[BMW 801]

I am doing a b30 swap and took the Timing cover off my 99k mile used engine to put the oil chain tensioner mod on. I found 2 broken timing chain guides. Seeing I have to replace the guides should I do the chain and a head gasket too? The engine is on a stand and it would not be that hard ?

 

[Vass]

Wouldn't lift the head unless really necessary. Potential to introduce new issues and heaps of extra work, would avoid unless the head gasket is clearly blown or you're worried about excessive oil burning and want to put on new piston rings as well.
The chains themselves don't really wear out or need replacing in normal circumstances but you could put new ones on if you want, not overly expensive, would set you back around a hundy for all three OE iwis ones.
What is worth doing is fitting a slotted oil pump nut with safety wire, or a quick spot of weld to prevent it from backing off. Unlikely unless you're driving at redline all the time but good to do as a precaution regardless.

 

[M.Blacktree]

I wouldn't mess with the head gasket, unless there's an issue. These engines are known for the head bolt threads pulling out of the block. So a head gasket refresh will probably involve time-serting the block.

As for the timing chain, that's a judgment call. Take the chain, and try to flex it sideways. If it flexes a lot, then it's worn and should probably be replaced.

 

[andrebimmerandre]

mm, you know the history of this engine? This usually doesn't happen with these engines and especially not on such a low mileage one. Like the others said, I wouldn't go all the way in to do the head gasket as well. Just for pease of mind, I would replace the complete chain, including the tensioners and guide rails.

 

[Zimo32]

how badly corroded is your headgasket where you removed the timing cover? If its in good shape forget about doing the headgasket. Also make sure all your oil squirters are not broken on your b30.

 

[BMW 801]

Wouldn't lift the head unless really necessary. Potential to introduce new issues and heaps of extra work, would avoid unless the head gasket is clearly blown or you're worried about excessive oil burning and want to put on new piston rings as well.
The chains themselves don't really wear out or need replacing in normal circumstances but you could put new ones on if you want, not overly expensive, would set you back around a hundy for all three OE iwis ones.
What is worth doing is fitting a slotted oil pump nut with safety wire, or a quick spot of weld to prevent it from backing off. Unlikely unless you're driving at redline all the time but good to do as a precaution regardless.

Nut is in hand and safety wire is ready 🤘🏼

how badly corroded is your headgasket where you removed the timing cover? If its in good shape forget about doing the headgasket. Also make sure all your oil squirters are not broken on your b30.

Rubber looks rough to me

mm, you know the history of this engine? This usually doesn't happen with these engines and especially not on such a low mileage one. Like the others said, I wouldn't go all the way in to do the head gasket as well. Just for pease of mind, I would replace the complete chain, including the tensioners and guide rails.

salvage engine. Was told it drove off wrecker. Automatic car and it looked like it was taken Care of by owner. Block had BMW coolant in it and date stamped BMW 21 WP and T”Stat

 

[paraklas]

Should be doing the oil/timing chain sprocket while you're there

 

[Michal_]

If you decide to remove the head, definitely replace piston rings for better oil ring design and also do the valve job.
Head gasket and good head bolts (avoid aftermarket Victor Reinz bolts) costs more than good piston rings and OEM conrod bolts.

 

[Effduration]

I have done 8+ M54 rebuilds.. I only take the head off if I have a reason to.

I would just replace those guides, wire up the oil pump sprocket and call it a day. If you have the oil pan and baffle off, checking the oil squirters is a good idea.

You haven't mentioned it, but if you do the rear main seal...remember to put sealant (not threadlocker) on the two large horizontal bolts at the bottom of the RMS carrier.

 

[markusmarkus]

I have done 8+ M54 rebuilds.. I only take the head off if I have a reason to.

I would just replace those guides, wire up the oil pump sprocket and call it a day. If you have the oil pan and baffle off, checking the oil squirters is a good idea.

You haven't mentioned it, but if you do the rear main seal...remember to put sealant (not threadlocker) on the two large horizontal bolts at the bottom of the RMS carrier.

I think BMW solved the RMS problem by 2003. So the decision to R&R the RMS should be made on the basis of the production date of the engine.

 

[Effduration]

I think BMW solved the RMS problem by 2003. So the decision to R&R the RMS should be made on the basis of the production date of the engine.

I agree with the belief that you might only replace the RMS if it is leaking... But since OP has the engine out of car he should look at/ consider it... There is always a risk of replacing it incorrectly and having it leak when it did not leak before.

Markus, I wasn't referring to any problem with the RMS....Do you believe a post '03 RMS is a "lifetime" part?

 

[mega_stihl]

Wouldn't lift the head unless really necessary. Potential to introduce new issues and heaps of extra work, would avoid unless the head gasket is clearly blown or you're worried about excessive oil burning and want to put on new piston rings as well.
The chains themselves don't really wear out or need replacing in normal circumstances but you could put new ones on if you want, not overly expensive, would set you back around a hundy for all three OE iwis ones.
What is worth doing is fitting a slotted oil pump nut with safety wire, or a quick spot of weld to prevent it from backing off. Unlikely unless you're driving at redline all the time but good to do as a precaution regardless.

Or weld the nut to the sprocket. I've done this (well, my brother has done this. He used to be a welder, but we had a shitty welding station at the moment )

 

[TobyB]

I think BMW solved the RMS problem by 2003. So the decision to R&R the RMS should be made on the basis of the production date of the engine.

I hate to be the bearer of bad news, but the one rear main I've done on an M52/54 has been on a 2004. I may be an outlier.
That car also leaked from the front.

