N55 swaps/interchangability

CalvinNismo

Corporal
Nov 1, 2020
106
155
0
Any chance you have a new style vacuum pump laying around? Would it be possible to just swap the back half of the vacuum pump instead of the entire thing? Would save a bunch of work for me with what I am trying to do... Looks like the front half of the vacuum pump is the same and it's the back half that mates to the HPFP that is different (hpfp mount is different and new style doesn't have the vacuum port since it's EWG).
Did you find out the answer to this? Seems like the main stumbling point for swapping from an N54 style HPFP N55 PWG, to any other N55. Would be nice to just have to swap the back half of the vacuum pump and not have to mess with the timing chain sprocket.
 
Last edited:

jooobie

New Member
Nov 16, 2022
5
2
0
Did you find out the answer to this? Seems like the main stumbling point for swapping from an N54 style HPFP N55 PWG, to any other N55. Would be nice to just have to swap the back half of the vacuum pump and not have to mess with the timing chain sprocket.

I finished my swap a few months back and no you can't use the pump that's attached for the newer hpfp to retrofit it on the n54 hpfp.
Unfortunately you need to take it the engine chain and re-bolt it with the older style vacuum pump to make it work. Its not difficulty to do but it does requires the proper tools to hold the sprocket in place so that you may torque it to the correct value.
 
  • Like
Reactions: CalvinNismo

CalvinNismo

Corporal
Nov 1, 2020
106
155
0
Thank you!

Its not difficulty to do but it does requires the proper tools to hold the sprocket in place so that you may torque it to the correct value.
Did you get hold of genuine BMW tools? Or did you buy some? Any brands/part numbers so I can get a rough price for the tools?
 

Fru5tum

New Member
Dec 19, 2023
5
2
0
East Coast
Ride
E92 335i 6MT
Bringing this back as it’s the only lead I have on it.
Any chance you have a new style vacuum pump laying around? Would it be possible to just swap the back half of the vacuum pump instead of the entire thing? Would save a bunch of work for me with what I am trying to do... Looks like the front half of the vacuum pump is the same and it's the back half that mates to the HPFP that is different (hpfp mount is different and new style doesn't have the vacuum port since it's EWG).
I have a 2016 435i N55 EWG and I’m trying to use a 2011 335i N55 in it.

Were you able to make any adjustments to the vacuum pump setup to accommodate for the chain tensioner?

On a whim, I used an F-Chassis Oil Pump on my older n55, however, I had to dremmel out the hole on the chain bracket for the oil pump sprocket so the bracket would sit flush. E-chassis style bracket with leaf spring tensioner with F-Chassis style hpfp and vacuum pump combo. (I am not entirely sure if it’s necessary to use the f style oil pump, but we lost a block and blamed it on the e pump. It’s no trouble to cut ears out on the bracket to make it flush)

For a while I didn’t have issues with this, but it seems there’s a problem area that blows the bracket constantly. Either the tensioner will go, or now even, the bracket appears to have also split in half after the tensioner gave out.

At the end of the line with this, might just be better to get an f-chassis block just to use newer hydraulic tensioner.

How far did you get along with this any of this? I like the idea of swapping the front of the vacuum pump to the E-chassis half, to match the e chassis tensioner. Seems like that might even be the only possible option left. Did you do this? Did it work for you?
 

Bnks334

Lieutenant
Dec 1, 2016
524
340
0
New York
Bringing this back as it’s the only lead I have on it.

How far did you get along with this any of this? I like the idea of swapping the front of the vacuum pump to the E-chassis half, to match the e chassis tensioner. Seems like that might even be the only possible option left. Did you do this? Did it work for you?
Yes, this is what people do. Use the e-series vacuum pump. I don't recall if you can just swap the back-half of the vacuum pump. It does come apart but I never had both on hand to see if they mate together.
 

Fru5tum

New Member
Dec 19, 2023
5
2
0
East Coast
Ride
E92 335i 6MT
Yes, this is what people do. Use the e-series vacuum pump. I don't recall if you can just swap the back-half of the vacuum pump. It does come apart but I never had both on hand to see if they mate together.
Still tuned in, going to see if I can share some pictures soon, as I have both on hand and want to figure this out.

