Jesel Belt Drive, Crank turns Cam and Belt Stationary
06-13-2016, 07:42 AM
#22
Hopefully it didn't happen, but I would think at least a couple valves were hanging open when the cam stopped turning and the piston contacted and bent a valve(s). A borescope would help you see, or when you get it back together and find one or more cylinders have no compression.
06-13-2016, 08:06 AM
#23
Hopefully it didn't happen, but I would think at least a couple valves were hanging open when the cam stopped turning and the piston contacted and bent a valve(s). A borescope would help you see, or when you get it back together and find one or more cylinders have no compression.
06-13-2016, 09:20 AM
#24
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Before I even tear into it any further I am going to back off the rockers and pressurize the cylinders. My plan is to start with the port side as it is easy access. If there is a bent valve, pull the motor, at that point I would have to take the front of the motor off and possibly both heads. Not fun to do in an engine bay. I have a leakdown tester so it will definitely tell all. Have to figure out a way to lock the crank so it wont spin when pressurizing, blower pulley has 1/2" drive insert that i can utilize in some way. I really feel like dropping this off and have someone work on it. My worry is backlog this time of year and getting it back before the 4th.
06-13-2016, 09:40 AM
#25
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Before I even tear into it any further I am going to back off the rockers and pressurize the cylinders. My plan is to start with the port side as it is easy access. If there is a bent valve, pull the motor, at that point I would have to take the front of the motor off and possibly both heads. Not fun to do in an engine bay. I have a leakdown tester so it will definitely tell all. Have to figure out a way to lock the crank so it wont spin when pressurizing, blower pulley has 1/2" drive insert that i can utilize in some way. I really feel like dropping this off and have someone work on it. My worry is backlog this time of year and getting it back before the 4th.
06-13-2016, 09:47 AM
#26
I did move the cam slightly, that is why I didnt really want the crank to move, could have changed the valve position just enough to hit? To detect interference I guess I can rotate the crank slowly via the blower drive 1/2" drive receptacle, if it makes a revolution I am good to go.
06-13-2016, 09:51 AM
#27
It would probably be quicker to just replace the belt and see if it has compression than it would be to back off all the rockers and do a leakdown test, you will hear it in the starter if it bent one. The damage is already done if it did bend things. The fact that all this seemed to happen while the motor was not running certainly helps your cause. I've seen so many interference engines not bend valves because they jumped either at startup or at an idle. I've seen the same engines absolutely destroy the motor from jumping at highway speed.
06-13-2016, 10:31 AM
#30
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It would probably be quicker to just replace the belt and see if it has compression than it would be to back off all the rockers and do a leakdown test, you will hear it in the starter if it bent one. The damage is already done if it did bend things. The fact that all this seemed to happen while the motor was not running certainly helps your cause. I've seen so many interference engines not bend valves because they jumped either at startup or at an idle. I've seen the same engines absolutely destroy the motor from jumping at highway speed.
Not that it matters, but what are the odds of the belt just breaking and the wave was a coincidence?
