M20 crank bolt is X inches above/below reference" (reference could be a straight edge across the bottoms of the frame rails)
"Center of M60 crank bolt is Y inches above/below reference without subframe spacers and with stock pan"

I've never seen X and Y published anywhere, despite the fact that they are EASY to get during the course of the swap.

I have seen such for an iX, and would *probably* be the same for a RWD car.

Bad pics but i measured this way the M20 had theese measurments. (and this is how i mounted the M50 too)

34,3cm


9,9cm

[The Dark Side of Will]

Well, that's not true. I had full suspension travel and plenty of ball joint articulation with 20mm subframe spacers installed, regardless of the ride height setting on my coilovers (which can go pretty damn low).

The main impact it will have is on bump steer, and nobody that I'm aware of has measured the bump steer curve before and after the spacers to know what that impact will be. I do know that I had no more *noticeable* bump steer with them, but this is obviously subjective, especially on a street car.

Right; the spacers don't change bump steer... they put the suspension at a different point on the factory bump steer curve... just like lowering the car.

If someone is spacing the RACK up or down while not moving the subframe, that's a different story.

What Will is saying is that it's possible that neither the subframe spacers nor the oil pan notching are needed to get the correct drivetrain angle, since it seems that nobody has measured to find out.

Somebody gets it. :up:
Thanks.

I can't say for sure what the proper engine height is for correct alignment, but I do know that without the subframe spacers that I used to run, or the notched oil pan / lower engine mounts that I currently run, my trans tunnel would need cut out and rebuilt to clear the 420g. That's enough incentive for me to keep the engine lower, regardless of the drivetrain angle, especially since I now have 20k miles on this setup without any unusual drivetrain wear.

Interesting info about the 420G. Is the bellhousing area what would interfere with the trans tunnel?

I'm basing my estimate of "driveline alignment" on the idea that a swapper uses the ZF 5 speed which bolts straight to the stock mounts, thereby making sure that the trans output is right where it was stock. At that point, the only variable is how high the front of the engine is.
Someone who's changed to the 420G would have another variable in the mix, in terms of how high the 420G output is relative to stock.

[JGood]

If someone is spacing the RACK up or down while not moving the subframe, that's a different story.

That's also a necessity with the notched pan approach: Using an e36 rack, with no spacers below, and moving the upper tabs down, flush with the subframe. I'm sure it could be done with an e30 rack too, which would likely require the same thing, although you prob need to fab new lower mounts as well.

That was my experience, anyway.

Interesting info about the 420G. Is the bellhousing area what would interfere with the trans tunnel?

I'm basing my estimate of "driveline alignment" on the idea that a swapper uses the ZF 5 speed which bolts straight to the stock mounts, thereby making sure that the trans output is right where it was stock. At that point, the only variable is how high the front of the engine is.
Someone who's changed to the 420G would have another variable in the mix, in terms of how high the 420G output is relative to stock.

There are 4-5 spots on the trans that are about 2mm from the tunnel while the car is sitting still. I have some marks where contact has been made, so under load it must hit. Mainly up near the bellhousing.

The zf320 and g420 have the same output flange to mounting ear measurements, as far as I could tell (didn't get real precise with it). And my trans mount simply extends the mounting ears, it doesn't change the height. So in theory, the 420g doesn't change the alignment in comparison to the zf310, but it is larger, so it will be closer to the tunnel... Or against it, in my case. I'm sure chassis differences and chassis movement over 30 years will determine just how close it will be.

[JGood]

I just went out and measured mine. It's nearly impossible with the big radiator, btw. I laid a flat edge across the top of the frame rails, and measured straight down to the bottom the crank pulley, since I couldn't see the center. Got 7". Measured my spare crank pulley... 6" diameter. So 7-3=4".

That guys pic looks like 10cm. 10cm=3.94".

