Watch me ruin a Z4M Coupe: build thread

[mattfwalters]

Originally Posted by yousefnjr

Well that ramped up fast lol. Looks like a lot of fun, great thread. Looking forward to your thoughts on the cams when all is done, and videos of this 9k rpm banshee

I can't wait to shoot that video unfortunately I don't think my impressions of the cams will be useful to most given how extensive the engine modifications are - but overall I'm hoping that it generally maintains the character of the S54 and just gives it a bad case of the red mist.

e: and yeah, I've said "well, that escalated quickly" to myself more than once in the past few months.

[Vanne]

Glad you picked the 288/280's, anything more aggressive becomes a complete pain in the arse to get running right.

[mattfwalters]

Hahaha, crap.

I finally had some time to work on the project today. Realized after turning the intake cam 360* that I hadn't put shims in. Pulled the intake cam, cleaned up a few marred buckets () making heavy use of a stack of neodymium magnets, got shims installed on the intake side, and managed to get shims into the exhaust side without pulling that cam. Only two exhaust shim buckets needed cleaning up at least. Re-installed the intake cam, got everything torqued, and was out of time.

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I didn't want to bag the head again so I dropped the valve cover on as a dust cover. It's so badly warped that I can rock it corner-to-corner. Like a 4mm gap.

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Guess I found that oil leak I'd been chasing...

[wdb]

Originally Posted by mattfwalters

Guess I found that oil leak I'd been chasing...

Hmmm. I wonder if that's what is going on with the Moupe I just got. The prior owner was obviously skilled and had done the valves himself at 60K, and yet there is seepage at the gasket. Hmmmm. I'll have to keep that in mind when I do the VANOS this winter.

[Taskmaster]

I have a N52, and my plastic (OEM - brand new) VC was cracked. So it can happen.

[SaltyNC]

Your post about the rod bearings has me a bit worried. I'm doing vanos work now, and plan to do rod bearings in the very near future. I do know about the ARP bolts, and some have recommended against using them due to the amount of force needed to seat them properly. I was speaking to an indy last week that said he replaced bearings on an M3 (S54) with the treated OEM bearings and ARP bolts, and the M3 lost the engine at the track within a year of replacing the bearings.

Is proper rod bearing replacement something only a race shop can perform? I was planning on using stock bolts, but leaning toward the treated OEM bearings.

Salty

[wdb]

Originally Posted by SaltyNC

Your post about the rod bearings has me a bit worried.

I'm not sure if I'm more worried or if I need to reach for the salt shaker. The reason car companies go to the expensive length of splitting conn rod big ends that way is that it makes it pretty much impossible to assemble them INcorrectly. Now here's this guy saying the opposite.

[mattfwalters]

Originally Posted by wdb

Hmmm. I wonder if that's what is going on with the Moupe I just got. The prior owner was obviously skilled and had done the valves himself at 60K, and yet there is seepage at the gasket. Hmmmm. I'll have to keep that in mind when I do the VANOS this winter.

Originally Posted by TheAxiom

I have a N52, and my plastic (OEM - brand new) VC was cracked. So it can happen.

Yup. Definitely check the valve cover with a straight edge when you take it off.

Originally Posted by SaltyNC

Your post about the rod bearings has me a bit worried. I'm doing vanos work now, and plan to do rod bearings in the very near future. I do know about the ARP bolts, and some have recommended against using them due to the amount of force needed to seat them properly. I was speaking to an indy last week that said he replaced bearings on an M3 (S54) with the treated OEM bearings and ARP bolts, and the M3 lost the engine at the track within a year of replacing the bearings.

Is proper rod bearing replacement something only a race shop can perform? I was planning on using stock bolts, but leaning toward the treated OEM bearings.

Salty

Originally Posted by wdb

I'm not sure if I'm more worried or if I need to reach for the salt shaker. The reason car companies go to the expensive length of splitting conn rod big ends that way is that it makes it pretty much impossible to assemble them INcorrectly. Now here's this guy saying the opposite.

Yeah, I think there's salt to be taken with anybody's opinion on the "absolutely correct" way to build an engine. My guy's position is that you're going to get different clamping force on each side of the rod depending on the mix of (1) irregular surfaces not quite mating perfectly; (2) different tensile strength in the torque-to-yield stock rod bolts; and / or (3) inability to use a bolt stretch gauge to accurately set clamping force. He has a bunch first-hand of data* about big end roundness and bearing wear in raced S54s using ARP hardware and aftermarket rods vs. stock rods and stock bolts (or even ARP bolts). He had a very strong preference for the Molnar / ARP setup.

His explanation makes sense to me, and a couple of other S54 / S65 race engine builders on the web agree**. I think it all comes down to risk management and engine goals. I want my build to be supported by my engine builder, he believes that this is the correct approach for real safety, and the difference in cost simply isn't enough for me to worry about it overall.

It's worth noting that Andrew Lang's data on ARP bolts causing the big end to oval is based on a model - it may be correct, but a lot of people's experience of the OEM -> ARP rod bolt transition is that the top / bottom bearing wear on the rod big end disappears with their engines after switching to ARP bolts.

Bottom line: YMMV. :shrug:

* I didn't ask to see it, so this is effectively me assuming that the plural of "anecdote" is "data"
** Something, something, opinions and assholes, something, something

[SaltyNC]

Matt, thanks for taking the time to provide the additional info. Really appreciate it. Can't wait to see where your build is going next.

Salty

[mattfwalters]

Originally Posted by SaltyNC

Matt, thanks for taking the time to provide the additional info. Really appreciate it. Can't wait to see where your build is going next.

Salty

My pleasure! Happy to flap my gums about this (obviously); hopefully some of it is even useful to the community in general.

