540i P1346 and P1347 cyl 3 misfire after timing chain guides + vanos

[Mach540]

One suggestion, when you go to put it back together again, leave the cams off until the head is mounted and everything is static timed. Then clamp the cams down.

[JimLev]

Any chance the exhaust cam sprocket wasn't tightened properly, maybe the sprocket slipped. But that doesn't explain why the other valves in that bank are OK.

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One suggestion, when you go to put it back together again, leave the cams off until the head is mounted and everything is static timed. Then clamp the cams down.

That might not be possible.

[philly98540]

Very odd it's only 2! Really big job ahead to pull head. You seeing if any whole engines are available as an option, if price is decent...

[joekitch]

not that big, i'm most of the way there. just drain coolant from block, pop the rear accumulator bolts, then pull the vanos unit off to get the chain off, pull head bolts and its off.
problem is i need CW's presence for timing tools and such, also general expertise since he's done head pulls before i believe.
and i'm only pulling bank 1

i mean if i could find a whole engine that's had the TCGs and valley pan done recently for a decent i'd be all for it, but i think i'm falling into the sunk cost fallacy right now, having already dropped $1850 on this job already

[JimLev]

Did you look into the exh port with your camera? Maybe it's just carbon on the stem that is preventing the valve(s) from closing.

[geargrinder]

I did back of the envelope and it looks to me that based on firing order #3 would be the one w exhaust valves in boner mode when in timing position, therefore first to kiss piston if the motor was turned while cams locked (or cam sprocket bolts loose..)

Somebody check me on that but has hallmarks to me of a static whack like that - no major piston damage, only one cylinder and "the first one you'd hit from TDC"....

Btw there's the "freak random piece of debris jammed a lifter or valve guide" theory too i considered, however being both exhaust valves also points way more to a timing incident.

[Mach540]

Yep, makes sense.
Firing order 1-5-4-8-6-3-7-2.
1 @ TDC-F
6 @ TDC-E
3 @ 90 Deg before TDC-E with Exhaust Valve fully open.

One would have to turn the crank ~90 Degrees clockwise with the chain removed for the piston to contact the open valves.

[joekitch]

Did you look into the exh port with your camera? Maybe it's just carbon on the stem that is preventing the valve(s) from closing.

i did, also recorded video, stems had the normal white coloration, no excess carbon around the top of the stem near the seal as far as i could tell
i'd upload video but i need to go to bed for work, and my video editing software is being a real POS right now

so here, have a screengrab.

cyl 3 exhaust valves.jpg

[geargrinder]

Yep, makes sense.
Firing order 1-5-4-8-6-3-7-2.
1 @ TDC-F
6 @ TDC-E
3 @ 90 Deg before TDC-E with Exhaust Valve fully open.

Thanks brother, yeah that was my quick bar napkin too.

One would have to turn the crank ~90 Degrees clockwise with the chain removed for the piston to contact the open valves.

As menched, or exh. sprocket loose. And not all 90 obv (hence your "~" I know..) - you'd have to have some pretty specific clearance and cam profile measurements and dust off the old trigonometry texts to say at exactly what point the valve whacks... but with it in full-boner-mode I'm gonna guess its well before the full 90 degrees... I've never bent a valve myself but I'm told it's pretty easy to do by mistake.

[JimLev]

GG, you still got the tu heads I gave you? Turn the exh cam so the 2 dots are pointing up and see what position the #3 exh valves are in.

[geargrinder]

Ha ha didn't think of that. I'm in Ando unfort and heads are in Rocko, so no can do for the momes.

