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Picture request: M20B27 325e/525e ETA camshaft

E28 technical advice asked and given! Troubleshooting, modifications and more.
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szacsi72
Posts: 342
Joined: Nov 13, 2022 3:41 AM
Location: Hungary

Picture request: M20B27 325e/525e ETA camshaft

Post by szacsi72 »

Hi all,

So this info is floating around that the ETA has only 4 cam bearings vs 7 in the normal 25i head. OK, sounds fair to me with such a low rev limit - however; every single picture I have found online of a #200 head has 7 cam bearings, not 4. I have not found a single picture where it had 4.

OK - I thought maybe the camshaft only has 4 journals and at those 3, the diameter is just machined smaller - but I have not found a SINGLE picture of an ETA cam.

Any help here?
Thanks.
JohnH
Posts: 724
Joined: Jan 24, 2007 9:55 AM
Location: Surrey,UK

Re: Picture request: M20B27 325e/525e ETA camshaft

Post by JohnH »

Heres a pic of an eta cam that I removed from a 200 head (build date sept 1986). The one above it is a 520i cam from a 731 head (build date Feb 1986).
  Image
turbodan
Posts: 9366
Joined: Jan 09, 2007 10:19 PM

Re: Picture request: M20B27 325e/525e ETA camshaft

Post by turbodan »

szacsi72 wrote: Jun 16, 2025 8:09 AM Hi all,

So this info is floating around that the ETA has only 4 cam bearings vs 7 in the normal 25i head. OK, sounds fair to me with such a low rev limit - however; every single picture I have found online of a #200 head has 7 cam bearings, not 4. I have not found a single picture where it had 4.

OK - I thought maybe the camshaft only has 4 journals and at those 3, the diameter is just machined smaller - but I have not found a SINGLE picture of an ETA cam.

Any help here?
Thanks.
The journals in the eta head are machined and finished as if they were going to be used. The difference is that the cam only has four journals and the head is only drilled to lubricate the bearings that are utilized.

You can plug a seven bearing cam directly into a -200 or super eta -885 head if you drill four additional holes required to properly feed across the cam and supply the extra three journals. 
szacsi72
Posts: 342
Joined: Nov 13, 2022 3:41 AM
Location: Hungary

Re: Picture request: M20B27 325e/525e ETA camshaft

Post by szacsi72 »

Awesome. Thanks a lot.
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