540i wont start after timing chain guide job

[agustinz96]

Hey everyone, we recently did a timing chain guide job and had a shop put the engine in the car but I just got a call and they told me that it's cranking, but wont start, and he when he turned it over he could feel that it has no compression. He the did a test and verified that it indeed had low compression (Didn't specify).

Some background on the engine: It has about 140K. my buddy took it out of one of his cars because it had bad timing guides and took it apart (took the heads off). it sat taken apart for about a year and he decided to put it back together and put it in another car. it has new guides, he bought timing tools but he wasnt able to use the flywheel locking pin because the engine did not have a flywheel on it. he put the close as close to tdc as he could without the pin.

Currently, I'm thinking the problem lies somewhere in the timing but don't know where to start. any help would be appreciated

- - - Updated - - -

I Should mention he also did the vanos seal. Car is an 01 and engine is out of an 01

[StRaNgEdAyS]

It sounds like bent valves to me unfortunately...


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[Mach540]

Do a leakdown test.
Air coming out of the exhaust = bent valves

Air coming out of the oil fill = "bore wash"

[agustinz96]

I've read a couple threads that mention "bore wash" im not too sure how this works. Can someone explain?

[StRaNgEdAyS]

Bore wash is when excessive fuel or other solvent (like Aerostart) has washed the thin film of oil that provides the seal between the rings and the bore, and it allows the rings to wear the bore directly and cause serious damage.
It's more often seen with the alusil I6 engines, but the V8s can suffer it too.


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[agustinz96]

thanks for the explanation. I just read a post on a jaguar forum about bore wash and it sounds similar, just the the starter noise but no compression. im going to head out to the shop tomorrow to see what I can do and get more info.

[JimLev]

Has this shop ever done a job like this before? Sounds like they screwed it up.
Did they happen to take the flywheel (or flex plate) off? If it was put on wrong the engine won't start or if it was close to right it will run like crap.

[agustinz96]

Has this shop ever done a job like this before? Sounds like they screwed it up.
Did they happen to take the flywheel (or flex plate) off? If it was put on wrong the engine won't start or if it was close to right it will run like crap.

I doubt it was something the shop screwed up on, as they didn't do the guides, timing, etc. they just had to swap the engines in the car. I've personally messed up with the flywheel before so I made sure to tell them to do that right so I really don't think it's that. When I messed up the flywheel on another car it had compression unlike this

[StRaNgEdAyS]

It doesn't take much movement of the crank to bend valves unfortunately... But the low compression on all cylinders makes me suspect that the timing was a little off.

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[JimLev]

So you guys did the guides. Was this the first time you've timed a 540tu?
What did you use for timing tools?

[agustinz96]

So you guys did the guides. Was this the first time you've timed a 540tu?
What did you use for timing tools?

Yes first time timing that engine. Honestly I'm not sure what brand the timing tools were. I just went to the shop and while I was there he compression tested 5 cylinders. 3 cylinders on bank 1 which had 20-50 psi and 2 cylinders on the 2nd bank, which both had about 50 psi

[Mach540]

Well, 50 PSI probably negates the bent valve theory. You'd get zero psi with even a minor bend.

Leak-down test??

[geargrinder]

I doubt the borewash, its not that common for these motors, and, mainly given the circumstances I'm gonna guess timing is either way off or you/he borked a buncha valves.

Given the heads were entirely off then clearly there's every chance the valve timing could be off in La-La-Land.

How did he confirm TDC when it was sitting on the stand? Did he measure a fixed piston drop left/right and set to midpoint? Or pure eyeball? The factory marks are about as useful as a set of pink pompoms in a barfight.
Did he get the cam blocks on the right cams (the exhaust and intake ones are different)? Did he block them up before the heads got bolted down?

With a running "good" motor at least you are pretty sure you got TDC pretty close because you blocked everything up from "known good" when it came apart.

But in this case - if he didn't meticulously set TDC on the block before reassembly, and/or, turned the cams to line up the blocks after the heads were on the motor... well... then there's your answer. Heads are junked (or at least need lotsa valve work now).

Well, 50 PSI probably negates the bent valve theory. You'd get zero psi with even a minor bend.

I'm not sure about that MachoTaco. Joe got some compression off his bent intake valves on 2 holes. Bad enough to see a sliver of light, but good enough to make some compression and even to fire the cylinders.

[JimLev]

Sounds like a bad timing job. Watch this.
https://www.bimmerforums.com/forum/s...a-540tu-engine

[Ziponby]

My 540i started making a clanking noise, oil light flashed red. Had the car towed. Trying to determine if it’s a rod, valve, or timeing chain.

[bimmer7410]

My 540i started making a clanking noise, oil light flashed red. Had the car towed. Trying to determine if it’s a rod, valve, or timeing chain.

Sounds like it might be valve guides, but either way you might get better responders in your own thread

[agustinz96]

Wanted to give you guys an update. We ended up having the car towed home, and I tried the usual fixes for borewash. a little oil down the spark plug holes, then crank with the throttle open a few times, then with the throttle closed. I cranked quite a few times and could feel that the engine was turning differently and compressing. I did a compression test and it was about 165 psi each cylinder, which was a massive relief, but the car still wasnt starting. so there is compression, it is getting fuel and spark. Right now I think the mechanic installed the flywheel incorrectly because this has happened to me in the past did the same it is currently doing so we're gonna have a talk with the mechanic.

Although the car isn't starting, we're just happy that the there arent any belt valves and the engine has compression, thank you guys for your help

[geargrinder]

Huh.

1. What do you have for codes? If you're not reading codes at all then stop guessing for sure and make that #1 priority.
2. Flywheel is not impossible but given you warned the mechanic about it, unless he's a complete moron/a-hole, that's somewhat doubtful.
3. You never answered how your bud confirmed TDC. Your valve timing could be way the fork off honestly. If the crank & cam signals are too far off the DME (ECU) wont fire the motor. The cam shutters are a little funky to set and if you don't understand the tools you can set those WAY off even using the jigs.
4. Did you change DME / ECU in the car in this swappapalooza w your buddies parts? Cuz you can't do that without changing everything else. Did the battery go low at any point in the process? Could be EWS got out of sync if so.