JD 4455 missing @1800 and above

fordfx413

Member
I just replaced a head gasket on my JD 4455. Head gasket was replaced due to an oil leak. I had the head checked over and they also surfaced it. I replaced the gasket along with the head bolts and all other gaskets. I adjusted the valve lash to spec. I had my injectors tested and they were low. I installed reman injectors from spencer diesel. I changed the fuel filter. When running the tractor it runs fine at 1800 and below, after 1800 It starts to miss. I cracked each inj line one by one and the rpms change. What am I missing?
 

Either have a valve too tight or a bad injector would be my guess....I would run the valves again...then maybe start cracking injector lines to see if it's one particular injector
 
I agree with rechecking the valves, make sure your on TDC,,run that sequence, then one full turn and do the rest..
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Ok I'll check my valves again. That's the sequence I used. Intake .015 and exhaust .020. That is what it says in my it book anyway.
 
Did anyone happen to check the reman injectors before installing them ? I would not automatically assume they are good.
 
I pulled the valve cover. Engine was at operating temp. I can not get my feeler gauges in. the valves are warm tho. Why would they be so far off? I set them perfect yesterday.
 
Ok. I just set my intakes to .018 and exhaust to .028... I ran the tractor again, now when I reach 2100 it starts to run a little ruff RPMs vary about 30 rpms. Doesn't really sound like a miss. I have checked all fuel connections for a possible air leak but everything looks ok.
 

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