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Old 07-12-2017, 06:51 PM   #1
Nix328ti
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Join Date: Nov 2015
Location: Minnesota
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Default M54b30/M52b28 cam swap

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' 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!
Attached Thumbnails
Click image for larger version Name:	VanosGearMod_5mm.jpg Views:	3398 Size:	30.8 KB ID:	16901   Click image for larger version Name:	exhaustVanosWashers.jpg Views:	3808 Size:	60.5 KB ID:	16902  

Last edited by Nix328ti; 07-12-2017 at 07:12 PM.
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