For the 4 series, it was easier to source a F Block and not have to bother with it at all. I highly recommend going that with that option, so much less headache, and the car loves it :)

The problem prevails; as I have it now I have an N55 E chassis block going into a F30. I have no issues mounting the entire E Chassis (n54 style) vacuum pump and HPFP. Bolts up no issue, but I have to swap the hard lines out. The plug for the HPFP is different, they are similar but keyed enough to where they will not connect. If someone has done this before, have you done this and just spliced in a N54 style connector?


We’ll still be trying both ways,

1. Take the back half of the F pump and attach to front half of E pump.

2. Leave E pump as a whole, and splice in connector.

I am familiar with coding but hoping I don’t have to cross that bridge. Will update soon.
 

Fru5tum

New Member
Dec 19, 2023
5
2
0
East Coast
Ride
E92 335i 6MT
Got a little bit of an update, I know a lot of people were saying the housings couldn’t be split and matched, and that is indeed the case. I got some pics of this and why.

E chassis vacuum pump/HPFP has a big fan pin (for lack of better words) that separates and fits between the vacuum pump cover, and the HPFP. This is the vacuum pump internals.

F chassis vacuum pump/HPFP has a big fan pin that does not separate from the HPFP. From what I can tell, it is part of it. If it does come apart, the two ends are significantly different, with the E chassis having a big dowel cut in the middle to the drive, and the F chassis not.

In theory, you can take the F HPFP and Fan Pin and put it into the E chassis vacuum pump housing, but congrats, you just created an F chassis Vacuum Pump/HPFP, with the same F chassis internals and drive as you started with, and will run into the same compatibility issues with the tensioner.

Pictures should be in my next post. I know it was mentioned before, here is the visual reason.

Next step is N54 harness snip for the connector, and some fuel pressure measurements.
 
  • Informative
Reactions: houtan

Fru5tum

New Member
Dec 19, 2023
5
2
0
East Coast
Ride
E92 335i 6MT
IMG_1252.jpeg

IMG_1255.jpeg
 
  • Informative
Reactions: houtan

Dynamics99

New Member
Nov 28, 2023
12
9
0
Philadelphia, PA
Ride
Blown up N55
So, I'm in the middle of swapping the oil pump system from the S55 into my 2011 N55 which carries an older style oil pump (shared with n54). The chain guide rail for the oil pump does not line up and needs to be shaved to enlarge a bit and cut to fit the protrusions. I already have the S55 oil pump system kit so I don't want to give up and go back to using the old design when the pump flows 18% more oil and has a pickup and baffle system to prevent starvation. Is there a way to frankenstein the newer design while maintaining the leaf spring tensioner? It's a PWG motor and I know they switched the design somewhere in 2012-2013 looking at realeom to a hydraulic tensioner. The new design has "cat ears" to clear the protrusions on the oil pump. A forum member on e90post had to cut the chain guide rail to fit the new pump protrusions but never posted pics. Any help or guidance would be appreciated since I'm rebuilding the motor for autox and track.
 
  • Like
Reactions: wheela

houtan

Lieutenant
Nov 2, 2017
611
293
0
Ride
135i N55 DCT; PS2
So, I'm in the middle of swapping the oil pump system from the S55 into my 2011 N55 which carries an older style oil pump (shared with n54). The chain guide rail for the oil pump does not line up and needs to be shaved to enlarge a bit and cut to fit the protrusions. I already have the S55 oil pump system kit so I don't want to give up and go back to using the old design when the pump flows 18% more oil and has a pickup and baffle system to prevent starvation. Is there a way to frankenstein the newer design while maintaining the leaf spring tensioner? It's a PWG motor and I know they switched the design somewhere in 2012-2013 looking at realeom to a hydraulic tensioner. The new design has "cat ears" to clear the protrusions on the oil pump. A forum member on e90post had to cut the chain guide rail to fit the new pump protrusions but never posted pics. Any help or guidance would be appreciated since I'm rebuilding the motor for autox and track.
Have you reached out to this person? This is the only person I know that’s actually installed one and made the modifications.

 
  • Like
Reactions: Dynamics99

Dynamics99

New Member
Nov 28, 2023
12
9
0
Philadelphia, PA
Ride
Blown up N55
Have you reached out to this person? This is the only person I know that’s actually installed one and made the modifications.



