M30 head rebuild... could it GO any slower...

[Robin-535im]

Some in-process pictures of the head rebuild. Not much time to work on it but it's getting there. Head was CNC ported at BEE, I've added new valve guides, 8 new valves, new Eibach valve springs, new Schrick 284 cam, new rocker arms shafts, and a few new rocker arms as required.

As of today I have the rocker arms all put back in, and no need for a special "Iron Maiden" tool if you do it one half at a time.

http://picasaweb.google.com/bobritts/BMWhead/photo#5073697463871482050
http://picasaweb.google.com/bobritts/BMWhead/photo#5073697558360762578
http://picasaweb.google.com/bobritts/BMWhead/photo#5073697639965141218

[BigKriss]

Robin, why didn't you get Schrick valve springs with the new cam?


Some in-process pictures of the head rebuild. Not much time to work on it but it's getting there. Head was CNC ported at BEE, I've added new valve guides, 8 new valves, new Eibach valve springs, new Schrick 284 cam, new rocker arms shafts, and a few new rocker arms as required.

As of today I have the rocker arms all put back in, and no need for a special "Iron Maiden" tool if you do it one half at a time.

http://picasaweb.google.com/bobritts/BMWhead/photo#5073697463871482050
http://picasaweb.google.com/bobritts/BMWhead/photo#5073697558360762578
http://picasaweb.google.com/bobritts/BMWhead/photo#5073697639965141218

[Robin-535im]

Robin, why didn't you get Schrick valve springs with the new cam?
It was like pulling teeth to get anyone to admit the springs were stiffer than stock, and I only found they were Eibach after I read the packaging. No one I spoke with at any of the big BMW hotrod places (Korman, BMP, VAC) knew much about their products besides what was written on the web site. I kind of crossed my fingers and went with VAC since I was getting the cam from them. This was the matchup they "recommended" so I took a risk and trusted they were right. I don't even know I could get Schrick springs... TMS has them now that I look... But even then they list the same part for 1984-1993, and I think the timing chain sprocket is different from the earlier to the later engines, and I know the valves are different, so will the early cam work on the later engine and will the guy on the phone know what the heck you're talking about? As you can see I have low confidence in getting good answers on the phone after this experience! :)

I tested them all out and they're about 50% stiffer than stock, but with a shorter throw (which doesn't matter because once they're mounted on the head the height is constrained by the valve and/or rocker arm).

You should have seen how tough it was to get the right valve guides! Twice we were shipped parts with a different OD than advertised, had to mic them to see what size they really were and send 'em back.

[winfred]

if you have a new cam you really need all new rockers, the cam and rockers break in to one another, and personally i wouldn't do all new rockers on old rocker shafts or vice versa as they wear in to one another, but they are a little less critical then the rocker to cam relationship

[Robin-535im]

if you have a new cam you really need all new rockers, the cam and rockers break in to one another, and personally i wouldn't do all new rockers on old rocker shafts or vice versa as they wear in to one another, but they are a little less critical then the rocker to cam relationship
Good to know - thanks Winfred. What's nine more $15 items at this point... I got some on the way from BMA. This thing is gonna be frickin tight...

[Jon K]

Be glad you don't have 24 valves ;)

[ryan roopnarine]

why is it that your only replacing valves on 4/6 of the cylinders (or 6 exhaust and 2 intake, or &c. &c.)?

[BigKriss]

Acutally I just looked through the schrick catalgoue then. they don't say they are necessary only recommended.

http://img385.imageshack.us/img385/5880/cams1kw4.jpg

[Robin-535im]

why is it that you're only replacing valves on 4/6 of the cylinders (or 6 exhaust and 2 intake, or &c. &c.)?

The head only had 50k miles on it, and many of the valves were not measurably different from the new ones. They were as in-spec as the new ones were so I figured there was no need to replace them. Some of them didn't look like they had even had a grind put on the lip - they were that close to the new ones. The intakes were an off-brand and showed a bit more wear so I replaced all of them with TRW's.

The new cam looks SH compared to the old one. Steeper ascent, and the stock eccentrics work on it just fine. The old cam I had was a regrind and needed oversized eccentrics.

[Robin-535im]

Be glad you don't have 24 valves ;)
No kidding... At least the rocker arm/shaft cost would be gone, but then you're times two on everything else in both cost and effort, not to mention the VANOS ...

[Martin in Bellevue]

The new cam looks SH compared to the old one. Steeper ascent, and the stock eccentrics work on it just fine. The old cam I had was a regrind and needed oversized eccentrics.
What is SH, super hella?

[Robin-535im]

What is SH, super hella?
"Sierra Hotel"

ala

**** Hot

Although I like Super Hella too, as a west coast version :)