m-6 or 635 cis quest questions

[kepperly]

Hi, My name is Keith Epperly and I just wandered over from the
Porsche Board to ask some advice. I have 5 months left on my
VW lease vehicle and have always wanted an M6. From being a Porsche owner for the last three years, I have discovered there
are a few models of Porsche to stay away from especially the early 928's. I was lucky and bought an 87 slant nose carrera
cabriolet wide body and it has turned out to be a great car.
As with Porsche I'm sure there are certain years of m-6 that are
either too finicky or have flaws but I am starting here for advice.
Anyone familiar with 635's or M-6's please chime in.

Thanks
Keith Eppperly

[KC Ron Carter]

CSI from 1985 are functionally the same.
Me in mine.



1988 and later USA model got the Euro bumbers.

M6 is a 1985 and up also, with the happiest being the 1987 and 1988 models.

Do not be afraid of the Gray market since they are almost the same. On the s38 USA or M88 Euro dual cam multi TB engines there is an issue on the Euro M88 getting a valve spring change.

Here is a link on the issues found.

http://normgrills.net/bcg/Fundamentals_FAQ.html#anchor2383905

Later,

[snowman]

THe main issue with an euro M6 is the valve spring upgrade, it is MANDATORY. The other issue is the 415 wheels. The original 3 piece BBS rims were recalled. They tend to crack and release all the air at once, not a good thing at 150MPH!!! or even any other speed. The one piece ones are safe, but you only have one choice in tires. This is not such a bad thng as I could not feel the difference between these 415 rubbers and the latest Mich Sports 255/40/ZR17 ( except in wet weather).

The euro models have 10.5 compression vs 9.8 compression in the US models. The performance is much better at 10.5 but you just can't get gas for it. You need steady access to 93 octane to make it work. Even the 9.8 can be problematic with the gas situation. There is no knock detector on the euro model. I do not know if the us model has one.

All in all I would rather have the euro model. Learn to live with 104 octane booster and lousy gas. You can retard the timing with the switch on the back of the computer by about 2.5 degrees which will save the engine.

An updated spark and fuel sysyem, such as electromotive or Motec would make it possible to obtain full power, but at the added price of the system. It might be possible to use the fuel/spark system from a later M5.

I rebuilt one myself and it cost about $6K in parts alone. Not cheep but its worth it.

If the pistons are still good ( not likely with the crappy gas we have) it may only cost about $4.5K, Thats JUST PARTS AND MACHINE LABOR! A fastory short block is about $15K. Still leaves the heads.

DO NOT let just anyone work on the heads!!! They cannot be shaved, nothing, nada!!! There are NO thicker head gaskets available. THe heads must be straightened with a solid block of metal attached, and heat cycled in an oven. ONe to 3 thou max, if its absolutely necessary, no more. If you do you will have to compensate the valve timing. This may or may not be possible. Use ONLY a shop that Dinan uses for the heads, NO ONE ELSE!!! Or you are on your own. IF you have the head shaved remember the cam. It must also be straight, Not possible if the head is shaved at an angle. THIS IS AN EXPENSIVE< READ EXPENSIVE HEAD!! Get the replacement price first if you have any doubt.

If you rebuild consider converting to a double timing chain. Contact someone like Bekker (SP???) Imports, see any Roundel.

Its an excellent car. I have had one for over 225K miles and will never sell it.

[kepperly]

finally, you guys don't visit your board often enough. thanks for the two
posts. Ron is yours a stick.

Keith

[KC Ron Carter]

Later,

[kepperly]

Guys,
need help, just found an 82 633 5-speed on ebay with 61000 miles , 5 speed original owner. D\Car will probably go for 7500.00
is there anything that I need to ask before bidding. please chim in fast because auction ends on Sunday..


Keith Epperly 87 slant nose turbo look cabriolet carrera

[snowman]

accidents, compression check, (inspection by bmw mechanic as final condition of purchase), rear suspension mount breaks, a lot, on this model, has it been reinforced? finally thats a high price for an 82. Check the blue book and prices at the mileage it has on it. I have seen 82 thru 85 6ers for about $3,500 to $4,500 in CA.

[kepperly]

Snow man, thanks the price is relevant but what can a guy buy for under 10k thats worth a ****

keith

[prairieman]

wow - I live about 40 miles south of Wichita, but I commute there daily.

A decent 633 or 635 can be had for a lot less than 10K. A nice M6 or M635 will cost you more than 10K.

As for the 633/635 - there was a significant chassis change in 1981-1982. These cars are based on the 5 series. The early 6 series is similar to the E12 and the later cars are based on the E28 layout.

I prefer the earlier cars - simpler electronics and arguably, a more rugged suspension.

If I were pursuing an M car - it would have to be an M635. More power, more attractive bumpers.

I know a guy at Boeing who is contemplating the sale of a late 635CSi, but it's an automatic.

be patient, it took me a couple months of deliberate searching. Bought a very nice 1979 633CSi for 4K dollars.

e-mail me if you have additional questions. I'm in Wichita everyday.

Prairieman
1979 633CSi
1981 745i
1988 M3
1992 735i

[snowman]

Any car, under $10K, is a risk, even a brand new one. A BMW, 3.0, 5, 6, or 7 series for under $10k can be a bargain, if everything is right, or a downright total loss. To get a good one you need to know the original owner, have complete maintainence records, and have the car inspected by a very competent, experienced, factory trained, BMW mechanic. Or be just downright luckey. In general you tend to get what you pay for, so do not expect more.

[Jared at Pelican Parts]

Also, try to avoid any car with Self Levelling Suspension problems as the parts are incredibly expensive to replace, not to mention some parts are now unavailable.

[snowman]

Originally posted by Jared at Pelican Parts
Also, try to avoid any car with Self Levelling Suspension problems as the parts are incredibly expensive to replace, not to mention some parts are now unavailable.

Don't let this be a deal killer as standard suspension can be substituted for the self leveling at no more cost than replacing just the standard suspension components, ie shocks and springs.

[kepperly]

Praireman,
You must work at the GE engine facility in Ark City. You will have to come up to the Porsche shed some Saturday and meet someof the Guys.

Keith Epperly

[prairieman]

hi Keith.

I worked there for awhile, but I'm in Wichita now, covering Boeing and McConnell. I'm in Wichita all day Mon. thru Fri.

Is it your slantnose I've seen on McConnell property ?

[kepperly]

praireman, no mines yellow, the green one you might have seen
belongs to an Air Force Captain. Just saw another 6 car on ebay in ne, 89 with 89000 miles looks very nice white pearl with tan.
see what you think.

keith

[prairieman]

I thought you wanted a 5-speed car.

the late model 635CSi's are more cruiser than sports car.

that one appears to be a decent example, but I wouldn't bid unless I had a CARFAX report.


if you want an automatic, there is a nice car in Wichita.