BMW 635CSi Restomod

[gazzol]

So I thought I'd introduce you to my new project.........635CSi, dog leg manual and LSD...... yummy, also lots of rust......not so yummy.
I'm the third owner of the car this year as two other people bought the car, got scared and passed it on. Fortunately for the car I'm far to dumb to get scared so I guess I'll just have to crack on and save it
The aim is to create a stripped out no nonsense back road blaster. The car is going to be as light as possible but there will be a small amount of trim like door cards and maybe even a carpet.

[gazzol]

Before any body repairs can be done I need to strip the car to a bare shell. This started at work because the first job was to take the engine and gearbox out which is much easier on a ramp than it is at home lying on the floor.

Edited by gazzol on Tuesday 7th November 22:26

[gazzol]

Got the car home and started taking it to bits, found a few extra bits of rust. The inner wings are normally really bad on these cars but this one is surprisingly good in these areas but shockingly bad in others like the inner sills which had steel sections glued on instead of welded this method "repair" is not only illegal but really really unsafe and I'd really like to meet the person who did this, I'd shove all the repair sections (which I pulled off by hand) one by one up their @rse. My step son was a huge help and started removing all the sound deadening for me so we could see how bad the floors are.......... they're bad.







[URL]|https://thumbsnap.com/MQfrAAMs[/ur[url]

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TheDoggingFather said:

Interesting project.

Any thoughts as to what you're going to have powering it?

Hi mate , the engine I'm using is a BMW M30 unit which was what was fitted originally. I have the engine out of my last car which I am going to fit for now but I have a much higher spec head to go on it. I'm going to stay NA as I love the induction noise and ultimate power isn't my goal, close to 300 brake is more than enough for the North Pennines where I go to relieve the stress.
Have a listen/look at this, the noise alone has got to be worth more than the extra power that a turbo would give.

https://youtu.be/WA9kg-Uut4U?si=t4-5eDzO2oJxXWQk

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Court_S said:

I that’s going to be very cool when it’s done. I assume manuals are fairly rare?

What’s the availability of parts like? I assume a fair amount of fabrication will be needed to sort the rust rather than new panels.

I've managed to buy 4 footwells and a pair of outer sills the patch panels I will make myself. The car is going to be as light as possible with the exception of a little trim with that in mind I'm going to get new from wings, bonnet, front and rear bumpers in GRP. I'd also like a GRP boot lid and door skins but these aren't available to buy so if I go that far I'll have to make those myself.

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Pflanzgarten said:

Aren’t these things meant to be really difficult to drive at the limit?

If they are anything like my last car (BMW E9) which they are an evolution of then I would say definitely not.

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shalmaneser said:

Sounds cool - any plans to fiddle with the steering? As these have a steering box would a change to a rack be an improvement at all? I've wondered whether a later subframe could be fitted?

Will you be going with a full interior but no rear seats? clubsport spec I suppose?

With regards to the steering I'd love to convert to a steering rack because it would be much easier to get a decent equal length exhaust manifold but I've decided to leave it standard for now and see what it's like as it's only 3 turns lock to lock unlike my old E9 which was 4 turns. Everyone bangs on about e46 purple tag racks which are 2.7 lock to lock so there isn't that much in it. Another thing to consider is what rack to use because the e24 steering is behind the axle whereas the e46 etc is infront of the axle so I couldn't use an e46 one as the steering would be the wrong way round unless you used a LHD rack but then the mounts wouldn't be right. On top of all that the rack would have to be mounted quite a long way back from the subframe in order for the track rods to be inline with the rack which is doable but a lot of work for a very small benefit.

[gazzol]

Stick Legs said:

Loved my 2.

Excellent cars and an absolute hoot on the limit.

I wish I’d kept mine now.

Bilstein B6 & Eibach M635CSi springs.
M635CSi 4 pot calipers.
Thicker anti roll bars.
Front & rear strut braces.
6 branch exhaust manifold & full stainless system.
Alpina B9 3.5 cam & ECU with later ‘big valve’ head of an E34 535i.
850i 16” wheels.
Manual & LSD.

