High compression numbers, with blue smoke? (1 Viewer)

[Benjitis1]

1972 F motor, '75 Cali Spec Aisan Carb. After idling for a while i start to get blue smoke, and after a little while longer it starts to run rough with even more blue smoke. Did a compression test today with 2 different guages, one a screw in with rubber hose, the other was a rubber press on style. Numbers were the same on both after multiple tests. Before checking compression i warmed it up to operating temp, pulled all plugs, and had both fuel plates wide open. Did the test dry, no added oil. I have NO IDEA if this motor was rebuilt or not. It runs great, starts great, and pulls great! Only problem is the smoke and running rough after it gets warm. Any ideas? Adjusted valves not too long ago, i have ZERO oil leaks. Its a trail only rig so doesnt get driven everyday. Oil is a tad low after a few wheelin trips. Thought about valve seals, but cant tell if theyre bad or not.

1-165
5-165
3-164
6-165
2-165
4-160

 

[Poser]

Is this something that has just started or has it done this since you have owned it?

Have you ever been in a steep ascent or descent and had the engine start smoking on you?




How is your PCV valve?

 

[texfj40]

A lot of folks dont consider the amount of oil in the crankcase. Do you have the correct dip stick....did you put in the recommended number of quarts and did the dip stick level match, or did you just pour oil to the dip stick full mark? I cannot remember but I think the F recommends 7-8 quarts with filter. Overfilling oil is not good.

 

[Benjitis1]

There may have been a light amount of blue smoke on the last trail ride in August 2009, and around the driveway since then. Then on our trip last weekend it seemed to be a lot worse. May have been worse when pointing downhill. Did not have the big cloud of white smoke like others have experienced due to PCV hose location, when going downhill. I'll check the PCV here in a minute, gotta find out if i need to pull the side cover to get to it. I filled with the recommended, just shy of 8 quarts of oil. And it matches the dipstick. Oh, and the Cylinders 1,5,3 have caked on dry-ish carbon buildup on the plugs and smell like oil, not fuel, wheres 6,2,4 are light to dark brown as they should be.

 

[Benjitis1]

Okay. Looks like the PCV valve is supposed to slide into the rubber grommet on top of the 90 degree elbow that is on the side of the crankcase cover. The previous owner had a barbed fitting pressed in the grommet, there is no PCV valve on it. After pulling the barbed fitting out there is some mayo looking goo. Gonna go get a valve and some new plugs and install them. I wouldnt think that would cure the blue smoke though. Just another gremlin taken care of i guess.

 

[Benjitis1]

PCV is ordered, and i used some seafoam. Smoked like an sob!! Re did compression test after seafoam, and no change in numbers. Good thing? I'll get the new plugs in tomorrow with the PCV.

 

[Benjitis1]

After seafoaming the crankcase and the intake, changing the plugs and changin to 20w-50 oil, the smoke has stopped. I need to run it for a continous hour or so to really make sure shes not gonna smoke. But it does feel like i lost some power off the bottom end.

 

[motoloco]

remember, oil rings and compression rings are two different things.