1986 2m4 Hi all, my old Iron Duke is burning oil even though the sparks are perfect clean. The engine got about 187,000klms on it. I guess I will have to ring the pistons and I know the valve stem oil seals are gone. So what is a must in doing the engine?
187,000 kilometers is way too soon for a duke to be burning oil if it was cared for properly. I rebuilt my 88 duke at 200,000 miles (320,000 kilometers), and even then, it wasn't burning oil. So inspect everything. Something has to be wrong somewhere. And yes, the heads do tend to crack on dukes. Mine had a very small crack in it. I replaced it with a later model duke head (better breathing).
Check for oil in the air cleaner. If it's the rings you will have excessive blow-by. Another way to tell is while the engine is running remove the oil fill cap and put your hand over the opening. Do you feel air blowing out?
Just started it up and there is blow by from the oil cap. So I guess the rings then? Also there was no blue smoke like sometimes that it does and let it idle for 10 minutes or so and no sign of blue smoke. Probably when it's warmed up and drove down the road it will start to burn. But I did see blue smoke when I start it up earlier the week.
[This message has been edited by newfiejeff (edited 05-20-2014).]
You can do the valve stem seals with just the valve cover off. If you can have someone follow you while you drive and see if they see blue smoke at any time. Have you checked the PCV valve?
A buddy of mine was behind me and he told me that when the strain was on it was blue smoke, I am thinking maybe black smoke as she is not ideal or I THINK she could be better on gas. Will check Thursday night as I had a side job tonight and tomorrow night.
after it's warmed up , take it for a ride (someone following you) run it through the 1st 2 gears (foot to the floor. then let off the gas and slowly come to a stop.) Does it smoke when you are Accelerating ? OR when you are Letting Off the Pedal ? ON Pedal = Rings, OFF Pedal = Valve Seals. You Said you KNOW the seals are gone, so..... why not just do them first, you don't even need to pull the head, only the valve cover.
after it's warmed up , take it for a ride (someone following you) run it through the 1st 2 gears (foot to the floor). then let off the gas and slowly come to a stop.) Does it smoke when you are Accelerating ? OR when you are Letting Off the Pedal slowing down (not braking)? ON Pedal = Rings, OFF Pedal = Valve Seals. You Said you KNOW the seals are gone, so..... why not just do them first, you don't even need to pull the head, only the valve cover.
UPDATE!! Just done a compression test and the 3 cylinders closest to the passenger side was aprox 150 +/- 5 pounds, the one closest to the thermostat was around 90 and then I put a drop of oil in and got it up to around 100. I didn't bother doing a wet test on the others as they were so high.
if all it came up was 10psi, sounds more like a bad Valve. how many times did the engine turn over for the wet test ? did you put in a "Few drops" OR a Squirt ?
when you do the "compressed Air", be careful, Make sure that piston that you are putting the air into IS AT THE BOTTOM ! (if it's at the top, the compressed air WILL Spin The Engine Over.
Update Just tried another compression tester as mine never went back to 0 so I used to subtract that off the reading. Anyways, tried another one all cylinders are around 125 to 135. So that looks good. When you race the car over you get a little blue smoke. Would that be rings or just that I probably dont have any valve stem oil seals left?
Just put new seals in it, took it for a short ride down the road. When I race the car over you can see a light blue smoke, so I guess the new valve stem seals didn't do the trick on that only when I start it up.
I will have to ring the car this winter. Anyone got some awesome tips on this...lol?
How many quarts are you losing in how many miles? What weight of oil are you using. Also make sure your PCV system is good. Also are you sure you dont have any leaks, valvevcover is notorious.
Well all good questions. I am going to drive it the summer and see how it goes. I will check it every couple of days and see what it is going through and report back. I am using 10W30. No leaks as of writing this, you know with the old dukes
[This message has been edited by newfiejeff (edited 06-04-2014).]
Update! PCV valve is not working. Also when I put the valve stem seals in I put the umbrella type on the intake along with the o-ring. I just put the o-ring on the exhaust. The machine shop gave me white plastic umbrella type for the exhaust, but I didn't use them as they didn't fit over. I was told later they just ride up and down on the valves, just shielding oil away from the valves. Would the missing exhaust umbrella's cause it? There was none there when I took it apart.
Also, got a slight miss, you can hear and see it in the exhaust. Going along the road you can feel but hardly noticeable, not sure if this is related or not.
