3.8 into M635csi ???

hi,

I have recently purchased a (uk model) M635csi with a blown engine.

A friend has a crashed e34 M5 3.8 (again uk model), and has offered it to me for a good price.

i was wondering if anyone knew how easily any of the parts will transfer over to the M6??? specifically the engine, ecu and 6 speed box, lsd rear diff, brake discs and calipers, 17" alloy wheels

The brakes will swap over although you will need to run 17's. i have this set up basically on my car. The wheels will fit if they are no bigger than 9" rims at the back. The engine should just slot straight in as it is the same basically as an M6 engine and i have seen an M6 with a 3.6 M5 engine in it. I don't think the gearbox and diff will work, but the standard M6 box and diff will be up to the power and is probable a stonger set up than the 6 speeder as these are not as strong. As for the ECU i would not know, but i am sure a good sparky could make it work. It's gona be a big job though, but you are looking at quicker car than an Alpina B7s. Do bear in mind though that the value will be less than an M6 after you have finished, but that does not matter if you are going to keep it.

Whilst the two enginges are very similar there are differences.

I believe the engine mounts are in a different place & the sump is different too. This doesn't stop the transplant, it just makes it harder. Staying with the 5-speed box will make life simpler too.

Post your query on http://bimmer.roadfly.org/bmw/forums/e24/ as there's a guy on there who's just fitted one to his LHD Six.

He'll be able to tell you what's needed.

I don't think the length of the engine will change as the blocks are the same, it's the internal bore size that is different. As for the value i looked at an M6 with a later model M5 engine in it and asked for some advice from Munich Legends and they said that the value would be less and i would be better of buying a standard six for resale in the future.

Just passing this on

I have to agree with Sohlman on this one. Even an average M6 is worth a bit of money and as time goes by they will become rarer and hence more valuble. As cars become older they also start to appeal to a different kind of person, the kind of person who is buying more for reasons of nostalgia, herritage etc and not because they want to drive it hard. These kind of people tend to be looking for a standard car. When you modify any car old or new you limit the number of people who will want to buy it, this is worse for classic cars as the kind of people who would buy a modified car don't tend to like older cars. A perfect example of this is the RS500 Cosworth, where unmodified cars are worth more than modified ones. 

I'm not saying don't do it, I think it is a great idea. I am one of the people who would buy a modifed older car. What you need to think about is the cost of fixing the std engine versus the reduction in value if you put in the M5 engine. 

AndyS wrote: ...mess about with a standard Six instead.

...which is precisely what one mad US owner has done with his 1983 Six (imported Euro-spec, not US). The work he describes is as follows:

"14 months and one week later, the 1983 euro 635 converted to balls
out M6 is done; mechanically anyway. I'm still staying below 5,000 RPM for
the first 1-2,000 mile or so. We're guessing around 350 hp and 300 ft/lbs
(or lb/ft, same as I recall from reading this digest).

The next step is to do some minor cosmetic work, clear coat issue on trunk
lid, front airdam, nothing too major. But what a pain to find a good shop
to take this on. If it is not remove, replace, paint, and bill insurance,
it's like pulling teeth to get anyone to even consider. As well, you get
the "It's a 6 series." Like it is some pain in the ass to get parts; who
let them in on the secret anyway, ********!

For whatever reason, these cars are getting harder and harder to find folks
who will do any kind of work on them beyond the simple. It's like there is
a growing attitude of, "I've had enough of those sixes." "No Mas!"

Most BCG'ers know what all I had done to the motor, exhaust, brakes,
suspension, etc. Recently, through a group purchase, we bought the 840Ci
Brembo set up for the front and Haygood just sent me the ATE Power Discs -
324mm yowza! I'll get to that later.

The early open lug Alpinas really go well with the Delphin Grey and bi-level
OE euro (pin) stripe.

I'll be showing it at the Mid-May clean car in San Diego, BMW CCA chapter
event. And I will have it at the BMW CCA Nat'l Oktoberfest in Lost Angels
Ass in July.

I'm hoping to have the cosmetics done by then. Many have helped and
inspired over the last 14 months, Thank you very much, YKWYA!

New Motor basically, oil pump & chain & gear, timing chain, guides, sprockets, Dinan exhaust sprocket, balanced crank and flywheel, new bearings, Conforti chip, new 10.5:1 pistons, rings, overbored to 3.6 ltr, head perfect, parts as necessary, intake cleaned up - minor porting, balanced and flowed injectors, water pump, K&N cone - cold air box to follow, plug wires, much externals polished, shined, re-crinkled, etc. Euro header jet coated silver to a 3" exhaust, M6 clutch, 3.73 LS diff, 7 series brakes all way around - for now, 7 series master cylinder, ss brake lines, ATE blue fluid, carbon metallic pads, steering box mount welded and permanently reinforced, tri-color M treatments throughout. Hood internals all replaced - hoses, pads, clips, etc, brackets & screens painted, etc. New fan clutch, all and I mean all hoses and belts, alternator urethane bushings, new p/s and alternator brackets - those mounting teeth go flat, M6 radiator. Momo steering wheel - Fighter. New shift knob - OE, new shift boot, M treatment on gauge faces, Bilstein sports, Eibach Pro-kit springs - not 100% happy with those, may sell it and go custom, fat suspension technique sway bars, sway bar mounts welded and reinforced, new gas tank, new fuel filter, fuel lines. New Alpina wheels and caps, 16X8 all way 'round - thanks JR Calvin! (requires 10mm spacer upfront) New Kumho MX's - too soon to provide opinion. Front seats near new leather, rears in B+/A-. Renewed ECU, new SI board.

Am i forgetting anything? Ya probably.

I've yet to have the courage to add up all the costs. Maybe one day. I
guess if dealers would just let us with the car "disease", pay a little at
time, when we could, in varying amounts, we could all be driving M3 GTRs;
but would we want to? Personally, I love having Six.

Mark Robbins
1983 635CSi M6 conversion"


The significant comment he makes is "I've yet to have the courage to add up all the costs." This is what you'll have to spend if you start with the standard Six as a basis.

You have been warned.

Edited to remove objectionable language, please read the forum guidelines

Edited by Horsetan

Horsetan wrote: Edited to remove objectionable language, please read the forum guidelines

Oops! Must've slipped through the net...

It all comes down to how much money you are prepaired to spend, but if you are going to do it you want to start with a good car either 635, 628 or M635. That means no rust in the chassi at all and solid in this department. There is no point in spending all that time and money doing the work to have the car full apart in a years time due to tin worm.  It will be one quick six mind you when you have finished. Something in the league of a new M5 e39 in performance terms, but without the handling.