E46 M56 Valve Cover Swap
Swapping out the original plastic M54 valve cover for the aluminum M56 valve cover is slowly becoming popular. The M56 has a much simpler Crankcase Vent/Oil Separator system than M54 - a labyrinth built into the cover and vent valve to let vapors escape. This is a much more sealed system that helped BMW meet a stricter evaporative emissions standard (SULEV).
Here is what I learned on this swap (Pros and Cons):
+ the swap itself is easy with only a few parts to buy
- M56 parts are very expensive and some can only be bought from BMW (no cheaper aftermarket option). Once you add up the parts cost and factor in DIY labor, dealing with the M54 CCV may be better off afterall.
- M56 are in short supply. The car was sold in only a handful of states so if you’re not in one it’s hard to find used parts (eBay). Even in one of these “SULEV states” M56 was sold alongside M54 models. In the salvage yard near me the ratio was 4:1 for M54. If pulling from a salvage yard, grab as many parts as you can (see above point).
+ M56 CCV has only one external hose, unlike M54 with 4
-the M56 vent hose will fit the M54 Distribution Piece on the intake manifold but it's not a direct fit
- M56 CCV is simpler but non-serviceable
+ M56 is a stronger valve cover that won’t crack or warp like the plastic M54
- M56 valve cover is aluminum with loads of oxidation. And the “beauty cover” is ugly.
When I broke the second clip on the CCV cap I almost bailed on the whole project. THERE'S NO REPLACEMENT CAP AVAILABLE. If you break the cap you’re either buying a new valve cover or making your broken cap work somehow. I found two forum dudes who had plans to make their own. But they don’t appear to have followed through. There’s a BMW part # on the cap but it doesn’t work in their parts system. I got my BMW parts supplier to lobby BMW NA to sell the cap separately but NA denied us. They don't seem to care about the logic of it. WHY didn’t BMW make this a serviceable part?!?! Why force anyone to buy a $900 valve cover just to get a $10 piece of plastic. With a little lube the cap did eventually pop free. I ordered the rubber membrane for it from a 3rd party supplier in Russia (of all places) but shipping took 1.5 months.
I paint all of my parts so, of course, I planned a finish for this. This piece is a real PITA to clean. The raw aluminum oxidizes easily and gets caked on. There are also tiny crevices where the ignition coils go that are impossible to scrub. I wish I could have had it professionally cleaned. I called three shops: two didn't answer their phones multiple times and the other said they only work on Diesels and "didn't want to touch it." Idiot.
But I kept at the cleaning using a variety of methods. KBS Klean worked best for the grease and dirt. But the best way to get the oxidation off was a dry scrub with a brass brush and brown Scotch-Brite pad. It didn't scratch the aluminum at all and the oxidation turned to powder and fell right off. Eventually I got it to a condition I considered paint-able. Before I primered I soaked it in KBS RustBlast for 20 minutes and got a great zinc phosphate etching layer on it.
The swap is super easy. It should be since it's all factory parts and from the same engine family. All I did was install new gaskets and paint the valve cover nuts that go around the perimeter.
So far there are just two fitment issues:
1. the crankcase vent hose does not fit well from the valve cover to the M54 Distribution Piece on the manifold. The M56 Distribution Piece is different and sealed to the M56 intake manifold. I've tried several custom hoses with varying results. If you have the opportunity also buy the M56 intake manifold.
2. the ignition coil harness doesn't seem to clip onto the valve cover. It's sitting loose on the cover. It doesn't seem to pose a problem but vibration could break something. I'll have to look closer at an M56 and see if there is a bracket or clip to use.
3. a TON of oil dripped from the cam tray or original valve cover during this job. I think my original cover was worse than I realized. The oil pan, undertray, and exhaust were covered in oil. Be prepared to wipe down and clean up the oil and don't drip any on the ground.
