1984 633CSi Rises again!

[baders]

Your car is really shaping up nicely Song, a credit to you !

[songzunhuang]

Be prepared to curse a little on the rear sway bar links. I removed mine completely and it still took some sweat equity to press them on. Lots of lube will be needed.

Cursing at this car is something I am all too familiar with. The good news is that the cursing is happening with less frequency now. Thanks for the tip. I'll reserve an afternoon with some beer and choice curse words.

[Ralph in Socal]

Your car is really shaping up nicely Song, a credit to you !

++ I agree Paul. We do need some recent pics though. Ideally, a few before and after to show cleanliness and improvements. Would be nice if Derrick did as well. But it's easy for me to ask as I'm not the one having to take time to get it done.

Ralph

[songzunhuang]

Your car is really shaping up nicely Song, a credit to you !

Hey thanks. I'm bound and determined to use this as a dependable daily driver. I am getting real close. There are only a few annoying things left. Then again, it's fun to tinker on it.

[captain awesome]

Be prepared to curse a little on the rear sway bar links. I removed mine completely and it still took some sweat equity to press them on. Lots of lube will be needed.

Cursing at this car is something I am all too familiar with. The good news is that the cursing is happening with less frequency now. Thanks for the tip. I'll reserve an afternoon with some beer and choice curse words.

Glad to hear things are shaping up. I've been able to drive mine worry free for the past few weeks(knock on wood). There is still work to do, but it sure is nice to just enjoy the drive.

[songzunhuang]

I was cruising eBay for interesting 633csi stuff and I came across an original sales brochure! It arrived today and I must say that it was really cool to go through the almost 40 pages of full color photos with many large foldouts!

This beauty shot looks a lot like my car!

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Now I know what a brand new clean engine is supposed to look like. This is the best representation yet. I'll strive to get mine close to this quality again. This was a 4 page foldout and is really quite impressive in size. It captures so many details so that I know what direction to nudge my car.

Wow, so that's what my engine is supposed to look like.

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Here's a closeup so you can see the detail too!

Beautiful shot of engine.

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Here's a page with a bunch of technical talk regarding the advanced building of the car.

All you wanted to know about the car.

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In addition, it was very entertaining to read all the marketing copy about the car. They sure were proud of the 633csi! The car sounds awesome and I would have bought one after this brochure.

Several times they acknowledge how expensive the car is and that it's worth it since the engineers put everything they knew into the design and building of the car for ultimate performance. A real hoot! Get yourself one of these if you come across it!

I got this for around $15.

[songzunhuang]

After sitting in my trunk for 3 weeks, I finally had time to put on the new replacement OEM foam. I did spend a few hours trying to get all the nasty old cement that was hardened and fused to the hood. I drove about a week and a half with out hood foam and started to wonder if it was really even necessary. Well, since I already had the stuff, I thought I would put it on. Of course, more hours of cleaning with Goof Off, then Mineral spirits and then lacquer thinner. That old cement was hard to get off.

This is the passenger side foam. It's like a giant sticker. The labeling on top looks like it's an original BMW part.

This appears to be an OEM BMW part.

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After the two sides went well, I was wondering how to place the large center section.

Two sides in place and looking good.

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I thought of a crafty trick. I only opened up the center of the adhesive. This gives me a chance to position and secure the middle and then do each side without it's positioning being compromised.

Removing the center allows me to secure it in position and then do the left and right sides separately.

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All done! I must say it looks nice. Now, I wonder if it really does anything...

All the foam in place. It looks brand new!

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So, another nice thing ticked off of my todo list. Now I have a trunk full of suspension bits to put on over the next few weekends.

[sharkfan]

Well done; I have this to do soon and will also replace the parts and air-con stickers as mine are dry, wrinkled and ruined.

[captain awesome]

Keep up the good work Song. I'm waiting on my garage to get built before tackling any new projects. Hopefully the next few weeks everything comes together.

[songzunhuang]

So after I completed the hood foam, I also changed the oil in my car. I went from a 5W30 to a 10W40. I am told that these older BMWs need a bit thicker oil from an BMW racer friend of mine.

So after driving the car to work this past week, I must say that the engine sounds seemed to be a bit more muted from within the car. I am not sure if the hood foam or the oil change made the bigger difference, but the car is definitely quieter in operation - well at least that how it appears from the inside while driving the car.

Also, the hood foam appears to have adhered quite well. I didn't use any additional cement (Scotch #80) like I had read in some other threads.

