I was told that the stock S52 heads come already ported and polished from the factory. Is this true?
Juker008
Originally Posted by 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.
Turbo '99 M Roadster
11.49@130.4 and 570whp@16psi on a stock m52 shortblock.
WTB: Low compression M52 pistons & GT30r or 35r
FS: PT-67 DBB turbo, freshly rebuilt
PM me with questions.
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...Originally Posted by Juker008
Originally Posted by aMiR M3
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..Originally Posted by Juker008
The s50/2 come with a 3angle valve job from the factory.Originally Posted by Juker008
500+ HP TURBO M3 FOR SALE!
Almost all multivalve engines manufacturered today will have a 3 angle valve job.Originally Posted by Mpty3
And more angles doesn't always equal better...
Originally Posted by EMC
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.Originally Posted by aMiR M3
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.
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.
Nick Glantzis
2005 330i ZHP auto with Technique Tuning turbo kit (currently For Sale)
interesting because I was told otherwise by people with a lot of experience with bmw enginesOriginally Posted by NickG
Who's got a copy of ETK? Just check the part numbers.Originally Posted by Spencer
Originally Posted by 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
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.Originally Posted by 98M3_SC
Originally Posted by Spencer
I still have doubts the 325 is probably different cause of no vanos 92 motors...
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.Originally Posted by Mpty3
So what purpose does a 5 angle job serve?
Better seal...seems like overdoing it to me?
Vanos and non-Vanos motors have different cylinder head casting p/n's.Originally Posted by aMiR M3
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.
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.
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.Originally Posted by Balthazarr
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.
Sorry to hijack alittle, but how much would this cost on a 12v?
3 angle cut.
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.Originally Posted by Juker008
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.Originally Posted by Def
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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