Was it worth it? Hard to tell so far. If the valve cover doesn't leak, the CCV cap doesn't fail, and the CCV hose can be made to fit then this was a success with very little downside. The only negative would be the cost. It's more expensive for even used parts than new M54 crankcase vent parts. The M56 cover also weighs a lot more and it's weight up high on the chassis. But the trade-offs are likely worth it.
Read MoreHere is what I learned on this swap (Pros and Cons):
+ the swap itself is easy with only a few parts to buy
- M56 parts are very expensive and some can only be bought from BMW (no cheaper aftermarket option). Once you add up the parts cost and factor in DIY labor, dealing with the M54 CCV may be better off afterall.
- M56 are in short supply. The car was sold in only a handful of states so if you’re not in one it’s hard to find used parts (eBay). Even in one of these “SULEV states” M56 was sold alongside M54 models. In the salvage yard near me the ratio was 4:1 for M54. If pulling from a salvage yard, grab as many parts as you can (see above point).
+ M56 CCV has only one external hose, unlike M54 with 4
-the M56 vent hose will fit the M54 Distribution Piece on the intake manifold but it's not a direct fit
- M56 CCV is simpler but non-serviceable
+ M56 is a stronger valve cover that won’t crack or warp like the plastic M54
- M56 valve cover is aluminum with loads of oxidation. And the “beauty cover” is ugly.
When I broke the second clip on the CCV cap I almost bailed on the whole project. THERE'S NO REPLACEMENT CAP AVAILABLE. If you break the cap you’re either buying a new valve cover or making your broken cap work somehow. I found two forum dudes who had plans to make their own. But they don’t appear to have followed through. There’s a BMW part # on the cap but it doesn’t work in their parts system. I got my BMW parts supplier to lobby BMW NA to sell the cap separately but NA denied us. They don't seem to care about the logic of it. WHY didn’t BMW make this a serviceable part?!?! Why force anyone to buy a $900 valve cover just to get a $10 piece of plastic. With a little lube the cap did eventually pop free. I ordered the rubber membrane for it from a 3rd party supplier in Russia (of all places) but shipping took 1.5 months.
I paint all of my parts so, of course, I planned a finish for this. This piece is a real PITA to clean. The raw aluminum oxidizes easily and gets caked on. There are also tiny crevices where the ignition coils go that are impossible to scrub. I wish I could have had it professionally cleaned. I called three shops: two didn't answer their phones multiple times and the other said they only work on Diesels and "didn't want to touch it." Idiot.
But I kept at the cleaning using a variety of methods. KBS Klean worked best for the grease and dirt. But the best way to get the oxidation off was a dry scrub with a brass brush and brown Scotch-Brite pad. It didn't scratch the aluminum at all and the oxidation turned to powder and fell right off. Eventually I got it to a condition I considered paint-able. Before I primered I soaked it in KBS RustBlast for 20 minutes and got a great zinc phosphate etching layer on it.
The swap is super easy. It should be since it's all factory parts and from the same engine family. All I did was install new gaskets and paint the valve cover nuts that go around the perimeter.
So far there are just two fitment issues:
1. the crankcase vent hose does not fit well from the valve cover to the M54 Distribution Piece on the manifold. The M56 Distribution Piece is different and sealed to the M56 intake manifold. I've tried several custom hoses with varying results. If you have the opportunity also buy the M56 intake manifold.
2. the ignition coil harness doesn't seem to clip onto the valve cover. It's sitting loose on the cover. It doesn't seem to pose a problem but vibration could break something. I'll have to look closer at an M56 and see if there is a bracket or clip to use.
3. a TON of oil dripped from the cam tray or original valve cover during this job. I think my original cover was worse than I realized. The oil pan, undertray, and exhaust were covered in oil. Be prepared to wipe down and clean up the oil and don't drip any on the ground.
Was it worth it? Hard to tell so far. If the valve cover doesn't leak, the CCV cap doesn't fail, and the CCV hose can be made to fit then this was a success with very little downside. The only negative would be the cost. It's more expensive for even used parts than new M54 crankcase vent parts. The M56 cover also weighs a lot more and it's weight up high on the chassis. But the trade-offs are likely worth it.