[joekitch]

Actually the GAS timing tools guide has a nice picture of it, and yes the cyl 3 exhaust valves are fully open when at cylinder 1 tdc



cams_cyl1_tdc.jpg



if the concern is that the crank was rotated by hand such that it hit the valves, that seems unlikely since CW locked the flywheel and both cams long before taking the chain off

[joekitch]

just finished a good fifteen minutes conversation with Joe of Joe's auto service of worcester ma
He was just as baffled as you guys, and confirmed that if timing was off, the entirety of bank one's exhaust valves would be bent, not just one cylinder
His strong speculation was that some debris got in during the several weeks it was on jack stands that i didn't clean out properly, and he brought up something i totally missed during the job, blowing out the cylinders with compressed air. d'oh

The reason i called was to ask if he could do a valve job on the just exhaust of cyl 3 and he said absolutely, but I'll need to remove the cam shafts and lifter buckets before dropping it off with him, which is fine

tempted to just go ahead and pull the head without locking any timing (using an adjustable wrench for the cam shaft holding when removing the sprockets) , since it'll need a retime afterwards anyway, should i?

[dannyzabolotny]

I'd at least lock the crankshaft... if the crankshaft and camshafts are completely out of whack with each other it'll complicate the timing process significantly...

[joekitch]

hmm, bank 2 is still timed and i'm leaving that unlocked, i'd imagine what i need to do is just leave it at TDC before pulling the heads and the crank won't be able to move much because it'll have to rotate bank 2 to do so but..
at locking pin is only $30 from fcp euro, not so bad

[dannyzabolotny]

hmm, bank 2 is still timed and i'm leaving that unlocked, i'd imagine what i need to do is just leave it at TDC before pulling the heads and the crank won't be able to move much because it'll have to rotate bank 2 to do so but..
at locking pin is only $30 from fcp euro, not so bad

I mean, if you're going to the trouble of redoing the timing you may as well borrow the full timing tool set or just buy the GAS timing tools, they're only $250.

[joekitch]

i'd love to borrow it but the fellow who did the timing and has all the tools has been unresponsive for a few days, i assume he's busy
renting the tools ($275 upfront, $75 rental fee for two weeks) is another option
but honestly i just want to go ahead and get as much done as possible instead of waiting around for things, so i'l get the locking pin from fcp euro, make sure my biggest adjustable wrench can do 27mm (or buy one that can)...
although, middle of that thought, i'll need a way to keep the chain up and out of the chain valley while i'm doing all this. hmm

i mean if someone else in the central mass area has some timing tools lying around...

[JimLev]

Your adjustable wrench will probably be too big to fit in there. I bought a Kobalt wrench to hold the cam.
Use a piece of wire to hold the chain up.

[geargrinder]

His strong speculation was that some debris got in during the several weeks it was on jack stands that i didn't clean out properly,

Sounds so familiar...

there's the "freak random piece of debris jammed a lifter or valve guide" theory too i considered, however being both exhaust valves also points way more to a timing incident.

I am still not convinced as the #3 part, and both valves part seems way too coincidental... But we are left with no other good theories at the moment...

Pin the crank FOR SURE.

[JimLev]

And pull that head.

[joekitch]

Your adjustable wrench will probably be too big to fit in there. I bought a Kobalt wrench to hold the cam.
Use a piece of wire to hold the chain up.

hmm, CW had a 27mm wrench but specifically mentioned he used a shaved wrench, don't have the hardware to shave the mouth of a wrench, but would a regular 27 be fine?

[JimLev]

Yes, the Kobalt 27mm I bought was a combo open end and box wrench. The open end fits in the space just fine.
Craftsman didn't have a 27mm which is why I bought the Kobalt.

[dannyzabolotny]

I just use a regular Craftsman 27mm wrench, haven’t needed to file it down or anything.

[joekitch]

alright well, 27mm wrench and flywheel locking pin on the way, will be here friday i believe.
i'll finish everything up and pull the head friday, then deliver it to joe's of worcester on Saturday to see what he thinks and hopefully he can change the two valves in like half an hour

[JimLev]

Have you asked him if he has a valve spring compressor that will work on a BMW head?
My old school one wouldn't, had to go to plan B and make up an attachment that would reach down into the pocket to compress the valve spring yet allow for room to get the valve collets out.