Nice car and nice spec. Mine is going to be a bit more hardcore.....stay tuned

Edited by gazzol on Tuesday 21st November 23:07

[gazzol]

A little bit more progress, I decided to remove all the seat mounts because I suspected that there would be rust between the mounts and the floors........I was right. There aren't going to be any rear seats so the rear mounts were redundant anyway and for the front seats I'll make some FIA style mounts once all the welding repairs are done.















Once that was all done I welded in some box section to keep the shell rigid as there is going to be quite a lot of metal cut out once the repairs start.

[gazzol]

R6tty said:

Might have missed a bit: love the car and what you're doing but where is the 'mod' part?

Before I can mod it I think I'd better make it solid. No?

[gazzol]

rm36house said:

It's sounds mega! Love it, Sir! Is it your car in that youtube channel too? It goes like on the rails and together with N/A soundtrack and power, heaven! )

Thanks for your comments, that was my old E9. The E24 will be a better developed version of that car

[gazzol]

J4CKO said:

Indeed, I remember working at a car pitch in the late eighties early nineties and we had two of these through and both were rusting back then.

Think he was asking what the plans are once you have done the weld a thon ?

I am going to make the car as light as possible with the exception of a small amount of trim so all superfluous brackets removed, perspex windows, fixed windows in the back no winders in the front just straps to hold them up, no underseal whatsoever (summer car) fiberglass front and rear bumpers front wings,bonnet, door skins and boot skin and possibly even the roof skin. The boot floor is all coming out and will be replaced with a more aero efficient one made in aluminium, alloy fuel tank yada yada yada.........you get the idea, as light as possible but with door cards and lightweight carpet. I'm hoping for 280-300 bhp with the new engine mods (currently 240) so it should be brisk enough.

[gazzol]

Zephyr Speedshop said:

Wow, pistonheads delivers again. Another bucket list car being built! Who said forums are dead!

I'm guessing is not that simple but couldn't you not fit a e46 subframe and use all of the the e46 setup? Or perhaps there's a better choice . I know my old 840 shared a lot with the later e39?

Anyway old skool forum build threads are where is at with a smokey whiskey in hand !

Bookmarked !

Ultimately anything is possible if you throw enough time and money at it but I if I were to go down the route of modifying an e46 subframe then I would have to use an M or S 50 or higher engine because of where the sump fits in relation to the subframe. Whilst that would have the advantage of saving even more weight cos the M30 is a BIG old lump I have a lot of money invested in the engine that's going in so I really want to use it, also I simply don't want to put the extra time in because it will add many months to an already long build.

[gazzol]

ingenieur said:

You MUST sort the steering. Even if you do nothing else.

I did 20,000 miles in my 635CSI and the steering was terrible. It was a top-spec low mileage car with LSD.

A mate of mine had a MG ZT190 and chasing him down a country road, despite the 635 having better figures it could not get anywhere near the - slower on paper - MG ZT-190.

The reason for this... even in a straight line the steering was hard to control so I could not keep my foot down solid.

This is in the real world. Yeah, on a motorway maybe it wouldn't be a problem. But you said at the beginning of the thread that you wanted this to be a b-road blaster.

Sort the steering, you will regret not doing that. Take some parts from another BMW which had a rack.

The car is going to be either race spec poly bushed or have spherical bearings in the suspension, all the steering components will be new so there won't be any play in the steering at all. I cant just puts a rack on from another BMW because all the cars that had racks on had the rack infront of the subframe.......right where my sump is going to be. I can't put said rack behind the subframe because then turning the steering wheel left would make the car turn right. Other racks are available but it simply isn't worth the hassle. If steering box systems are so woefully terrible as you make out then why did BMW persist with it for so long and use it till the 90s? I'm not sayin racks aren't better but there isn't a problem with what I've got, trust me I know what I'm doing.
If your old car was as bad as you say it was I can only assume it had a fault either mechanical or with the alignment. I had my E9 off the clock and it never felt anything other than absolutely planted

Edited by gazzol on Sunday 10th December 01:27

Edited by gazzol on Sunday 10th December 22:39

[gazzol]

So, not much of an update but I finally got the car completely stripped to a bare shell. Starting on the driver's side I started cutting away at the rot. I had to remove the lower section of the rear quarter panel so that I could cut away the central section in order to fit a complete new inner sill. The inner sill is going to be hand fabricated by yt but in no way will I be trying to replicate the original......there's no point as it's not that kind of car.