Looks like this is what he said in the post:
"The hole in the chain guide and tensioner bracket that the snout of the oil pump goes through needs to be enlarged as the snout on the s55 oil pump is larger."


So I have a cheap eBay chain guide rail for testing purposes. Gonna either make the hole larger or cut out the cat ears and see. I'll try to upload pics.
 
  • Like
Reactions: wheela

Fru5tum

New Member
Dec 19, 2023
5
2
0
East Coast
Ride
E92 335i 6MT
Looks like this is what he said in the post:
"The hole in the chain guide and tensioner bracket that the snout of the oil pump goes through needs to be enlarged as the snout on the s55 oil pump is larger."


So I have a cheap eBay chain guide rail for testing purposes. Gonna either make the hole larger or cut out the cat ears and see. I'll try to upload pics.
I did what you’re suggesting myself when we were experimenting with our HPFP, we also tried using a newer style oil pump with the dog ears, and grinded out the chain bracket with a dremmel to fit the dog ears on the newer oil pumps, and it created a weak section on the bracket. (I traced the dog ears from a newer bracket, and matched them up delicately) This section snapped right at the ear on the right side, but I’m not 100% sure if it was because of the decreased durability in that section, or because of the leaf spring tensioner driving newer HPFP issue, or both. (i.e the tensioner broke, bounced around and broke the weak section)

We then tried welding the leaf spring tensioner to the newer style bracket that already had dog ears. We welded the leaf spring tensioner on, using a rivet in the original location, very small weld, but it seemed fine. This did not work either. We suspect the bracket got hot and the weld popped out. It held for about a week, and was the only fail point on that set up. (Big fail)

What you’re talking about is similar to the first thing we tried with our setup once we found the compatibility issue. We are about 99% convinced that that leaf spring style tensioner chain guide will not be reliable on anything other than the PWG N55, with the flat style oil pump, and N54 style HPFP. Anything else isn’t worth the lack of reliability and risk to us. We got extremely lucky to even save that block, considering we broke 3 brackets, the second time it threw metal shavings everywhere, and the last time it spun the crank hub oil gear.

We ended up getting a whole F Chassis EWG block that came with the hydraulic tensioner mounting holes, and newer bracket with dog ears.
This car has about 5k miles on it as we speak, on full E, FX-180, JB4 with MHD BEF. Our stress was eased, and if we wanted to test a S55 oil pump setup, or another oil pump, we wouldn’t have any concerns on the drive system for it. It is solid.

We still have that PWG E block to experiment on. Unfortunately, we had some things come up, so we haven’t done any testing on the set up that I mentioned in my earlier post. We had the valvetronic worm gear give out, and haven’t recovered quite yet. To clarify on that, we ended up using an N54 HPFP with the E chassis PWG leaf spring bracket and older flat style oil pump without the dog ears. This hasn’t been tested yet, but we’re confident it shouldn’t be an issue, as it’s identical to the OEM PWG E Chassis set up. (Our only concern is the efficiency of the N54 HPFP with the F Chassis DME)

Ultimately to my last point, our last option and one we debated on before doing what we did, was using the EWG, F Chassis Hydrotensioner Bracket, with the F Chassis Oil Pump (ears), and whatever HPFP setup we choose, by welding the hydraulic tensioner to the bracket, instead of mounting it to the block, or creating any weak sections in the aluminum bracket. We were skeptical of this, since our peasized weld before didn’t work for the leaf spring tensioner, however,

The Hydraulic Tensioner fits on a foot, on the F Chassis EWG bracket, and has a significantly larger surface area. We looked at so many options, and planned on welding the hydraulic tensioner, to the bracket on this foot. This was the next, most viable, and probably last option.

I know that you’re on a different adventure. If you’re not changing the HPFP, then I think it’s doable with a quality bracket. Just a thought. Plz share updates, as these things are a huge bottleneck for people doing N55 swaps in different year ranges.
Good Luck!!
 

Attachments

  • IMG_0806.jpeg
    IMG_0806.jpeg
    569.3 KB · Views: 1
  • IMG_2992.jpeg
    IMG_2992.jpeg
    423.6 KB · Views: 1
  • IMG_0988.png
    IMG_0988.png
    632.9 KB · Views: 1
Last edited: