View Full Version : M54b30/M52b28 cam swap

07-12-2017, 05:51 PM
I've posted a number of times into a thread in this same (engine) forum to share the information I found for OEM cam details. In that same forum I promised to attempt swapping the M54b30 cams into my M52b28. I did this swap last week and figured I should share what I did.

It was fun but also a bit nerve-racking as I could only find a couple references to people that had swapped in the intake side but I found no references to swapping in the exhaust side. I had to be the guinea pig for this one. Here's what I did:

In the OEM cam specs thread I outline the cam specs which is why I landed on attempting this swap. In short, the stock M52b28 cam specs are:

M52B28 // int: 230(9.0mm) // open:1 close:49 // exh: 228(9.0mm) // open:39 close:9

While the M54b30 cams are:

M54b30 // int: 240(9.7mm) // open:-6 close:66 // exh: 244(9.0mm) // open:47 close:17

I think the values speak for themselves. As part of my plan I also thought I should try to retain the opening cam timing of the M52b28 so I advanced the intake cam by 3.5 upon making the final vanos gear installation. I'll get to that later in the post.

For those who are new to this concept, there is a minor tweak to make to the inner vanos gear of the M54 intake cam so it will work well with the M52 vanos hub gear. Basically, it's necessary to cut ≈5mm of the end of the gear so it clears the inside of the vanos hub during vanos actuation. I've attached a pic of what I mean. On the left is the M54 cam with the clipped inner vanos gear; The left is the M52. Try to make it just a mm or two longer than the stock m52 gear. It's pretty easy.

Then all of the M52 cam gear assembly bolts directly onto the now modified M54 cam. Drop it in and done. Fits right into the same lifter tray.

With that done I moved to the exhaust cam. The challenge here is the M54 exhaust cam uses a vanos cam gear assembly with a clutch plate, just like the M52 intake vanos cam gear set. It uses 3 retention studs, also like the M52. The problem is the M52 exhaust cam and gear uses 4 bolts.

After a few sleepless nights of pondering I landed on a plan to attempt to simply lock the stack of gears that are part of the M54 cam gear assembly so it doesn't spin. That way it would act in a similar fashion to the single-vanos setup.

In the end I decided to lock the assembly together using the three, outer most retainer nuts. I discovered that I could do this by adding a simple hardened washer over the studs allowing the retainer nuts to clamp the whole stack together (without the clutch disc).

I eliminated the exhaust vanos hub so it was possible to install the intake vanos and make the appropriate adjustments to the cam timing as well.

It turned out that the M54 vanos gear stack was a tight fit but did have enough clearance when fully assembled so no modifications were necessary on the outer retainer plate. I've attached a pic to basically show what I did. (the one with the washer pic on it)

I installed the vanos (after rebuilding it with Beisan Systems' (http://beisansystems.com/) single vanos rebuild kit and rattle fix).

It was a lot tougher to get move the clutch without a tool to line up the vanos gear; As is the procedure. The up-shot was that the 2mm extra on the inner vanos gear made that whole 'make sure sprocket is spun all-the-way over' fiddling unnecessary as the gears were already lined up.

I made up for the fiddling issue with my new exhaust side modification. LOL.

I finished up by advancing the intake ≈3.5 to put the opening timing where I wanted it by removing cam retainer block from the intake and measuring it with a dial angle gauge on a long shaft wrench. Not super accurate but slightly advanced none-the-less. I tightened all the nuts with blue loctite. I torqued the retainer nuts to 15nm (vs. 10nm).

I then removed the timing block and pin and cycled the engine to make sure there wasn't any apparent binding. And installed the 3 torx retainer bolts on the exhaust gear/sprocket/shim stack. My hope was to lock together the main sprocket shims and give the retainer nuts less to do.

I buttoned everything back up with marginal confidence and put my hand on the ignition with a hair of trepidation. But I forged ahead and it started right up!

07-12-2017, 06:22 PM
I've been driving on this mod for about a week now and finally had the balls to work up to running a few gears up to 7k rpm.

I figured I'd post some anecdotal observations as I have no dyno numbers to share yet.

It sounds a bit different! Unexpected changes:

1. Quieter at lower RPM. That may be due to the cam opening profile. See pic below:
2. Pulls more evenly at higher RPM. With the stock M52b28 cam, the engine would start an exhaust rap at about 6k. It would start to feel like it was flattening out at around 5.5k. Not it pulls very evenly right up to 7k and feels like it will not stop.
3. Apparent increase in low end torque that gives me a bit more confidence to stay in a lower gear while passing on the interstate.

I'm hoping I can get a dyno profile to see where peak torque is now and how wide it is.

As before, the car isn't a super power but is very fun to drive.

08-09-2017, 03:33 PM
i'm looking into doing a 330i from e46 into my 318ti, how much of a pain i should be expecting. Also the 330 is automatic and 318 is a stick. Am I correct in assuming that the 5 speed from the 318 will work as long as I don't go crazy with power? First time project so let me know. Thanks all.

08-10-2017, 01:54 PM
It's as much a pain as any other swap. Mostly in the wiring, I'm guessing. Everything else should bolt right up though. I've always planned on this swap after I tire out the M52. It sure would be great to hear from anybody else who's done this one though...

I'm also working on a long time project: LS1 VegaGT Road course car. That's a **** ton of fabrication so this swap will seem pretty easy. Good first time project, IMO.

