Head and exhaust cam hurt, jumped timing, need input for cause
Sep 16, 2014, 05:35 AM
#1
Head and exhaust cam hurt, jumped timing, need input for cause
I had the exhaust cam start to eat part of the rotating surface after 21 miles on the motor. Im assuming this cause the exhaust cam to jump timing due to resistance. belt was still tight. Final failure happened at idle and left oil on top of the spark plugs in cly 1&2 only. not sure how that happened either with new gaskets everywhere. Of anyone has any ideas to the cause of the failure please let me know. I did put the motor through a bit of high rpm and no load to break in the lifters per my tuners request. It was understood that this would not be an issue. I'm not pointing fingers, but searching for a cause of the failure as I need a second head and don't want to put it on if I will have the same failure if the cause is unknown.
Sep 16, 2014, 01:42 PM
#5
Sep 16, 2014, 02:06 PM
#7
Lubricant was not missed, almost the entire cam was covered as well as the seats for the cams and the cam caps. I'm very tedious. If you look you can see that only half the cam journal is worn and the other half is still normal.
Debris may be a possibility. Not sure how I would miss something big enough to cause that. Another thought is that I did not have a tool to check the oil galley for debris or to see if clear of obstructions before mounting.
Last edited by dsm nexus; Sep 16, 2014 at 02:08 PM.
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Sep 16, 2014, 04:47 PM
#10
It has oil, the other cam journals look fine from the one picture that has all of them in it. This wasnt a pump gear issue since the damage is one cam journal and jumped time. Cams have never been dropped? The cam gear sits on the dowel pin without interference?
edit- Also the gritty debris in the cam seal area I presume is the cam? Or is it some form of media since I can only see it in the pic and not feel it.
edit- Also the gritty debris in the cam seal area I presume is the cam? Or is it some form of media since I can only see it in the pic and not feel it.
Last edited by JohnBradley; Sep 16, 2014 at 04:52 PM.
Sep 16, 2014, 06:07 PM
#11
It has oil, the other cam journals look fine from the one picture that has all of them in it. This wasnt a pump gear issue since the damage is one cam journal and jumped time. Cams have never been dropped? The cam gear sits on the dowel pin without interference?
edit- Also the gritty debris in the cam seal area I presume is the cam? Or is it some form of media since I can only see it in the pic and not feel it.
edit- Also the gritty debris in the cam seal area I presume is the cam? Or is it some form of media since I can only see it in the pic and not feel it.
The gray stuff is soft, like arp assembly lube. Found some in the oil galley. Not sure what you mean by media unless you mean cleaning material like media blasting. Does not feel metallic but have not used a magnet.
Sep 16, 2014, 06:38 PM
#13
Thanks for clarifying a farther point in the oiling system.
Do y'all think this would possibly be replicated if I put a fresh head on? I'm worried about spending the money for another to eat itself.
Sep 16, 2014, 06:45 PM
#14
Tscompusa suggested a specific amount of time at specific rpms to get the lifters filled. Not going into more detail without his approval. I clarified that it is a new motor and was deemed ok. I don't think this would be too bad as even Buschur states that his motors are built to be ran not babied. This discussion however is a two way street for break in procedures. Cams and head were not brand new though, just refreshed and reused from my original motor.
