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DEZIAC
06-05-2008, 11:12 PM
I just recently picked up an '81 e21 320i and my Dad's telling me it may need an engine rebuild. I'm not to auto mechanically inclined, so my question is:

Engine rebuild or engine swap?

Any feed back would be much appreciated. I've read that it my me better to rebuild and throw a turbo on for more bang for the buck. Is this true? Also, if anyone can suggest what engine swaps and approximate costs? Any shop suggestions? I live in the GTA, and cost is a factor. I know this may not be cheap but all the help would be greatly insightful.

Thanks!

igbastian
06-06-2008, 11:47 AM
Engine rebuild or engine swap?

Thanks!

A swap is cheaper 9 times out of 10. For the price of a rebuild you could probably swap an m20 into your 320i. This is a well-documented swap...I've always liked the idea of an m42 in a 320i. i'm sure this has been done before as well, just not as much.

I'm sure that guy in Kingston has some extra stock engines he'd let go cheap though...if you have the opportunity to hear the engine in the car before it is swapped out that is always a good idea.

Good luck!

DEZIAC
06-06-2008, 12:56 PM
do know how much roughly that swap would cost?

igbastian
06-06-2008, 01:28 PM
it depends on where you get your parts, and if you can do the work yourself.

I would think you could convert to M20 (6cyl) for around 1000 in parts

and swap your M10 (4cyl) for 250 in parts.

Labour is another story...if you have to pay someone to do it the price will increase a lot.

You should probably have someone look at the car before you jump into anything. Maybe it doesn't need a new engine and just some work. What is wrong with it?

jm1602
06-06-2008, 08:08 PM
I just recently picked up an '81 e21 320i and my Dad's telling me it may need an engine rebuild. I'm not to auto mechanically inclined, so my question is:

Engine rebuild or engine swap?

Any feed back would be much appreciated. I've read that it my me better to rebuild and throw a turbo on for more bang for the buck. Is this true? Also, if anyone can suggest what engine swaps and approximate costs? Any shop suggestions? I live in the GTA, and cost is a factor. I know this may not be cheap but all the help would be greatly insightful.

Thanks!

What is telling you it needs a rebuild? Before you go down that road, how are the brakes and suspension?

Swap is all well and good but how do you know that you're not just putting another lump of worn out crap in the engine bay. If it really needs it, get it rebuilt otherwise just drive it man.

DEZIAC
06-07-2008, 12:36 AM
I'm not quite sure whats wrong, i have the car in Kingston. I know he metioned something about the valves, i'm not quite sure. I just wanted to inquire into getting a new engine. LOL

Zorin
06-07-2008, 10:20 AM
I can trade you m20 for your m10.
Let me know if interested.

1fst327
06-08-2008, 10:51 PM
If you are not mechanically inclined and cost is a factor then you are going to be in for a rough ride with this car. I've owned four e21's and rebuilt one almost from the ground up.I have more money invested than I care to mention and I'd be lucky to see 10 cents on the dollar if I were to sell it. If you are willing to learn and have a place to work on it(driveway, garage) then that will help with the cost factor. Get some tools and a manual. Find some buddies that are mechanically inclined. As far as swaps or a rebuild, I would start with looking into exactly what your current engine needs. Could be as simple as a valve adjustment. Do a compression test on it. This will tell you if the engine is done for or not. Sometimes you can tell if its the head or the bottom end that needs work. Just for reference I had my head reconditioned at a machine shop for about $600 five years ago. Engine swaps are not for novices unless you have a fat wallet and can pay someone to do it. They do not go as smoothly as you would read on the internet. My advice would be to try and fix what you have, if its shot, find another M10 or whatever parts you need to get it running. I have boxes of e21 parts as do others on here. If your willing to get your hands dirty you can save a lot of coin. Here are some swaps you can research:
M20 from E30
M20 from euro 323i
S14 from E30 M3
These are probably the most documented. Lots of guys have turbos, I've even seen S50's from the E36 chassis. I have a lot of paperwork that I've printed off over the years about all kinds E21 stuff. If you want I can photocopy and mail all the engine swap stuff I've collected. Good luck with your car, don't hesitate to ask any questions. We need more E21 guys on here!

DEZIAC
06-10-2008, 11:13 PM
It looks like the car just needs a valve adjustment. Just curious, whats cheaper to throw a turbo on an m10 or to swap the engine w/ a m20? Also which will give me more bhp gain? Thanks