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A/C Compressor Upgrade

Posted: Tue Nov 14, 2017 1:57 pm
by cory58
I've been reading the Hack Mechanic's series in the weekly Roundel about adding A/C to an early E24 and it got me thinking that I should start planning ahead for my E12. One of my E30s needs a new compressor and the adapter brackets to use a Sanden compressor on the M20 are NLA.

In the Roundel series, Rob mentions 2 adapter options for the M30 - one was designed for E28s and is sold by a guy on mye28.com, and the other was designed for an E9 and sold by a guy named Layne Wylie (L.C. Wylie & Co on FB). They both start with a late-model M30 mounting bracket for a "wing cell" compressor, and then add custom adapter brackets to it.

Has anyone here updated their E12 A/C with a Sanden compressor and/or used either of those mounting solutions on an E12?

Thanks, Cory

Posted: Tue Nov 14, 2017 9:08 pm
by CabbageFumes
The bosses in the block where the a/c compressor bracket mounts are the same throughout the years on the m30; its the bracket itself that has changed. What this means is all you have to do to use a later style compressor is use the later brackets, meaning almost anything with an m30 after ‘82 or so is considered a later bracket, compared to the earlier ski-jump style bracket, as I like to call it. When the bushings in those wear out, you’re pretty much hosed anyway. Just look for an ‘80s e24/28 in the wrecking yards and grab all the a/c hardware. It’s a direct fit.

Posted: Wed Nov 15, 2017 10:10 am
by cory58
CabbageFumes wrote:The bosses in the block where the a/c compressor bracket mounts are the same throughout the years on the m30; its the bracket itself that has changed. What this means is all you have to do to use a later style compressor is use the later brackets, meaning almost anything with an m30 after ‘82 or so is considered a later bracket, compared to the earlier ski-jump style bracket, as I like to call it. When the bushings in those wear out, you’re pretty much hosed anyway. Just look for an ‘80s e24/28 in the wrecking yards and grab all the a/c hardware. It’s a direct fit.
Thank you! Very helpful, since it looks like I need the later bracket and hardware regardless of the update option I choose.

I'm wondering if anyone here has updated to a newer style compressor, like the Sanden, or if everyone is just using rebuilt versions of the compressors that came on the later M30 cars, which are less efficient with 134a, because they are R12 compressors that have been rebuilt with 134a seals.

Cory

Posted: Wed Nov 15, 2017 1:18 pm
by Mike W.
I don't like the wing cell compressors in 84 and newer cars, they're rough, noisy and always seem to leak at the compressor seal. But with either compressor, they're not the limiting factor with 134a, the condenser is.

Posted: Wed Nov 15, 2017 8:46 pm
by T.Hanson
For drill, I have never tried either of two a/c's in umpty years. Just assumed fooling around with the r12 recharge monkey business wasn't worth it.

What are the odds the compressors spinning around forever, otherwise neglected, might fire up and work, however one goes about the system re - charge ?

Posted: Thu Nov 16, 2017 8:50 am
by cory58
Mike W. wrote:I don't like the wing cell compressors in 84 and newer cars, they're rough, noisy and always seem to leak at the compressor seal. But with either compressor, they're not the limiting factor with 134a, the condenser is.
Agree on all counts, which is why I’d like to use a newer style compressor when the time comes, rather than a wing cell. In order to get good performance from 134a, condenser and expansion valve would also need to be updated.

My a/c is currently better than any other older BMW I’ve owned, so I was shocked to find out it’s been 134a converted. I think it has an older style Bosch compressor. Would be awesome if the condenser’s already been updated. Haven’t checked it yet.

Posted: Fri Nov 17, 2017 10:56 pm
by Robert Bondi
I updated my A/C in 2006 to R134a. Everything outside the firewall was replaced; nothing under the dash was touched. On the compressor, BMP at the time sold a compressor kit for M30 engines - it included a custom aluminum bracket and a Seltec compressor, IIRC. I installed an increased capacity Al condensor from Vintage Air and a new aux fan with roughly twice the volumetric flow rate of the original. System still going with performance at least as good as the original R12.

