Metric Mechanic M20: Is it worth it?

[craigrolf]

What do you guys think of this motor? I want to upgrade my engine to either a rebuild with mods, or a Baby Six 2900. What is the most cost effective way of the two? The Baby Six is a 2.9L, correct? With all that extra displacement, wouldn't there be torque to match that 205hp rating? Alright guys, I won't expect any immediate answers, but at least I tried. Hehe . --Craig

[Spencer]

How much do they want for the M20?

IMO, an S52 powered E30 is the way to go.

[craigrolf]

Well Spencer, they want $4,995 for the 2900 HiFlo ST 325i & 323i and $1200 core deposit. If you want to look at the engine, it is at:http://www.metricmechanic.com/pg8.htm I think it's too expensive, and that I can get an S52 w/tranny for less and make more power. What do you think?

[Jon325i]

The MM motors are considered a bit pricy by many. I suppose if you were hell-bent on keeping an M20 under the hood but with better power it could be an option. Of course you could build a M20 stroker of your own by piecing together some eta parts or using a 524td forged crank. Heck...even an M50 or S50 crank for that matter.

You are correct in your observation about the price. For that kind of money you could easily stuff a twin-cam under the hood and have considerably more power and torque everywhere in the revband. Another option is dropping in an M30 from a E28/E34 5 series or E32 7 series. Someone on here is in the process of doing this swap. These motors can be had for dirt cheap pricing...and if you think the M20 is durable, the M30 is all that and more. Probably the most robust straight 6 ever made by BMW. With just small mods such as JC chip, higher low rate injectors and perhaps minor tweaking to the intake will have you in the solid 225+HP range and torque at or near 240ft/lbs.

Finally, the weight penalty of the M30 is very similar to dropping in a twin cam motor, so you could expect similar handling traits. Of course, suspension tweaking will help combat this.

Jon

[jcsomerset]

Yup the M30's are THE BULLETPROOF engines for sure.

Knowing what I know now- if i decided to do something that large ticket to my e30 - I'd just get a turbo kit from TCD and get better Hp/Torque; etc. and still have a dirt cheap engine to deal with.

That is the trade off for going with M50 or S52 vs M20 or M30 - you may get more power but you also get higher parts costs (and higher mod part costs). I had the head welded (broken rocker shaft bosses) remanufactured on the E30 with all new exhaust valves for like $650.

[craigrolf]

Excellent tips guys, I appreciate it! I would certainly like a big six under the hood. I miss having the torque of larger displacement six cyl. The M30 sounds like a real nice motor. How are they for pricing and just where should I look for one? I'll do some searching, but are there some sites in particular that would refine my quest? Thanks, in advance. --Craig