Weekend update: initial valve clearance set on the bench.



Took longer than I'd hoped, but I got a reasonable result:

View post on imgur.com

I wasn't happy with intake 5B but left it just in case I didn't have enough of any specific shim size.

(Note the empty slot in the shim kit in the first photo... )

But with a target of 0.25mm lash for both intake and exhaust, being inside -0.013mm/+0.029mm ignoring 5B (and still inside -0.021mm/+0.029mm including it - basically +/-11%) I feel like I did alright. I was planning to err on the side of loose, because I don't want to burn a valve; after talking to Minos at Achilles today, I'll be re-shimming the loose (~.279mm) valves to be slightly tight. The 0.04mm increments on the BMW shims is irritating but Minos' advice is that leaving more lash makes the shims more prone to jumping out of the buckets due to the more aggressive cam profile and the stronger springs, and that .22mm (but of course as close to the .25mm spec as possible) is fine for the Schrick 288/280 cam setup. Going down one shim size for each of the valves currently lashed to .279mm should make them all ~.239mm, which should be fine.

Some things I learned yesterday:

(1) The used valve cover I bought rocks on the head exactly like the other one did. I am officially afraid that there's something wrong with the top of my head.
(2) I totally, totally forgot about the fact that the cams aren't currently connected the timing chain. Valve-valve contact between all four #1 valves. Little surface marks but no real damage as far as I can tell, but that sucked so hard. Scared the living hell out of me.
(3) Using a cheap set of digital calipers sucks for this (I noted +/-0.02mm variance in measured shim thickness, which led to a lot of hunting around for the correct substitute shim... ugh). Ordered a good "absolute origin"-based set last night and hope they make the lash setting easier when I install the head... which is actually my next task.

I'll document the cam removal / installation procedure I'm using when I assemble the short block, also, since it seems to work well (fingers crossed) and is safer than the current how-tos without buying the BMW tool that wouldn't work with aftermarket springs / cams anyway.

[Vanne]

top notch Matt, good shit right there man.

i have an oem valve cover lying around you can borrow if you like.

[TRiCC]

Absolutely ruined!

[jns_e85]

Originally Posted by wdb

Hmmm. I wonder if that's what is going on with the Moupe I just got. The prior owner was obviously skilled and had done the valves himself at 60K, and yet there is seepage at the gasket. Hmmmm. I'll have to keep that in mind when I do the VANOS this winter.

Gasket selection matters! I have done numerous VCG on a variety of BMWs and when I did the valve adjustment on my M I also replaced the VCG. At a friend's recommendation, I got the Victor Reinz VCG. After installing it, there was a slow leak in the back off one of the half moons. Annoyed at myself, I reinstalled it, and it continued to leak. Then I tried again with a high degree of James May OCD on doing it proper, anddddd still leaked.

Pissed I ran to the dealer and bought an OEM gasket, and wouldn't you know it, no more leaks!

[mattfwalters]

Originally Posted by Vanne

top notch Matt, good shit right there man.

i have an oem valve cover lying around you can borrow if you like.

Thanks! I actually bought a second one from a local guy, and it does the same thing as the cover that came off of my engine. I'm starting to suspect that the head is designed to deform under the load of the head bolts - this might be why the machine shop explained that S54 rebores need to be done under a torque plate. I'll check everything again with the head bolted in (this should be straightforward with the ARP stud kit). Going to make a couple of calls to see if any of the shops I'm dealing with know the answer for sure.

Originally Posted by TRiCC

Absolutely ruined!

Right now it is And for the street... probably ruined.

Originally Posted by jns_e85

Gasket selection matters! I have done numerous VCG on a variety of BMWs and when I did the valve adjustment on my M I also replaced the VCG. At a friend's recommendation, I got the Victor Reinz VCG. After installing it, there was a slow leak in the back off one of the half moons. Annoyed at myself, I reinstalled it, and it continued to leak. Then I tried again with a high degree of James May OCD on doing it proper, anddddd still leaked.

Pissed I ran to the dealer and bought an OEM gasket, and wouldn't you know it, no more leaks!

Oh. That's literally the same leak I've been fighting for 3 years. I've always assumed that I'm doing something wrong - either not enough sealant, too much sealant, wrong torquing sequence...

Well, then. I guess I'll pitch the pair of Reinz VCGs I have in the garage and buy some OEM ones... but not until I've tried just once more since it should be much easier to get this done properly with the engine on a stand.

Fun related fact: a buddy did a bit of back-of-napkin math on the 7 ft-lbs / 10 N-m torque spec for the valve cover nuts, and determined that it generates around 14k pounds of clamping force, which is something like 75-90% of the yield strength of mild steel...

That doesn't take into account the fact that the gaskets are under the nuts, of course. But still.

[GPower]

Not sure where's the "ruin" in the main thread. Well done, Sir. Subscribed. Keep'em coming

[comics69]

Nice Project!!! thanks for sharing

[mattfwalters]

Small progress this weekend: took video of the cam removal with clamps process, and installed the ARP head studs. Upcoming weekend will be head install, cam install, and maybe initial mechanical timing. I'm going to take video of as much of this part of the process as possible, since there's just not a lot of good video out there for working on S54s.

So here are some photos of at least one new thing:

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...love those JE pistons.

[Beedub]

NICE, those pistons are wow!!

[wdb]

Purdy.

[RGlenn]

Rebuild is looking great. You're making me jealous with how clean your rebuild is! Very excited to see the final product.

[MeisterS]

You, good sir- deserve an award for this.

[mattfwalters]

Thanks, all. It's taking awhile, but I am really enjoying the process. I hope it turns out to be as epic as I'm picturing.