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Old 01-07-2015, 01:02 AM   #1
Hsquad12
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Default Bent valves or something else?

Hello,
I am working on an old 318is thats been sitting for the last 10years and have run in to a problem. The first thing i did after getting the car home was remove the plugs and soak the cyls with marvel oil before moving back to purge the fuel system.
After a week of soaking I removed the plugs and tried to turn the engine (M42) by hand. She was very stiff to turn by i managed to gently get the pistons moving in both directions and then clunk, the motor is solid as if a valve is hitting the piston. revere direction and after ~90deg rotation the same result. My initial fear was bent valves so i removed the valve cover and cleaned off the lifters/followers with penetrating oil. I went back to the engine tonight after work and used an airlines and lots of PB plaster and WD40 to get all the followers clean and so free that i can spin them in the bores with my little finger.
I put a feeler gauge down there and all the lifters are so close to the cam profiles i can barely get an 8" shim under them. the point being that all the followers are tracking the camshaft lobes.
If there were bent valves in the engine i'd expect some 1-2mm or more of gap as the lifter stays down close to a bent valve.
This is puzzling me so my next step prior to pulling the head is to remove the sump and see if anything is locking up the crankshaft.
Any thoughts?
Thanks in advance
e

Last edited by Hsquad12 : 01-07-2015 at 01:03 AM. Reason: I forgot to include the engine model
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Old 01-07-2015, 01:15 AM   #2
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I wouldn't ever turn the engine backwards, but I don't know if on an m42 would it matter. At the point of sitting for 10 years I'm thinking pulling the head and getting it run through wouldn't be a bad idea.
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Old 01-07-2015, 02:21 AM   #3
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I'd pulling timing cover and looking at the chain as well.
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Old 01-07-2015, 02:13 PM   #4
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put it in neutral.





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Old 01-07-2015, 02:31 PM   #5
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Default

thanks guys.
wiglaf - the car is in neutral and the car rolls freely. (how i wish this was the problem)

nomade30 - yes, i agree that turning the engine backwards is never considered best practice for any engine. under the circumstances i felt i'd nothing to lose and did not do this more than a couple of times to verify the hard stop. i was doing that to see if i could gently free off any rust deposits in the cyls. as it turns out the motor is very clean (pistons, sump, cams, valve gear etc) which makes me event more mad with myself if i bent a valve(s).

inkk - i will have a go at removing the timing chain cover once i've takes some pics of the crankshaft from underneath with my iphone (my head is too fat to get under there without axle stands.)


i also made a visual check last night and can confirm that with #1 at TDC the alignment marks on both cam sprockets, the crankshaft pulley and timing case and also the flats on the back of the camshafts are all to the best of my 20:20 vision in the correct orientation.

will let you know what i find out going forward.
thanks again for your help.
cheers
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Old 01-07-2015, 08:33 PM   #6
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Personally, I'd want to know what's going on inside an engine that's been sitting for 10 years. It's one thing to swap in a relatively fresh running engine, but a whole decade has past here. Who know what's been going on inside...

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Old 01-08-2015, 12:11 AM   #7
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are all 4 pistons going up and down ? put a long screwdriver thru each sparkplug hole and watch as you rotate thru the 90deg of movement to make sure pistons move ? you have access to a bore scope? worth looking into the bores
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Old 01-08-2015, 10:56 AM   #8
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you'd think it wouldn't wiggle at all if that were the case?
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Old 01-08-2015, 10:38 PM   #9
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Spdracrm3- yes,ni have checked the piston movement with a long screwdriver all four pistons are moving in the block and smoothly I might add.
#1 is passing TDC. Can't remember about the others.
The temps are below zero in tx now so I've decided to try and tow the car up the gentle hill to my house and put it in the garage so I can strip the engine in relative comfort. I've also seen a bores ope on craigslist for $30 that I'm going to try and snag in the morning for grins.
I. Did out of desperation Jack a back wheel and check that that wheel turns freely and it does in cae the clutch plate was frozen. I also plan to check and see if the starter pinion is engaged and locked on the flywheel. All desparate checks of a man clutching at staws. Am sure everything will become clear once the head is off.
Thanks for the input. I will post again once I get to the bottom of the problem.
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Old 02-01-2015, 10:01 PM   #10
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Default bent valves update and some more questions

so i managed to get the car indoors last weekend and the crankshaft wrench arrived on Friday.... so with the help of a long snapOn breaker bar and 5ft pipe the crankshaft nut came off like a dream to reveal......... an imaculate looking timing case with no terminal damage to the timing chain, guides or idle sprocket aside from light rust on the frame of the chain guides.... this sparkling image left me with mixed feelings. - whilst it was great to see the timing gear in such good shape and clean it means that my issue is 99% certain to be bent valves... oh, well.

So I've more that a little chuffed with myself for getting the c/s nut off and the time case opened in an hour today but now i need to take stock and consider what i'll be replacing in the timing case while i wait for the E12 socket to arrive for removal of the head.
Everything looks very clean in the timing case so i was planning to reuse the upper and lower chain guides and all the sprokets as the engine has only 131K miles on it.
I plan to replace the following:
The two vertical chain guides
timing chain
woodruff key
c/shaft bolt (is this really necessary???)
timing chain tensioner
If anyone thinks it is madness to re-use all the sprockets, idler and the upper and lower guides please speak up now and share your wisdom.
I also found that the water pump is a brand new unit as declared by the seller and was installed right before the car was parked in 2004. The pump has a plastic impeller so would you guys roll with that one or drop in a new unit with the metal wheel?

FWIW the car is a barn find that will only ever be worth $2500 so i don't want to sink big $$$'s into something that is nothing more that a fix for fun to drive for fun project. i paid $675 for the car and have about $200 in her so far for fuel pump, filters, tools etc and i want to keep the initial spend to get the machine on the road to ~<$1000. aside from the engine work it needs two tires and all the rubber hoses replaced.
If i love the way the car drives i'll upgrade the brakes and suspension etc over the next 12months once i have the car running. Point being, i don't want to replace every single item in the engine so please let me know which items are consider "must do" and which would be "nice to have"



im struggling with IranView to reduce the size of some pics so will add those later.



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Last edited by Hsquad12 : 02-01-2015 at 10:23 PM. Reason: added pictures
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