Is this engine toast?

[pkh540]

Howdy, I bought a ‘97 540 for $800 that the PO claimed “suddenly made a sound like the timing guides failed so immediately stopped and had the car towed home.” Dropped the oil pan and this is what I found... So much for stopping immediately 🤣 The big piece is from the inside of the lower timing cover (that I’ve yet to remove) and there’s aluminum shavings everywhere including the oil filter.

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I’d love to save it but one way or another I figured this 540 might be a good project for my son to learn a bit about cars. Worse case scenario, the project would be beyond repair and I could raid it for parts for my ‘97 540 that I picked up via Euro delivery. (17” 7-spoke wheels and tires, heated steering wheel and sports seats, premium stereo and CD player, etc.)

Thoughts?

[JimLev]

Pull the front 3 timing covers off, that will tell you a lot.
The aluminum is most likely fro the center u guide and from where the chain was rubbing on the inside part of the lower timing cover.

[pkh540]

Thanks. Pulled the top two but haven't pulled the lower as I haven't been able to get the engine to TDC... Can't even turn the crank. So I pulled the intake manifold and it's not a pretty picture. The intake and exhaust valves for all of the cylinders appear to be stuck open. Here are pictures from just cylinder 1 and 2...

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[JimLev]

From your pic it sorta looks like the valves stems are slightly bent, but that could just be from the camera lens.
Sure the cam isn’t keeping them open??

[redlineracer]

I lucked out once with a mitsubishi eclipse non turbo. it had a belt that broke but same thing pistons hit the valves. i lapped in new valves and it ran good afterwards. you wanna look at the valve guides and pray the pistons aren't damaged too. either way sounds like it has to come completely apart and cleaned

[pkh540]

I shined a light down through the spark plug hole and then looked through the intake valves and saw the light shining in the cylinder... On all 8 cylinders. The exhaust valves are open on all 8 as well. Not sure why all of them are open. Perhaps the PO kept driving until the engine seized causing the valves bend and lock in the open position? You'd think some of them would be closed but every valve is open. Strange.

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I borrowed a buddy's borescope the other day and all of the piston tops looked ok. But it wasn't until I took the intake manifold off that I spotted that all of the valves (intake and exhaust) are locked in the open position and I can see into the combustion chamber through the intake ports.

Not really sure it's worth rebuilding the engine as I'd never break even. But, it might be a good lesson for my son so that might make it worth our while to do.

[JimLev]

Might as well pull the heads. Never saw one that had all the valves stuck open on all cylinders. They all must be bent.
Maybe you could score some used heads for cheap at the junkyard.

[pkh540]

Pulled the heads this weekend (might be easier pulling engine but I don’t have an engine hoist or stand so doing things the hard way). As suspected, every valve is bent. Fortunately no significant damage to the piston heads and once I pulled the heads I could finally turn the crank. M62 heads are harder to find than the M62tu so am thinking of replace valves and seals. Thoughts? And if we rebuild the top end, should we just go all-in and rebuild the whole engine?

Have a look... Here are the cylinder heads pictured 1 - 8.

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I’ll post pictures of the cylinders in the next reply if I can.

[pkh540]

and here are the cylinders...

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[pkh540]

And the debris... Yikes!

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[JimLev]

The previous owner was full of sheeet, he drove it for some time after the guides failed.
That engine didn’t get any love. If you do rebuild it clean the carbon off the pistons. Maybe pull them, the ring lands are probably caked with carbon too.
Good luck.

[Gluoak]

it is bothering some to see all those metal shaving, which might have been pumped by oil pump everywhere through out the engine..... How to deal with that?

[philly98540]

Agree with above. Assess the condition of the bores before you commit anything more to this engine. If the bores are scratched or damaged, get another engine as the costs are prohibitive to bore properly and get oversize pistons/rings. If the bores are good, pull the pistons and clean the carbon from the ring grooves, check that they don't bind, and check the ring gap in the bores. Likely can save the engine if the bores are still OK.

[ross1]

Take it from me, the one who has thrown good money after bad more than once. Start over with another engine.
While the bores may be useable some of that debris has probably made it past the oil pump and perhaps past the filter if it became clogged and bypass opened.
It seldom makes financial sense to overhaul a BMW engine, especially one that has been traumatized. The cost of just the head work and gaskets will buy a used engine or better yet a rusty, good running E38 or E39.
Is this $800 car even worth the effort?

[pkh540]

thanks all, I sincerely appreciate your comments and advice. I knew going in there was a fair chance the PO wasn’t telling the whole story and that the car may need more work than it’s worth. (Secretly hoped we’d fix it for my son.) With 10+ pages of carfax showing consistent and timely maintenance up until 206k makes me quite sad what the PO did in the last 12k. He sounded like an enthusiast but guess he was just a hoon out for a joyride.

