Step by Step Process for S38 Head Removal

Specific conversations and info for the BMW E28 M5 and M535i.
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Syndrome
Posts: 128
Joined: Nov 23, 2021 3:46 PM
Location: DC

Step by Step Process for S38 Head Removal

Post by Syndrome »

Hi everyone. I need some detailed advice please. I have a pretty nice 1988 E28 M5 that has not run in several of years, after an overheat. I really would like to try to fix it myself rather than paying a mechanic to do it for me. My sense and hope is that it has a blown head gasket and possible cylinder head warping. I’m hopeful the block is OK and neither part has any cracking. Money is tight but I’m a hopeful type. Not naive, just hopeful.

Now, I’ve built a couple of old Porsche engines, so I’m not completely clueless, but I’m just a desk jockey who has no experience with BMW motors. I want to leave the engine in the car, just to make it more “fun”. I’ve been searching for many days and have not found a step by step guide on how to remove the cylinder head of the S38B35 engine, which is what I need. I have the BMW manuals, but they assume a lot of knowledge already, IMO.

Can anyone help me with a step by step guide to removing the cylinder head, starting with the basics, like having the engine at top dead center on cylinder one (the most forward cylinder) first, timing chain removal, etc. Can I leave the exhaust manifolds bolted onto the head, or do they have to come off first? Intake removal first, etc. Please please please help me with some positive information. I am fully aware that this isn’t going to be easy, and that I may find unpleasant issues when I’m in the engine. I just hope I can get it done without having to dump a bunch of money in.

Thanks in advance.
Fanclutchnut
Posts: 113
Joined: Jan 05, 2021 7:32 PM
Location: Westchester Co NY

Re: Step by Step Process for S38 Head Removal

Post by Fanclutchnut »

Hey, welcome to the club. Just a thought, and you didn’t mention the mileage on the motor, but why not do a compression test/leak down on it before venturing to take the head off? Your hopeful side might be rewarded. Good luck and keep us posted!
Syndrome
Posts: 128
Joined: Nov 23, 2021 3:46 PM
Location: DC

Re: Step by Step Process for S38 Head Removal

Post by Syndrome »

Hi. Yeah, I did a compression test and it was not good. Three cylinders don’t move the needle at all. Head needs to come off, unfortunately.
jhh925
Posts: 913
Joined: Jul 11, 2015 12:23 AM
Location: Reno

Re: Step by Step Process for S38 Head Removal

Post by jhh925 »

You might use google to see if anyone's posted an engine re-build thread at one of the forums. Even more promising, you might search to see if there's a good detailed thread of someone doing an S14 rebuild. (As you may know, the S38 and the S14 differ only in the number of cylinders); I seem to recall such a thread a few years back that I referenced a few times when I did my motor.

A few key points:
- Start your dismantling process with the #1 cylinder at TDC, confirmed by a visual on the cams (the lobes for #1 should be facing up & towards each other)
- Remove the cams by loosening the caps slowly with 1/8th or 1/4 turns on the cap nuts. The goal is to slowly let the cam rise as a single piece instead of removing caps at one end and working your way down. The latter is likely to result in snapping a cam.
- Loosen the head bolts similarly (a 1/8th or a 1/4 at a time) in the reverse order indicated for tightening the head bolts. The head bolts are reusable. The head bolt tightening order for the S38 is the same as for the M30, so you can use Bentley for that.
- When you put the cam tray back on an re-install the cams, you MUST reassemble with "assembly paste" smeared into the cam journals. Failure to do that is likely to cause a cam to seize in a journal on re-start. Redline makes a great product.
- Memphis Motor Works did my head and has done likewise for many here on this board. Very fair pricing for the quality of the work. (https://www.memphismotorwerks.com/)
- I know you're trying to minimize the cost (and if you're not, sorry for my misunderstanding), but doing this job without refreshing your valve train components is borderline idiotic. I can't recommend strongly enough doing the following: All new chain guides, new cam sprockets, new chain, new oil pump chain (note that BMW updated the design with a smaller sprocket & shorter oil pump chain to move more oil), retrofit the oil pump chain tensioner if you don't have that in place already - and do a new oil pump chain tensioner guide if you do have it.
- Doing the valve train will require removing the "Jeezus nut," unfortunately, and that will require installing a new crank hub seal in the front timing chain cover.
- You'll need to do your first valve shim adjustment after the rebuild but before the first start. Doing the valve adjustment will require a special tool (there are good aftermarket versions for under $100, I think mine is from "Sir Tools"?). An d there's a spreadsheet floating around that lets you input the 'before' measurements so that you can see which shims to replace. And you don't need to buy BMW shims. Valve used the same shims / sizes, and I think they're available in singles from FCP. Obviously, do your measurements before you order shims. I did a modification of that spreadsheet that made more sense to me and that I'm happy to share if / when you get there.

