HillbillyLes
New Member
- Joined
- Apr 9, 2016
- Messages
- 11
- Reaction score
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- Vehicle Year
- 1995
- Make / Model
- Ford
- Transmission
- Manual
Question then a little history.
In trying to troubleshoot a miss in cylinder 1 I bought the truck with, I got to the point of pulling the valve cover thinking/hoping? to find a stuck valve or something obvious. The engine is as clean as any I seen on the inside. absolutely no gunk or varnish. I rotated the engine to check for loose clearances or maybe a sticking valve (bent?) however what I found was odd.
The exhaust valve in cylinder 1 (with the miss and compression of around 30 psi) when up all the way and the pushrod should be able to be rotated or spun with some resistance. It is still so tight on the pushrod that I cannot rotate it at all. All of the other pushrods can be rotated when the valves are up (intake and exhaust). Appears the valve is not closing due to lack of clearance however there are no adjustments in the valvetrain so what would have been an adjustment issue of being adjusted too tight is not possible with this engine. Is is possible in such a clean engine for the lifter to be hydrolocked in someway and not be doing its thing? I have worked on engines for years and do not recall ever coming across this on a non-adjustable valvetrain.
The truck is an extended cab 5-speed 4wd and was bought with 250K miles and supposedly has had a newer engine put in it at some point. Overall it looks like it has been well maintained except by the prior owner who did not do much maint. The fuel gauge did not work so I replaced the fuel pump/sending unit in the tank...the fuel pump which was working fine was the original Ford pump... No coolant in the oil, no oil leaks, no pressure in cooling system, no overheating, no issues with the engine other than the miss....the engine starts very quickly and purrs except for the miss which is always there in all loads and rpm ranges and thus power is way down. plug in cylinder (or any of the others) actually does not look bad. In any case as with all vehicles I buy I did a complete tune-up including oil change, air and fuel filters, plugs, etc. I have run cleaner thru the fuel. With no noises, leaks, smoke, coolant loss or coolant in oil (etc), it seems like it should be a simple fix but finding o clearance in the exhaust valve/pushrod has me stumped.
Is there a chance someone might have bent a pushrod and replaced it with a longer one? That or a locked hydraulic lifter (no noises) are the only things I can think of but thought before I sunk more time and money into driveway teardown, I'd run it by y'all in case someone might have run across this before. This is my first 4.0 so other than what I have read when researching this is about all I know about the engine/engine family.
Thank you-
Les
In trying to troubleshoot a miss in cylinder 1 I bought the truck with, I got to the point of pulling the valve cover thinking/hoping? to find a stuck valve or something obvious. The engine is as clean as any I seen on the inside. absolutely no gunk or varnish. I rotated the engine to check for loose clearances or maybe a sticking valve (bent?) however what I found was odd.
The exhaust valve in cylinder 1 (with the miss and compression of around 30 psi) when up all the way and the pushrod should be able to be rotated or spun with some resistance. It is still so tight on the pushrod that I cannot rotate it at all. All of the other pushrods can be rotated when the valves are up (intake and exhaust). Appears the valve is not closing due to lack of clearance however there are no adjustments in the valvetrain so what would have been an adjustment issue of being adjusted too tight is not possible with this engine. Is is possible in such a clean engine for the lifter to be hydrolocked in someway and not be doing its thing? I have worked on engines for years and do not recall ever coming across this on a non-adjustable valvetrain.
The truck is an extended cab 5-speed 4wd and was bought with 250K miles and supposedly has had a newer engine put in it at some point. Overall it looks like it has been well maintained except by the prior owner who did not do much maint. The fuel gauge did not work so I replaced the fuel pump/sending unit in the tank...the fuel pump which was working fine was the original Ford pump... No coolant in the oil, no oil leaks, no pressure in cooling system, no overheating, no issues with the engine other than the miss....the engine starts very quickly and purrs except for the miss which is always there in all loads and rpm ranges and thus power is way down. plug in cylinder (or any of the others) actually does not look bad. In any case as with all vehicles I buy I did a complete tune-up including oil change, air and fuel filters, plugs, etc. I have run cleaner thru the fuel. With no noises, leaks, smoke, coolant loss or coolant in oil (etc), it seems like it should be a simple fix but finding o clearance in the exhaust valve/pushrod has me stumped.
Is there a chance someone might have bent a pushrod and replaced it with a longer one? That or a locked hydraulic lifter (no noises) are the only things I can think of but thought before I sunk more time and money into driveway teardown, I'd run it by y'all in case someone might have run across this before. This is my first 4.0 so other than what I have read when researching this is about all I know about the engine/engine family.
Thank you-
Les