E30 M10 a/c compressor mounting bracket

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Yvan@office - 17 Oct 2006 10:15 GMT

I have '87 E30 with M10 engine, and I am in a process of fitting a/c
from a wrecked car. It's time to fit a/c compressor now (everything
else is finished :-)

My first question is: does the compressor have to be at predefined
angle, or can I rotate it 30 degrees around rotor axis?

I am asking this because the compressor has a mounting bracket for M20
engine (not sure about that), and I have M10. Existing mounting bracket
attaches to the motor in a vertical plane, and for my engine that plane
is at 30 degree angle.

Since I do not knew in detail how does compressor operate, I do not
knew if rotating it for 30 deg. around the axis of rotor rotation would
do any damage. And it would be the easiest to fabricate bracket like
that.

Now my second question. If rotation can damage compressor I have to
fabricate more complicated bracket, that will be heavy if I use steel.
Would aluminum be good enough to hold (pretty heavy) compressor?

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Jack - 17 Oct 2006 18:19 GMT

Here's a link to the parts shown in Realoem for the '87 325i.
http://www.realoem.com/bmw/showparts.do?model=1111&mospid=47263&btnr=64_0521&hg=
64&fg=50

They show the same bracket used on the '87 320i but show a different bracket
used on the '87 318i
http://www.realoem.com/bmw/showparts.do?model=1011&mospid=47252&btnr=64_0503&hg=
64&fg=50

It appears that the 325 bracket uses different bolt locations for the
attachment to the block so that may present a problem.
I don't think that the orientation of the compressor around it's rotation
axis will have any effect on it although the hoses may not reach if they
were meant for the other mouning orientation.

I hope this will help you

>I have '87 E30 with M10 engine, and I am in a process of fitting a/c
> from a wrecked car. It's time to fit a/c compressor now (everything
[quoted text clipped - 16 lines]
> fabricate more complicated bracket, that will be heavy if I use steel.
> Would aluminum be good enough to hold (pretty heavy) compressor?

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Yvan@office - 18 Oct 2006 08:15 GMT

Nedavno Jack pise:

> It appears that the 325 bracket uses different bolt locations for the
> attachment to the block so that may present a problem.

I know about difference in bolt locations, and that is one of the
reasons I want to fabricate new bracket.

> I don't think that the orientation of the compressor around it's
> rotation axis will have any effect on it although the hoses may not
> reach if they were meant for the other mounting orientation.

What about lubrication of the compressor? IIRC when you transport home
refrigerator in non-vertical position, you should wait for some time
before you turn it on, and I think that the reason for that is that oil
that is inside needs to go down to the compressor. And that is my
concern here.

Hoses can reach compressor, I checked that.

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Ed Beroset - 18 Oct 2006 11:52 GMT

> Nedavno Jack pise:
>
[quoted text clipped - 9 lines]
>
> Hoses can reach compressor, I checked that.

There should be no problem. The compressor actually uses the
refrigerant for lubrication and unless the system is leaking, the 30
degree angle you're talking about should make no difference at all. As
long as the hoses reach, you should have no problem at all.

Ed

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Yvan@office - 19 Oct 2006 11:20 GMT

Nedavno Ed Beroset pise:

> There should be no problem. The compressor actually uses the
> refrigerant for lubrication and unless the system is leaking, the 30
> degree angle you're talking about should make no difference at all.
> As long as the hoses reach, you should have no problem at all.

That simplifies fabrication a lot. In this case I only have to get a
steal plate 15mm (1/2") thick, and drill few holes in it.

If compressor uses the refrigerant for lubrication, what is a/c oil than
for? My manual says that I have to put in correct amount of a/c oil for
every component I change (compressor, hose...)

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Ed Beroset - 21 Oct 2006 13:46 GMT

> Nedavno Ed Beroset pise:
>
[quoted text clipped - 5 lines]
> That simplifies fabrication a lot. In this case I only have to get a
> steal plate 15mm (1/2") thick, and drill few holes in it.

Sounds right. Also you made a funny joke there without even trying! :)
(I know English isn't your first language; steel = a kind of metal,
steal = to take something illegally). The advantage, of course, is that
steal plate is much cheaper. ;)

> If compressor uses the refrigerant for lubrication, what is a/c oil than
> for? My manual says that I have to put in correct amount of a/c oil for
> every component I change (compressor, hose...)