[dwcains]

I installed the self-adhesive hood foam maybe 6 months ago, and it's still adhering well. You shouldn't have any issues with it. It's also washable, which is nice. Before I installed it I had some motor oil drip onto a piece from the shelf above, leaving an oil stain about 4" across. I used some Simple Green and warm soapy water, and the stain came right out.

3w/30 is definitely thin oil for an old M30. I'm in a warmer climate than you are, but I use 15w40 or 15w50.

[songzunhuang]

So today, I finally had some time to put in some new dogbones (rear stabilizer link) and also the sway bar links. So there's a few tricks here to note... I've listed them in the notes below.

First of all, I though my dogbones were OK, then one day under the car I saw the rubber was cracking. Well, can't have that!

New DogBones from BavAuto

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Here's the Dogbone installed. I learned that you will need a 22mm socket (7/8" will work too) and a breaker bar. Those bolts are in there tight! Also, the inner bolt has a nut up top. You'll need to hold the nut while turning. That was a bit harder to do than it sounds.

Installed so that I can see the little logo of the car. I'm weird like that.

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Next was the sway bar links. The rubber on mine were all cracked so I got 2 new ones from Lemforder. Getting the upper part onto the sway bar required a vise and WD-40! It just slips on the swaybar, but it's tight.

New and old link side by side.

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Here's both parts installed. Note that you'l need a jack to list up the wheel arm assembly in order to install the lower part of the sway bar link. If you don't do that, there's just too much tension on the part to get the bolt and nut installed.

You can see the sway bar link and the rear link Dogbone in this picture.

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After the installation, I drove it around aggressively a bit to get it all to settle in. It feels pretty good, although I can't say I notice a huge difference. Maybe when I commute over the mountain next week I will notice it more.

OK, tomorrow I do the front links and I also get to mess with the Speedo again. The Speedo and odometer intermittently stops working. I figured I have a cold solder joint or a lose wire in there. I'll have to go poking around.

[songzunhuang]

I finally broke down and paid $200 for a new fuel level sender. I installed it this morning before heading to work. So as usual, I have a few observations an questions.

1. The new part fit ok, but it seems longer than the original. I am hoping it doesn't matter.
2. Can the fuel gauge be calibrated? After install, although the fuel level needle is less jumpy, I am not convinced that it's correct still. It still reads way above what I expect.

The length of these senders seem different to me.

They don't appear to be the same length. Hoping it doesn't matter.

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Here's the new part installed. Not much to look at, just nice and new.

Installed in only a few minutes.

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[songzunhuang]

The sender is all but impossible to repair. I tried, to no avail. The switch on the sender that operates the low fuel light is however fairly reliable. If you have a problem with the fuel sender variable float resistor, then that will adversely effect your OBC read out as well, as the OBC takes its input from it.

So I replaced the sender with a new one. After one day of commuting, I'm still not trusting the gauge. There's still weirdness. My OBC said 92 miles range and the gauge said 3/4 tank. Later on the way home, the gauge needle dropped to 1/2 and my OBC indicated 75 mile range. No way a 18 mile drive dropped the gauge by 1/4 tank!

Now I'm watching closely to see when the reserve light comes on. I may start carrying a gallon of gas in the trunk.

[baders]

The fuel gauge on our cars is only ever an approximation. Precision instrument it is not. Is there a part number on your old sender ?

[songzunhuang]

This afternoon I once again removed my instrument cluster trying to figure out so many things. Two of the most annoying things were my intermittent odometer and the speedo that would come on and off at will. Well, I think I found the culprit!

After close inspection and poking around the parts. I noticed that one of my odometer gears had a tendency to slide on it's shaft. Turning the wheel manually, I noticed that when the green gear was to the right side, it lost contact with the black gear and the odometer would stop turning. Ah ha! All I needed was something that would hold the gear to the left so that it would remain in contact with the black gear beneath.

In the picture below, you can see the gears disengaging to the left when the green gear slid to the right of the shaft.

I think this is the cause of my intermittent odometer! When the gear slides to the right, it disengages.

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I found a small round rubber piece and used it to hold the green gear in place. A dab of Krazy glue makes sure it stays put.

A little rubber piece served as a spacer.

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I also discovered 3 cold joints! So I removed the solder and put new solder in place. I think that this particular cold joint was causing an intermittent speedometer.

This was the worst cold joint. It was clearly not making continuous contact.

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So after all the repairs, I took the car out for a 30 minute drive all over town. The speedo and odometer never missed a beat. I really hope this was the issue.

