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Thread: Are the S52 Engine Stock Ported and Polished

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    Are the S52 Engine Stock Ported and Polished

    I was told that the stock S52 heads come already ported and polished from the factory. Is this true?






    Juker008

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    Quote Originally Posted by Juker008
    I was told that the stock S52 heads come already ported and polished from the factory. Is this true?






    Juker008

    Umm ported heads mean that the port size has been increased over the size of a stock port. How can the factory ports be bigger than stock?

    Polished is a different thing, and no the stock s52 ports aren't polished, but they are a bit smoother than some of the other auto manufacturers heads I've seen.

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    Ported from previous versions of the head. Isn't it the same head that has been used on older engine models?







    Juker008

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    Quote Originally Posted by Juker008
    Ported from previous versions of the head. Isn't it the same head that has been used on older engine models?







    Juker008
    they are similar but no because the 3.0l head actually flows better than the 3.2l head...

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    Quote Originally Posted by aMiR M3
    they are similar but no because the 3.0l head actually flows better than the 3.2l head...

    Huh??? U sure its not just the intake manifold?







    Juker008

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    Quote Originally Posted by Juker008
    Huh??? U sure its not just the intake manifold?







    Juker008
    Yes I know for a fact they do..as many change ther heads to the 3.0 heads with a 3.2 bottom end just to get better flow..

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    Quote Originally Posted by Juker008
    I was told that the stock S52 heads come already ported and polished from the factory. Is this true?
    The s50/2 come with a 3angle valve job from the factory.

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    Quote Originally Posted by aMiR M3
    Yes I know for a fact they do..as many change ther heads to the 3.0 heads with a 3.2 bottom end just to get better flow..
    ??? I don't know about that. I have a few cylinder heads sitting at my shop and I can't tell a difference betweek the ports. There are a few external differences, but I think you are talking about the intake manifolds.

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    Quote Originally Posted by Mpty3
    The s50/2 come with a 3angle valve job from the factory.
    Almost all multivalve engines manufacturered today will have a 3 angle valve job.

    And more angles doesn't always equal better...

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    Quote Originally Posted by EMC
    ??? I don't know about that. I have a few cylinder heads sitting at my shop and I can't tell a difference betweek the ports. There are a few external differences, but I think you are talking about the intake manifolds.

    I don't know the exact reasons but no it is not and i repeat again and again because of the intake manifold..that is another whole story. My bro's car which had the motor done by stickly has the lightweight 3.0 head on the 3.2l bottom end and he is making more NA hp than anyother NA M3 with the same mods as his..I have asked many people before and they say the 3.0 head just flows better and the 3.0 lightweight head even flows better. I am sure someone on here knows exact details and can chime in...

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    Quote Originally Posted by aMiR M3
    I don't know the exact reasons but no it is not and i repeat again and again because of the intake manifold..that is another whole story. My bro's car which had the motor done by stickly has the lightweight 3.0 head on the 3.2l bottom end and he is making more NA hp than anyother NA M3 with the same mods as his..I have asked many people before and they say the 3.0 head just flows better and the 3.0 lightweight head even flows better. I am sure someone on here knows exact details and can chime in...
    Castings are the same for all S50/52 heads to my knowledge.

    I think the 3.0 head on 3.2 is just a common occurence when 3.0 engine owners slap on a 3.2 bottom engine and retain the head.

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    BMW states in their literature that the S50/S52 (ie, M3) head is a ported and polished version of the standard M50/M52 head. But if you compare them, all the ports on the passages are identical. No porting or polishing was ever done. They all use the same part number casting also. So in effect, all these heads are exactly the same.
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    Quote Originally Posted by NickG
    BMW states in their literature that the S50/S52 (ie, M3) head is a ported and polished version of the standard M50/M52 head. But if you compare them, all the ports on the passages are identical. No porting or polishing was ever done. They all use the same part number casting also. So in effect, all these heads are exactly the same.
    interesting because I was told otherwise by people with a lot of experience with bmw engines

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    Quote Originally Posted by Spencer
    Castings are the same for all S50/52 heads to my knowledge.