That's because the oil is distributed within the refrigerant.
Technically my statement should have been "the compressor actually uses
the refrigerant *to distribute* lubrication." There's still oil
involved. The manual's method is an attempt to assure that you have the
right oil/refrigerant ratio. Too much oil and your AC becomes less
effective; too little oil and your compressor seizes due to lack of
lubrication.

Ed

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Yvan - 27 Oct 2006 19:49 GMT

Nedavno Ed Beroset piše:

| Sounds right. Also you made a funny joke there without even
| trying! :) (I know English isn't your first language; steel = a kind
| of metal, steal = to take something illegally). The advantage, of
| course, is that steal plate is much cheaper. ;)

:-)

| That's because the oil is distributed within the refrigerant.
| Technically my statement should have been "the compressor actually
[quoted text clipped - 3 lines]
| less effective; too little oil and your compressor seizes due to lack
| of lubrication.

Thank you.

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Stu - 17 Oct 2006 18:22 GMT

I am not sure exactly what you mean by rotating it by 30 degrees, however
the compressor needs to be fitted so that it runs in dead inline with the
crank pulley, otherwise the belt will come off and possibly take out the
PAS/alternator belts, etc at the same time. It also needs to be installed
so that you can get the belt on and correctly tension it. In addition to
this, the air con pipes will need to be able to fit onto the compressor
properly.

If you need to make a bracket, I would personally make it out of steel.
Can't you just try to get the proper bracket?

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Yvan@office - 18 Oct 2006 08:15 GMT

Nedavno Stu pise:

> I am not sure exactly what you mean by rotating it by 30 degrees

When you are in front of the car and look at the a/c compressor,
connections for the hoses are at the top of compressor. By rotating
compressor 30 degrees I mean that connections for the hoses are now not
on the top but 30 deg to the left. English is not my native language,
but I hope you understand now.

I am asking this because there is some a/c oil in compressor, and I
guess it it's there to lubricate something. If i rotate compressor that
oil might not where it is suppose to be, and that is not good.

> If you need to make a bracket, I would personally make it out of
> steel. Can't you just try to get the proper bracket?

I am on a tight budget, bracket alone is more than US$300. Check here:

http://www.realoem.com/bmw/showparts.do?model=1011&mospid=47252&btnr=64_0503&hg=
64&fg=50

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Mike G - 18 Oct 2006 18:13 GMT

> Nedavno Stu pise:
>
[quoted text clipped - 14 lines]
>
> I am on a tight budget, bracket alone is more than US$300. Check here:

I assume when you say you can fabricate a bracket in aluminium you mean
duraluminium.
Duraluminium would be fine. Just keep it as chunky as possible.
In fact the one in your link, looks like it's made from an ally casting
rather than a steel one.

Personally though, having access to a welder and a m/c shop, I'd be inclined
to fabricate one from steel. Not because I think it would be better or
stronger, but simply because I think it would be easier to make.
If you do take the welded steel fabrication option, you can reduce the
chances of it cracking, by having it stress relieved, once it's completed.
Either have it done commercially, or simply get it red hot it in fire and
let it cool slowly.
Chucking it in a nice bonfire would do fine. :-)
Mike.

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Yvan@office - 19 Oct 2006 11:20 GMT

Nedavno Mike G pise:

> I assume when you say you can fabricate a bracket in aluminium you
> mean duraluminium.
[quoted text clipped - 11 lines]
> Chucking it in a nice bonfire would do fine. :-)
> Mike.

Thank you for the suggestion. Since Ed suggested that rotation of
compressor for 30 degrees around rotation axis will not create
lubrication problem (anyone to confirm this?), fabrication will be very
simple. 1/2" steel plate and 7 holes to drill, and that's it.

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Mike G - 19 Oct 2006 17:44 GMT

> Nedavno Mike G pise:
>
[quoted text clipped - 18 lines]
> lubrication problem (anyone to confirm this?), fabrication will be very
> simple. 1/2" steel plate and 7 holes to drill, and that's it.

There wont be any lubrication problems, because the oil is atomised in the
refridgerant.
In effect this covers all the internals in an oil mist.
Mike.

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Yvan@office - 20 Oct 2006 10:55 GMT

Nedavno Mike G pise:

> There wont be any lubrication problems, because the oil is atomised in
> the refridgerant.
> In effect this covers all the internals in an oil mist.

OK, than my problem is solved.

Thank's to all.

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