Posted: Sat Nov 18, 2017 9:59 pm
by T.Hanson
Again, just for someday maybe. What are the odds my two compressors will only need a charge of R134a and work fine ?

Posted: Sun Nov 19, 2017 1:47 am
by CabbageFumes
T.Hanson wrote:Again, just for someday maybe. What are the odds my two compressors will only need a charge of R134a and work fine ?
Unless the system has had all the seals replaced with the 134 compatible ones, and especially if you have the ancient compression fittings with no seals, chances are you will spend the money every summer refilling your system/s. There's lots of original r12 systems that still blow cold, never being serviced.

Posted: Sun Nov 19, 2017 5:00 am
by T.Hanson
Thank you C.F., it's 20º outside, to probably need advice on something else that falls off before July.

Including my fanny freezing off.

Posted: Tue Nov 21, 2017 12:49 pm
by cory58
Robert Bondi wrote:I updated my A/C in 2006 to R134a. Everything outside the firewall was replaced; nothing under the dash was touched. On the compressor, BMP at the time sold a compressor kit for M30 engines - it included a custom aluminum bracket and a Seltec compressor, IIRC. I installed an increased capacity Al condensor from Vintage Air and a new aux fan with roughly twice the volumetric flow rate of the original. System still going with performance at least as good as the original R12.
Thank you Robert! Low probability that BMP would still have a kit, but worth a call.

Cory

Re: A/C Compressor Upgrade

Posted: Tue Apr 03, 2018 1:09 pm
by tlake
I bought a Sanden SD508 from Mesa Performance back in 2000, it came as part of a kit with an adaptor plate to mount the compressor. I also added a Vintage Air parallel flow condenser, so it has worked on R134a for many years.

Re:

Posted: Sat Apr 07, 2018 3:08 pm
by Mike W.
T.Hanson wrote:
Sat Nov 18, 2017 9:59 pm
Again, just for someday maybe. What are the odds my two compressors will only need a charge of R134a and work fine ?
Odds are very good that the compressors are still ok as long as the system was sealed up. However if you have any of the red hoses, especially on the high side, they are probably very porous and the system won't hold a charge, especially with 134a. Plus 134a gives poor performance as a drop in. I would replace any of the red hoses, you can do it yourself inexpensively, I did a FAQ on it many years ago, then charge it with something like ES12 or the office duster stuff which has been getting rave reviews in the E28 world and elsewhere. I believe it's 152a.

You could of course have a leak elsewhere besides the red hoses, but I've had nothing but trouble with them on assorted BMWs.

Re: A/C Compressor Upgrade

Posted: Sat Apr 21, 2018 2:05 pm
by Lock
On a similar note, my system is still on R12 and has a slight leak at the reciever-dryer connection and needs a charge (about half filled right now). I'm going to fix the leak, and then was going to switch it over to R134a with a new generic parallel flow condenser from ebay - but then I found now that since no one wants R12, it's dropped in price a lot down to about $30 a can vs $10 for R134a, so once the leak is fixed just going to charge it with R12. For the cost, why replace the condensor, hoses and expansion valve vs charging/recharging with original gas.
Seems we've come full circle and keeping an original non-leaking system with R12 is once again feasable.

Re: A/C Compressor Upgrade

Posted: Sat Apr 28, 2018 4:17 am
by tlake
Lock wrote:
Sat Apr 21, 2018 2:05 pm
On a similar note, my system is still on R12 and has a slight leak at the reciever-dryer connection and needs a charge (about half filled right now). I'm going to fix the leak, and then was going to switch it over to R134a with a new generic parallel flow condenser from ebay - but then I found now that since no one wants R12, it's dropped in price a lot down to about $30 a can vs $10 for R134a, so once the leak is fixed just going to charge it with R12. For the cost, why replace the condensor, hoses and expansion valve vs charging/recharging with original gas.
Seems we've come full circle and keeping an original non-leaking system with R12 is once again feasable.
True, if you have access to affordable R12 then stay all original. So long as all the system parts are clean and there are no leaks and all is working as it should, then the e12 a/c is ok, and much better than driving a car with no a/c when it's hot.