The M6 didn't work out. Just too much abuse, a real shame. Also from what I'm seeing, real nice, well-cared for M6s are outside my budget.

I'm looking at an 87 635CSi with 158K miles, 5 speed, very nice and an 88 635CSi, 165K miles, 5 speed, that's also in pretty good shape but not as nice as the 87.

I see that the 87 was speced at 3.4L, 8.0 CR, 182HP, 214lb-ft while the 88 and 89 was speced at 3.5L, 9.0 CR, 208HP, 225lb-ft. I've driven both and the 88 was much faster and pulled very strong while the 87 (which I drove first) was very smooth but little "zip". My previous car was a 98 M3 but I'm not looking for that level of "zip" from a sixer.

I'm just wondering what the trade-offs are between these 2 engines as far as durability and maintenance requirements given the mileage.

Thanks for any help here.

Ken

Between the 2 I'd go with the 88 - for starters, if it's a factory stick from 88; they only imported 185 factory sticks from 1988 (111 from 89, so those are even rarer).

I know that the heads for these cars were the same design used on the new bodied 7 series (E 32?) from that time. (that's why it has more HP/TQ, etc) and I THINK.. Check on this, But I THINK they don't require the valve adjustments that the earlier models do...

and just to get you thinking - slap a TCD turbo on either of those cars and you've got yourself a real M-killer.

Good Luck - and a really active 6er board is over at www.roadfly.org

The issue is the compression ratio.

All the Euro standard engines had higher compression ratios.

That requires higher octane and most are not chipable.

Also the USA 8,0 compression engine shares Bosch engine management systems with e28 and e23 in the same year.

If the feel of the car is the issue a change in differential ratio is the best performance for the dollar modification.

The e24 shares differentials with e30-6, E24, E28, and even the Z3 in a lower ratio.

Later,