M30B35 Swap Project

[Gregs3point0]

After a great deal of contemplation, I've made the decision to upgrade my engine and transmission (M30B35 paired with G 265/6 5-speed) so I have a bit more power, reliability and fun driving my E9. I live at 7500 ft elevation and between the altitude and automatic transmission, my car runs like an old lady. Also - I want to take my car around the country to various shows/events and enjoy driving it with other BMW enthusiasts.
I've contacted various "E9 people" across the country regarding this swap and appreciate the input thus far. I am leaning into as many of you as possible as I embark on this project and look forward to hearing any feedback and wisdom so I keep this mistakes at a minimum!
The donor car is a 1990 735ia that had 260k miles on it. The engine looked well maintained and I am hoping that when I pull it apart both the head and block are workable donors. I'll be posting more on that front as I open the patient up! What I am looking to do with this engine is replace all the necessary components in order to make it like new with the objective of having a reliable engine that will give me 250K miles without any major headaches! I have not yet sourced the transmission nor have I decided if I'm going to tackle that project with the help of someone like Don in Alemeda....to be determined.
At this point, the input I would appreciate is any thoughts/perspective on the component integration between E9 engine compartment and wiring considerations that I should make. These include, but not limited to:
1) Wiring harness integration to the E9 instruments/ignition/etc.
2) Fuel delivery/return upgrades and/or considerations
3) Cooling system considerations
4) Air conditioning considerations
5) Engine replacement parts suggestions.
Thanks in advance to those who are willing to share their thoughts at this juncture. This should be a fun project that will bring more enjoyment out of my car and I look forward to showcasing it in the future at the various BMW events around the country.
Thanks,
Greg

 

[Oldbmwcoupes]

Greg, to me, it sounds lIke you’ve made a wise decision for a driver car. I’m doing the same with mine. I had Don make me a wiring harness, injector rail, injectors (with the. correct impedance) proper fuel pressure regulator and pretty much everything to make this work. I’ll be using an early m90 intake with 320i plenums. I’ve sourced a sanden compressor and bracket and plan to rework the a/c at the same time. It will all be motronic 1.3 when Im done on the 10th of never. In the mean time, I dream about having time to sink my teeth into my, long time gathered, parts collection. Best of luck and let me know how you handle fuel pumps as I’ve yet to get to that part.

 

[x_atlas0]

I did this back in 2006, so my memory will be spotty.

The big question is if you want to use the M30B35 intake manifold vs the CSI style. There's issues with both methods, but I was able to use the Motronic one with a minimum of fuss. It doesn't look period correct by any means, but I didn't have to do much wiring, and the B35 manifold gives some nice bottom-end torque. The hard part was finding the 2002tii brake booster, and that's arguably easier now since there's a few people repairing them.

Also, please check and see if the G265 you are getting has a speedo drive, the later ones don't. I specifically got mine from a very early E28 so it still had the connection for it.

In terms of engine replacement parts, while it was out, I did most of the standard parts; timing chain guides, chain tensioner, timing chain, oil pump, rear main seal, dizzy rotor + cap, and every gasket. I did not replace rod or main bearings, nor did I take the cam out. I did check the lobes though for wear, particularly the front ones due to the oil spray bar not hitting the front lobes enough at low RPM.

If the donor car runs, it's a great time to do a leakdown and compression test, to determine if you have to do any major internal work.

 

[sfdon]

Greg, to me, it sounds lIke you’ve made a wise decision for a driver car. I’m doing the same with mine. I had Don make me a wiring harness, injector rail, injectors (with the. correct impedance) proper fuel pressure regulator and pretty much everything to make this work. I’ll be using an early m90 intake with 320i plenums. I’ve sourced a sanden compressor and bracket and plan to rework the a/c at the same time. It will all be motronic 1.3 when Im done on the 10th of never. In the mean time, I dream about having time to sink my teeth into my, long time gathered, parts collection. Best of luck and let me know how you handle fuel pumps as I’ve yet to get to that part.

let me know when you need the fuel pump - we have one for you.

 

[Gregs3point0]

I did this back in 2006, so my memory will be spotty.

The big question is if you want to use the M30B35 intake manifold vs the CSI style. There's issues with both methods, but I was able to use the Motronic one with a minimum of fuss. It doesn't look period correct by any means, but I didn't have to do much wiring, and the B35 manifold gives some nice bottom-end torque. The hard part was finding the 2002tii brake booster, and that's arguably easier now since there's a few people repairing them.

