Rontgen's 1990 325iS Build Thread

[Rontgen]

Now it's time to do the conversion from Automatic to 5-spd. This has been documented hundreds of times, so not much to say here aside from the differences with an airbag column. With the airbag column, the pedal box is integral to the column support. What this means is you simply swap the pedals (clutch and smaller brake) from the donor box and not the entire pedal box. Sounds easier, although getting the longer bolt in and through the pedals is easier said than done. I still need to work out a solution for the clutch switch, but since that's only used for cruise control, it's low priority at the moment.

I picked up a 325i single-mass flywheel and had it resurfaced locally, to include the 0.3mm step along the outside of the clutch disc surface. We're using a LuK clutch kit along with a late-production 325i Getrag 260. Shifter linkage will be stock for now, along with a stock repro shift knob and boot.

Gave away the Automatic transmission. As I discovered, they are quite literally worthless.

[Rontgen]

Brakes!

Despite some of the riggery I've found, the previous owner of this car was actually very good at keeping fluid changes up to date Every fluid I've run across was clean and looked fresh, to include the brake fluid. Perhaps that's because the car leaked so badly that he constantly had to add fluids, meaning it always had freash fluid! :) Regardless, I guess it's better than finding old dirty fluid.

The brake reservoir grommets were leaking and had stripped the paint off the lower half of the brake booster and most of the driver's side of the crossmember. Cleaned that up and hit it with some flat black rustolem to prevent rust in the future.

We then replaced the reservoir grommets (which was way more difficult than I'd expected) and all 6 brake lines with ATE OEM replacements. Used some DOT 4 fluid and completely flushed the lines using my Motive Brake Bleeder. We'll eventually do something with rotors and pads, but for now they look good and have plenty of meat left.

[Rontgen]

On to the fuel system. After inspecting the fuel system I found a mix of original 27 y/o hoses, replacement EFI hoses, and replacement NON-EFI hoses. In the engine bay, I found both the feed and return lines has been replaced with hoses that clearly stated "NOT FOR FUEL INJECTION" right on the hose. They were old, hard as a rock, and leeched fuel odor, so they needed to go. Back by the fuel filter, I found where the PO had decided to replace some of the hoses and thankfully he used EFI line. But rather than spend a couple dollars on the correct, molded BMW lines, he tried to make off the shelf hose work. Needless to say, the line that comes from the pump to the filter inlet (180 degree bend) was kinked badly, definitely restricting fuel to the engine. No wonder it ran the way it did...

Considering the age of the car, we started in on replacing all the rubber components we could reasonably get to. We ended up replacing:

- Fuel Filler cap
- Fuel filler-to-Body gasket
- Fuel filler tube to tank hose
- Evap hoses at expansion tank
- Fuel filter
- Fuel filter inlet/outlet
- Return line to tank
- Engine bay lines

After pulling the back seat, we saw no evidence that the fuel pump or sender seals had been leaking, so we left those alone for now. If we need to get in there later, that's not a big deal.

I also sent the injectors out for cleaning and flow testing by MEPEH (http://www.mepeh.com/)

[Rontgen]

Next was steering. The E30 rack that was in the car was leaking, had torn boots, and a bad inner tie rod on one side so this seemed like the perfect time to upgrade. I did some research on steering racks and decided that since my inexperienced son was going to be driving the car, I'd like a middle ground between the slow E30 rack and the quick Z3 rack. I settled on the 96-99 E36 M3 3.2-turn rack, which I found locally.

Since this is an airbag car, swapping racks means modifying the firewall and "boot plate". This was a pain in the ass with the engine removed - I couldn't imagine doing it with the engine and trans in place. Anyway, it took some time, but it turned out nicely, complete with new E36 outer tie rods. We have a new P/S fluid reservoir and we'll figure out WTF to do about lines once the engine is in place.

[Rontgen]

Now that the engine was built, it was time to turn our attention to the car itself. We started with the rear diff (4.10 LSD), which worked great but much like the rest of the car leaked badly. We pulled the diff and replaced the following:

- Output shaft seals & o-rings
- Rear Cover gasket
- Speed sensor O-Ring
- Rear bushing (Garagistic Poly)
- Redline 75W-90 Synthetic Gear Oil

[Rontgen]

After this, things began to pick up speed. The engine was assembled along with all new gaskets, seals, o-rings, etc. I covered it up and we began to work on the chassis in order to prep it for the engine & trans. Building the engine was a great learning experience for my son and although I'm sure some of it went over his head, I think he has a much better feel for how an engine works now.

[Rontgen]

The cylinder head was a different story. It had been previously replaced with a remanufactured head and was a mess. The camshaft was badly scored, there was evidence of a re-weld job on the rocker shaft boss, there was a broken valve tip, and the guides showed signs of oil starvation. Mileage on this head was unknown, so I decided to replace it. Much like the intermediate shaft situation above, I found no one local to rebuild this head and even if I did, the re-weld had me concerned. I contacted Autohead Performance out of Moody, AL (http://www.autoheadperformance.com/) and they set me up with a complete remanufactured 885 head.

