3.5 donor

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acat2002

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gruppe,

a few days ago I posted the contact info for a 1985 535i for sale. The car is less than 2 miles from my house and I feel compelled to buy it for a potential donor for a 3.5/5spd swap. I'm not even sure I want to embark on a swap right now, since my original 3.0 and auto tranny have both been recently rebuilt and both work well.

However, IF I wanted to go through with the swap.......
a) is the 1985 version of Motronics too old to consider? (1.0 right?)
b) what other parts should I consider salvagable for my coupe (air conditioning, window motors, brake booster etc.).
c) what should I be willing to shell out for a donor car, assuming that I'd have the top end rebuilt and clutch replaced prior to the swap? I would not be performing the swap myself and have to consider the labor costs, additional parts and fabrication associated with a conversion.

I think I could pay as little as $3,000 and the car has 173k miles from the original (elderly man) owner who has every maintenance record since new. Car drives nicely, aside from a sloppy shiter linkage and the motor sounds very tight and pulls strong through the entire RPM range.

My thought is that even if I "back burner" the swap project, I probably shouldn't pass on the opportunity to buy a decent 3.5/5spd in a very decent running/driveable car (that I could push home if I had to!).

Bottom line, is a 85 535i totally useless in the coupe world?

Any thoughts?
 
The main downside is you'd be switching in a M30B34, rather than a B35, so it is not the best choice. The trans is a good 265, although I don't think it will have the mechanical speedo provision that the older 265s will have, so that is a complication to consider.
 
x_atlas0:

When you wrote "M30B34, rather than a B35", do those designations refer to the engine, or to the version # of the Motronic fuel injection? If to the engine, how do the two designations differ? And, when was the B35 introduced?

acat2002:

If the engine is too early and the 5-speed too late (no mech speedo), then perhaps this isn't the optimal donor car. $3,000 isn't exactly cheap - perhaps a better use for this vehicle would be as a starting point for someone else's restoration project - after all, it is 23 years old, has a 5-speed, and is well maintained. Unless the body is trashed, perhaps it should be allowed to live.
 
The "b" is BMW nomenclature referring to liters. The b34 is 3.4 liters, regardless of what it says on the trunk. the b35 was introduced in the 6 and 7 series in 1988, and in the new 5er (E34) in 1989. The b34 was Motronic 1.0, the b34, 1.3. The b35 was not only 100 cc's larger than the b34, but it came with larger intake valves as well. The b35 is preferable, but the b34 is a fine motor. Reprogrammed aftermarket ECU chips are easily obtainable for both motors.

The trans from the '85 E28 is desirable as it has a separate gearbox and bell housing -- the only year this configuration was offered. If you're going to use Motronic, you'll want this trans as well for the flywheel sensors. The electronic speedodrive will be an issue, but can be swapped with the mechanical in in the tail of your current Getrag. Ideally, you'd use the bellhousing from the '85 and a G265 from an earlier car (eg, an E12) with a mechanical speedodrive.

Having recently sold our '87 535is, $3k isn't outrageous for 173k if it's in very good condition and has little to no rust. As a Boston area car I would pay close attention to that.
 
Thanks guys, this is EXACTLY what I needed to hear.

Yes, maybe this car deserves to live and I shouldn't be tempted simply because it was easy to find. This 5 has some rust at the rocker corners, but many, many new parts (new strut housings, struts, exhaust, computor/speedo head). Somebody should try to restore it, or drive it some more. I'll move on, it's not for me.

MichaelP-thanks for the detailed explanation regarding the valve size on the B35.

If I do eventually perform the swap, my intention will not be to build a rocketship, but the goal will be to retail ALL of the correct interior/exterior items (wheels, springs/ride height etc.). What I would like to create is a smoother, more reliable ride. One of my favorite all-time cars was my old 91 535i. I have NEVER heard of anyone performing a 3.5 swap in a coupe and keeping an automatic transmission, but I would like to explore the possibility of taking the ENTIRE 3.5/auto setup from a 89 or newer 535 or 88 and newer 735 (including the auto transmission). Just a personal preference.

Is this at all feasible?

I imagine that one of the hangups would be somehow retrofitting a late-model electronic speedo/tach in the original instrument cluster, but are there major clearance issues concerning the automatics that came in that series?

Please tell me if I'm thinking irrationally! I know anything can be done with enough money, but for a few more $$$ is the 3.5/Auto swap possible?

-PS I understand that this topic has been discussed ad nauseam and maybe I should start a new thread for the automatic topic, but I don't think I've heard of anyone trying to convert to a complete late model automatic.
 
acat2002 said:
I have NEVER heard of anyone performing a 3.5 swap in a coupe and keeping an automatic transmission, but I would like to explore the possibility of taking the ENTIRE 3.5/auto setup from a 89 or newer 535 or 88 and newer 735 (including the auto transmission). Just a personal preference.

Is this at all feasible?
Click to expand...

I remember seeing a coupe on eBay a couple of years ago with a 3.5L and an automatic. Takes all kinds... Carl Nelson might be the best person to talk about this. He does lots of 3.5L conversions and I'll bet he's done automatics.

Also, it dawned on me after I posted before that there's a really good page that explains a lot about M30 possibilities. There's an explaination of b34/b35 differences about 3/4 of the way down the page. Go here and select "E28 FAQ & Technical Articles."
 
Later model A/T in the E-9

By coincidence I had recently asked Carl that very question--

his response--the transmission tunnel is too small to accomodate the later 4+speed A/T's--maybe major surgery could provide space beneath but then you have all sorts of interior issues with which to deal--so answer is it's not feasible to undertake--maybe an outside possibility if ready to handle all the other issues in some manner.
 
Re: Later model A/T in the E-9

blumax said:
By coincidence I had recently asked Carl that very question--

his response--the transmission tunnel is too small to accomodate the later 4+speed A/T's--maybe major surgery could provide space beneath but then you have all sorts of interior issues with which to deal--so answer is it's not feasible to undertake--maybe an outside possibility if ready to handle all the other issues in some manner.
Click to expand...

Thanks Blumax - I'll move on and hopefully back down to reality!
That would be cool though-all the elegance of an E9 coupe, combined with the smooth feel, reliability and extra HP of a late model "5".
The idea is not completely dead, but it sounds like unless I wanted to spend the kind of money associated with an S38 transplant, a later generation automatic is not going to happen. Looks like I'll be keeping it original for now. Like I said before, love it as is, but if I could change a few things......

Much appreciated comments from all who added to this thread!
 
Well shoots....

I am keeping my '87 build 735i for just such a swap. Guess the trans will not accompany the motor, if/when I go there.

Fortunately I have the 265 already, unfortunately the motor is embarrassingly blue-smoky at starts in town. I feel a little uncomfortable about it at stops, and puff a good bit pullling away. Sometimes it's funny to gas the idiot who's right on my bumper, but it gets old after a bit.

I think maybe a top end refurbish once the kid is off at school again and the beater (88 Corolla) is available for daily use. Have a spare complete injected head, and just got a supposedly good bare head. Heads are us.
 
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