M50 head on M52

[Beej '86 325es]

What happened to Stu? He had all the answers to this type of stuff...

[E304life]

You can use a vanos block and head and dissable the vanos. You still use the vanos housing for the front cover, you just gut it. I know this for a fact the old shop I worked at did this on a few cars.

[PiercedE30]

if you go that route then you have a wider selection of cams as well, or atleast they are easier to get a hold of.

[DanThe]

How would you go about dropping the Vanos? Weld the gear in timing position? Different sprocket?

I was under the impression the NV head had better valve gear as standard?

[E304life]

How would you go about dropping the Vanos? Weld the gear in timing position? Different sprocket?

I was under the impression the NV head had better valve gear as standard?

You take the vanos unit off the front of the cylinder head, unbolt the bolts from the back of the vanos unit(this eliminates the gear on the vanos side that has teeth on the inside and outside, the one that slides onto the teeth
that stick out from the intake cam).

Then on the cam side you replace the funky bolts that have threaded rod/hex/threaded rod with normal bolts. Then you bolt the gutted vanos unit
back on the head, it is now just a cover for the front of the head.

The non vanos M50 has more agressive cams and dual valve springs.

[DanThe]

So the non vanos head is going to be the one to use, depending on the valve/piston clearance

[raimo]

the best combination would be using non-vanos m50 cams and valve springs on a m52 head (lighter valves and better lifters)
the m52 heads and 525i m50 heads are the same, realoem shows that too. the e36 have a differents part number but i think they are also the same.
i have both the heads at my garage but the m50 head is still on the engine. i will take the head off for some maintainence, then i can look into that valve-piston cleareance issue. i dont know yet when i have time for it, hopefully this month.


i have a question myself. if i use the m50b25 head and everything else on the m52b28 block, will the ecu work with a setup like this ? id like to go standalone but with all the bodywork and suspension work its not in my budget right now.

[raimo]

if i use the m50b25 head and everything else on the m52b28 block, will the ecu work with a setup like this ?

[DanThe]

ECU will work yeah, your only swapping the block, I took the head of a NV 2.5 today and the inlet valves protrude the head face slightly, unlike the 2.8 M52 I took apart the other week, so im guesing (hoping) the NV head will also give more compresion

Havnt got round to measuring cams and valves yet though

[DanThe]

Inlet cam on the M50 N/V has 1mm higher lobes than the the M52.

Think I will be stripping the M52 block and re-building the crank and rods into the M50 N/V as ive noticed the ally block has cylinder liners which apparently rise up and drop back down which leads to head gasket failure