I would also agree, though, that if the rear's not leaking at this point, I don't touch it either. It's better if it's an engine I've
had for a while, as I've found that sometimes, my choice of oil is different than the PO, and a previously dry seal
is no longer dry.
However, when I was young, I changed them 'preventatively' and found that I caused more leaks than I solved.

As to whether to strip the thing apart- that depends on YOU, OP. I have done both, for various reasons.
Sometimes it was a 'complete' car that I was doing as a project, I had money, time and desire to do everything-
so I did.
Sometimes it was a 'core' engine that I didn't trust- and I knew I wouldn't feel comfortable relying on it if I didn't look at everything.

Other times, it's been an engine I trusted for whatever reasons, so I fixed what was wrong, and off I went. I'm driving an E39 wagon
like that now- the one- owner car that had another bad water pump, and she was done with it. Put a new head on it,
the usual cooling system parts, a third water pump (Salieri, thanks very much) and off I go.

It's just your comfort level, is all

t

 

[Zimo32]

If you have the oil pan off, and motor on a stand i dont understand why you wouldnt change the RMS. if you cant install it without it leaking you should't be touching anything on the motor....
Everysingle O-ring and gasket thats easily accesable should be changed. You'll be happy when your motor is bone dry for years to come.

 

[BMW 801]

I am leaning toward a HG change seeing I don’t like the idea of it possibly leaking from the HG where it meets the timing cover. All HG fail eventually, and sooner on aluminum heads. 400k on my Toyota and 233k on my Honda and I assume with the state of the guides on my junkyard b30 engine she has seen a lot of city driving and heat cycles and missed a few oil changes and that is what kills seals. Ask a Hybrid owner about heat cycles if you think differently. I have done 6 different HGs with no issue. One was a RB25 in my Silvia just for PM before install Not sure why I should be so afraid of replacing gaskets etc.

I plan on front and rear main and every seal I can find while it’s stripped and out of the car.

 

[Vass]

Yeah if you're not afraid to take it on then go for it. From my personal anecdotal experience, I've found the widely-documented head-bolt-thread-stripping issue to be a bit overblown. Did a full rebuild on a 161,000km M54B30. Turned out if had been overheated and cooked the whole head. Bolted a new head on and all the bolts torqued to spec without issues or any scary sounding squeaks. Granted, my sample size is 1 of 1 but I wouldn't go preventatively timeserting the block unless there's clear indicators of an issue. Chuck on some new piston rings while you're at it, ideally with the 3-piece M52 TU oil control rings.

 

[andrebimmerandre]

I am leaning toward a HG change seeing I don’t like the idea of it possibly leaking from the HG where it meets the timing cover. All HG fail eventually, and sooner on aluminum heads. 400k on my Toyota and 233k on my Honda and I assume with the state of the guides on my junkyard b30 engine she has seen a lot of city driving and heat cycles and missed a few oil changes and that is what kills seals. Ask a Hybrid owner about heat cycles if you think differently. I have done 6 different HGs with no issue. One was a RB25 in my Silvia just for PM before install Not sure why I should be so afraid of replacing gaskets etc.

I plan on front and rear main and every seal I can find while it’s stripped and out of the car.

Head gaskets on the M54 almost never fail. Of course you can do the work, especially if you’re thinking about upgrading the oil control rings, but I think that would be a better reason to take the block apart than just for the head gasket.

 

[BMW 801]

If you have the oil pan off, and motor on a stand i dont understand why you wouldnt change the RMS. if you cant install it without it leaking you should't be touching anything on the motor....
Everysingle O-ring and gasket thats easily accesable should be changed. You'll be happy when your motor is bone dry for years to come.

Do you record

Yeah if you're not afraid to take it on then go for it. From my personal anecdotal experience, I've found the widely-documented head-bolt-thread-stripping issue to be a bit overblown. Did a full rebuild on a 161,000km M54B30. Turned out if had been overheated and cooked the whole head. Bolted a new head on and all the bolts torqued to spec without issues or any scary sounding squeaks. Granted, my sample size is 1 of 1 but I wouldn't go preventatively timeserting the block unless there's clear indicators of an issue. Chuck on some new piston rings while you're at it, ideally with the 3-piece M52 TU oil control rings.

Where is a good source for rings with updated wipers in the US. You're not the 1st to mention oil rings. I had a 03 330ci 8 years ago and I don’t recal any oil consumption issues.

 

[Vass]

Where is a good source for rings with updated wipers in the US. You're not the 1st to mention oil rings. I had a 03 330ci 8 years ago and I don’t recal any oil consumption issues.

Not sure about the US, I've seen talk of a few sellers on eBay and such but not what I went with. I got these Goetze ones for mine. Not a BMW product but the right sizes and ring gaps were on point out the box. Haven't run the engine for too long yet due to a persistent leak from the rear gallery plug but from the few startups so far, all is running smooth.

 

[Effduration]

If you have the oil pan off, and motor on a stand I don't understand why you wouldn't change the RMS. if you cant install it without it leaking you shouldn't be touching anything on the motor....

Tell that to 50's kid.....

There are a couple of easy way to mess up the RMS
1. Buy just the seal and don't mount it in the carrier correctly.
2. Buy/install a cheap after-market seal.
3. Forgetting to put sealant on two lower horizontal bolts (50's kid did this)
4. Don' use the plastic donut installation tool.

These are simple things to avoid, but for some reason they still trip people up.