M54b30 Rebuild

[Vass 690]

This thread is dedicated to my efforts of rebuilding an M54b30 engine to drop into my Touring. I figured as this is the biggest and most essential part of the project, I'd best separate it from the main thread to avoid the details getting lost amongst the rest of the noise.

The engine came out of a 2002 330i sedan with 160,XXX km on the clock. The internals seem to be largely untouched.

Before taking the engine out of the donor car, I ran a compression and a leak down test. The testers used were on the cheaper side of the scale so that might have contributed to the results jumping around somewhat erratically. Did give some indication of the state though. All cylinders did hold compression but obviously the engine isn't as fresh as it used to be.

Spark plugs 1, 5 & 6 came out being completely drenched in oil. I soon found out that the reason had been that the valve cover had split in several places, from someone clearly "making sure" the bolts were tight enough.

The cover was also missing chunk out of one corner, a chunk I would later find swimming in the oil pan, so I'll either be using the cover off of the current engine or getting a new one at some point.

Apart from that, oil leaks were aplenty. The return line going from the CCV down to the dipstick had somehow completely split, the valve cover was obviously leaking, as was the OFHG, VANOS pressure line, oil pan and seemingly the rear main seal as well as the crankshaft seal. Funnily enough, the one component that didn't have any visual leaks was the head gasket.

The two hard coolant lines under the intake were not unexpectedly completely rotted away at the ends and came off leaving the tip inside (hue hue).

A couple of minor observations that I'm not sure what to make of. The first being the water pump had seemingly gone right up against the separator wall and tried to eat away at it a bit. Probably nothing to be concerned about, but would be good to have some assurance?

Also, taking off the intake, I found a few of the bolt holes surrounded by rings of oil. Is this a sign of anything at all or just safe to assume it had dripped onto it from the outside somehow?

My biggest concern and dilemma at present is whether to take off the head and preventatively change the head gasket. Ideally I'd love to avoid doing that, especially knowing the threat of pulling the threads whilst re-torqueing the head bolts (would be getting brand new bolts of course). I'm leaning towards 'yes' in that regard. I'd pulled off a "high oil temperature" code from the ECU which made me a bit concerned so would be great to have it checked to make sure it's solid.

Apart from that, everything looks tidy enough so far. Will be taking the timing gears and the camshafts off in the coming days and deciding the full extent of the rebuild.

 

The plan of attack as it currently stands:

• Take off the head, have it checked for cracks & hardness, get the surface machined.
• Have the cylinders honed.
• Install new piston rings, will try find a kit with M52TU oil control rings.
• Install a slotted oil pump nut.
• New timing chain guides.
• New hard coolant lines under the intake.
• Rebuild VANOS with new seals & anti-rattle kit.
• Rebuild DISA flap and possibly diaphragm as well.
• New CCV & associated hoses.
• Clean throttle body, idle control valve.
• New coils, spark plugs.
• Obviously all new seals & gaskets throughout.

Things I would ideally avoid doing:

• Boring cylinders, new pistons - really don't think it'll be necessary.
• Rod bearings - shouldn't be a problematic component on these engines so shouldn't need to be replaced?
• Stem seals - haven't looked into this one much. Probably worth doing but require some sort of special tool?

Still not done with research and assessing the cost-benefit of some of those 'maybe' items. Advice and feedback very much welcome.

If there's any additional items worth addressing or minor mods/upgrades worth doing or considering while I'm at it, please do let me know. I've never done an engine rebuild or anything close to a task this big before so am bound to have a bunch of blind spots and obvious things I'm overlooking. I'm very much learning as I go along and would love to have others' experience and advice to fall back upon and guide me along the way.

Equipment wise, I'm near enough set. Have all the generic tools as well as torque wrenches of all 3 sizes and a few specialist spanners & sockets. Have also ordered a camshaft locking/timing tool kit. Might need some specialist tool to install the rear main seal so will figure that out at some point.

Probably missing a bunch of things so feel free to point it out if you notice anything.

Cheers

Edited February 1, 2022 by Vass

[Eagle 1514]

Looks like its had a rough life and your right it probably deserves a rebuild. Im going say likely an import? 

Water pump damage wouldn't worry me, cant do much about it anyway. Oil on the intake ports will be from the inside the manifold. Those feet with bolt hole where the gasket sits on the manifold are just a press fit and im sure allow oil to seep past.

Are those codes that have been cleared already? Factory software is good as it logs details of the fault and how many times it has occurred.

You could add:

1. O2 sensors to the list but they are hard to find without going universal (well one bank is anyway hence why i haven't done mine yet).
2. Injectors cleaned and tested + seals. Maybe fuel lines to rail

The rear main seal should come with a plastic cone tool which does the job.

