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Jimbo733i
03-19-2004, 05:41 AM
I know they have a higher risk of leaking, and cost more... but I found a place that advertizes $90 custom made copper gaskets, but states "prices are slightly more for OHC engines" so I'd assume less then $150 for one, and thickness can be .022,.032,.040,.043,.048 all the way to .125 inches. Such a range of sizes would allow for lowering or raising of the compression of the engine (not that I know which would be best), and I know a copper headgasket allows higher PSI...

I'm wondering if its too trouble some and they leak too much to bother to get one custom designed...

the main problem is, I'm having a problem finding a shop that even knows the 745i exists, let alone one that has a regular headgasket thats not in a set and doesnt cost an arm and a leg...

Thanks,
~James

J Stein, 85 745, celebrating 10 fun years
03-19-2004, 07:39 AM
With a stock head gasket, and with CORRECT !!!! fueling, these engines are good for a reliable 1.2 bar (est 425+ hp). So, w/a 3.91LSD ... that'll give you wheel spin at 80 mph on wet pavement.. ... btdt ... and it is more than I need...

The trade-off with copper is, IMHO, lots of worry, fuss and lack of reliability... ... but .... you have the bragging rights of "running a copper head gasket" ... I've got all the hp I want and "no worries mon..." with a stock gasket in a 242k mile engine...

So bottom line, keep it fueled corectly and in Jarmo's words (if I remember correctly) ... you can run up to 500 hp...

Remember ... when fueled correctly, the engine is not the weak link in this car... think drive-shafts & trannys (boom bang..) ..... jsRegards

John Stein

<img src="http://members.roadfly.org/john_stein/mugs1.jpg" height=61 width=97>

charlesmorris
03-19-2004, 11:41 AM
and although they did not have a template in stock, they would custom make one if I sent them the old head gasket. Same price range IIRC.

I wouldn't do it though, because of the water leak potential, and as has been pointed out, the stock head gasket is fine if you stay out of detonation and pre-ignition. I lost one while dialing in my 15 psi boost (one too many bursts of audible pinging). My forged pistons were fine though.

Something else to consider: If your head gasket is the strongest link and *doesn't* blow, the piston tops and their ring lands are the next thing to go and are much harder and more expensive to change!

J Stein, 85 745, celebrating 10 fun years
03-19-2004, 12:10 PM
Consider this...

As we (the 745 crowd...) remove the safety features...

ie.. the ~6 psi turbo boost modulation and the 10 psi shutdown Motronic feature, we start to stress other components...

the head gasket is the next safety valve... if you make the head gasket stronger ...next is pistons and rods....

Personally, I'd rather replace a head gasket than a bottom end...

just my .02... or is that $2k ??? jsRegards

John Stein

<img src="http://members.roadfly.org/john_stein/mugs1.jpg" height=61 width=97>

Bill Bowes
03-19-2004, 07:28 PM
Do you mean a cutting ring head gasket or just a regular M30 head gasket that comes with your run of the mill gasket set?

What I'm trying to identify is if the 745i head gasket that comes in their mega bucks 745i gasket is the same as what goes into every other M30 engine.

Thanks,

Bill Bowes

Jimbo733i
03-20-2004, 07:22 AM
apparently they are the same gasket for 745 and 735, according to the ETK they have the same part number of 11 12 1 730 223... so I'll be damned, my search for a 745i specific head gasket just got a hell of a lot easier.

~James

John Stein, 85 745 & 85 ///M6
03-20-2004, 11:01 AM
these things run in groups... Regards

John Stein

<img src="http://members.roadfly.org/john_stein/mugs1.jpg" height=61 width=97>


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