E30/M20 head rebuild

Les Davis · **Joined:** Fri Aug 29, 2003 2:04 pm **Posts:** 2059

I'm no BMW expert for sure, but more general engine knowledge. In this case as long as you were not having any bottom end problems before (rod/main bearings) I wouldn't touch them, as Bret stated, you can replace rod bearings while the engine is in the car but main bearings not so much and I wouldn't do one without the other. Either way if your gonna do anything to the bottom end of the motor, I wouldn't half ass it and I'd do a full rebuild ($$$), better to wait until the engine forces you into a full rebuild in my opinion than doing so preemptively unless you looking to do something that will give you some performance gain. The bottom end parts have been spinning together now for a long long time, leave them alone until they quit. There is some chance since you broke a rocker are them some debris got into the oil that could cause some bottom end trouble in the future, but I think you said you found all the pieces so your probably okay there. Definitely replace engine oil/filter and perhaps a magnetic oil plug if you don't already have one to be on the safe side. The baffled oil pan with crank scraper will only increase the likelihood of your bottom end staying together in the future, so if you can afford the extra expense and can swap it with the engine in the car, it would probably be a good idea. I think most of this has already been mentioned mostly, but do a full head rebuild if you gonna pull it. Get the head gasket set rather than just the head gasket, it should include everything you need/want to refresh in the process of pulling the head off.

I think most of it has been mentioned, but you want new rocker arms and valve stem seals obviously, you also most likely want new valve guides and a 3 angle valve job wouldn't hurt or be too expensive. Tom mentioned new valve springs and that is an excellent suggestion on a motor with that sort of mileage. If you drop your head off at CHS he will check everything else and let you know if you need anything else, valves/etc.

I don't know about the German sounding brand names that have been mentioned, I guess they get some special "Hans sauce" on them? I've always had good luck with Felpro stuff myself. And you CANNOT go wrong with using ARP fasteners in every location possible, some German name may sound cooler and in the world of Bimmerdom make you seem cooler, but ARP really makes some good stuff, seriously.

Les Davis · **Joined:** Fri Aug 29, 2003 2:04 pm **Posts:** 2059

Zach Hill wrote:

TomFreeman wrote:

The pan, while $, is a straight bolt on affair...granted you have to drop the front subframe a bit to install. You'd have to do that on the crank scraper anyway.

Oil pan replacement would be separate from head work, right? Drop subframe, drain oil, unbolt pan, install new pan, bolt back up, reinstall subframe, add oil, profit?

What I'm getting at is it sounds like I could do the pan upgrade next year separate from the head rebuild, before racing with sticky tires.

Thanks!

Exactly, there is nothing really about pulling the head that makes doing anything on the bottom end any easier.

Zach Hill · **Posted:** Tue Oct 23, 2012 3:23 pm

Les Davis wrote:

Exactly, there is nothing really about pulling the head that makes doing anything on the bottom end any easier.

Can you tell I've never done this before? :-D

Seriously though, thanks a bunch for your input, Les. Having the advice of people who have done similar jobs in the past is invaluable! :thumbsup:

TomFreeman · **Posted:** Tue Oct 23, 2012 3:36 pm

Zach Hill wrote:

TomFreeman wrote:

The pan, while $, is a straight bolt on affair...granted you have to drop the front subframe a bit to install. You'd have to do that on the crank scraper anyway.

Oil pan replacement would be separate from head work, right? Drop subframe, drain oil, unbolt pan, install new pan, bolt back up, reinstall subframe, add oil, profit?

What I'm getting at is it sounds like I could do the pan upgrade next year separate from the head rebuild, before racing with sticky tires.

Thanks!

Yes, yes, and yes.

