Cohny's E34 build thread

[cohny]

For years now I've always wanted to do some kind of build and document it on here. My 525i has been my DD for the last 4 years but things were starting to get to the point where I needed to either sell it or really put some work into it. Having grown attached to the E34 I've decided to do the latter. It's a 1995 525i and so far the plans are to do a respray in my garage, swap out the M50tu and tranny for an OBDII M52 ZF combo, and do a full suspension rebuild. I'll probably go through the interior afterwards but this is already a ton of work to get through so I'll get to that when I get there.

Here's a picture of the car as it sat when I started:
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Trim around the windows removed:
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Tearing the front end down:
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[cohny]

Now officially the owner of my own engine crane:
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Actually pulled an engine for the first time ever. It was a long day but satisfying.
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With the engine out I moved the car out of the garage and removed the fenders. I could see that there was a little rust on the back side but it definitely looked worse when I had them off. Luckily it's still all on the surface and I should be able to clean them up just fine. There's a little under the car as well but nothing terrible. The car is really clean overall considering it's seen 3 New England winters now.
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And here's how it sits now:
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I now need to start getting everything I need to paint the car. I ordered a 5hp 2 stage 60 gallon air compressor . Should be here in around 10 days or so. This weekend I'm going to try to get started cleaning up the engine bay and the air line setup.

Right now I need to decide whether or not I'm going to pull the ABS. I was hoping I could paint the bay with it still installed if I covered it up, but looking at it now it seems unlikely. I also need to figure out what to do to get the body harness out of the way. Right now it comes in front of the fuse box and then goes back behind the booster. I could lift it up to paint around it but that isn't ideal.

[katit2]

Very interested, keep updating with as much pics as possible. Mine is rust-free and I started other way around - interior. But I do like to learn how to paint myself at some point..

[moroza]

Lift it up and hang it from the rafters?

I just finished rebuilding the entire suspension on my 525iT, from the steerbox to the RTABs, all with OE parts except the shocks (Sachs and Bilstein B4, because OE for a Touring are ~$320 each). Even with garbage tires I can tell the car is functionally restored; it was very worth it.

S52 and 5-speed, huh? There are a good number of N5x six-speeds floating around these days...

[cohny]

Very interested, keep updating with as much pics as possible. Mine is rust-free and I started other way around - interior. But I do like to learn how to paint myself at some point..

I will. I'm planning on building a passable positive pressure booth in my garage for this job. It's not going to be cheap but equipment like the compressor will be a significant upgrade for my garage more generally so it should be worthwhile.

Lift it up and hang it from the rafters?

I just finished rebuilding the entire suspension on my 525iT, from the steerbox to the RTABs, all with OE parts except the shocks (Sachs and Bilstein B4, because OE for a Touring are ~$320 each). Even with garbage tires I can tell the car is functionally restored; it was very worth it.

S52 and 5-speed, huh? There are a good number of N5x six-speeds floating around these days...

I rebuilt the suspension on my M5 and I agree the difference was night and day. It's like having a new car.

Right now I'm just planning on an M52. The added cost for the extra .4L doesn't seem worth it right now. I may pick up an M54 rotation assembly and do a stroker, but I'll have to see how long it takes me to get to that point.

[moroza]

Oh, I misread. Anyway, my point was to look into E90 6-speeds that are becoming common.

[katit2]

Oh, I misread. Anyway, my point was to look into E90 6-speeds that are becoming common.

Are they direct bolt in to M50 E34s?

[moroza]

The bellhousing boltpattern is. The crossmember, shifter, and driveshaft are custom. The clutch and flywheel... apparently depends on which exact trans we're talking about.

[cohny]

Made some progress over the weekend. Prep is everything when painting a car and so a lot of the work right now is slow and arduous. After a solid effort trying to clean the bay by hand I went out and bought a small power washer. Getting the grime out of small crevasses and recesses in the seams was going to be practically impossible without it.

