What exactly is lifter bleeddown?
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Joined: Dec 2005
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From: poway
Know on a multi valve engine typicial in cars, when they stop leaving a valve in the open position, you can get some valve clatter. One of the worst ones I have ever had is RIP's new Subie Outback. I just shake my head when she starts it up when I am out in the shop.
Another interesting one is the Jeep I have been restoring for the last year. The engine was a factory rebuild that the previous owner let set and a freeze plug rusted thru and lead to overheating.
I went thru engine since the valves were coked up from oil going by the frozen rings and lifters were frozen I though.
I put everything back to spec including mismatching shell bearings to be mid tolerance. However, I still have a valve idle tap. It's the 1.5 AMC 4 cylinder. Torque non-adjustable rockers. All but a couple have a turn after no clearance. Two have 1 1/2 turns before bolt bottoms. That is only about .007 . Hard to get the valves length that close. Is it possible that extra turn would cause a click? Have not checked compression or leak down since overhaul. Only have about 300 miles on it. I have replaced the lifter now for the second time using
Federal-Mogul Motorparts Sealed Power when I checked the turn after no clearance.
I did not replace the rockers and the fulcrum looked good and still had the oil slots in them. However, they seem to have a lot of side to side motion but I could find no spec for that. Tick goes away with a little RPM but sounds like a diesel at idle. Idle oil pressure is 55 and running is 75. 75 seemed crazy high for a small four but that is to spec. Jeep 1993 has 299K on it and only had to rebuild AX5 five-speed, reseal the transfer and one universal on the front axle. Always heard Jeeps are trouble prone but YJ was built to go.
Another interesting one is the Jeep I have been restoring for the last year. The engine was a factory rebuild that the previous owner let set and a freeze plug rusted thru and lead to overheating.
I went thru engine since the valves were coked up from oil going by the frozen rings and lifters were frozen I though.
I put everything back to spec including mismatching shell bearings to be mid tolerance. However, I still have a valve idle tap. It's the 1.5 AMC 4 cylinder. Torque non-adjustable rockers. All but a couple have a turn after no clearance. Two have 1 1/2 turns before bolt bottoms. That is only about .007 . Hard to get the valves length that close. Is it possible that extra turn would cause a click? Have not checked compression or leak down since overhaul. Only have about 300 miles on it. I have replaced the lifter now for the second time using
Federal-Mogul Motorparts Sealed Power when I checked the turn after no clearance.
I did not replace the rockers and the fulcrum looked good and still had the oil slots in them. However, they seem to have a lot of side to side motion but I could find no spec for that. Tick goes away with a little RPM but sounds like a diesel at idle. Idle oil pressure is 55 and running is 75. 75 seemed crazy high for a small four but that is to spec. Jeep 1993 has 299K on it and only had to rebuild AX5 five-speed, reseal the transfer and one universal on the front axle. Always heard Jeeps are trouble prone but YJ was built to go.
As far as your tick goes, the last time I worked on a automobile motor was about 40 years ago and the closest I've come to automotive lifters is using some in HDs.
No clue as to where the noize could come from in a car motor. Hech at 299K the cam could be worn out.. I do know that if you set SnS cam gears up loose in TC with higher lift cam and heavy valve springs, it will rattle like a diesel at idle.
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From: Honah Lee
Cam chain and gears are new. I double checked the cam bearings with a gage from the bottom side and cam shaft spec was like new.
When I went in the second time, to do the lifters again, I ran it with a aluminum foil fence around the head and I could not fill the tap but when I took my hand off rocker would make it worst like the rocker arm slapping sideways but I could not see it.
However, maybe, those start ramps on the cam where worn and that is what it is, that would be hard to measure. The total lifts where within a few thousand and did not appear to show any wear. No wear on cam journals. Maybe, those frozen lifters damage the start ramp lift part of the cam. I did not even attempt to measure it.
Noise goes away with a few hundred rpm.
When I went in the second time, to do the lifters again, I ran it with a aluminum foil fence around the head and I could not fill the tap but when I took my hand off rocker would make it worst like the rocker arm slapping sideways but I could not see it.
However, maybe, those start ramps on the cam where worn and that is what it is, that would be hard to measure. The total lifts where within a few thousand and did not appear to show any wear. No wear on cam journals. Maybe, those frozen lifters damage the start ramp lift part of the cam. I did not even attempt to measure it.
Noise goes away with a few hundred rpm.
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HardyHarHarley
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Sep 3, 2010 09:00 AM
