14 years - 1991 325ix, Stroker/5-Speed (N52 swap?)

[jeenyus]

wonderful. after reading through all this I am curious why you never deleted your PS? Especially if you are driving a lot of autox.

Regardless, I love everything about this thread. Thanks for all the useful information, I will take that to my IX now.

[nando]

They can be redone, the main difference is honing.

If my cylinder walls are just glazed over, I can use an aluminum paste & ball hone that exposes fresh silica crystals and I can just re-ring it. If there are any scratches or scores, I'll have to bore it out. Porsche has been using Alusil blocks (and magnesium) since the 1970s, so there's lots of information to be found outside of BMW. here's a good read with lots of details:

http://www.sunnen.com/NewsDetails.aspx?NewsID=11

Supposedly the sillca bores are actually harder than steel bores, so I'm hoping I can just deglaze it. Otherwise, I've got to get aftermarket pistons which will be double what I paid for the whole motor. lol.

here's another discussion on honing alusil bores. it really doesn't sound too bad - you can't really overhone it because you're only removing a small amount of aluminum.

http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/603194-re-ring-alusil-bores.html

[digger]

How do you redo Alusil bores?

[nando]

Yeah, me too... Real progress will be building an oil pan! There's a lot of stuff i need to do though - wiring, plumbing, engine mounts, exhaust, fuel, tuning.. Not even including the engine. :|

[stonea]

Glad to see at least someone is making progress on their swap. For a while I thought Nisse was going to be the only who actually completed a swap, lol.

[nando]

They look pretty good. I'll probably replace the screens though. N52 vanos units seem much less problematic than any previous generation BMW motor - I think they still use them on the N55 and S55.

[tinkerputzer]

I bet there'd be 0 carbon buildup if they followed a shorter OCI. Remember this engine probably ran minimum 10-15k on one oil/filter.

Exactly what i was thinking. The vanos solenoids and filters might need some attention too.

[nando]

yeah. probably all highway. my 330i only has 113k.

I bet there'd be 0 carbon buildup if they followed a shorter OCI. Remember this engine probably ran minimum 10-15k on one oil/filter. I'm going to rebuild it anyway though, so it doesn't matter that much.

[CorvallisBMW]

Jesus, 258k?? That's a shit load of miles for an engine made in, what, '05?

[nando]

Still working on this - progress hasn't been that fast, but I need to clear my plate of other people's projects before I dive in too much..

I did in fact get it on a stand without a hoist - just needed a buddy to help. It was filthy as hell though, so I didn't want to touch it until it was clean - I started with a flathead screwdriver to scrape off about 5lbs of crud. Then I sprayed it with a bunch of brake cleaner which took off about 95% of the rest, and scrubbed it down with a brush and a water based cleaner. Now I can actually touch it without getting greasy. :p



I pulled the valve cover the other day and played with the valvetronic mechanism. it's pretty damn cool how it works. I want to measure valve clearance at TDC but I didn't have a good way to get leverage on the springs. it'll have to wait until I start disassembling all the rockers & vanos system.

For now I'm going to stop because I need to clear out space in my garage. The valvetronic system looks pretty easy to work on, but you have to be careful because each rocker is matched to the lobes on the eccentric shaft. they have a letter/number designation for each pair of rockers that match a specific lobe, so that when the valvetronic mechanism moves the valves open the correct amount. if I just tear it apart and have parts everywhere I'll never get it back together correctly..



There is a little carbon build up but really for 258,000 miles it's pretty clean in there. about 98% of the head is just a clean golden color and there is almost no wear on any of the valvetrain. Even the timing chain which I was expecting to replace looks brand new. I think this engine must have been well maintained for most of its life which is a good sign, because I'm going to beat the @#$*& out of it when it's done.. lol

[nando]

yeah. I have an S52 block in the garage, it's a heavy pig. I hated using that thing for mock ups! I'm pretty sure I will be able to get this thing on a stand by myself with no help, lol. The final config might end up a bit lighter since I won't have A/C or most of the intake manifold, lightweight flywheel, etc.

[2mAn]

the aluminum blocks are so light. I picked up my bare block and it was featherlight

[nando]

Liking this, I'm tuned in.

I'm curious, what is the magic that makes this and the r6 engine so light? I was reading a c&d article explaining the r6 engine with 30 lbs of new valvetronic hardware that lost 22 lbs overall compared to the m54. But the total 52 lbs in a vacuum between the two is a bigger difference than iron to alum blocks, and if the alum block made a 52 lb cut it'd barely have 10 lbs of metal left. There's either something else cool about these engines that I missed or they just went bezerk with the gram strategy to complement the magnesium.

the entire crankcase and everything was designed from scratch to be light. the M54 is an iron block design cast in aluminum - weight savings are minimal there because it would be weakened as the article said. It already had issues with crankshaft harmonics at high RPM.

There's lots written about the N52 by now, but some examples are the composite magnesium/aluminum block which was designed from scratch, the bed plate design, and even hollow camshafts. Most of the bolts are aluminum - that's an easy 5lbs of hardware, at least.

FYI, R6 was the internal code word for N52. They're the same thing.

[Sean]

Haha - Im planning on doing the swap/engine work on my rwd e30 that has the stroker in it now - not planning on keeping the IX real long. I want to enjoy the M20 and consider a swap down the road. M54 is definitely the top of the list now...but if you get this N52 thing working, I would consider that too. ;)

Pretty cool so far!

[whitebulat22]

Liking this, I'm tuned in.

I'm curious, what is the magic that makes this and the r6 engine so light? I was reading a c&d article explaining the r6 engine with 30 lbs of new valvetronic hardware that lost 22 lbs overall compared to the m54. But the total 52 lbs in a vacuum between the two is a bigger difference than iron to alum blocks, and if the alum block made a 52 lb cut it'd barely have 10 lbs of metal left. There's either something else cool about these engines that I missed or they just went bezerk with the gram strategy to complement the magnesium.