R56 cam timing question
#1
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cam timing question
Is it possible to skip a tooth on one or both of the cam gears? The transmission slammed into park going about 25 miles an hour. The gear selector was in drive the whole time. Car shut off and would not start ever since. I read there are no timing marks to line up so how do you set up cam timing if you had to rebuild cylinder head and valve train?
#2
Is it possible to skip a tooth on one or both of the cam gears? The transmission slammed into park going about 25 miles an hour. The gear selector was in drive the whole time. Car shut off and would not start ever since. I read there are no timing marks to line up so how do you set up cam timing if you had to rebuild cylinder head and valve train?
#3
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I have 2008 s R56. I do not plan on taking apart mmy cylinder head, I just wanted to know how to check the cam timing. I think it may have skipped a tooth or two. I am working on multiple issues including engine and transmission. Just trying to get the car to start. I inspected intake valves and noticed heavy build up. I am cleaning manualy because I do not want to get any shells in cylinders. Even dealerships have messed this up. The write up for this said that the two outer ports are closed when inner ports are open, however I'm seeing ports for cylinder 1 and 2 closed with 3 partially closed and 4 open. I can see if they are closed by solvent pooling up inside. What's up with that? When should each port be open/closed? Also still want to check timing. How can I see if ccams are lined up correctly?
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#6
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Thanks for your reply. Is it possible the chain could have skipped a tooth? I don't want to buy the alignment tool if I can help it. Regarding the valves, that is what I thought, they each open and close at different times following firing order of 1-3-4-2. So I don't know what texasmontego in carbon build up thread is talking about when he says the outside ports are closed the two inside ports are open.
#7
Possible but doubtful. What usually slips is the lower gear that's on the crank. It is not keyed or ridged. The only thing holding it in place is compression from the retaining bolt (ie friction).
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#8
Is it possible to skip a tooth on one or both of the cam gears? The transmission slammed into park going about 25 miles an hour. The gear selector was in drive the whole time. Car shut off and would not start ever since. I read there are no timing marks to line up so how do you set up cam timing if you had to rebuild cylinder head and valve train?
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#12
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flywheel pin
What diameter is the locking flywheel pin? I should be able to find 90°BTDC and then check alignment of cams, right? I've been through many of the cam timing threads, still trying to find out where or how everything is supposed to line up. I've read a little about marks on cam sprockets, chain links, and how I should see index writing on cams between #2 and #3. It's not very clear how does this thing line up?
#13
What diameter is the locking flywheel pin? I should be able to find 90°BTDC and then check alignment of cams, right? I've been through many of the cam timing threads, still trying to find out where or how everything is supposed to line up. I've read a little about marks on cam sprockets, chain links, and how I should see index writing on cams between #2 and #3. It's not very clear how does this thing line up?
#14
I got my flywheel off and the cam tool sitting on the bench next to the engine too. I'm at work, I work til 11. If nobody posts the diameter for ya, I will when I get home.
#15
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#20
Might have to massage that tool you make just a bit so it fits nice. It should just slide in and out with slight resistance.
What did you have lose or do ?
#21
Nevermind. Here.
Install the tool
Check the cams
Letters facing up.
Also, there's a square drive on the intake and the exhaust on the drivers side of the cams. There should be a flat on both sides of the cams pointing straight up and down. If they are straight up and down. Nothing's wrong. If one is slightly angled, yup, it moved
Install the tool
Check the cams
Letters facing up.
Also, there's a square drive on the intake and the exhaust on the drivers side of the cams. There should be a flat on both sides of the cams pointing straight up and down. If they are straight up and down. Nothing's wrong. If one is slightly angled, yup, it moved
#22
This may sound like a dumb question but just to clarify. When you say it won't start do you mean it turns over and won't start? Or do you mean it won't turn over at all. I'm asking because of your initial statement that it slammed into park while the gear selector was in drive and the car was traveling 25 mph. That says to me the selector cable is broken, came loose etc... or something failed internally on the transmission. If it's not functioning correctly or out of rig the position sensor would be off and the engine would not turn over when you try and start it.
#23
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possible bad chain tensioner???
The tensioner, chain, and guides were replaced about 20k miles ago when brand new cylinder head out in.
#24
If chain too lose, will it prevent car from starting? At first glance I thought my tensioner was good. Now I'm not so sure. My guide is is good shape. No cracks or sign of damage. As I rotated cams (from crank bolt) I noticed the chain dip down a bit, so I removed the top guide rail to get a better look. I rotated cams again (no guide rail) and saw the chain sag quite a bit between the cam sprockets and as I continued to turn the chain would tighten back up. So as cams rotated the chain would slacken, tighten, slacken, tighten... The tensioner, chain, and guides were replaced about 20k miles ago when brand new cylinder head out in.
Something's wrong. That should not have that much slack. Just start from scratch
#25
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This may sound like a dumb question but just to clarify. When you say it won't start do you mean it turns over and won't start? Or do you mean it won't turn over at all. I'm asking because of your initial statement that it slammed into park while the gear selector was in drive and the car was traveling 25 mph. That says to me the selector cable is broken, came loose etc... or something failed internally on the transmission. If it's not functioning correctly or out of rig the position sensor would be off and the engine would not turn over when you try and start it.
1) severe carbon build up - now mostly clean, I did this manually no walnut blast
2) Compression test post carbon clean revealed very low almost no compression in all cylinders. Didn't test before clean, no tester at that time. Dry test 1=15, 2<15, 3<15, 4=28. Numbers doubled wet but still waaaay too low. Test done with intake manifold off and all related electrical plugs not connected including valve cover connections and intake vanos connection. Valve cover was on but not tightened down.
3)not seeing any spark from any coil or any plug tried it against the heat shield and the flange coming off cylinder head. Hard to believe all plugs went out at same time.
4)While turning cams timing chain slackens a lot then tightens up. Bad tensioner? Not that old???
5)OBD scantool revealed only P0962. Pressure Control Solenoid "A" Control Circuit Low. I think the wiring harness needs to be replaced but the number 6 solenoid in valve body might be bad.
6) Suspect hpfp. White residue all over back of hpfp where fuel lines attach. Also didn't see or smell any fuel in cylinders after cranking a while.
Last edited by shanksamillion; 03-15-2015 at 08:31 PM. Reason: typo in #4 compression