M20 885 Cylinder Head w single valve spring

[Motorsport1207]

What is the difference between the 885 cylinder heads that has the dual valve springs vs this one that has the single valve spring. Thanks in advance Ted Sent from my iPhone using Tapatalk

[e30austin]

the cylinder head with single valve springs, is off a 325, Super ETA. the camshaft is also different, than the one found off the 325i.

[Motorsport1207]

the cylinder head with single valve springs, is off a 325, Super ETA. the camshaft is also different, than the one found off the 325i.

Ok, Still learning here. So my next question is what is a super ETA head and where is this used. Can this be used in a standard M20 325 engine? Thanks Sent from my iPhone using Tapatalk

[e30austin]

Ok, Still learning here. So my next question is what is a super ETA head and where is this used. Can this be used in a standard M20 325 engine? Thanks Sent from my iPhone using Tapatalk

the super ETA cyinder head, is exactly the same as the 325i cylinder head. add the 325i twin valve springs and camshaft, and you've got a 325i cylinder head. i would not recommend installing it on a 325e engine. you will drastically lower the compression.

[digger]

isnt there a difference in the drillings for the cam lubrication?

[Motorsport1207]

So is the only difference between a 885 std head and 885 super eta head is the single valve spring.? Is the cam different? Does a super eta head provides more performance to the M20 Sent from my iPhone using Tapatalk

[McGyver]

The m20b25 885 head and the seta 885 head have different cam profiles. I believe the seta cam has less lift, meaning it can't be reground to use as a high performance b25 cam.

I've also heard that there are differences in how many cam bearings have oil journals.

I have both 885 heads sitting in a box, so I guess I could go measure stuff...

more info:

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/274267-885-i-vs-885-seta-strait-answer-please

Ask Matt for more info: MR 325

[ForcedFirebird]

I can help with this, might have done an m20 head, or two, hehe.

885 heads came with single springs in 1988 only. As mentioned, just add inner springs, change the cam to the "k" cam and be done with it. The castings themselves are identical.

I have never heard of, or seen a 4 bearing 885 head. A member on e30tech years ago posted about one, but AFAIK they are all 7 bearings and have a unique 88-only eta 7 bearing cam.

I have converted 200 head to use b25 cams, simple process, just have to angle drill the passages. Never measured a seta cam, but to the eye, it appears closer to the eta than b25 cam with it's pointy lobes (shorter duration). The seta had 8.5:1 compression, b25 8.8:1 and eta 9:1 - so, cams would be different in OEM applications.

[digger]

there is definitely no 4 "bearing" 885, maybe they put a 4 journal cam into the 7 "bearing" head with a different machining applied to the casting. The bare head part numbers are the .different between the 325i and SETA which could be a machining difference applied to the same 885 casting p/n.

The easiest ways is to post pics of the top of the head to show the oil drillings or compare to a m20b25 head.

the SETA barely made more ponys than the regular ETA so the cam must be as weak as the proverbial even though it was hamstrung with a lower CR.....

[Motorsport1207]

The m20b25 885 head and the seta 885 head have different cam profiles. I believe the seta cam has less lift, meaning it can't be reground to use as a high performance b25 cam. I've also heard that there are differences in how many cam bearings have oil journals. I have both 885 heads sitting in a box, so I guess I could go measure stuff... more info: https://www.r3vlimited.com/board/for...-answer-please Ask Matt for more info: MR 325

Maybe I don’t understand, but if the SETA cam has less lift - how can it be re grounded to be a performance camshaft. I thought the performance camshaft would have a higher lift and duration to allow more air into the chamber. Thanks Sent from my iPhone using Tapatalk

[Motorsport1207]

I can help with this, might have done an m20 head, or two, hehe. 885 heads came with single springs in 1988 only. As mentioned, just add inner springs, change the cam to the "k" cam and be done with it. The castings themselves are identical. I have never heard of, or seen a 4 bearing 885 head. A member on e30tech years ago posted about one, but AFAIK they are all 7 bearings and have a unique 88-only eta 7 bearing cam. I have converted 200 head to use b25 cams, simple process, just have to angle drill the passages. Never measured a seta cam, but to the eye, it appears closer to the eta than b25 cam with it's pointy lobes (shorter duration). The seta had 8.5:1 compression, b25 8.8:1 and eta 9:1 - so, cams would be different in OEM applications.

Thanks for the good information. So basically the SETA head was a low performance vs the 325i. The SETA cam is less cam lift as compared to the 325i. I have the camshafts and both heads. I will take a few pics and measure the cam lobes. Also what do you mean by “K” camshaft. Thanks Sent from my iPhone using Tapatalk

[ForcedFirebird]

There's a white "K" painted on a stock 325i cam.

[Motorsport1207]

There's a white "K" painted on a stock 325i cam.

Ok thanks. I will look for that Sent from my iPhone using Tapatalk

[McGyver]

Maybe I don’t understand, but if the SETA cam has less lift - how can it be re grounded to be a performance camshaft. I thought the performance camshaft would have a higher lift and duration to allow more air into the chamber. Thanks Sent from my iPhone using Tapatalk

Re-read my post. I said the seta cam has less lift, so it cannot be reground.

Also, from your original post; Your 885 seta head clearly has 7 cam bearings. It also clearly has all 7 drilled for oil passages to the bearings. To convert that to a b25 head, you'll need dual valve springs and the "k" cam mentioned by ForcedFirebird. If you're putting in a new (or reground) cam, you should either resurface your rockers or replace them so that the hardened pads are square to the new cam.

[Motorsport1207]

Re-read my post. I said the seta cam has less lift, so it cannot be reground. Also, from your original post; Your 885 seta head clearly has 7 cam bearings. It also clearly has all 7 drilled for oil passages to the bearings. To convert that to a b25 head, you'll need dual valve springs and the "k" cam mentioned by ForcedFirebird. If you're putting in a new (or reground) cam, you should either resurface your rockers or replace them so that the hardened pads are square to the new cam.

Ok Thanks, I did not catch that. Sent from my iPhone using Tapatalk