M30B35 air conditioning

[st.petebiodiesel]

I’ve been driving my 87 M30B35 swapped sedan for a several months now without issue.

Nothing special just a 87 sedan with a M30B35 mated to a G240. Here is the build thread. (Lots of good info)

https://www.r3vlimited.com/board/showthread.php?p=4843210

I live in Florida and it gets downright hot, so having A/C is a necessity. That and I plan on turning this car into a family car. One we can take on long road trips with the family. Our first child is due in 63 days so that’s the deadline. The car is super reliable with the swap, I’ve driven it over 6,000 miles without a single issue.
The car was originally a 87 325, which uses the same A/C compressor as a 535i, 635csi, 735i, and a e30 M3.
Today I took my car off the road to mock up the A/C compressor.
My M20 A/C compressor fits perfectly on the M30 compressor mount.


Don’t mind the filthy compressor, just using it for mock up. I plan on buying a new one.
With the M30 A/C bracket mounted to the block it became very obvious the pulley wouldn’t clear the radiator.


I’m using a e36 2 row radiator. Maybe a e28 535i radiator would give me more clearance.




Sent from my iPhone using Tapatalk

[ThatOneEuroE30]

Gonna have to go r134 if you dont already plan on it. Finding r12 is difficult

[st.petebiodiesel]

M30B35 air conditioning

Gonna have to go r134 if you dont already plan on it. Finding r12 is difficult

I used to think this also. But R12 is still readily available. Finding R12 is super easy. Have you checked eBay?


Sent from my iPhone using Tapatalk

[lukeADE335i]

The e28 radiator should give you the clearance you need looking at the thickness of the core on the e36 radiator.

[st.petebiodiesel]

I found this diagram of a e28 535i radiator.

Only 32mm thick at the core, not sure about the caps. My e36 radiator is 40mm, so I’m gonna pull the trigger on the e28 535i radiator.
Check out this Japanese R12 on eBay.



Pricey? Yes, but I’ve converted several older Benz’s to r134a and it didn’t perform all that great. Forum members highly recommended staying with R12 for optimal A/C performance.
e30s never came with r134a, so the expansion valves were designed for r12. Even if you buy a brand new valve it’s still a r12 expansion valve.



Sent from my iPhone using Tapatalk

[st.petebiodiesel]

Got the 535i radiator in the mail today. Pretty quick considering I ordered it only 28 hours ago on eBay! Check out eBay store partscontainer, they ship everything out super fast. (I’m not being compensated to say this)

Check out the thickness difference.

Even the sides are thinner, but not by much.

Well I placed the radiator in the car and it didn’t fit. Stupid tab for the fan shroud was hitting the A/C compressor clutch.

Fixed.

Radiator slid in no problem. I was hoping to gain a little more clearance with this radiator.


Little less than a 1/4 inch of clearance between the A/C compressor clutch. I don’t think I could even get the belt in there if I had to without removing the radiator.
Might try a few other things to gain some more clearance.


Sent from my iPhone using Tapatalk

[jdance30]

To install the belt, just remove the compressor from the bracket and put the belt on, then reattach the compressor. I know it doesn't matter as you haven't fully installed the cooling system yet, but it sure beats removing the radiator, making a mess of coolant, and needing to rebleed the system.

I have about that much clearance between the compressor and radiator. However, I do have 80a poly motor mounts that keep the motor from sliding forward under hard braking. Haven's had anything come in contact yet.

I had to find a proper belt to fit the same setup you have by trial and error. I will try to get you the part number on it if i can find the receipt or box. Trust me, it'll help you out a lot lol. I think I tried 4 belts before I found one that fit properly.

I never felt the AC in my car with R12, but I recently converted to R134a. The air blows as cold, if not colder than my E39. I replaced the expansion valve, condenser, evaporator, and all seals and the air blows ice cold. The compressor is definitely in bad shape as it is very noisy while driving. But the R134a conversion, as of a week, has been well worth it.

[dishwab]

Hate to say it but I haven't found a better solution than taking off the radiator to do anything belt related on my M30 swap.

I have the same setup as you, M535i radiator and E34 compressor.

[st.petebiodiesel]

Ordered all the the final bits to finish the A/C system. Here is the parts list.
-E28 535i radiator.
-Remanufactured compressor.

-new parallel flow condenser.

- new Behr dryer

- O ring kit
- R12 refrigerant( x3 12oz cans)
- Ester oil
I’m not changing the evaporator or the expansion valve. Hopefully this won’t end up biting me in the ass and wasting $100 in R12.
I have a really decent vacuum pump and A/C gauges. I plan on pulling a 28”-29” vacuum and letting it sit overnight, hopefully without a rise in vacuum before I charge the system.
Should have a really big final update in about a week.




