hi guys, ive been driving my duratec powered mgb for a fair few miles but recently ive noticed it smoking a lot. It seems to be worse as the engine
warms up, and then when the engine is hot it smokes a little if i lift off the throttle (high vacuum) and then go back on power. The smoke goes away
when im actually going along and put a little power on. Does this sound like valve stem seals? I built the engine myself so i could have missed
something or incorrectly fitted the seals.
Adam
Valve stem seals are the easiest and first port of call.
Worth a look S you can take the cover off.
There are ways of doing the stem seals without taking the head off.
A compression test and a spoon of oil own the bore will give a clue on rings
But don't forget, breather pipes can, if blocked or restricted force oil past the rings
Start simple
thanks, the compression was 170psi in each bore. i know about the rope in bore technique but im unsure how to compress the spring when the head is in situ
Anyone know how?
Just to check are you certain it is oil and not running rich? Are the plugs oiled up, blue smoke, smell of burning oil etc?
yeah its def not running rich, its light blue smoke. The plugs when i removed them yesterday were oily in cylinders 12+3, 4 seemed much drier.
Okay and you've also got oil consumption?
Another one to check is whether you've done the PCV valve modification (or don't need it because you've got vacuum from the inlet
running to it). Where do you run the cam cover breather and the oil PCV outlet to?
If it is the valve stem oil seals you may be able check for oil on the stems by viewing through the inlet and exhaust ports on the head (okay on the
inlet if you've got throttle bodies but a pain on the exhaust - manifold off).
When you originally replaced the valve stem oils seals you should have had green and black seals, which did you fit to inlet and the exhaust?
I replaced them in the correct order, green on inlet and back on exhaust. I did the breather mod and run both breather hoses to a catch tank. Last night I went for a drive and I had a little smoke from lifting off then on power. It cleared once I got going, I then checked oil level and it was low so I topped it up, drove car hard in low gears generating plenty of vacuum and I could not get any smoke. I let it idle for ages, getting hot, drove more, nothing! Weird or what!
You've not got a new cat on by any chance, first time I got my cat up to temp it smoked like hell and then caught fire, must have been some oil
in there from the manufacture - frightened me to death, since then absolutely nothing
I replaced them in the correct order, green on inlet and back on exhaust. I did the breather mod and run both breather hoses to a catch tank. Last night I went for a drive and I had a little smoke from lifting off then on power. It cleared once I got going, I then checked oil level and it was low so I topped it up, drove car hard in low gears generating plenty of vacuum and I could not get any smoke. I let it idle for ages, getting hot, drove more, nothing! Weird or what!
Def no cat, just single silencer. Sorry for repeating that last post, stupid phone did it lol
quote:
Originally posted by itsawindupuk
I replaced them in the correct order, green on inlet and back on exhaust. I did the breather mod and run both breather hoses to a catch tank. Last night I went for a drive and I had a little smoke from lifting off then on power. It cleared once I got going, I then checked oil level and it was low so I topped it up, drove car hard in low gears generating plenty of vacuum and I could not get any smoke. I let it idle for ages, getting hot, drove more, nothing! Weird or what!
no not at all, im driving it every few days. It smoked a LOT on thursday and a bit on sunday. But so far nothing this week.