Building an M42

[wazzu70]

That was me, however I'm running the 279/274's. They are basically the biggest you can go whilst retaining hydraulic lifters. I did however replace all lifters with new OEM's also put in VAC dual valve springs, hardened retainers, and SuperTech SS +1 valves. Also this I feel is a very low estimate of what those cams can actually do. In the next year or two I'm planning on higher compression and ITB's with possibility of solid lifter conversion.

Yes, you were one of the cars I was thinking of for sure although you had bigger cams. There have been some other cars with the 269/269 combo that have had good results too.

I agree with you, I think the setup has a lot more potential with the mods you listed. Hopefully we are right :)

[I8UR911]

Bought my build motor and started tearing it down today. Head looks good. Debating on having cams reground to same spec as VAC's "hot" cams to save money.

Pro's vs Con's?

Pardon my ignorance, but what is the point of a crank scraper?

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[MazterDizazter]

http://www.crank-scrapers.com/What%20is%20a%20crank-scraper.html

The internet is a wonderful place. I'm interested to see what you put together with this M42!

[I8UR911]

http://www.crank-scrapers.com/What%2...k-scraper.html

The internet is a wonderful place. I'm interested to see what you put together with this M42!

Interesting.......

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[FredK]

You know what I've always wanted to try out for the past 10 years or so? A 97-98 Z3 2.8L M52 swap. It might be 40 pounds heavier than an M42 including flywheel, clutch, and transmission, rather than 100 pounds with iron block M5x engines. It would have a nice broad, flat torque curve. It seems like engines are more available than they were years ago, since it takes a lot less for an insurance company to total a Z3 2.8.

I guess you could even use an M54 with a stock DME, gain the benefit of double VANOS, though you could potentially suffer from oil pump issues.

[wazzu70]

You know what I've always wanted to try out for the past 10 years or so? A 97-98 Z3 2.8L M52 swap. It might be 40 pounds heavier than an M42 including flywheel, clutch, and transmission, rather than 100 pounds with iron block M5x engines. It would have a nice broad, flat torque curve. It seems like engines are more available than they were years ago, since it takes a lot less for an insurance company to total a Z3 2.8.

I guess you could even use an M54 with a stock DME, gain the benefit of double VANOS, though you could potentially suffer from oil pump issues.

Fred, if I get tired of my M42 some day that is the route I plan on going. FWIW only the 3L engines have the nasty harmonics...same as S52. The 2.5L version or a 2.8L M52tu will not have the same issues :)

I think I would rather stick with the lighter engine for now and develop that. I think there is plenty of potential in the M42!

Sorry for the OT!

[bmwman91]

It is great to know that I am not the only one that has dreamed about swapping a Z3 2.8L M52! Can you guys elaborate on the oil pump / harmonics issue that S52 and M54 engines have?

wazzu, an M42 build is a LOT of fun. My 2.1L pulled nice and hard before it had a valve spring die (I should be back on the road in a few weeks), and that was even with the wrong injectors! The M42 revvs like a champ stock, and with 50% more power and a 50% lighter flywheel it REALLY likes to spin. Now it can at least keep up with most new sport-economy coupes and sedans (Nissan Altima, bitchezzzzz)! lulz

[FredK]

The M54 3.0L when driven on a track and repeatedly rev'd past around 7200 or so has a tendency to break the oil pump drive shaft.

The S50US and S52 also have harmonics that make the oil pump nut back off, but this is easier to cure with safety wiring the oil pump nut to the oil pump gear.

[bmwman91]

Holy shit lol. Well, it is good to know that the S5x engines can be fixed with a relatively-easy mod. The M54...that sounds like a major oversight on BMW's part.

[wazzu70]

Well safety wiring just makes you snap the oil shaft on the S50/S52. The S52 has the exact same bottom end as the M42b30 so same issues! The only way to actually fix the problem is with a damper made for that rev range (such as the ATI unit). The safety wire/weld oil pump nut is an lolz fix that really does not fix anything, just slightly delays the inevitable!

I just posted some harmonics info in hovetinguys thread in the S54/M54 section.

http://www.r3vlimited.com/board/showthread.php?t=116803&page=11

Also if you search around there is lots of discussion on the topic.

Bmwman91, check out my build thread on M42 club. I didnt go all out yet because I was focusing on the VEMS install. Should be able to take advantage of the cams now :) I really hope your engine issues are sorted once and for all so you can actually enjoy the thing :)

[FredK]

Sure, the safety wire prevents the nut from backing off but not against the pump shaft from grenading. But pump shaft failure can't be as common in tracked S50US/52s as it is in the M54 3.0L, just anecdotally speaking, as I haven't seen nearly as many people complain about pump shaft failures in comparison to M54 pump shaft failures.

I think the ATI damper helps both engines out, but the magnitude of the vibration is likely exacerbated by having a block made of a less stiff material.

I think if you go beyond 7200 in either engine you're just asking for trouble. The top end starts having problems above maybe 7400.

[getouth]

^^ I thought this was an M42 thread.....just saying. Lets get back on track here guys.

[I8UR911]

Installed my Supersprint exhaust today. Nice tone. Not too loud but good at WOT.

Can't wait to hear sound when the rebuilt M42 is installed with cams and possibly itb's :)

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[I8UR911]

Contacted machine shop yesterday and got pricing. I'll be replacing valve guides, valve seals, doing 3 angle valve job, slight porting and cleaning the head. I'll then install new, stiffer valve springs and VAC "hot" cams.

Also talked to them about boring block for 86.5mm pistons......we'll see on that one.

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[I8UR911]

Ordered new Supertech valve springs today. Also ordered my cams from VAC....it'll be a bit before I see those :(

M20 flywheel and head will be going to machine shop next week. Also ordering VW lifters (lighter weight).

I'll start porting and polishing the intake manifolds and throttle body soon too. Hopefully the head will be ready in the next 3 months. Will probably install M20 "lightweight" flywheel though in the next few weeks :)

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