[Vass 690]

8 minutes ago, Eagle said:

Looks like its had a rough life and your right it probably deserves a rebuild. Im going say likely an import?

You know it, good old Japanese expat.

8 minutes ago, Eagle said:

Are those codes that have been cleared already? Factory software is good as it logs details of the fault and how many times it has occurred.

Can't remember if I cleared them or not but the car's in bits and gone to scrap now anyway. Did keep the ECU off of it but don't know if I'll bother hooking it up just to check old codes. Planning to reflash the current one in the wagon. The one that came off the donor was an MS43. I suspect the wagon will have the same?

Really need to start getting to grips with the software side of things. Did get my K+DCAN cable in the mail a couple weeks ago but haven't gotten round to installing standard tools yet.

8 minutes ago, Eagle said:

You could add:

1. O2 sensors to the list but they are hard to find without going universal (well one bank is anyway hence why i haven't done mine yet).
2. Injectors cleaned and tested + seals. Maybe fuel lines to rail

True, good points, thanks for that. Are O2 sensors something that you can just clean up the tips on to prolong their life a bit or that's not how they work at all?

The injectors yeah, was definitely meaning to clean and put new seals on. Is that something you reckon that's DIY-able or best have someone that knows what they're doing look over it?

8 minutes ago, Eagle said:

The rear main seal should come with a plastic cone tool which does the job.

I was looking at this video on it and guy had some sort of special tool that seated the seal a certain depth within the housing, 22 minutes in. Can probably make due without somehow but... meh.

https://youtu.be/5S7-gNEgJoM?list=PL691E5829632F8FF7&t=1329

Thanks for the reply. Keep 'em coming 

[Eagle 1514]

Yeah should be both MS43. Maps are likely different but you are reflashing.

I've never tried cleaning them myself. Never saw the point when you can replace them for 150ish and be done with it given they are already decades old. Suppose be done every 150000km.

You can clean them yourself via diy methods but they proper machines will spray, flow and leak test them well. Was around $25 per injector last time I did it so not too expensive.

I was thinking installing seal on crank not the cover. I've always just put them in flush. A workshop maybe able to do it or have something machined up maybe if tool is costly.

 

[dirtydoogle 383]

GOETZE P208678534 should be the ring pack you're after with the m54 1.2mm top ring and m52tu 3 piece oil control ring 

VAC do a kit too i think. Probably a few options these days 

[Vass 690]

9 hours ago, dirtydoogle said:

GOETZE P208678534 should be the ring pack you're after with the m54 1.2mm top ring and m52tu 3 piece oil control ring 

VAC do a kit too i think. Probably a few options these days 

Thanks for that. Couldn't find the part number you specified but these seem to be what you're referring to?

https://www.ebay.com.au/itm/273104514430

[dirtydoogle 383]

https://spareto.com/products/goetze-engine-piston-ring-kit/08-137400-00

No idea what part number I pasted there before sorry. Its a VAG fitment part ,but just consider you will hopefully remove one VAG product from the road by buying them 😉 

[Young Thrash Driver 1020]

I refreshed some injectors once. Then one of them went mental and stuck open about 2 weeks after I stuck them back in- so ended up sending them away for a proper clean/flow test etc etc. Was about $30 each from memory.

[Vass 690]

11 hours ago, dirtydoogle said:

https://spareto.com/products/goetze-engine-piston-ring-kit/08-137400-00

No idea what part number I pasted there before sorry. Its a VAG fitment part ,but just consider you will hopefully remove one VAG product from the road by buying them 😉 

Sorry to be that guy but I'm not particularly clued up on the VAG inside joke. What's the deal? 😄

44 minutes ago, Young Thrash Driver said:

I refreshed some injectors once. Then one of them went mental and stuck open about 2 weeks after I stuck them back in- so ended up sending them away for a proper clean/flow test etc etc. Was about $30 each from memory.

Yeah good call, probably worth going that route too. Thanks for that! 

[HalfJobHarry 106]

Great to see this project, M54B30 was the second engine I ever rebuilt from my 330i back in 2012/2013. Brings back memories. 

[dirtydoogle 383]

4 hours ago, Vass said:

Sorry to be that guy but I'm not particularly clued up on the VAG inside joke. What's the deal? 😄

Yeah good call, probably worth going that route too. Thanks for that! 

Vw stuff, I don't care for their gear 

In all fairness if you are rebuilding, the oem replacements are fine anyway, they only start consuming oil after 15 years of neglect and low oil temps. If yours was an oil consumer it will have a bunch of varnish combined with carbon around the ring pack 

[Vass 690]

2 hours ago, HalfJobHarry said:

Great to see this project, M54B30 was the second engine I ever rebuilt from my 330i back in 2012/2013. Brings back memories. 

