Ok, so driving down the road the other day and all of a sudden out of nowhere my car just dies (violently) and it pouring oil out of somewhere, but thats a different issue. but I discover its my rear main seal so i pull the engine out to fix that and to be able to examine what else could be wrong with the car now. Upon further inspection i discovered my head gasket is leaking oil, so I pull the head off and when i took the cam gear off i noticed that the dowel pin is gone just plain gone. now this is the 3rd cam this has done this to me. any ideas? I mean out of the 4 neons i have owned i have never had this as a problem, also i bent 4 valves and im pretty sure that the pin breaking is what shut my car off, am i right?

 

I need some photos to help me understand where your at. Are you tightening the cam bolt properly? What cams? What cam gears?

 

yes im installng it properly im using the 8mm to hold the cam still and torquing it down. and its stock cam gear with stock cam.

 

Yes the pin breaking caused your timing to jump way out of spec which in turn bent the valves because they got hit by the pistons.

Dude. Rebuild the engine.

 

I have never had this happen. Does the cam gear slide over the pin snug, or did it have slack? I would question the cam gear or a loose timing belt causing it. Were the cam journal clearances checked?

 

yea that is what im doing now i was just tryng to fgure out how in the hell it happened.

 

yea everythng is snug i mean i dont have to beat it on with a hammer but it is a snug fit and the belt seemed tight i mean it s a new tentioner so i hope so and the cam journals....idk i would have never thought about it. from just feeling it with my hands the cam doesnt have alot of moving room inside the head so dk. but lik i said it has happened before on the last head witht eh other cam now with this head and this cam. idk im thinking of just putting a dohc in there, cuz i seem to have bad luck with the sohc.

 

Truly this could be an unfortunate series of things that all lead up to:

a) premature failure caused by an poor quality parts, incorrect re-assembly, etc.

b) a hidden defect that finally broke under a load/strain (such as a cam pin that had micro-fractures and just could not take the strain anymore).


c) bad karma, bad judu, luck of the irish.....

Really, unless you have a crystal ball, the only thing you will ever know is what broke, not why. You can only figure out the why if while you are rebuilding the motor, you get lucky and remember something you did not do but should have; did something but shouldn't have, or did it wrong; see that something that is/was missing that should be there; see something that broke off and lodged in a place where it shouldn't be, etc.

I hope you do get lucky and figure out why. More importantly, I hope this
time, when you get it done, it lasts. Good Luck.

 

Bad luck wont cause 3 cams to eat pins.

I have money on it being a harmonic issue. Possibly its something in the rotation thats making more resistance then it should, or to much play which will do the same thing. It would make the cam shaft move back and forth rapidly which may have ate the pin.

 

ok just got the head back from the shop and said that the cam journals and etc are with n the spec. so idk what it could be. im just gong to get a damn dohc and call it day