I also tried to adjust the needle of the fuel gauge a bit. I turned the needed a bit counter clock wise so that it would be closer to the red section when the reserve light comes on. I am not sure this was a good thing as I went to the gas station right afterwards and filled up the car. Now it only shows 3/4 tank when it's full. Sigh, this fuel gauge thing is really bugging me. In time this too will be resolved... In time.

[songzunhuang]

Today's car fun began with new heavy duty sway bar links. I noticed that the rubber on my passenger side link had torn so it was time for a replacement. I used Meyle heavy duty links. Although the bolt sizes are the same, the nut was not The Meyle uses a 15mm bold while the original used a 17mm. Oh well, it all seemed to work well.

In the picture below, you can see the torn rubber on the old link. This started this slippery slope.

The originals looks whimpy next to the heavy duty ones.

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Installing this was fairly easy with the wheels off.

New front sway bar links in place.

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Now, came the hard part. The alignment was off. I had to do my best to approximate. I measured the frontside and backside of the front tires and tried to make it so I had a slight toe in. I am going to need to get this professionally aligned soon. I also noticed that my tie bars had torn rubber. Dang. I'll need to replace the tie bars and then it's off to the alignment shop.

Messing with the tie bar to fix a weird pull to the right.

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Well, that's enough of that! Time to move on to some cooling system fun.

[songzunhuang]

A long time ago when I started this adventure, I had to do some cooling system work. I noticed that the thermostat housing on the car was severely corroded. In fact one of the necks for the hose had a hole in it! However, it was in a place that could be covered up with a hose and clamp. So I left it for the time being. Well, today that changed.

First I labeled all the wires so that I would know which ones went where. Note that I used clock positions to make it clear.

Labeling all of the sensor wires so I can keep it straight.

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Here's a picture of the new thermostat housing next to the old. Man, the old one was nasty!

Nice new housing. The old one had a hole in the neck!

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I cleaned up the thermostat cover the best I could and put it all back together. The new unit looks rather nice. Note that the new housing had one extra hole in it! (9 o'clock position in picture) I had to find a plug to fit. Miracles of miracles, I found a plug that was in the radiator I bought all those months ago! I saved a trip to the store and a lot of frustration. Every once in a while something goes completely right.

New thermostat assembly ready to go on the car.

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Here's the entire assembly installed in the car.

New thermostat housing in place.

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OK, so you think all would be great right? Well no, one step forward - two steps back. I took the car out for a spirited drive and noticed that the temp gauge was showing that the motor was running hot. It was at the edge of the red! What? I used the same thermostat I had in before (replace when I first got the car) and had been keeping the car at a nice midpoint on the temp gauge. Why was it running hot now? I did clean up all the sensors, but surely that didn't change their reading?

I did realize after the fact that I had put in the rubber gasket below the thermostat and not on top of it. Looking at realoem, the exploded diagram showed the gasket on top. Would that matter that much? I took out my infrared temp sensor and checked all over the motor. Here's what I saw after running the car for 25 minutes. All readings are with the car parked and idling.

• Thermostat cover - 147 degrees
  (Note that the thermostat is between the cover and housing, so it was clearly open)
  Thermostat housing - 158 degrees
  Oil filter housing - 185 degrees
  Engine block just under intake manifold toward front of car - 193 degrees
  Engine block near firewall - 195 degrees

This doesn't seem like an overheating condition does it? My temp gauge was pointing very near the red zone on the far right. What is normal operating temperature?

It looks like there's more research and exploring for me. The fun never stops.

[Ralph in Socal]

I see a letter "A" next to the extra plug you had to add. I think that is the later housing and requires a different thermostat. Research here as it's been discussed previously.

Ralph

[hornhospital]

Yup, I was noticing the same thing.

See this thread viewtopic.php?f=2&t=19520&p=138856#p138856 about the two different thermostat housings and the correct thermostat for each. Also note that the gasket/O ring goes on the outside on one, and the inside on the other!

[Ralph in Socal]

Thank you Ken. I'm sure Song thanks you too!! He's good people.

Ralph

[songzunhuang]

Yup, I was noticing the same thing.

See this thread viewtopic.php?f=2&t=19520&p=138856#p138856 about the two different thermostat housings and the correct thermostat for each. Also note that the gasket/O ring goes on the outside on one, and the inside on the other!

Oh crap!
I actually ordered another lower temp thermostat (71 C) and installed it today. It runs a little cooler, but still hot. Of course now that I read your comments, I think I know why! The Wahler thermostat I replaced it with was again the wrong type. It looks like the type "A" housing is not as deep (by 6mm) so that means it is restricting the flow and not really opening up all of the way. I Did notice that the thermostat was being compressed into the housing while I screwed the cover over it. I was wondering how the coolant was going to get by... Who woulda known?!