Aye cool! Would be keen to hear more about your experience, how deep you went into it, what you'd do differently if you were to do it again etc. Cheers

6 minutes ago, dirtydoogle said:

Vw stuff, I don't care for their gear 

In all fairness if you are rebuilding, the oem replacements are fine anyway, they only start consuming oil after 15 years of neglect and low oil temps. If yours was an oil consumer it will have a bunch of varnish combined with carbon around the ring pack 

Yeah will check it out.

I've kinda started having second thoughts about lifting the head now, not for the first time. Had a chat with a few more people and they're all telling me it's real likely the bolts would strip the threads out of the block the second time round and you'd need timeserts. Really not keen on having to do that. Will do some more digging around..

[dirtydoogle 383]

2 hours ago, Vass said:

 

I've kinda started having second thoughts about lifting the head now, not for the first time. Had a chat with a few more people and they're all telling me it's real likely the bolts would strip the threads out of the block the second time round and you'd need timeserts. Really not keen on having to do that. Will do some more digging around..

Unlikely to strip on an m54, often the issue is down to a few factors: 

Most suppliers send M50 head bolts (quite a lot shorter) 

And poor prep and installation (unclean, or too much lube) 

In very rare cases it's a soft or distorted block

[tawa 150]

Good stuff guys, I have an M54B30 in my garage awaiting a rebuild so shall watch for any tips and trick here

[Vass 690]

3 hours ago, tawa said:

Good stuff guys, I have an M54B30 in my garage awaiting a rebuild so shall watch for any tips and trick here

Feel free to go first so I can learn from your mistakes instead hahah 😄

[tawa 150]

18 hours ago, Vass said:

Feel free to go first so I can learn from your mistakes instead hahah 😄

Haha, I'm still a ways off it yet, gotta clear out a few other projects, and save up some coin...

[Vass 690]

Right, so I phoned around a few machine shops on Friday to get a gauge on an approximate budget for machine work. For the head, I've currently settled on a hardness & pressure test + getting it surfaced; for the block I'm getting a hardness test and a cylinder deglaze/hone, and have both the block and the head acid dipped & cleaned. With some variations in scope between different shops, I'm looking at around $600-1000, which I guess is fine.

Also asked about timeserting/helicoiling the head bolt threads in the block and was strongly recommended to not take it on as a purely preventative measure as it's likely to be a waste of money for potentially a poorer outcome. The recommendation was that a hardness test would give a good indication whether the original threads are likely to strip out or not, and if the test indicated that the block has gone soft, then there are bigger problems to worry about.

That seemed to make sense and, having read through a few more engine build threads on e46 fanatics where the standard head bolts have re-torqued just fine, I decided to box on.

Quite a bit of gunk stuck all over the cam tray studs. Lifters were also quite gunked up. Unfortunately it doesn't look like the car had been blessed with regular servicing.

The exhaust cam bearings looked mostly fine, but two of the exhaust ones had a wee bit of a munch at some point. Does look pretty bad but hopefully nothing a bit of fine sand paper can't fix.

The oil pickup tube spit out a whole bunch of RTV worms as well as tiny plastic particles, likely chunks off the cam cover.

The pistons had quite a bit of carbon buildup. Those will take some scrubbing.

The cylinders looked in pretty good shape. Bit of varnish but the factory hone marks are still clearly visible so I'm hoping to get away with just a minor hone/deglaze. Only visible defect was a mark on cylinder 6 which I'm not sure what to make of. Hoping the hone will sort it out.

The rod bearings looked worse than I'd hoped for. Did read that they'd supposed to be pretty solid on the M54 but these looked well shot. Another item added to the shopping list.

At this point, all that's left on the block is the crankshaft. Made the mistake of checking how much replacement cap bolts cost and got cold feet.

Yikes!

Read a few threads of people using just regular M10x90mm 10.9 bolts (instead of 92mm factory) from a hardware store for years without issues. Also of people reusing the old bolts similarly trouble-free. So... one to think about.

Anyway, long weekend well spent. Will get onto a further teardown and cleaning duties next.

 

Edited February 7, 2022 by Vass

[dirtydoogle 383]

Main bearing bolts are not particularly worrisome and aren't under a lot of stress. Using a 10.9 grade fastener is fine. 

You're taking all the right steps 👌

Be very gentle cleaning the cam caps up, I would remove any high spots and leave it at that. The rod bearings aren't really a worry with that "wear" pattern, thats pretty standard. There however has been some contaminated oil judging by the scoring

Doesn't appear to have anything worrying going on, just a lack of general maintenance casting the oil control rings to stick 

[HalfJobHarry 106]

On 2/3/2022 at 3:21 PM, Vass said:

Aye cool! Would be keen to hear more about your experience, how deep you went into it, what you'd do differently if you were to do it again etc. Cheers

 

.