I’ve enjoyed working on the car and there are plenty of good bits I can use on my 540... Really would’ve liked to get the project 540 back on the road. I’m in no hurry so I may keep my eye out for an engine and see if anything comes up. Or i may dig in further. But you all have given solid advice whichever direction we decide to go.

Again, thank you!

[kingfisher1]

thanks all, I sincerely appreciate your comments and advice. I knew going in there was a fair chance the PO wasn’t telling the whole story and that the car may need more work than it’s worth. (Secretly hoped we’d fix it for my son.) With 10+ pages of carfax showing consistent and timely maintenance up until 206k makes me quite sad what the PO did in the last 12k. He sounded like an enthusiast but guess he was just a hoon out for a joyride.

I’ve enjoyed working on the car and there are plenty of good bits I can use on my 540... Really would’ve liked to get the project 540 back on the road. I’m in no hurry so I may keep my eye out for an engine and see if anything comes up. Or i may dig in further. But you all have given solid advice whichever direction we decide to go.

Again, thank you!
That is such a shame.but,this is why I don't by these cars from kids.Sorry man,I bet the previous owner would be sick to find out this.Maybe you can find a decent Junk yard motor.?

[Bwingnutt]

I bought a 03 540 auto for $1000 they are out there . I would junk that motor.

[pkh540]

I bought a 03 540 auto for $1000 they are out there . I would junk that motor.

I’m still considering just pulling a bunch of parts for my 540, parting out the rest of the project 540 and be done with it... Son is working me to fix it... lol

[goz777]

cheaper to get a second hand motor from the junk yard.....do all the preventative maintance while its out of the car pop it in & happy motoring

[pkh540]

So I picked up an M62tu from a 2001 740iL with bad timing guides ($200). Figured I’d just harvest the valves but upon tearing it all down found the pistons had recesses for the valves (not sure what this is called) and the cylinders were in fantastic shape (compared to mine which I am a little concerned about). Now I am considering switching the block... using the M62tu block with the M62 heads with the harvested valves and using the M62 timing covers. Doable? Any issues to be aware of? Thanks!

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and these are the new heads that I will harvest the valves from...

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[JimLev]

Look at your second pic, the very top left hand corner of the block. See that small oil check valve? That for supplying oil to the heads for the vanos and preventing it from draining back when you shut the engine off. I’m pretty sure your M62 heads don’t have a hole in the heads for this oil port. As long as the head gasket will block off this hole I think you’ll be OK.
The notch in the tu pistons will slightly reduce your compression.

[wagons ho]

No, the m62 and m62tu head gaskets are the same, and both use the same oil supply check valve.
There will be no problem putting m62 heads on.
In fact, you can run m62tu heads on an m62, if you plug the vanos oil supply at the check valve on the front end of the head. Under the vanos tower.
The only thing you can't do, is use m62 pistons with vanos.

[pkh540]

great! thanks guys, I really appreciate your feedback. cheers!

[JimLev]

No, the m62 and m62tu head gaskets are the same, and both use the same oil supply check valve.


Thanks for the info wagons. It’s been a while since I ripped apart a non vanos engine.

[pkh540]

well, I’m back at it. The engine I purchased came from an ‘01 740iL with 190k (M62tu). Planning to build a Frankenstein engine using the M62tu block, pistons and valves combined with everything else from my M62. Will be replacing timing guides, valley pan, valve stem seals, all the gaskets, water pump, hoses and all of that (Sure it’s a lot of $$$ but hoping to share the experience with my son.)

However, the block is a mess so considering taking it and my M62 heads to a machine shop to clean them up (there’s aluminum shavings from the failed guides so figured this was the best bet). Thoughts? What about replacing the bearings? I’ll examine the rings but unless there’s damage not planning to replace. What about the timing guides and tensioner between the cams? Reuse or replace? What about the main timing chain tensioner and the chains themselves? Are there any other items that should be replaced “while I’m at it?”

Thanks

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[JimLev]

The tensioner between the cams can be disassembled and cleaned. Replace the top and bottom chain pads on them.
The chains themself usually will last a long time, it’s your $$$ so inspect them and decide.
The bearings you can use some plastigauge to see if they are still in spec, my guess it they probably are.
Clean any built up carbon out of the rings and pistons.
The top front inner corners of the block (your 2nd pic) have an oil check valve, pull it out and make sure it’s clean. You can only access it when the heads are off.

[ross1]

From what I see of the piston tops and combustion chambers it looks old but normal. I don't like the aluminum shavings part but that is what the oil filter is for.
Me? I'd take off the first main cap that sees oil from the pump and if that bearing is good I'd button it up with a new oil pump and leave well enough alone. Once you start poking out pistons and removing rings you've opened a can o worms.
As for the heads you can wash at home with solvent. If a machine shop dismantles them I guarantee they'll want to grind valves, resurface, etc.
You can invert the heads and check vale sealing yourself with denatured alcohol poured into the chambers.
Was a 200k engine all you could find?

