My 72 Bavaria Smokes and smokes - fix or replace engine?

Eric

Eric

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I can get an engine (well the whole car--but the auto tranny is shot) out of a 1987 635csi--but it is an automatic with fuel injection. Can I use that engine and swap the dual webber carbs? Can I use still use the stock manual tranny? It works great and has a new clutch.

I really like the idea of staying somewhat original with the car. The engine was replaced by me with one out of a 75 or 76 E21--which I fine. I really like the dual carbs and the manual tranny on it.

What would you do?
 
deQuincey said:
smoke ?, yes but what kind of smoke ?, white, blue, black ?
what fluid consumption is associated to that smoke ?
Click to expand...

Blue smoke. It is pretty much James Bond or Spy Hunter style (in other words, lots of smoke). I am not sure about oil consumption--as I cannot drive it much more than up and down the street where I have it parked.
 
Have you recently changed oil? My '73 had a pretty significant smoking habit, but several months later it went away. I think I changed oil somewhere in there, maybe... Or maybe the rings were stuck a bit and then got back to business...

Point is, smoking isn't always a sign that you have to replace/rebuild. If you want to dive into a project, it's your time and your money, but one ought to have some careful thought invested to be certain of just why and what is going on first.
 
Honolulu said:
Have you recently changed oil? My '73 had a pretty significant smoking habit, but several months later it went away. I think I changed oil somewhere in there, maybe... Or maybe the rings were stuck a bit and then got back to business...
Click to expand...

I did change the oil in the engine and used a BG flush. I have no idea how long the engine sat before it was installed in my car. I have let the car idle for a total of 2 hours plus drove it about 2 miles. I can't really drive it much farther.
 
Eric said:
I can get an engine (well the whole car--but the auto tranny is shot) out of a 1987 635csi--but it is an automatic with fuel injection. Can I use that engine and swap the dual webber carbs? Can I use still use the stock manual tranny? It works great and has a new clutch.

I really like the idea of staying somewhat original with the car. The engine was replaced by me with one out of a 75 or 76 E21--which I fine. I really like the dual carbs and the manual tranny on it.

What would you do?
Click to expand...

I put a 1988 model m30b35 in my Bavaria. You can use the just the long block from the 635, install the Webers on it and bolt it right up to your manual tranny setup. You will need a BMW adapter nut for the cam so you can use your Bavaria distributor drive, you may or may not have to keep the Bav oil pan and pump, depending on whether or not the pan will clear your suspension. If you keep the Bav oil filter you will need to plug the hole in the block inside the oil filter cavity.
 
Have you checked the compression? If the compression is still good, it may just be horribly bad valve seals or a bad head gasket.
 
I believe compression to be as it has plenty of power. The plan is to have my shop check compression. If compression is good I am thinking I have dried out valve seals. At that point the head has to come off, correct? If compression is good, the wings are likely ok? Is there any might as well do stuff while the head is off? Do I go for a full valve job?
 
My 2 cents- Engines that sit

and just get reinstalled, coupled with a flush, need to be run back in. Even the BMW owner's manual says to occaisionally run it hard BEFORE going in for a service. Just starting it up and idleing won't do it. Go beat on it, rev it up, run it on the high way, give it lots of italian tune ups ( no offense to the Italian constituancy) hard down shifts. Buy some techtron at Exxon or Porsche dealer, otherwise known as top end cleaner. Seafoam it, slowly. Find out which cylinder is doing it and concentrate there. Smoke it up or break it is my prescription.

Said another way- the enigne gets junked up, never gets hot enough to burn off deposits on the valves and combustion chambers, rings, etc. I've seen cylinder compression go from 120 to 170 in a M30 that had been sitting or only idled by grandma driving habits :shock: so they can be pretty bullit proof.

Since you didn't post a picture, let's also assume you don't have the valve cover vented to the carbs, emmission control equipment, etc that's doing something wonky. The engine is realitivy clean, no oil near / near vacuum leaks. The intake manifolds/ nuts with just wave washers can be loose so go back over the carbs, etc.

Since you said it idles, I assume reasonably ok. You changed the oil- what weight? Terribly important to use a corrrect heavy weight. Happens all the time.

Adjust your valves. What did the top end look like?

What do the plugs look like? What kind and heat range of plugs?

What year is the head? Has it been replaced already?

Don't get me wrong, if it's purely mechanical wear then it's got to be fixed or replaced.

Yep, you can bolt up a later 3.5 with the carbs you've got.( Check the right side motor mount on the 87 for both mounting positions so you don't have to buy/ fabricate an adaper plate.

But usually, unless you're rebuilding it or at least refreshing it, you're just switching out to new problems by dropping in something used unless you absolutely know the condition beforehand.
 
Update

So--I did seafoam it (induction method). I filled it with premium gas and have done limited driving in it. There is no smoke on start up--but it does smoke a lot under acceleration.

The carb vent is routed properly.

I will do some more serious driving on it soon.

Another suggestion was to add a 1/2 a quart of ATF to the crankcase.

Any more thoughts?
 
Explain further

upon acceleration. By that I mean can you tell if the carb secondaries are opening? If one is and the other not-- smoky. I had one of mine stick closed at WOT couple weeks ago. Better to run it up steady for a while at highway speed.

You're going to have to drive it on the highway to blow out the deposits and burn off the excess that's built up over time.

Adjust your valves. Do a compression test. Watch the color of your spark plugs ; especially the dark ones or they aren't.

I would not thin my oil. I would change my oil as modern oils tend to have cleaners and that will aid in getting the engine back to normal. I understand the trick though- it's supposed to soften the valve seals.
 
It is under any acceleration--not just WOT. I will get it on the highway as soon as I get some new tires on it. It has 20 year old Michelins with large cracks in the sidewalls.
 
Update

I did some hard driving today--it is smoking all over the place to the point I can put a smoke screen to cover all 4 lanes of the highway. The biggest smoke comes at high revs as I work it through the gears.

By the end of the drive, I noticed the water pump is leaking. I don't really feel like putting a water pump on an engine that I don't even know is worth keeping. I am thinking I am ready to swap the engine with the one from the 1987 635csi--or possibly just sell the entire car.

If I do decide to swap the engine and put my dual carbs on it--would the full fuel injection have any value to anyone?

Any input is appreciated.
 
Did you check that the brake booster isn't full of brake fluid? That will REALLY smoke.
DaveG
 
There are some very smart people responding to your post- you need to listen to them carefully though.
Brake fluid can be sucked into the intake manifold through a bad master cylinder leak.
You need to collect information and not spend money- pull the plugs and do the compression test. If you have 1 bad ring, treat that cylinder only. Which plug is nasty?
 
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