[Rontgen]

Loooong overdue update! Since this is my son's car, I've made a conscious effort to only work on it when he and I are both around. With my travel schedule, his school schedule and the summer heat, that's been easier said than done but we're finally making some progress. It's a budget build, and we're trying to stay focused on the goal - a safe and reliable car for him to drive. I realize most builds here are performance oriented, but this one is more of a restoration I guess...

We got the short block torn down and found cylinder bores that looked good and crank journals that looked great. We cleaned the block and all associated parts thoroughly, honed with a flex hone, and after finding all critical measurements in spec - we re-assembled with new freeze plugs, Glyco bearings, and Goetze rings. We went through the entire blueprinting process, checking all bearing clearances, and recorded the data into a spreadsheet for future reference.

The Intermediate shaft bearings presented another problem. Thanks to some solid info found here (& at E30Tech prior to it's death), I knew exactly *how* to replace these bearings. But, it's not a DIY job, so I needed to farm this work out to a machine shop. One of the many downsides to living in the middle of nowhere is that exactly zero machine shops I contacted showed any interest in working with a BMW block. For the most part, if it wasn't a small block Chevy, they were clueless and disinterested in stepping out of their comfort zone. So, I made the command decision to leave the intermediate shaft bearings as-is. They didn't look bad, but had some wear. Clearances as measured with a dial bore gauge were still in spec, so I have my fingers crossed. We shall see. I figured this was a safer gamble than expecting a local machine shop to do it correctly.

[Rontgen]

Progress!

My son and I decided to pull the engine & trans last weekend - a mere 6 days into ownership. The M20 was leaking like sieve and had been for long enough that the undercarriage was a complete mess. Time to do a simple re-ring, new bearings, gaskets, etc and drop it back in after an extensive cleanup effort.

We also scored a Getrag 260 & driveshaft locally and we'll be installing that along with the rebuilt M20. Still need a couple odds & ends, but I think we have the bulk of what we need. We have the engine stripped down to the short block - bores look good and I can still see the factory cross-hatching so that's a good sign. Assuming the bore measures within spec, we'll have it cleaned & honed.

We'll get the short block disassembled in the next couple days and I'm hoping to find normal bearing wear and nothing that requires extensive machine work.

[Rontgen]

UPDATE:

When I purchased the car, the seller told me that the engine had "low compression". When I asked "how low", he told me that several cylinders were in the 90psi range and the 2 middle cylinders were around 60psi. :( He then went on to tell me that those figures were from a compression test he did 4 YEARS prior. Obviously, those wouldn't improve over time so I was expecting the worst. He also mentioned that the engine burned about a quart of oil every 5-7 days and the smokeshow out the exhaust seemed to support that story.

I got the car for a good deal, so this wasn't a dealbreaker. I drove the car home and did a compression check yesterday and was pleasantly surprised by the results (in psi):

1: 150
2: 162
3: 125
4: 140
5: 150
6: 145

Obviously #3 is a concern, but overall much better than I'd expected. Not sure what was up with the seller's numbers, but I can only assume that he had a faulty gauge, leak in his gauge line, or somehow did the test incorrectly.

I added about 2 tablespoons of engine oil to #3 and re-performed the compression check - 190psi. So, I've definitely got some ring wear and blow-by happening. I didn't do the oil test on the other 5 cylinders, but I'm guessing I would see a similar increase due to worn rings.

The existing plugs looked old, but honestly don't look like an engine that has been burning a significant amount of oil over an extended period of time. I tend to believe that most of the oil loss is due to the various leaks that the car has. It definitely does smoke, most noticeably during starting and revving, so I'm thinking valve stem seals is the cause of the smoke.



Decided to put brand new plugs in just to eliminate them from the list of suspects:



Regardless, even if it is using oil - it should run better than this. I'm going to try and figure out what's up before I pull the engine for rebuild so I'm not chasing pre-existing gremlins with the new engine. I did notice after the drive home that I had a significant amount of oil on the two vacuum lines that go to the brake booster and the intake itself in the same general area (blue circle below). Makes me wonder if the car is sucking oil via the crankcase vent...

More to follow!

Picture borrowed from the internet

[Rontgen]

Really clean and nice looking car! I just got my first e30 a couple months ago. Black 89 325is. Runs great but cosmetically is pretty rough. Can't wait to see the progress on this build, good luck!

Thank you!

[Rontgen]

Coming from an e46 and e39 you will find that the e30 is much easier to work on for the most part. Start with simple tune up items such as air filter, plugs, new fluids, fuel filter and go from there. This car looks extremely solid!

Oh...and fix the transmission ;)

Thanks! Can't believe I forgot to mention it in the first post - a manual swap is definitely in the plans. It won't be a slushbox for long!

[sampayne]

Really clean and nice looking car! I just got my first e30 a couple months ago. Black 89 325is. Runs great but cosmetically is pretty rough. Can't wait to see the progress on this build, good luck!

[jhaurimn]

Coming from an e46 and e39 you will find that the e30 is much easier to work on for the most part. Start with simple tune up items such as air filter, plugs, new fluids, fuel filter and go from there. This car looks extremely solid!

Oh...and fix the transmission ;)

[Staszek]

Looks in pretty good shape. I have a 90 25is as well, good luck with the project!