[pkh540]

Well, finally back at it. Removed the engine and trans from the car. Removed upper oil pan and there are no aluminum shavings in the crank case. According to the 13 page CarFax, the previous owners were consistent and had regular oil changes every 3k or so... All the way until this last owner who only had the car for about 12k or so. The engine is actually pretty clean for 218k. I removed the rod cap to check the bearings...

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I’m leaning towards using the original engine vs the donor from which I harvested the valves. The donor engine (190k) had sludge and looks like the PO’s rarely bothered with oil changes which is another reason I am leaning towards sticking with the original engine.

Question, as long as I am in this far, should I replace the rod and crank bearings? And if so, are the bolts one-time use like the head bolts? Or should I slap the harvested valves in the heads, lap them and then put everything back together again?

[JimLev]

Use some plastigauge to check the bearing clearances.
Technically the rod and crank cap bolts are one time use. IIRC they are pretty expensive.
I’ve heard of some peeps re-using them without issue. Your $$ your call.

[seagreen323i]

That is such a shame.but,this is why I don't by these cars from kids.Sorry man,I bet the previous owner would be sick to find out this.Maybe you can find a decent Junk yard motor.?Bought mine at 18 and I treated it just fine.

Sent from my SM-G973U using Tapatalk

[pkh540]

Use some plastigauge to check the bearing clearances.
Technically the rod and crank cap bolts are one time use. IIRC they are pretty expensive.
I’ve heard of some peeps re-using them without issue. Your $$ your call.


Yeah, the bolts are more expensive than the actual bearings! Leaning towards reusing bolts unless others feel strongly otherwise?

[JimLev]

If your just driving it normal and not drag racing or shifting at 7K they will probably be fine.

[ross1]

Well, finally back at it. Removed the engine and trans from the car. Removed upper oil pan and there are no aluminum shavings in the crank case. According to the 13 page CarFax, the previous owners were consistent and had regular oil changes every 3k or so... All the way until this last owner who only had the car for about 12k or so. The engine is actually pretty clean for 218k. I removed the rod cap to check the bearings...

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I’m leaning towards using the original engine vs the donor from which I harvested the valves. The donor engine (190k) had sludge and looks like the PO’s rarely bothered with oil changes which is another reason I am leaning towards sticking with the original engine.

Question, as long as I am in this far, should I replace the rod and crank bearings? And if so, are the bolts one-time use like the head bolts? Or should I slap the harvested valves in the heads, lap them and then put everything back together again?

Appears a cared for engine. Crank and bearings look okay. As long as it's apart it would be interesting to know clearances but I'd wager you could button 'er up as is. If you've removed the main caps be sure to get all the oil from the bolt holes before re-torqueing.

[philly98540]

The rod bolts are TTY (torque to yield) but like Jim said may be fine to re-use, but its up to you. They are expensive for some stupid reason. When my engine was apart, I took apart just two of the rod bearing caps, decided the bearings looked good, so I never took the other rod ends apart. I bought two new sets of rod bolts to reassemble the two I took apart. The torqueing process is a pre-tighten to a set torque, then angle tightening. Those bolts really feel like they are getting stretched some when you get to the final angle.

Just giving you my example, but its really up to you. Safest thing is to take them all apart, evaluate bearing condition, replace if needed, and put on new bolts, but that is expensive. Your bearing in the pic looks pretty good. Some minor spotting, but original surface is still intact. Cheapest route is to re-use bolts. Up to you.

[ross1]

Rod bolts could be measured and compared against new to see if indeed they have yielded. If not necked I'd use them. BMW builds a lot of margin into these engines.

[wagons ho]

I've reused my bolts. With the snap on wrench, it logs the torque value after the degrees.
All my bolts were between 51.1 and 51.2 lbs if memory serves.
Any soft torque would indicate a failed/stretched bolt.

[JimLev]

I know this is a different bolt, however when I did my guides I bought a new crank bolt from BMW. I measured the old one so I could see how much it stretched compared to the new one. The new bolt was about 2mm longer than the old bolt I took out. Both bolts were made by the same manufacture.

[BimmerBreaker]

Shop for ARP rod bolts - sometimes it's cheaper to go aftermarket (plus, they are re-usable). The speckled, mottled appearance of the bearing does concern me a little bit, it's hard to tell from the photo if that is pitting (from cavitation or dirt being shoved through the oil channel and abrading the surface) or just normal surface wear of the bearing. The crank does look okay though
I can't personally fathom re-using TTY rod bolts... elsewhere on the engine, maybe, depending on the context - but not rod bolts... those bolts are under the most stress of any other hardware in the engine

Personally I would also disassemble the engine completely, at the bare minimum have a machine shop clean the block... those metal shavings are everywhere inside the oil galleys and only waiting to cause an issue down the road. Plus you want to pull the pistons to inspect the bores as others have mentioned. It won't run well, or long, with scoring on the bores or with metal in the oil