It was a total rebuild down to the bare block, machined, oversized bearings the lot. 

Probably many things I'd do differently , the biggest thing I'm glad I did though was fit an aftermarket oil pump. 

I did not have any issues with torquing the head down. 

I had the supervision of an experienced engine builder as this was my second proper rebuild. 

In hindsight I'd have a clearer goal for the project, given this is an NA engine and I wasn't aiming for vastly increased power the rebuild didn't have much point other than gaining good experience. In later builds I've had a clear goal (like super charging a K20, or hitting 500 WHP with the N54) etc. 

Good fun though. 

[Vass 690]

11 hours ago, dirtydoogle said:

Main bearing bolts are not particularly worrisome and aren't under a lot of stress. Using a 10.9 grade fastener is fine. 

You're taking all the right steps 👌

Be very gentle cleaning the cam caps up, I would remove any high spots and leave it at that. The rod bearings aren't really a worry with that "wear" pattern, thats pretty standard. There however has been some contaminated oil judging by the scoring

Doesn't appear to have anything worrying going on, just a lack of general maintenance casting the oil control rings to stick 

Thanks mate, pretty glad to see there ain't anything catastrophically wrong in there. Bit of encouragement to soldier on.

OE rod bearings look to be just $49 USD from FCP so not a big shell out to switch them out. The main bearings are $106 USD so won't be too terrible either if they'll need replacing. Will take the crank out in the coming days.

9 hours ago, HalfJobHarry said:

It was a total rebuild down to the bare block, machined, oversized bearings the lot. 

Probably many things I'd do differently , the biggest thing I'm glad I did though was fit an aftermarket oil pump. 

I did not have any issues with torquing the head down. 

I had the supervision of an experienced engine builder as this was my second proper rebuild. 

In hindsight I'd have a clearer goal for the project, given this is an NA engine and I wasn't aiming for vastly increased power the rebuild didn't have much point other than gaining good experience. In later builds I've had a clear goal (like super charging a K20, or hitting 500 WHP with the N54) etc. 

Good fun though. 

Good stuff! I'm probably in a similar boat as you were with your first build - doing most of it more out of interest rather than necessity. Not really chasing any serious power so will be keeping most things stock, just wanting to recondition and have a reliable engine to power the daily driver/weekend cruiser for the next 10+ years. Power output wise I was actually reasonably happy with the 2.5L, it just made more sense to rebuild a 3.0L.

With the oil pump, do you mean you upgraded the shaft & sprocket or just changed out the whole thing? I was going to just give it a good clean and fit a slotted nut with a safety wire. Didn't think it was a problem area unless it's a race build?

[dirtydoogle 383]

Check for colored marks on the backside of the bearings before ordering, measure the clearance of the old bearings (plastigauge or micrometer, either is fine for this application) 

There are 3 colour codes, off the top of my head it goes Yellow, Green, White in order of largest to smallest clearances. Hopefully there is a spec for the colour coding easily available 

Replace the rod bolts, too. Use the old bolts when clearance checking the journals 

 

And oil pump will be fine with lock wire. If budget allows, replace chain and gears. Otherwise just check em carefully

Edited February 8, 2022 by dirtydoogle

[Vass 690]

Took off the cam tray studs today to be able to flip the head over and have a better look at the valves.

Quite a lot of carbon caked on. Don't have much experience to gauge how bad it is. Doesn't look like anything that won't clean up but what does this generally indicate? Lean mixture? 91 fuel? Car did have a lot of oil leaks, CCV was clogged up and also split, valve cover wasn't sealing properly being cracked and I assume had a bunch of vacuum leaks as well, so a bunch of things wrong that would all have contributed?

Will borrow a valve keeper tool off a mate and see what the valves are doing beneath the surface. Will also remove the crank and then pretty much set for the machine shop.

[dirtydoogle 383]

Oil control rings, pull a piston, I dare ya 

[Vass 690]

33 minutes ago, dirtydoogle said:

Oil control rings, pull a piston, I dare ya 

Pistons are out yeah, will take some pics tomorrow

48 minutes ago, dirtydoogle said:

Check for colored marks on the backside of the bearings before ordering, measure the clearance of the old bearings (plastigauge or micrometer, either is fine for this application)

Yeah I read about the bearing coloring. What's with the whole plastigauge though? Is that absolutely necessary or enough to just order the same color as the current ones?

[dirtydoogle 383]

8 hours ago, Vass said:

Pistons are out yeah, will take some pics tomorrow

Yeah I read about the bearing coloring. What's with the whole plastigauge though? Is that absolutely necessary or enough to just order the same color as the current ones?

Always check clearances. Plastigauge is easy enough and cheap enough