New engine or Rebuild

[Big Berk]

Im planning on getting a high milage e30 325i but due to the high mileage it'll probably give out in a couple months maybe, Im talking 200k+ miles. Im new to doing big jobs on a car so Im not well knowledged on it all like most people on these fourms. My question is, for a new guy working on these cars, should I just take a risk at buying another engine that has lower miles ( if what the guy that sells me the engine tells me the real mileage) and work on switching that out with the current engine OR should I try and rebuild the engine? I have no experience in either of these fields but we all need to start somewhere.
1. If I choose to change engine what are some things I should watchout for that will cause problems later on and , if any, what parts do I need to replace for the new motor to fit in or any parts that I should renew while the engine is out?
2. If I choose to rebuild the engine, basically what parts do I need to get to replace in the current engine. The main question is how do I rebuild a engine? What do I replace and what do I do? If I actually get past putting everything together, do I need to get it tuned? I know I come off as a complete new guy to all this but I really want to learn and even if I cant do it Ill get some experience out of it until I can
3. Are the parts I need for the rebuild easy to find? Any certain site you guys use often that have reasonably priced parts that I can order them off?
4. How much will each cost me, I know an engine goes for 400 but a rebuild I keep seeing goes for like 3 grand. Im more on the side of rebuilding since I personally will know whats been done to my cars engine instead of relying on some random engine I find.

I know Im asking for a lot of info but whoever out there could help me with these questions I would really appreciate it. Im just a teen trying to get into e30 and more in depth in working on engines.

Any extra information would be really appreciated. Thank you for your time.

[Ether-D]

Well, a 200k motor may well last another 200k. So you could be ok. Read as much as you can. Look up bulletride's build in the m20 sub forum. It's super informative. Good luck and welcome.

[jlevie]

A 200k engine almost certainly will need an overbore and new pistons. That alone will cost at least $800 in machine work and parts. And the head from that engine will need new guides, exhaust valves, and probably a new cam and rockers, Probably $2-3K. So figure $5-7k in all for a zero time engine rebuild. A good lower mileage (less than 150k) may run no more than $1500, but it will probably need a head refresh, injector rebuilds, and all new gaskets and seals. Figure on about $2500 ready to be installed.

[Big Berk]

I want to rebuild this car to be a DD and just small modifications after. What is the minimum or maybe a little more I can do to rebuild the engine. Nothing big or crazy unless it's necessary. I've been reading up on it and some say just replacing seals gaskets hoses and things like that is enough.

[jlevie]

Replacing hoses and gaskets does nothing about the internal wear in the engine, but it will eliminate leaks. Other than being somewhat down on power and perhaps using more oil, a 200k engine may be okay for a daily driver. These engines are pretty rugged and unless mistreated will last well past the 200k mark. Hot compression and leak down tests will tell you a lot about the degree of wear in the block or the head.

[Jon325i]

You made no mention of it in your post, so I will ask....

What are your concerns for wanting to rebuild/replace your M20? Is it burning an excessing amount of oil....maybe to the point you have smoke belching from the tailpipe (especially under load, like accelerating)?

Have you done a compression AND leak down test on all cylinders? This alone can tell you a lot about the health of a motor.

Is the motor considerably down on power?

Just because an M20 is approaching (or has exceeded) the 200k mile mark does not mean that a rebuild/replacement engine is required. You have a low post count here so I can only assume you're relatively new to E30s? Speaking from personal experience, I've had 3 E30s in all......2 of them had over 200K miles and were running strong when I sold them. A friend of mine used to have an E30 which did occasional track days and was a strong runner with 260K miles on the clock. My point is this: if an M20 has been properly maintained and not thrashed on day-in and day-out, getting 300K miles out of one is not unusual, especially the 'eta' models.

Before you plunk down your hard earned money, have the engine evaluated by at least 2 different independent shops/mechanics. Heck, have an oil analysis done too if you want to see what metallic particulate matter may be suspended in your oil. Really look at all options before you make the (considerable) investment in your E30.


Jon

[Big Berk]

I am new to e30s, all engines too, your right about that. I do not know about these engines, other then everything you guys have told me, now that I know that they last a decent amount Ill probably just keep maintaining it well but I still need this info for when the day comes that I need to rebuild or change the engine.
Also, about those tests, Im guessing I gotta take it to a mechanic or can I do them myself?
And, any other tests or problems I should look out for now that can give me big problems later on?

[TurboJake]

200k miles? That's it? It's still a toddler... Past its teething age, but still a young'n.

[Jon325i]

I am new to e30s, all engines too, your right about that. I do not know about these engines, other then everything you guys have told me, now that I know that they last a decent amount Ill probably just keep maintaining it well but I still need this info for when the day comes that I need to rebuild or change the engine.
Also, about those tests, Im guessing I gotta take it to a mechanic or can I do them myself?
And, any other tests or problems I should look out for now that can give me big problems later on?

Compression/leak down tests can be done if you have the tools for the job, if not, consult a pro you know & trust.

Oil analysis can be done by simply collecting a sample and send it to a local lab in your area.

Those are the big ones....they can reveal a lot about the health of an engine. Aside from that, just follow the maintenance intervals. If you track or auto-x, perform the intervals closer together since you're accelerating the wear on parts when driving hard.

For the M20s, timing belts are important. If you don't know the age of yours, replace it ASAP and do the tensioner, water pump, coolant hoses, and thermostat (you'll be removing all these to get to the timing belt...might as well throw new stuff in since you have the motor apart).

Run good oil & filter and change them every 3K miles. Decent oil and filter won't cost you more than $25-30 on this car. Go with Mobil 1 and spend a few more bucks if you want.

Make sure valves are properly adjusted.

Maintain coolant level and flush every year (perhaps more frequently if you track or auto-x).

These are just basic common sense things you would do for any car. Stick to these and your M20 will last a while.


Jon