As far as the Getrag 250, I'd just run it. Unless you're racing the car or doing adolescent level burnouts, it should be just fine. Besides, you can save up for a ZF while you're trying to burn it up. LOL.

08-10-2017, 02:05 PM
Thanks for the insight.

08-10-2017, 02:23 PM
I'm just worried about having two cars apart and find out it not a smooth transfer. Really like to hear from a few guys before taking them apart. Thanks.

08-14-2017, 03:58 PM
This is the best overview of swap challenges I've seen. Here's the link:


Your post got me really digging to find out what the swap challenges are. I still don't understand why swapping the wiring from one car to the other is a challenge other than to try not to dig down to these components and swap them out.

My point is, if you have a donor car available, start taking it apart to dig out all the engine management components. I figure you can be careful of the wiring but not respectful of the car's hard components. That way you get the entire engine management wiring extracted. Then you can decide best if it's less work to try to simply swap the harness to the engine and build a custom solution like the one this guy is suggesting.

Since I'm already very comfortable to taking on some major fabrication, and the fact that I've already stripped an earlier car down to make it into a cheap racecar, it seems less complicated to keep the later engine management.

That said, I could really benefit from your take on this. Look into what this guy is talking about and let me know what you think.

You gotta become a member to see the pix; Might be worth it.

From a higher perspective, all swaps are challenging, and there are always parts of the process that suck. You will be frustrated and overwhelmed. Creating a new thing like this is a serious commitment. I will say this though, the drive when it's done is SO fulfilling. You seriously feel a sort of affinity with Frankenstein and feel some sympathy for his efforts to create life. It's an awesome feeling of accomplishment or a sincere sense if disappointment if not finished. I've done both.

For me, it's worth it. But, like any endeavor involving cars, it's just going to cost money. The trick is to buy your happiness with the expense. It's really got to be a hobby that makes you happy in the end. That is the best thing to support with our hard-earned money, IMO. We only live once and we gotta find a way to happiness or none of this matters.

Wow, sorry dude. I guess it's too late to skip all that self-important blather I just wrote. If you read this far, definitely keep me posted on what you find. I'd love to hear your perspective on this.

04-03-2018, 06:24 PM
How's your washer locking single vanos conversion holding up?

I'm considering doing something similar and putting M54B30 cams (intake and exhaust) in my M50TUB25, with the M54 trays.

Just to clarify, which part number did you remove, and where did the washers go?


04-03-2018, 07:24 PM
Thanks for prompting an update. I've been running it since July last year (2017). No issues. I don't take it easy on the car but I haven't yet been able to get it to the track.

I've run it through the winter now too. I did notice some extra noise during warm up. Sort of a whirring/whining sound that fades over a couple minutes. This did not happen during outdoor temps above 60... That could be due to the fact that the stack of parts on the M54 sprocket is pretty damn close to the valve cover. I haven't had the valve cover off but I think it is indeed rubbing very slightly on the underside of the valve cover. I'll have to pop it off and give you all an update when I get a chance.

As for the parts I used/didn't use:

I simply left the vanos hub off: "06 SPLINED SHAFT" (from that link you posted).
I kept everything else in it's proper install order as shown but added the washers to lock the stack and keep it from turning.

Hope that helps.

04-06-2018, 11:31 AM
Thanks, I had the M54B30 camshafts in front of me, but did not have the physical gears. I was trying to figure out a method to lock them from the realOEM pictures only.

I didn't realize that the stud bolt's shoulders (part 2) go all the way through parts 7 (Stop disk), 8 (DIAPHRAGM SPRING), and 9 (IMPULSE SENDING WHEEL).

This means the washers have to have a big enough ID to fit over the shoulder to compress the entire stack, right? Something like 9.6mm (3/8") ID or bigger?

(I've got some used gears from eBay now)

04-06-2018, 11:56 AM
Yes. That's a good point. I should have been more clear about that. I reread my post and realized I didn't put the size of the washer I used. It is necessary to compress the whole stack so it has to go over the stud. I can't remember the exact size but 9mm does ring a bell.

If you can get a solid number on that after you do this, post it, and I'll edit the first post to include it.

Thanks man!

04-07-2018, 10:30 PM
I measured it at 9.57mm (see attachment).

When you tightened the stack down, did #8 DIAPHRAGM SPRING fully collapse?

If space is tight, #8 could maybe be removed, or #9 maybe can be removed too if you don't need an exhaust pulse wheel (like on my M50). But the risk is that the more plates that get removed the less the load is spread out, and I don't know how much is needed to make sure nothing moves.

04-09-2018, 03:24 PM
I did include the whole stack. I agree with what you're. It's worked fine for me but you could probably leave out stuff. It's up to you.

05-10-2018, 02:00 PM
Very cool, any chance to get it on a dyno yet?

Are you running the M50 or M52 intake manifold? Tuned for the cams at all?

Looking at stock M52 dynos, you can see where the power drops at 5.5k rpm. Being able to pull hard to 7k would be pretty sweet on track. If the M54 cams are cheap then this could be a nice alternative to S52 cams.

05-10-2018, 05:28 PM
I haven't yet... Sad. I will have to look into that. The power delivery did smooth out at the top end by a lot. Sounds a lot less over spun too.

As far as power delivery it feels better but not a massive change in overall performance. More like enhanced feel at the top end.

We'll see if the dyno shows anything. I'll see if I can get off my ass to get that to happen.

Thanks man