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The good news is that from this point onwards everything is progress or to put it another way: it'll never be as f#cked as it is now.

Edited by gazzol on Sunday 10th December 01:12

Edited by gazzol on Sunday 10th December 01:21

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ferret50 said:

Not sure, OP, if you are very brave or just daft taking that on!

Trust you have plenty of welding gas?

If you can find the time, have a with me.

Daft and brave mate........actually not that brave just daft I've done plenty of restoration work so it's not that daunting

[gazzol]

Another quick update, had time to get in the garage tonight so I made a start fabricating a new inner sil. No attempt was made to copy the original design I simply rolled in a wavy bead pattern and cut some holes and dimpled them to give the panel a little more rigidity.

[gazzol]

rob0r said:

This is going to be epic and utterly down my street! I'm also an M30 enthuisiast with E23s, an E30 with M30B34 and even an E3 3.0si which was bought with no interior or engine, that I have marked out for similar treatment...

The plan with mine is swapping the steering box out of an E12 M535i and bolting up an entire E28 rear axle, both being direct fitment. I believe E3s are the same in the front as an E9 so I'm curious if you have any tricks or tips... Is there a thread on the E9?

Thanks for your positive comments.
Not sure about an E3 thread but I'm sure there's an E3 forum run alongside the e9 one but I may be wrong. You're right about e3s and e9s being mechanically identical same with the e12 too. When I had my e9 I used E12 M535 front struts (better choice of brake discs) with Bilstein inserts but converted to adjustable platforms with 2.5 inch id springs rear shocks were Bilstein again from an e24, rear springs were standard but cut down. I kept my suspension soft for compliance but went big on the anti roll bars. Still have springs and shocks etc if you're interested. Also have a 5speed dog leg too.

Edited by gazzol on Tuesday 12th December 23:07

[gazzol]

In order to fit the new inner sill panel properly everything that was fastened to the old one had to be cut off. Once the inner sill was welded in all the other pieces could be repaired and welded back in.





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BlueBob said:

Headers; RHD equal length can be done with steering box, and with dry sump pump and twin brake masters. Made some for my RHD e12 race car, tight, but can be done.

300bhp from an m30 is quite a challenge and costly. Alpina only achieved about 260 with higher compression and head work. Getting that extra needs much to be done. A dry dumped 3.5 m30 race engine producing somewhere around 310/320 will cost £20k+ now.

Start thinking re wheel width at bodywork stage. You will find you are limited without 2.25" coilover conversion on the front and possibly a recess in the trailing arms at rear.

Edited by BlueBob on Wednesday 3rd January 14:24

Thanks for your positive comments re my work. Yes I know it is possible to get equal length headers whilst keeping the steering box but they're custom/hand made and therefore very expensive as opposed to off the shelf ones like the ones that Schmeidmann sell for £250 plus taxes which sadly don't fit RHD vehicles. With regards to wheel width I'm more or less committed to going with an e9 group 2 style wide arch kit like the Luigi race car so I'll be able to have very low or even negative et on the wheels so suspension clearance won't be an issue.
With regards to 300bhp.....yes I know that is a lot to achieve from an N/A M30 but the people who did Scott Osbourne's M10 head which was just shy of 90bhp per litre did mine, plus mine has more compression more cam and REC race valves. If I can make 85 bhp per litre I'll be very happy but I'm not interested in huge numbers anyway if I were I would have turbo'd iit. Incidentally the same people get 380 from their M30 race engines.
If anyone feels the need to go on a crusade to tell me about scrub radius and other associated problems with high offset on the front please don't.