    I think the 3.0 head on 3.2 is just a common occurence when 3.0 engine owners slap on a 3.2 bottom engine and retain the head.
    Who's got a copy of ETK? Just check the part numbers.

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    no no

    Quote Originally Posted by Juker008
    I was told that the stock S52 heads come already ported and polished from the factory. Is this true?






    Juker008

    Hi Juker


    They are not ported or polished but the port shapes are excelent from the factory. The new s54 head ports are CNC ported from the fatory. The wall finish is also very fine wich is good for the exhaust side.


    Osh M

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    Quote Originally Posted by 98M3_SC
    Who's got a copy of ETK? Just check the part numbers.
    Did a quick serach. The 3.0, 3.2 and 2.8 all have cylinder head casting p/n 11 12 1 703 637. The 2.5 p/n is different.

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    Quote Originally Posted by Spencer
    Did a quick serach. The 3.0, 3.2 and 2.8 all have cylinder head casting p/n 11 12 1 703 637. The 2.5 p/n is different.

    I still have doubts the 325 is probably different cause of no vanos 92 motors...

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    Quote Originally Posted by Mpty3
    The s50/2 come with a 3angle valve job from the factory.
    All modern engines come from the factory with a 'three angle' valve job. You need to have three angles to form a sealing surface on the valve seat.

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    So what purpose does a 5 angle job serve?
    Better seal...seems like overdoing it to me?

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    Quote Originally Posted by aMiR M3
    I still have doubts the 325 is probably different cause of no vanos 92 motors...
    Vanos and non-Vanos motors have different cylinder head casting p/n's.

    This debate whether or not different year heads flow better is really not worth discussing unless someone can flowbench different heads which I doubt is going to happen.

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    95 m3 lightweight got the exact same motor as the one in the normal m3's but they just put the strongest of the 3.0's in the lTW's the engines are identical.

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    Quote Originally Posted by Balthazarr
    So what purpose does a 5 angle job serve?
    Better seal...seems like overdoing it to me?
    If done correctly, more angles equals more flow around the valve, especially at low lifts. It serves to blend the port into the valve seat and combustion chamber. Creating a smooth passage for air.

    You really only need 1 angled cut to make sure the valve seals, not three. Although almost every modern engine has three or more angles(or cuts) due to the large efficiency benefits as I mentioned earlier.

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    Sorry to hijack alittle, but how much would this cost on a 12v?
    3 angle cut.

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    Quote Originally Posted by Juker008
    I was told that the stock S52 heads come already ported and polished from the factory. Is this true?






    Juker008
    I just walked out into my shop where we have a brand new S54 sitting on an engine stand. The intake ports have been machined 'smooth' from the factory although there are quite a few tool marks. The exhaust side is left as cast although the casting is relatively fine.

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    Quote Originally Posted by Def

    You really only need 1 angled cut to make sure the valve seals, not three. Although almost every modern engine has three or more angles(or cuts) due to the large efficiency benefits as I mentioned earlier.
    That's not entirely true (the part about 1 angle) unless you're talking about a model T. The object of valve seat grinding is to obtain a valve seat of the correct width and uniform width all the way around. The valve seat must also be located in the correct position on the valve face. Valve seat width is critical. Too wide a seat tends to trap carbon (as you would have with 'one angle') and too narrow a seat does not transfer heat fast enough and can cause burning.

    The valve face usually has a 44 degree 'interference' angle on it and the sealing surface of the valve seat is usually 45 degrees. In order to position the valve seat correctly on the valve face a 30 degree cut is taken from the top of the seat and a 60 degree cut taken from the throat to narrow and position the seat in the proper area.

    There are several excellent books on engine machining including the one which I got the above info from called, 'Engine Service' by Gary Lewis, Prentice-Hall Publishers. Gary is a teacher at DeAnza College's Automotive Technology department in Cupertino, Ca. If you are local to the bay area you should be able to pick up the book in the book store or from the tool crib in the auto tech department.

    -Scott Tucker

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