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Thread: No Hotrod Valves for M30...

  1. #1
    Join Date
    Jan 2004
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    1,235

    Default No Hotrod Valves for M30...

    Just an FYI for anyone rebuilding an M30 head... So far I haven't been able to locate anything other than stock valves, called Korman, BMP, VAC, and visited with local "builders". Lots of choices for hotter springs and various cams available but no one sells lighter/stronger valves. Which is good I guess, says something about stock parts.

    Local guy charges $44/$45 for exhaust/intake valves, and that was a "special" deal for me because he's such a nice guy. BMA has them for half that!

    I'm thinking of cutting down the part of the valve guide that hangs into the throttle throat like a big brass tonsil. I don't suppose anyone has any experience with that? BMW usually does things for a reason I assume, so maybe it's needed for stability. The guy at Korman (not Ray, a guy in sales) was pretty confident it was just fine. Sure looks like a major obstruction in the airway though.

    - Robin
    Robin

    72 Chevy K10
    01 E39 M5

  2. #2
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    baton rouge, loserana
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    Default

    ireland has 38 39 and 46 47 mm, depending on year some of those are upgrade sizes https://secure17.nexternal.com/share...unt2=198997139
    all america wants is cold beer warm cat and a place to take a poop with a door on it

  3. #3
    Join Date
    Jan 2004
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    4,150

    Default There's always

    lighter and stronger, depends on the pocketbook





    Quote Originally Posted by Robin-535im
    Just an FYI for anyone rebuilding an M30 head... So far I haven't been able to locate anything other than stock valves, called Korman, BMP, VAC, and visited with local "builders". Lots of choices for hotter springs and various cams available but no one sells lighter/stronger valves. Which is good I guess, says something about stock parts.

    Local guy charges $44/$45 for exhaust/intake valves, and that was a "special" deal for me because he's such a nice guy. BMA has them for half that!

    I'm thinking of cutting down the part of the valve guide that hangs into the throttle throat like a big brass tonsil. I don't suppose anyone has any experience with that? BMW usually does things for a reason I assume, so maybe it's needed for stability. The guy at Korman (not Ray, a guy in sales) was pretty confident it was just fine. Sure looks like a major obstruction in the airway though.

    - Robin
    Attached Images Attached Images   


  4. #4
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  5. #5
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    Default

    Quote Originally Posted by Bill R.
    lighter and stronger, depends on the pocketbook
    I'm afraid to ask what they would cost... Sure look like more than a $23 part to me!
    Robin

    72 Chevy K10
    01 E39 M5

  6. #6
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    Jan 2004
    Location
    Melbourne, Australia
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    Default

    The M30 camshaft and inlet tract including the head ports are carefully designed to give good mid range torque and overall performance. It looks to me as if the port is shaped as it is to help guide the intake charge smoothly past the valve guide boss, which compared to many heads does not project much into the actual airstream.
    I had my cylinder head ported by a professional who had done many of these heads. My aim was to make the thing work as well as possible without resorting to 'performance cams' and bigger valves and I particularly did not want to destroy the bottom end performance.
    Hogging out the ports may help high rev performance but will surely stuff it up everywhere else.
    The head guy did not remove lots of material from the head - the main object was to smooth the flow, remove sources of turbulence, and improve flow into the cylinders at low valve lifts. He did not touch the valve guide boss much at all and we reused the stock valves and springs, but with new valve guide inserts.
    Anyway the result is about 12 to 15hp increase in max power but more importantly (to me) improved torque right throught the range. And it pulls very strongly all the way to 6800 rpm in the lower gears, with typical surge from about 3800.
    I realize some of this improvement would be due to the fresh head irrespective of the porting, but the engine had only done 65000 miles so the head was pretty 'fresh' anyway.
    Unless you plan to turn your M30 into a different kind of beast altogether and regularly drive in the rev range 6500 to 7000 plus I doubt you need bigger and lighter valves and all that stuff.

    Bill G Melbourne Australia

  7. #7
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    Default

    Quote Originally Posted by bill g
    The M30 camshaft and inlet tract including the head ports are carefully designed to give good mid range torque and overall performance. It looks to me as if the port is shaped as it is to help guide the intake charge smoothly past the valve guide boss, which compared to many heads does not project much into the actual airstream.
    ...
    Unless you plan to turn your M30 into a different kind of beast altogether and regularly drive in the rev range 6500 to 7000 plus I doubt you need bigger and lighter valves and all that stuff.

    Bill G Melbourne Australia
    I agree 100%. I tend to have faith in the design team at BMW, even if the shade tree hot rod in me has different ideas. I plan to use the stock valves, and maybe new stock springs or new HD springs, with a Schrick 284.

    Jeff N and I discussed this last week. I could imagine low-flow velocity & low end torque could suffer if the inlet was too free flowing, especially if there is a point in the flow where it slows due to an enlarged area.

    My secret plans for this beast include m5 throttle bodies & headers, which are already on the way from Germany. Probably I'll end up screwing it all up and will have cool throttle bodies with terrible flow! Still not sure about hogging out the guides with the tb's... Definitely will take your experience under consideration...
    Robin

    72 Chevy K10
    01 E39 M5

  8. #8
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    Dec 2003
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    1,640

    Default Whatever you do, take lots of pictures...

    Robin - BTW, I may have some answers forthcoming on the tuning problems I related on the phone. I'm arranging a meet-up with Dan Miller from Miller Performance to see what they may be able to do. Spoke with them on the phone and they seem be pretty interesting, smart guys who can tackle the problem.


    Quote Originally Posted by Robin-535im
    I agree 100%. I tend to have faith in the design team at BMW, even if the shade tree hot rod in me has different ideas. I plan to use the stock valves, and maybe new stock springs or new HD springs, with a Schrick 284.

    Jeff N and I discussed this last week. I could imagine low-flow velocity & low end torque could suffer if the inlet was too free flowing, especially if there is a point in the flow where it slows due to an enlarged area.

    My secret plans for this beast include m5 throttle bodies & headers, which are already on the way from Germany. Probably I'll end up screwing it all up and will have cool throttle bodies with terrible flow! Still not sure about hogging out the guides with the tb's... Definitely will take your experience under consideration...
    Bellevue WA
    90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
    86 Porsche 951 - Track Toy

  9. #9
    Join Date
    Dec 2003
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    1,640

    Default uh...how many of those daughters are you willing to forego?

    .
    Quote Originally Posted by Robin-535im
    I'm afraid to ask what they would cost... Sure look like more than a $23 part to me!
    Bellevue WA
    90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
    86 Porsche 951 - Track Toy

  10. #10
    Join Date
    Jan 2004
    Posts
    128

    Default

    Which M5 TB's, E28 or E34 ? Diameter of the throttles ? Which type of ECU and cam are you using ?

    How are you mounting them to the head ?

    I started a similar project with some E28 M5 TB's on my M30 but gave up on it inplace for some thing simpler(see pic below), a friend who is more dedicated to seeing the project done had them off me for his E30 335 turbo.

    He ended up having to chop one of the pipe stubs from the 'stat housing and use an angled/bent bit of tubing from another car to clear the TB's. You should be OK on the E34 chasis but he had to move the brake servo over, use a smaller servo and had to cut/weld a bit of the plenum to fit. Plus some other stuff needed doing to get them to work, a PITA in other words.

    Good luck with the project, i hope it goes well for you.

    (still not fitted properly yet, twin 60mm TB)


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