I know you want to do all this with the bottom end in the car, but if the car has sat with a blown head gasket for a few years, you may have other issues you'll need to deal with that may require the block, mains, etc. getting aligned bored, etc. You'll also almost certainly get crap & debris in the various oil & coolant galleys, as well as in the sump. You should plan to drop the pan. And as you think that through, you may (should) logically come to the conclusion that pulling the engine will make this job way easier.

Good luck.
Syndrome
Posts: 128
Joined: Nov 23, 2021 3:46 PM
Location: DC

Re: Step by Step Process for S38 Head Removal

Post by Syndrome »

Thanks so much. Just to be sure I understand this, you are saying that the camshafts have to come out of the head before removing the head? And the way to do this is (from top dead center on cylinder one), loosen the caps 1/8 turn on the nuts/bolts one by one until loose. Is there an order of loosening of the caps on the cams? I know there is on the head bolts, but I don’t know about the cams. Thanks.
jhh925
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Joined: Jul 11, 2015 12:23 AM
Location: Reno

Re: Step by Step Process for S38 Head Removal

Post by jhh925 »

Yeah. Looking just at the block & head:
- there's the block
- on top of that there's the head gasket
- on top of that is the cylinder head
- on top of that is the "cam tray" - there is no gasket b/w the head & cam tray.
- on top of that is the valve cover

The head bolts are accessible only after the cam tray is removed. You can only remove the cam tray if the camshafts are removed.

Oh, also, I almost forgot. There's a kind of end cap on the cam tray that's a real bear to R&R with the engine in the car - and it has to be removed to get to the last two bolts that hold down the cam tray. I assume you're familiar with RealOEM? This is a screenshot of the main groups under the engine section. The picture at far left is the actual cyl head. The middle pic is what's usually called the cam tray, The pic at far left just shows the valve cover.

Image
jhh925
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Re: Step by Step Process for S38 Head Removal

Post by jhh925 »

jhh925 wrote: Feb 01, 2022 9:29 PM You can only remove the cam tray if the camshafts are removed.
Let me walk that back a bit ... I'm looking thru a bunch of my old build pics. I can't remember if you need to remove the cams first. However, I do know that I did ease the cams out b/f I removed the tray, and I'm pretty sure I only reinstalled the cams after the cam tray was back in.
Randomg
Posts: 480
Joined: Jul 12, 2007 3:12 PM
Location: Seattle

Re: Step by Step Process for S38 Head Removal

Post by Randomg »

I think this is asking for trouble without the shop manual. Do a bit of searching and see if you can find e24 m6 manual pdf.

If you removed the cam tray with cams installed, the valve tips will slide on the underside of the cam followers in a weird way, since the valves are at an angle and you're removing the tray straight up. Might be fine, but again something I wouldn't risk.

Regarding the trick for removing the cam, you're loosening (and tightening in case of install) each nut a little at a time (I do a 1/4 of a turn) so that you don't snap the cam or ruin the cam tray bearings. Order isn't necessarily important, I move from one end to the other. What you're trying to do is keep the cam bearings as close to the same height during install/removal.
demetk
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Re: Step by Step Process for S38 Head Removal

Post by demetk »

I have a pdf entitled M6 Cylinder Head Rebuild Final - 122312.pdf. Not sure where I found. Let me know if you guys want a copy.
Syndrome
Posts: 128
Joined: Nov 23, 2021 3:46 PM
Location: DC

Re: Step by Step Process for S38 Head Removal

Post by Syndrome »

Thanks guys.

Randomg, I do have the workshop manuals. I think they’re really not very good, unfortunately. For example, it does not say to remove the cams before removing the head. Also, it says the the head comes off with the exhaust manifold bolted on. I’m not sure how to interpret it.

Demetk, I would absolutely love to have that pdf of yours. I’m looking for instructions and or lessons learned from someone who has already done the same work. Right now, I just have the valve cover off and the engine is at TDC (based on piston position in cylinder one, and cam timing marks. Putting together a strategic plan of attack before carefully diving in.
demetk
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Location: CT, USA

Re: Step by Step Process for S38 Head Removal

Post by demetk »

A bunch of stuff uploaded here: https://mega.nz/folder/jEgAHBjC#ntSOGyKVpokgRKyuK0veQQ

The s38 how-to is in E24.

FAQ has a couple of faq files that are a compilation of all sorts of helpful info pulled from the net that is almost long gone by now.

Get them now before they're down again on Feb 16.
Syndrome
Posts: 128
Joined: Nov 23, 2021 3:46 PM
Location: DC

Re: Step by Step Process for S38 Head Removal

Post by Syndrome »

I pulled copied of the documents I didn’t already have, thank you! The one scary bit is the idea of breaking camshafts, but they have to be removed to get the heads off. While I gather up the courage to get started, I have used a borescope to have a peek at the combustion chambers, hoping to see nothing scary. I’m afraid I have some cracks between some valves…. Breaks my heart. Here are some pictures of what I found.