Sent from my iPhone using Tapatalk

[st.petebiodiesel]

Today I measured what size belt I would need. Borrowed the wife’s tailors measuring tape and wrapped it around both pulleys.

86CM with the ac compressor as inboard as possible on the adjuster.

Then I began pulling the expansion valve. I had to take the glovebox off and a plastic trim piece to get to it.


I know I had said earlier that I wasn’t going to change the evaporator because I thought it would be hard to remove. Then I realized it is stupid easy to remove, it literally just slides out. I was always under the impression that you had to dismantle the dash to take it out.
Plus it would be a shame if it had a leak. A replacement one is only $123.


Judging from the green stuff in the coils I’d say it had a small leak.

The A/C system was intact when I bought the car, but it didn’t have any pressure in it.

Here is where the evaporator lives in the dash. I guess e30 don’t have cabin air filters.


Now I will have changed every component in the system except for the A/C lines themselves. I hope they hold pressure.

I think I’ve spent about $700 so far on A/C parts (if you include the radiator) That’s more than I paid for the car. Oh well gotta have A/C.





Sent from my iPhone using Tapatalk

[IRON-E]

F12 can be had by many local A/C shops, if you had an existing r12 system they would have refilled it no problem. At least here in Cali they would, but it does eat up seals, so it is recommended you change those out first.

[st.petebiodiesel]

I flushed out all my lines, put the necessary ester oil in the system in various places, and pulled a vacuum for an hour.

No rise in vacuum after several hours. We are good to service with R12 now that I know I have no leaks.

One small problem. I thought that my A/C tap would screw right on to a can of R12 just like R134a. IT DOES NOT.
I said fuck it and bought 3 cans of R134a, because I’m impatient and irrational at times like this. I serviced the system with 2 cans of 134a, 24oz to be exact. And my pressures where looking pretty high on the high side.

With my ambient temp of 85 I shouldn’t be over 250psi.
And if I rev the engine it gets much worse.

Almost 380psi!!! Not good.
Not only that but my engines cooling system is struggling to keep up. After idling for 30 minutes with the A/C on blast my coolant temp is way too high.

It appears that I don’t have enough air flow over my condenser. I did install a new spal 14” pusher fan, but it is only rated at 1000 CFM.
When the car is moving my A/C blows pretty cold, but at lights and in traffic it is marginal at best.
I’m going to get a 16” 2000 CFM fan and see how it does. If it works out well I might keep the system R134a. But if a bigger fan yields no improvement, I’ll buy a R12 can tap, suck out the R134a, and refill with the R12.






Sent from my iPhone using Tapatalk

[lukeADE335i]

Good to see you're progress! Hopefully the larger fan sorts it out. If not, maybe some water wetter (the Redline Diesel water wetter you can run mixed with coolant) might help a bit too - the e36 guys seem to run this when they do a clutch fan delete.

If I reinstall my AC, I'm thinking of refitting a clutch fan by running either an even thinner radiator than the e28 - the e60 radiator looks slightly promising & is all aluminium although the lower part of the end tanks would need modification to fit between the e30 chassis rails (the radiator is too wide otherwise), and it uses quick fit fittings; or a Porsche 944 radiator in the front cowl.

e60 radiator:

https://www.turnermotorsport.com/p-15082-oem-bmw-radiator-17117519212/

[st.petebiodiesel]

Good to see you're progress! Hopefully the larger fan sorts it out. If not, maybe some water wetter (the Redline Diesel water wetter you can run mixed with coolant) might help a bit too - the e36 guys seem to run this when they do a clutch fan delete.

If I reinstall my AC, I'm thinking of refitting a clutch fan by running either an even thinner radiator than the e28 - the e60 radiator looks slightly promising & is all aluminium although the lower part of the end tanks would need modification to fit between the e30 chassis rails (the radiator is too wide otherwise), and it uses quick fit fittings; or a Porsche 944 radiator in the front cowl.

e60 radiator:

https://www.turnermotorsport.com/p-1...r-17117519212/

Thanks,
I’m betting the fan will do the trick. The A/C is pretty cold if you can keep the car going faster than 30mph for a minute.
Normally my engine temp sits right at the 1/4.

I run a 750i thermostat. With the A/C going at a long traffic light it will rise to little above 1/2, as soon as I get it going again it cools right back down.
Hopefully an additional 1000cfm will do the trick.



Sent from my iPhone using Tapatalk

[lukeADE335i]

Sounds like the bigger fan will sort it.