Jordan Normark · **Posted:** Tue Oct 23, 2012 4:59 pm

I can also recommend CHS for cylinder head work. I have had 2 heads rebuilt there including unshrouding the valves and larger valves in one head. If you go into the bottom end, I can recommend T-Hoff in Raleigh for the crank work. There are not many places in the area that can work on cranks, but T-Hoff employs a guy from Latin America that really knows his stuff. I had my crank underground .010 at the begining of the year, I plasti-gauged it to double check the work and it was dead in the middle of the factory specs on every journal. You may only need to have the crank polished, but if it needs to be underground you could tell him to take it close to the limits of the specs to free up a little more power :thumbsup:

Charlie Guthrie · **Joined:** Thu Aug 28, 2003 8:14 pm **Posts:** 832

To pull the oilpan I didn't drop the subframe, I just took the bottom nut off the RH engine mount and used a small bottle jack to raise the engine slightly. Seems like I had to drop the oil pump to do this, but it's been a while.
Charlie G

Zach Hill · **Posted:** Mon Oct 29, 2012 6:20 pm

Got the head off, with the help of a friend.

The head:

The broken rocker:

The block:

Ordering all the parts I think I need tonight and will take it to CHS as soon as the parts come in. :thumbsup:

I really appreciate everyone's input. I'll post again when I have more news. I'm hoping to take it on track on the 10th, but we'll see...

Steven Carter · **Posted:** Mon Oct 29, 2012 9:33 pm

Look at those clean injectors

why does #5 & #6 cylinder piston look so different from the others?

Scott Johnson · **Posted:** Tue Oct 30, 2012 7:02 am

coolant probably runs front to rear so 5 and 6 are the hottest.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Hey Zach - I didn't read this whole thread but wanted to chime in on one thing re rockers. BMW updated the OEM part and added extra material where the old style had been failing. If you are concerned about legality you may want to cancel the IE ones and get OEM. I had a rocker failure back in the day and did oe replacements with no issues... they are beefier.

It is easy to reassemble the valvetrain including rockers and rocker shafts at home on the bench, no need to have George do that. Let him do all the work to the valves and springs and complete the assembly at home.

Also my M20 had badly worn cams and I put in an OE replacement when my rocker cracked back in ...gulp... 2001.

Pic of rocker at the track ... Ron S towed me home!

you can see how bad the cam is here:

Zach Hill · **Posted:** Wed Dec 05, 2012 11:43 am

As I'm sure some of you noticed, the cylinder head reinstall was completed and we autocrossed the crap out of the car last weekend! :-D

It runs great, and the butt-dyno says it's a little more powerful (but I suppose that will be truly tested once I get some timed laps on track).

As for Cylinder Head Specialties, I wasn't blown away with their work. I had them clean some parts in the parts washer, and they still had some crap on them that was cleaned afterward with just brake cleaner. The valve cover I believe was cleaned with the oil cap still attached, so now the seal leaks a bit. And when we went to adjust the valves, two of the rocker eccentric adjusters were installed backwards and we had to remove them and swap them. The motor does run great though, so I suppose the important bits were done right. I might shop around next time I need a head rebuilt.

Thanks a lot to everyone who posted the wealth of useful advice in this thread. :thumbsup:

Chuck Branscomb · **Posted:** Fri Dec 07, 2012 9:57 am

MikeWhitney wrote:

Also my M20 had badly worn cams and I put in an OE replacement when my rocker cracked back in ...gulp... 2001.

Time flies! I remember that video you posted from your E30 on Patriot course from maybe 10 years back now. It was the first time I had paid attention to Patriot and thought what a neat course/car combination that was to simply have fun... Link still active someplace?

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

Ask and ye shall receive

Flashback to 2004:

https://www.youtube.com/watch?v=J-Y3ywm ... e=youtu.be

I'm trying to remember the details of that lap, but IIRC, it was shortly after PC was completed and THSCC wanted a recon of the course in CW orientation. I got the opportunity to go out one afternoon to take a lap at speed to report back.

Chuck Branscomb · **Posted:** Tue Dec 11, 2012 9:23 am

That's it, thanks Mike. That course is so much fun to drive that it's really a shame that events solely dedicated to it can't make a business case of it (I suppose).

We should have a club specE30 and hold a time trial event on Patriot with it. You-wreck-it-you-pay type of thing. Heck, VIR should have a stable of those things to rent to clubs to use. I love 400whp as much as anyone else, but there's something about the low/mid-hp balanced package of a well setup E30 that just makes it a lot of fun on a course like Patriot.

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E30/M20 head rebuild

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