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Next is to start sanding but there are a few body panels I need to find beforehand. I picked up a trunk lid this weekend to replace my rusty one, and I got the narrow grill nose panel I need for the conversion last week. Now I just need a narrow grill hood and early mirrors. Goals for this week are to find at least one of those and to get started on the cooling lines I'll need for the air setup.

I'm uploading the photos to the site itself so they won't disappear in the future. Unfortunately this means they're on the smaller side. If you open the image in another tab you can see a much larger version of the photo.

Here's one quick shot of the car as it sits right now.
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[moroza]

Why the early mirrors? They are slightly larger housings with slightly smaller glass.

[cohny]

One of my original side mirrors was cracked and I just think the earlier ones look a lot better. The later mirrors don't flow with the lines of the car as well.

[summitp]

Nice work so far. I like these kinds of threads. I painted mine in the garage this September, it was fun, a lot of work, but fun. I too got a much bigger compressor for painting a while back, and I LOVE IT.

[cohny]

It's been a while since I last updated this thread but a lot has happened. Right in the middle of this build I came across a clean E32 740i. I've always loved the E32 and had to grab it. This set me back about 2 months but it makes for a pretty sweet DD.

Next designing and building an air setup suitable for a decent paint job was a lot more work than I expected it to be. Before I started I'd never soldered pipe before, but thankfully once I finally got the whole assembly built and ran the compressor for the first time I had no leaks.

When painting a car the chief enemy is water in your lines. Real shops use refrigerated air driers to solve this problem but those are prohibitively expensive for a DIY'er. Harbor freight sells one that's apparently good for $400, but it has limited intake temperature capacity and still requires a decent length of tubing between it and the compressor. So instead the poor mans air dryer is a long length of copper tubing. This serves as a big heat sink that cools the air enough to condense the water vapor back into liquid so it can be filtered out.

My compressor is a 60 gallon 5hp two stage and feeds into a little over 50' of 3/4" type L copper tubing. The assembly is tilted to the right and drop lines with drains are placed at the ends so any liquid that condenses early enough can be collected and drained later. The copper lines feed into a water separator, regulator, and Motorguard M60 coalescing filter. All three of these are 1/2 NPT in and out rather than the more common 1/4 or 3/8 NPT which is important for proper air flow. For a hose I got a 50' 3/8" with 1/4 NPT ends I then paired with high flow Milton "V" style couplings. Those are crucial and must be used for painting.

I spoke with lots of guys who paint professionally and the consensus was that what I've described above is actually about the bare minimum for getting good results... This was a significant investment but I like a challenge and am looking to build something that will allow me to do this more than once. Having air at home for general use is also pretty awesome.

[katit2]

Hi! It's definitely "overdoing" it. I totally get what you say.. And I personally want to learn how to paint (this is my next skill to develop after upholstery). After a lot of research and seeing how it's done prefessionaly and not - my verdict is that we (amateurs/perfectionists) probably overcomplicating whole thing.

There is a lot of cars painted outside and they look decent. And if you get into professional booth with best air setup and best airgun - you will get runs and other issues. And PRO can paint outside with HF paint gun and it will be decent. This is how I see it. Lot's of imperfections in paint can be fixed later, polished where you won't even see it.

And 90% is in prep/sanding/masking. So yeah..

[cohny]

I have to disagree. A professional can use an HF gun and get a good paint job for sure, but I'm no pro and won't be when I go to paint the car. A pro could also paint a car outside and it would look decent, but there's no pro who'll tell you you won't have contaminates in the paint. That and no matter who you are you still need dry air. Without some kind of dryer you can only paint as long as the compressor can go without getting too hot and dumping water into the air, maybe a panel or two at a time. That's fine but it just means a lot of mixing and waiting which I'm not really interested in. So yes while this seems like overkill the feedback I got from the pros I talked to was that if you don't want a 10 foot job one of the things you'll need to get is a supply of clean, dry air.

I definitely agree that the prep is 90% of the equation though. I'm dropping the rest of the suspension right now so I'll be able to clean the unibody.