Why didn't the guy at the BMW dealership tell me this when I ordered the new housing? This is so annoying.
In hopes of saving others the days of grief (and wasted money!) that I have gone through, let me show you in pics.

Notice the one for the new housing sits much higher than the older one(on right). This means that the bottom of the thermostat is not blocking a passage and the thermostat doesn't have to open as much to begin to let coolant through. Also I noticed that is used the o-ring rubber gasket instead of the square cross section version. This explains a lot. It was too tricky to install that thermostat and gasket combination.

The thermostat on the left is what you need if you are using a repalcement housing!

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I actually drove over 180 miles in the last 2 days with the hot condition. Luckily it never got to overheating territory, but it was hot even on a 66 F day here in California.

OK, tomorrow I order ANOTHER thermostat and we try this all again. i also ordered a new temp sender and the thermostat cover. I was basically changing everything. Sheesh.

Thank you Ken and Ralph for the confirmation. At least I know what I'm chasing now.

[songzunhuang]

So I ordered and picked up my new thermostat. I don't have time to put it in this evening as it's too late. But I did do a side by side with the 80C thermostat that I replaced with the 71C thermostat.

Here's a picture below with the side by side. They are VERY different. The 6mm variance at the bottom makes a huge difference. The old thermostat completely blocks a passage at the bottom of the thermostat housing - all of the time. The new one lets coolant through until the thermostat opens, then it slowly blocks the coolant flow at the bottom of the thermostat housing. I drove the car 275 miles with the wrong thermostat and running a bit hot.

New and old thermostat. It's pretty different.

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Also the upper portion is hugely different. The gasket is now possible to mount without resorting to some kind of glue to hold it in place while you assemble. Yeah, I did that. Also the o-ring is on top and it makes sense. The older one was really hard to install with the o-ring on top. I can also see why a paper gasket is unnecessary with the new thermostat. Also it goes much higher into the housing. I'm expected a huge difference.

I'll get to do the swap again tomorrow evening and then I'll drive it Friday to see how she does. I hope my thermostat woes are over...

[songzunhuang]

After weeks of annoyance, I installed the new thermostat and everything is good in e24 land again. The car runs with the temp gauge at the 11 o'clock position now! I got a 75C thermostat. It was advertised as a "performance" part since it's 5C lower than the stock 80C. I figured that summer is coming and I might as well give it a shot.

Anyhow, I drove the car to the auto parts store to return the thermostat that didn't fit. I also returned the gasket. With the new thermostat, the rubber o-ring worked perfectly and I didn't need the gasket.

Here's the new thermostat right before I put it in the car.

This looks like the right thermostat. I can't wait for it all to work.

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All is good with the cooling system. Oh, and my odometer works like a charm. I got 275 miles before I freaked out and pulled over for gas. I only had to put in 12.5 gallons, which means I probably still had 4 gallons or 80+ miles to go! For those following along, my odometer and fuel gauge have never worked right. I have run out of gas because I just didn't know what was accurate. I think I finally may have a good odometer. Fuel gauge still suspect.

[songzunhuang]

I purchased a new fuel level sender at a cost of $200 to fix my whacky fuel gauge. Well, my fuel gauge is still whack. I decided to take the old sender and see if I could verify that it was working. I took a few reading using a multimeter to see what the resistance specs were. I am hoping that someone can verify for me that this fuel level sender is actually within specs and working well. If that's the case, I'm going to eBay it. I don't think I can return the new sender that I have already installed.

So here's a picture, followed by some specific measurements.

Fuel level measurements at empty and full.

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Looking directly into the connector with the pins labels left to right (1,2,3), here is what I am seeing.
The resistance seems to vary linearly from 3.8-72.4 ohms as measured across pins 1 & 2. I got readings at 3.8, 19, 25, 36, 46, 53, 58, 60 and 72.4 as I slid the float by tilting the unit.

Pins 1 & 2 Full Tank = 3.8 ohms
Empty Tank = 72.4 ohms

Pins 2&3 Empty = 72 ohms, otherwise it was an open circuit
Pins 1&3 Empty = 0.2ohms, otherwise and open circuit

Can anyone verify that this unit is working as designed and within spec?
=====

Quick update, I just answered my own question. I looked in 6:4 of the Bentley manual and verified that the sender is definitely within specs. Oh well, I am leaving this post just for completeness of data.