Also, please check and see if the G265 you are getting has a speedo drive, the later ones don't. I specifically got mine from a very early E28 so it still had the connection for it.

In terms of engine replacement parts, while it was out, I did most of the standard parts; timing chain guides, chain tensioner, timing chain, oil pump, rear main seal, dizzy rotor + cap, and every gasket. I did not replace rod or main bearings, nor did I take the cam out. I did check the lobes though for wear, particularly the front ones due to the oil spray bar not hitting the front lobes enough at low RPM.

If the donor car runs, it's a great time to do a leakdown and compression test, to

determine if you have to do any major internal work.

Thanks for this input! The brake booster from a Tii? Am I correct in assuming that the existing E9 brake booster is too big for the M30B35 fit? Is the Tii booster the only option or can I potentially use others?
The input on the speedo drive for the 265 is great! I will make sure that's the case for mine! Can't imagine driving without the speedo working after all that work.
I'll try and perform the leakdown and compression test, yet the engine is currently not running and I'm not sure how much hastle I want to endure to get it to run prior to removing the engine/transmission. I'll see if I can get it to run...the gas tank was emptied prior to me taking ownership and after putting a gallon of gas into it...it still wouldnt fire up....not sure what to think of that just yet. It will crank over however....just won't fire up.

 

[x_atlas0]

Thanks for this input! The brake booster from a Tii? Am I correct in assuming that the existing E9 brake booster is too big for the M30B35 fit? Is the Tii booster the only option or can I potentially use others?

There are also hydroboost options, like from the E28, but most people don't like the associated failure points that go along with that. As far as I know, the only one that works is from the 2002tii. It clears the B35 intake with ~1-2" to spare. I was then able to fit the same master cylinder, lines, and everything else up with it, so it was basically drop-in.

The input on the speedo drive for the 265 is great! I will make sure that's the case for mine! Can't imagine driving without the speedo working after all that work.
I'll try and perform the leakdown and compression test, yet the engine is currently not running and I'm not sure how much hastle I want to endure to get it to run prior to removing the engine/transmission. I'll see if I can get it to run...the gas tank was emptied prior to me taking ownership and after putting a gallon of gas into it...it still wouldnt fire up....not sure what to think of that just yet. It will crank over however....just won't fire up.

That's an OBD1 car, you should be able to pull codes to help speed you along. You could use the pedal trick to get it to display if you can't find a reader.

 

[Jim Stone]

let me know when you need the fuel pump - we have one for you.

Don, I could use a fuel pump for my M30B35 conversion. Internal or external fuel tank?
Thanks. Jim

 

[sfdon]

Hello Jim- with the holidays I missed this!

we use a custom bracket with Walbrow pump in tank.

Sending you a PM

 

[rsporsche]

@sfdon ... my pump and everything in my tank is shot ... please send me what i need to get
thanks
scott

 

[x_atlas0]

I used a standard Motronic unit from an E28 mounted external to the tank, it's been working well for a long time. The sock can get clogged in the tank, though, especially with modern fuels.

 

[ScottAndrews]

Thanks for this input! The brake booster from a Tii? Am I correct in assuming that the existing E9 brake booster is too big for the M30B35 fit? Is the Tii booster the only option or can I potentially use others?
The input on the speedo drive for the 265 is great! I will make sure that's the case for mine! Can't imagine driving without the speedo working after all that work.
I'll try and perform the leakdown and compression test, yet the engine is currently not running and I'm not sure how much hastle I want to endure to get it to run prior to removing the engine/transmission. I'll see if I can get it to run...the gas tank was emptied prior to me taking ownership and after putting a gallon of gas into it...it still wouldnt fire up....not sure what to think of that just yet. It will crank over however....just won't fire up.

You can do the lead down test without the engine in running condition. Here is a slide presentation I did for the for the E24 guys back in about 2005...

 

[scrappydog]

Good luck with the engine swap. I did this about 5yrs ago using an M30B34 engine from an EU spec 535i mated to a 5sp box. We decided to go with direct to head throttle bodies from Jenvey and a new ECU (Emerald). Sounds awesome and adds some eye-candy to the engine bay. Something worth considering and it made all the electric/electronic integration you mention relatively straightforwards.

Not my car, but some info here.

PS. I'm in the UK, so I don't know what the prices of engines and gearboxes are like in the US, but its amazing to think that 5yrs ago engines, gearboxes and rear-diffs were a few hundred £s each and now just the transmission is more than what I paid for the whole powertrain+drivetrain!