Hey it's awesome that you finally got it to idle! By how smooth it runs, I doubt it'd be a sticky valve. When it happens, it doesn't seem to affect how it runs. This one is tricky for sure! By how intermittent it sounds, it makes me doubt it'd be a exhaust leak. How warm was the jeep? Does it make it when it's cold? The sound reminds me of my stuck heat riser, when I'd shut off my jeep hot fuel would boil and leak onto the exhaust and make a similar noise, more intermittent, but longer. Really sketchy I know. If it doesn't do it when it's cold, I'd tie the heat riser weight on the up (open) position and see if it stops doing it. I know you replaced it, but I remember that the spring is too weak to move the weight when it's warm. Good luck!
Exactly, I was thinking that if there was a hole in a gasket somewhere the sound would be continuous on that cylinder. I was guessing a valve being stuck because it sounds a lot like a burst of extra exhaust that is suddenly cut off, like an exhaust valve wasn't fully closed until the combustion process happened and closed it? It definitely makes it when it's warm but I hadn't listened when it was cold. The heat riser is new and not stuck. The sound persists regardless of how I move the riser itself using the counterweight. I can close it manually or hold it open, no change. Until recently, I was using the original heat riser spring. It was drooping worse because rust and time had taken its toll. The replacement one works much better than the original but there's not much else I can do here except shave weight off the counterweight. There's only one or two vendors out there making new springs for these heat risers. Metalshaper says none of them are good.
@@SunkCostGarage Did you compression test it? If I recall there's a butterfly in the heat riser, did you disable it? Have you tried to drive it? How's the oil pressure?
@@mikeloki2064 It drives fine. I took it for a 15 minute drive yesterday. The heat riser is new and works fine. Oil pressure gets up to 50 when driving, 20-25 at idle. Compression numbers were 125, 115, 110, 110.
@Mike Loki I haven't pulled the manifolds and valve cover to check them since it was all put back together. (With compression numbers like that, I didn't want to pull it apart if I didn't have to.)
Hey it's awesome that you finally got it to idle! By how smooth it runs, I doubt it'd be a sticky valve. When it happens, it doesn't seem to affect how it runs. This one is tricky for sure! By how intermittent it sounds, it makes me doubt it'd be a exhaust leak. How warm was the jeep? Does it make it when it's cold? The sound reminds me of my stuck heat riser, when I'd shut off my jeep hot fuel would boil and leak onto the exhaust and make a similar noise, more intermittent, but longer. Really sketchy I know. If it doesn't do it when it's cold, I'd tie the heat riser weight on the up (open) position and see if it stops doing it. I know you replaced it, but I remember that the spring is too weak to move the weight when it's warm. Good luck!
Exactly, I was thinking that if there was a hole in a gasket somewhere the sound would be continuous on that cylinder. I was guessing a valve being stuck because it sounds a lot like a burst of extra exhaust that is suddenly cut off, like an exhaust valve wasn't fully closed until the combustion process happened and closed it? It definitely makes it when it's warm but I hadn't listened when it was cold. The heat riser is new and not stuck. The sound persists regardless of how I move the riser itself using the counterweight. I can close it manually or hold it open, no change. Until recently, I was using the original heat riser spring. It was drooping worse because rust and time had taken its toll. The replacement one works much better than the original but there's not much else I can do here except shave weight off the counterweight. There's only one or two vendors out there making new springs for these heat risers. Metalshaper says none of them are good.
@@SunkCostGarage Did you compression test it? If I recall there's a butterfly in the heat riser, did you disable it? Have you tried to drive it? How's the oil pressure?
@@mikeloki2064 It drives fine. I took it for a 15 minute drive yesterday. The heat riser is new and works fine. Oil pressure gets up to 50 when driving, 20-25 at idle. Compression numbers were 125, 115, 110, 110.
@@SunkCostGarage And all your valves are to spec?
@Mike Loki I haven't pulled the manifolds and valve cover to check them since it was all put back together. (With compression numbers like that, I didn't want to pull it apart if I didn't have to.)