Image

Assuming these are what I think they look like, what do I do now? I mean, these heads are not common, so it isn’t like I can just go out and buy another one, not easily, anyway. Can these be repaired? I would think so, but is that expensive? Would I be better off finding another head without cracks in it, somehow, somewhere? Thanks.
Randomg
Posts: 480
Joined: Jul 12, 2007 3:12 PM
Location: Seattle

Re: Step by Step Process for S38 Head Removal

Post by Randomg »

Syndrome wrote: Feb 03, 2022 4:01 PM Randomg, I do have the workshop manuals. I think they’re really not very good, unfortunately. For example, it does not say to remove the cams before removing the head. Also, it says the the head comes off with the exhaust manifold bolted on. I’m not sure how to interpret it.
One of the steps is "Remove timing case - see 11 12 080"

One of the first steps of removing the timing case is "Remove camshaft - 11 31 000"

Again, I'd be very careful about following the instructions of the official shop manual, not just glancing over them. It's pretty rare that the pdf version has something wrong or missing.

The stock US exhaust manifolds can be removed I believe both out the bottom or the top. Getting the euro headers in and out requires messing with removing certain studs to get enough room if you don't want to lift the engine. Probably easier to just leave them on, like the manual says...
ymiatgmi
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Joined: Feb 24, 2023 1:19 PM
Location: Scotts Valley, CA

Re: Step by Step Process for S38 Head Removal

Post by ymiatgmi »

demetk wrote: Feb 03, 2022 5:25 PM A bunch of stuff uploaded here: https://mega.nz/folder/jEgAHBjC#ntSOGyKVpokgRKyuK0veQQ

The s38 how-to is in E24.

FAQ has a couple of faq files that are a compilation of all sorts of helpful info pulled from the net that is almost long gone by now.

Get them now before they're down again on Feb 16.
@demetk - is there any chance you could refresh your link to these documents. Sadly I'm in a similar position to @syndrome

My M5 has 145k on the ODO, and during the recent valve clearance check I found a broken valve spring (one of the two springs). So the head must come off... These resources would be hugely helpful. And I'd love to see an update on our progress @syndrome

Also if any contributors to this thread would be interested to drop me a DM and have a chat to share your knowledge on this topic it would be much appreicated!
jhh925
Posts: 913
Joined: Jul 11, 2015 12:23 AM
Location: Reno

Re: Step by Step Process for S38 Head Removal

Post by jhh925 »

ymiatgmi wrote: Feb 24, 2023 1:23 PM
demetk wrote: Feb 03, 2022 5:25 PM A bunch of stuff uploaded here: https://mega.nz/folder/jEgAHBjC#ntSOGyKVpokgRKyuK0veQQ

The s38 how-to is in E24.

FAQ has a couple of faq files that are a compilation of all sorts of helpful info pulled from the net that is almost long gone by now.

Get them now before they're down again on Feb 16.
@demetk - is there any chance you could refresh your link to these documents. Sadly I'm in a similar position to @syndrome

My M5 has 145k on the ODO, and during the recent valve clearance check I found a broken valve spring (one of the two springs). So the head must come off... These resources would be hugely helpful. And I'd love to see an update on our progress @syndrome

Also if any contributors to this thread would be interested to drop me a DM and have a chat to share your knowledge on this topic it would be much appreicated!
PM me your email address and I'll send you what I have (including that illustrated M6 cylinder head replacement PDF).
ymiatgmi
Posts: 2
Joined: Feb 24, 2023 1:19 PM
Location: Scotts Valley, CA

Re: Step by Step Process for S38 Head Removal

Post by ymiatgmi »

jhh925 wrote: Feb 26, 2023 3:58 PM
ymiatgmi wrote: Feb 24, 2023 1:23 PM @demetk - is there any chance you could refresh your link to these documents. Sadly I'm in a similar position to @syndrome

My M5 has 145k on the ODO, and during the recent valve clearance check I found a broken valve spring (one of the two springs). So the head must come off... These resources would be hugely helpful. And I'd love to see an update on our progress @syndrome

Also if any contributors to this thread would be interested to drop me a DM and have a chat to share your knowledge on this topic it would be much appreicated!
PM me your email address and I'll send you what I have (including that illustrated M6 cylinder head replacement PDF).
jhh925 - sadly since I'm new to the forum the DM feature isn't enabled on my profile yet. You could send an email to my username above at Hotmail. I also am happy to give you my name/details, just trying not to post that unless needed. Hopefully I get through the post filter soon!
I have some hot pics of my cam tray removed and a broken valve spring... It's not good, two valves have excessive carbon buildup. I plan to do a leak down test today to decide what to do next. I hoped to not remove the head unless necessary... Everything else looks good. Cam chain guides excellent, cam lobes and valvetrain excellent. Just two carbon covered exhaust valves...
I'll poke around for the photo upload feature - sure everyone would be interested in the disassembly.
jhh925
Posts: 913
Joined: Jul 11, 2015 12:23 AM
Location: Reno

Re: Step by Step Process for S38 Head Removal

Post by jhh925 »

ymiatgmi wrote: Feb 27, 2023 12:46 PMYou could send an email to my username above at Hotmail. I also am happy to give you my name/details, just trying not to post that unless needed. Hopefully I get through the post filter soon!
Test email sent.
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