installing used engine

[Montius]

Hi All,

I will be purchasing and installing a used engine in my 318 next week, I am just wondering what all I should have done while the engine is out of the car.  The engine I am getting has approx. 160k km or 100k miles.  I already have a head gasket kit and timing components, as well as all cooling system parts ready to install, and the head will be going to the machine shop to be checked over.  My main concern is should I replace anything in the bottom end, such as rings, pistons, main and rod bearings?  Any information would be great.

Thanks
Cris

[peerless]

Doesn't sound much like your installing a used engine, sounds more like your going to rebuild your used engine.

If you open up the bottom end, your opening your wallet to increased expenses.

I have rebuilt 2 M42s now and they average about $2,500 to do it correctly for parts and labor.

You can really upgrade the longevity of these engines by upgrading the short block, just be aware of the expanding budget. Main bearings and rod bearings can be upgraded. The oil releif valves have been superseded.

The front cover is junk by now. You may also have rust damage on the front face of the block that will need to be machined. The crankshaft may have experienced thrust surface damage.

But it sounds like the engine is rather low mileage so hopefully things will be ok, just be aware of potential trouble spots.

Pistons should be fine and the block will only need a quick light hone to seat the new rings. Goetze rings are recommended and come in .2mm oversize as standard replacement.

When your ready to really tear into it, let me know and I will help you out with all the little tricks and durability upgrades.

[Montius]

Thanks for the advise.  

After rebuilding several of these engines, have you noticed much wear in the bottom end?  

I would love it if I could get a way with just doing the head work and maybe some new rings to get this thing back on the road.  

I'm not really looking for a performance build, more of a refresh to an older engine without breaking the bank.

Your advise is greatly appreciated.

Cris

[nickmpower]

these engine have been known to go over 300k miles. My advice would be to just put the engine in the car, and replace the timing components in the near future. and maybe the t stat and water pump

[peerless]

The only major wear I have seen on these engines is the thrust surface of the crankshaft. The problem stems from BMW only using a 180* thrust surface bearing, a half shell. This cannot support the loads generated by these higher revving engines.

We pulled the crank from a running E36 M42 and the crankshaft was junk/scrap. The other M42 I built the thrust surface was just within tolerance and had taken some minor damage.

The front cover and oil relief valve are very important. The original relief valve is made of steel,...in a aluminum housing. When this gets all scored up it seizes and you lose oil pressure and kaboom, by by M42.

Here is a picture of the differences in the relief valves:


And when it seizes and fails. Their is actually 5 holes in this block! You should have seen the fireball that came out from under the car. It was at night and it looked like the little 318is had just had a direct hit from a RPG! (as a note this was a well maintained engine, but it did have 250,000 miles on it)



Its going to cost you some money. If you don't do it right, you will be doing it again.

You might be interested in this thread I just made today. Just for reference the engine in the following thread only had 160,000 miles.
http://m42club.com/forums/showthread.php?p=52249#post52249

[Wise Old Dog]

100k miles is just getting broke in. Only thing I would replace on that engine is the water pump and the rear main seal. I would also pull the lower pan and loc-tite the oil pick-up bolts. Did you run a compression check on your new engine? If so, and it gave positive results, why would you want to go into it? Just my 2 cents.

[RED IS 91]

100k miles is just getting broke in. Only thing I would replace on that engine is the water pump and the rear main seal. I would also pull the lower pan and loc-tite the oil pick-up bolts. Did you run a compression check on your new engine? If so, and it gave positive results, why would you want to go into it? Just my 2 cents.

I agree with the "old dog" ,the motor is just broke in . unless your looking for more power then leave it alone.