First Time Engine Rebuild

[abdeweese]

Doing my first ever engine rebuild here in a month. Need all the help and wisdom I can get.

93'
525iT => e34 & M50
190,000

What special tools will I need?
Have:
-Eng & Metric sockets
-open & boxed wrenches up to 9/16's and 15mm
-a few torx
-and patience

Check vack soon

Thanks All,
Ab

[wingman]

Bentley?

[joshua43214]

You forgot 12pound sledge, assorted chisels and a cutting torch.

reassembly is simple, hammer to fit, file to flush, paint to hide.

If it brakes on disassembly, it needed replaced any way.And as always, its German, so it just neds a little force.

You also need a 1/2 torque wrench and a 3/8 torque wrench. If you have to chose between them, get a 3/8" that can go 20% above the head bolt torque, you will need the lower torque accuracy for the rod and main bearings. I recomend NOT using a click type, the double beam wrenchs are inheritlanly more accurate, and the cheap clickers have a narrow accuracy area and that is spotty. An 18" or longer breaker bar is nice also. A ring compressor for installing the pistons.


Get litle box's or cans. sort fasteners by system or location. IE, all PS fitting in one can, all intake in another. Don't feel like you have to be macho about it, take pictures, make drawings etc, anything to aid your memory putting things back together.

On reassembly, tighten fasteners as you put them in, that way you won't forget to tighten something, it would really suck to forget to tighten a rod bolt. Its OK to do silly things like tie a piece of yarn arround a bolt that you have to tighten later. There is alot to keep track of, and most professional mechanics have trouble remembering everything unless they spend alot of time doing heavy engine work.

Pay extra close attention to the orientation of things like rod and main bearings, which side of a gear faces forward, what direction the pistons face. Mark all parts as you remove them in a maner that can not be cleaned off, numbered stamps are good, but take care in where you stamp items to prevent distortion of parts. Don't count on the service manual to tell you how to put a part back on, make sure you see how it came off, like I said, a camera is your friend. Even after many many years or fixing cars for a living, I still make an occasional drawing for reference.


never ever ever set a piston on its top with the rod installed, lay it over on its side.

its a big job, be patient and good luck.

[yaofeng]

Full set of 3/8" drive and 1/2" drive metric socket wrenches up to 27 mm. 1/2" drive breaker bar, 3/8" drive and 1/2" drive torque wrenches. Beam type is better I agree. Open wrenches all the way up to 32 mm will help you a lot. !5mm is not enough.

Get an air compressor and impact tool when you have the urge and when budget allow. You'll ask yourself later, "Why didn't I get theis sooner?"

[Dave M]

Aside from your basic sockets etc covered above, Bentley will cite a number of BMW tools, most related to cylinder head timing. If you want to puchase a camshaft locking tool, the cheapest i found was from Catalyst Racing in Colorado. In hindsight, you don't need it, just use a straight edge across the squared ends of the cam.

For the secondary chain tensioner, I used two safety pins.

I don't recall needing a wrench or socket larger than 21 or 22 (for the crackshaft nut). I borrowed a 600ft/lb torque wrench from a machine shop to tighten the b!atch and a 4ft steel pipe i found to loosen it.

Keep asking questions along the way as many of us here have done this job,

Dave M

[genphreak]

You forgot 12pound sledge, assorted chisels and a cutting torch.

reassembly is simple, hammer to fit, file to flush, paint to hide.

If it brakes on disassembly, it needed replaced any way.And as always, its German, so it just needs a little force.

Now I see why it takes me so much time... my method, process and planning are all wrong for the jobs at hand...

I can see how valid these points are, just wish I'd known them earlier too. Perhaps one can make up for deficiencies in these areas by drinking lots of beer, especially if jacking the car up, working underneath it or removing anything fragile and heavy with power tools. Thanks for the tips Joshua!

[DaCan23]

and dont forget, this applies to any work on our cars.... expect about a 50% breakage of any little plastic part you encounter... unless you do what I've done... send the GF to the stealer when you cant drive cause the car is in pieces...

Last example... when doing the complete front light rebuild... those stupid plastic cones on the headlights... somehow the stealer gave them to her for $1 each, retail was $2.20... she is a BMWCCA associate member as I send her to the stealer often, I think this is the largest discount I've had w/ them, thats 55% off woo hoo.

If the plastic pieces are cheap, dont waste time, just F'em and have all new ones ready...

[Anton CH.]

I am actually going to do the same thign this summer but without the vanos. I don't recall seeign all the specifciations in the Benteley for engine rebuilds. Where would I find all the tolerances and tighting torques for varous components inisde the engine.

[Dave M]

I am actually going to do the same thign this summer but without the vanos. I don't recall seeign all the specifciations in the Benteley for engine rebuilds. Where would I find all the tolerances and tighting torques for varous components inisde the engine.

Bentley does not go beyond cylinder head removal / dis-assembly. If you want instruction on dismantling the bottom end, Chiltons and Haynes cover this, with the Chiltons being the better manual (although Haynes does have nicer pictures of the 'perm guy' ). For tightening torques, there is a downloadable (pdf?) file around which has been a big help to me. I believe Bill R. posted it a while back. I printed it all and bound it.

Dave M

[abdeweese]

Thanks to all for the helpful responses.

-Bentley. Check.

-I was eyeing a torque wrench at Pep Boys the other day. But it can wait until the trip to Harbor Freight. Are both the 1/2" & 3/8" really needed? Would one wrench and an adaptor do both jobs? If so which? What is "beam type"?

-Plan to change: timing chain [and associated gears], water pump, anything else while I'm in there? Any sensors? Thermostat?

-An engine lift? [Have a floor jack]

-Anyone have access to that PDF that Dave M mentioned?

-Surely there aren't any plastic parts in the engine. But as for gaskets I just assumed I could buy a rebuild kit with all new gaskets etc.

Ab

m50, e34, 190,000 miles