Can we put this topic to rest now? :)

[mattdk318i]

Ok, after some measurements this is what I got. Measuring with a 59.4mm tall level from the top of the frame rail pinch. NOTE: This is after i modified the pan on the M62. There is 1.125'' from bottom of pan to top of subframe. The camera angle is not in line with the reading, so within line of sight i got these measurements

M62: Im measuring 5.5''(13.7cm) from the top of the nut to top of the level

M20: Im measuring 6.375''(16.2cm) from the top of the nut to the top of the level.


So if we do the math, keeping in mind that the nut on the M62 is 28mm and the M20 nut is 22mm.

Center of M62 crank to top of frame rail is 9.16CM (13.7CM-59.4MM(level height)+14mm(center of crank)

Center of M20 crank to top of frame rail is 11.36CM (16.2CM-59.4MM(level height)+11MM (center of crank)

[mattdk318i]

Please feel free to check my math, as im sure you will. As others have mentioned, The transmission when i initially installed the M62 was hitting the top of the tranny tunnel. Not allowing me to install the trans brace. After looking at all of the side effects of the pan hitting the subframe i came to the realization that everyone else has with this swap.

The engine has to be brought down.

[JGood]

My notched pan is about 5mm from the subframe. So when you bring your engine down ~20mm like I did when I made my mount arms (to replace my 20mm subframe spacers), you'll be almost dead on with the factory m20 alignment.

Conspiracy busted ;)

[mattdk318i]

Mounts

Well, now that the pan is where i wanted it. I decided to go ahead and make the mounts. With the consideration to interference with the exhaust. And addressing the oil filter relocation.

After thinking about it, I decided to go ahead and make my own version of the X5/aftermarket mount that everyone buys, But i wanted this one to utilize the factory oil filter housing. The M62 doesnt have a whole lot of mounting potential towards the center of the block. Which left me with the idea for a "factory" type mount.

Knowing the location of the motor mount and the actual mounting position on the block, i knew it was going to have some cantilever action going on, Which i dont really want. But with using all of the factory bolts and mounting location i feel that it will be alright. There are probably a million other design options, this is just one that i decided to go with.

Afterall, this is a prototype. The mount will probably change before this is all said and done.

Driverside mount

[mattdk318i]

Driver side mount continuation

[mattdk318i]

I got the mount installed and im really happy with how much room i have for the exhaust. Didnt get any pictures of the mount in, but i will update later on. I made the bungs for the oil filter on the lathe.

Im going to try to find a more efficient way to attach the factory filter housing. For someone that wants to use just the bungs, I was thinking of just using a 3/8" pipe tap or a AN fitting adapter. That is just what i came up with for now. Obviously overly complicated.
After i finished the driverside mount the passenger side was pretty easy. After making the mounts im going to do some tweeking in autocad. A few of the holes had to be oversized due to slight misalignment, and parts of them look clunky.

[Jean]

Dude, that is awesome work!

[RobertK]

Hell yeah, I always like progress.

[The Dark Side of Will]

Ok, after some measurements this is what I got. Measuring with a 59.4mm tall level from the top of the frame rail pinch. NOTE: This is after i modified the pan on the M62. There is 1.125'' from bottom of pan to top of subframe. The camera angle is not in line with the reading, so within line of sight i got these measurements

M62: Im measuring 5.5''(13.7cm) from the top of the nut to top of the level

M20: Im measuring 6.375''(16.2cm) from the top of the nut to the top of the level.


So if we do the math, keeping in mind that the nut on the M62 is 28mm and the M20 nut is 22mm.

Center of M62 crank to top of frame rail is 9.16CM (13.7CM-59.4MM(level height)+14mm(center of crank)

Center of M20 crank to top of frame rail is 11.36CM (16.2CM-59.4MM(level height)+11MM (center of crank)

Thanks! Can we make this post a sticky? ;)

My notched pan is about 5mm from the subframe. So when you bring your engine down ~20mm like I did when I made my mount arms (to replace my 20mm subframe spacers), you'll be almost dead on with the factory m20 alignment.

Conspiracy busted ;)

Finally!