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.

 

up up up

 

Never seen that happen. Any chance your timing belt was way too tight?

 

Don't think so, rotated multiple times 30-60 min apart and the grenade pin foot back every time. I am using an English racing under driven oil pump gear.

 

I'm hoping this has nothing to do with the English Racing oil pump gear... I just installed mine...

 

was the head rebuilt?

I have a few ideas.

debris got in there

you did not put assembly lube or lubricant in there

tension was too tight

 

If tension was too tight, the grenade pin would not have been able to be put back in multiple times. Also, I would think that you would see issues on both cams not just exhaust.

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.

 

Forgot to mention the head rebuild. It was pulled from my original running motor and sent off to be decked and a valve job. Valve guides were replaced as well as valve seals.

 

My guess is also debris hidden in the oil galley only to be forced out by oil pressure.

 

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.

 

Never dropped the cams. Cam gear fits fine and were set to tq rating.

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.

 

were the cams new or used?

something got in there or there was a something on the cam journal.

Def not a starvation issue, as the other journals further away from the oil pump were fine = cyl 4 exhaust cam journal for example.

That sucks man.

 

They were used and from my original motor.

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.

 

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.

 

how do you know head shop didnt misplace that cap? happens all the time.