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Engine Specific Info and Questions => IDI Engine => Topic started by: R.O.R-2.0 on December 18, 2010, 01:33:18 pm
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so, i got an AAZ head.
started cleaning it up, noticed fairly quickly that the lifter head on #2 exhaust valve was GONE. and upon further inspection, what was left of the lifter was still stuck in the lifter bore. but thats not the problem. i got the lifter out with a little help from the dremel.
but, my question is:
the valve does not look like it contacted the piston. the valve is not bent, and not cracked that i can see, and i looked it over pretty good. the valve and valve seat are still in good shape. altho, there are several TINY pits around th esealing edge of the valve. the pits looked much better after i took a little grinding compound and ground the valve just to see how well it was seating, the sealing edge, and valve seat both look to be what i would call useable..
is piston contact the only thing that can break a lifter? or can it be a manufacturing defect/fatigued piece? it looked like it was cracked about 1/3 of the way around the diameter for some time. (could see where the crack was shiny)
and another thing. 4 out of the 7 lifters in the head would not compress. they felt like solid lifters..
had to squish them in the vise to get them to compress.
all 8 of the lifters i pulled out of my 85 GTI (w/ 345k mi on original engine) still compressed fairly easily. but the ones out of the aaz head were rock hard.
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Without knowing what the engine sounded like before the head was removed, it would be hard to speculate. It is entirely possible that the lifters had failed. I have seen it often enough on the PD TDIs. I would say, do a solvent test (take cam out, fill ports with solvent, check for leakage). If all looks good, clean the hell out of it and install new lifters and possibly a cam.
Was the cam damaged?
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head is said to have 20k miles.
cam looks great. valves with broken lifter still seals pefectly in the seat. i checked it with some grinding compound.
what about the lifters not being able to be squished?
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keep in mind that hydraulic lifters are just that. It is unlikely that you will be able to squish a lifter with your finger. If it is full of oil then it will not compress. It is also likely that you have some shîtty lifters. Like I said, its hard to tell without knowing the specifics of the previous engine. I would speculate that you would be just fine with new lifters and a good cleaning. Dont forget to check the valve springs on the damaged valve/lifter portion..
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all springs looked good.
the only thing i saw that even looked halfways worn, was a valve seal or 2..
all the valves slid right out, and didnt have much play in the guides.
springs from the bad lifter were in decent shape. there still the same height as other springs, and not broken.
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Are the lifters out of the head when you attempt to compress them?
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yes. no sign of oil came out of them when i squished them in the vise. i understand there all prolly shot, but i plan on replacing all of them.
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Sounds to me like you should just replace them all, leave the valve alone on the questionable lifter and call it a day ;)
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thats kinda what im thinking. and the head was said to be pretty noisy. valve issues are going to show themselves are they not?
i would be able to see it being bent, or cracked, or something like that.