Upper timing chain snapped on me.
#21
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My concern is that turning the engine to get to this position 3 cams will be turning and the 4th will be in an unknown postion with the posibility of some valves being extended. He has to loosen the cam anyway using the zip tie method so why not remove it and get the engine lined up.
We know the disabled cam stopped in a position where its valves do not now impact any pistons as the engine is turned.
When the engine is locked down, Test_point says all pistons are guaranteed to be out of range of any valve, and so the disabled cam can then safely be turned to any position.
So he won't have to loosen that cam, just turn it manually, right?
Last edited by Dennis07; 05-04-2011 at 01:10 PM. Reason: clarity (at least it wasn't spelling this time)
#22
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The original poster, xjrwithproblems, exhaust chain broke so there is no ZipTie solution for that side. In the thread I think I am following, the results of the pressure test says that there are no bent valves. The engine has been spun in that condition with no valve/piston interference. And, no, you do not have to remove the cam bearing caps to turn the cam.
#23
#24
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#25
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Hey Paul, I have the engine apart right now. There is no way to slip the secondary chain by tilting the cam. It is physically impossible. I had to remove the primary tensioner and one of the chain guides to slip the primary chain off the sprocket to, then get the secondary chain on.
Last edited by xjrwithproblems; 05-10-2011 at 03:57 AM.
#26
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O.k. Today, i got the secondary timing chain on, put everything back together except for the pullies, and at first, hand cranked the motor to make sure i could do a couple full rotations. I was able to and then started the car. It ran for a few seconds and then turned off. Because it was on for such a short period of time, I can't really say how it was running; not sure if it was smooth or rough, but it was over 1k rpm. I then proceeded to try and start it again; from here on out, it would not start. I did a compression test and found 0 psi on one of the cylinders. I was bummed, knew for sure i had a valve make contact with a piston. I started tearing apart the car again, and a few hours later got the head off. I was expecting to see some damaged pistons, but there was not a single marking, divet, or dent in any of my pistons. I have not taken apart the head yet to check for bent valves, but i don't think i need to based off of my observation? I did push down on each valve to see if they would slightly compress and they all did. Now, i am thinking my timing could have been off slightly; i assume that this could cause 0 psi in a cylinder as the valves are not opening/closing when they should at the correct time?
I spent a whole lot of work getting this head off, but would be thrilled to know that it was all for nothing!!! hoping to get this thing on the road tomorrow!!
I spent a whole lot of work getting this head off, but would be thrilled to know that it was all for nothing!!! hoping to get this thing on the road tomorrow!!
#27
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xjr,
Have I got this right ... you had to remove the primary chain from the cam sprocket at one point?
Unless both the cam and the crankshaft were locked at that point, then timimg between crank and cams could be lost. (If you mentioned locking the crank, sorry, I missed it.) That could certainly explain funny compression reading(s).
But why should the car start one time??
I'm also confused about this tilted-cam idea to replace a broken secondary chain. Seems like that's been discussed before this thread, but your experience was that this will not fly, right?
Edit: forgot this one ... any chance you had disabled fuel injection in one way or another for safety but then forgot to undo that?
Good luck as you press on ...
Have I got this right ... you had to remove the primary chain from the cam sprocket at one point?
Unless both the cam and the crankshaft were locked at that point, then timimg between crank and cams could be lost. (If you mentioned locking the crank, sorry, I missed it.) That could certainly explain funny compression reading(s).
But why should the car start one time??
I'm also confused about this tilted-cam idea to replace a broken secondary chain. Seems like that's been discussed before this thread, but your experience was that this will not fly, right?
Edit: forgot this one ... any chance you had disabled fuel injection in one way or another for safety but then forgot to undo that?
Good luck as you press on ...
Last edited by Dennis07; 05-10-2011 at 06:39 AM.
#28
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Hey Dennis, unfortunately, primary chain was removed and the cam was not locked at this point. However, in reinstalling everything, i locked the cams on both sides as well as the crank. I am wondering if the timing is slightly off, if that would cause screwy compression readings?
why it started once, i don't know?
I am 100% positive the cam is not "liftable". I have researched this and some people say it is possible, but i have never found an explanation or seen pictures. There is a carrier for the intake cam with 4 very long bolts that cannot be removed with just the valve covers removed.
No fuel injection relays or fuses pulled. my goal is to get this bad boy on the road today.
why it started once, i don't know?
I am 100% positive the cam is not "liftable". I have researched this and some people say it is possible, but i have never found an explanation or seen pictures. There is a carrier for the intake cam with 4 very long bolts that cannot be removed with just the valve covers removed.
No fuel injection relays or fuses pulled. my goal is to get this bad boy on the road today.
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