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I am in the process of rebuilding an Aristo 2jzgte. Upon inspection of the cams journal I discoverd some scoring on 2 of the exhaust cam caps and the cam. Factory max oil clearance is .0039, any solution to repair this or is my head a paper weight now. Pic below.
I would check the flatness of the cylinder head with a straight edge, straight across and from corner to corner and see how flat it is on the bottom, and also try it on the top which is where the problem could likely be if the bottom was milled before, see if you can tell if the bottom has been milled before (would have less depth in cylinder than a non milled head), or do you personally know if you milled it before or ever overheated it.
it could also be as simple as it was not torqued down properly in sequence, or an oil issue.
the first part I said to check for if the head is warped is cause it tends to do that to cams and journals. if a head has been overheated till it warps, then a machine shop can mill the bottom flat again, what most people skip over is the fact that the whole head warped, so that means the journals and all are not perfectly in line anymore... they will be slightly off. milling the bottom only makes the bottom flat as the head is still warped. most of the time you hope its within clearance and the cams can take that little bit if it was not a severe warp, there is a certain amount of warp that is allowed in a cylinder head and anything past that the book says to junk it, so its worth a check when you see somehting like that.
If all looks good I would just replace the cam and journal cap, and be sure to re-torque in the proper sequence and lube it properly so it doesn't score on first start.
I don't think the head had been taken off before. I am sending it to the machine shop to check for flatness.
Originally Posted by Ali SC3
I would check the flatness of the cylinder head with a straight edge, straight across and from corner to corner and see how flat it is on the bottom, and also try it on the top which is where the problem could likely be if the bottom was milled before, see if you can tell if the bottom has been milled before (would have less depth in cylinder than a non milled head), or do you personally know if you milled it before or ever overheated it.
it could also be as simple as it was not torqued down properly in sequence, or an oil issue.
the first part I said to check for if the head is warped is cause it tends to do that to cams and journals. if a head has been overheated till it warps, then a machine shop can mill the bottom flat again, what most people skip over is the fact that the whole head warped, so that means the journals and all are not perfectly in line anymore... they will be slightly off. milling the bottom only makes the bottom flat as the head is still warped. most of the time you hope its within clearance and the cams can take that little bit if it was not a severe warp, there is a certain amount of warp that is allowed in a cylinder head and anything past that the book says to junk it, so its worth a check when you see somehting like that.
If all looks good I would just replace the cam and journal cap, and be sure to re-torque in the proper sequence and lube it properly so it doesn't score on first start.
similiar scoring, I plan to get new 264, but dont want to risk getting them scored by the bad journal. New head is 1600...
I would ask a machine shop, get several opinions if you have to. I don't want to sound like an optimist or pessimist when it comes to this because I've never had issues like this but I do know the machine shop guys see the worst of the worst.
09-08-15, 08:23 PM
Scored Camshaft Journal help.
