Blue Smoke At Startup

[Gav240z]

Hi guys I recently aquired a nice 240z. It is running an L28 F54 bottom end with E88 head and ZX valves. I've noticed on startup in the mornings it seems to burn at bit of blue smoke indicating some oil. I was wondering if the most likely cause would be valve stem seals or hopefully not oil rings. I haven't done a compression test yet but I do plan on doing it. The car had been sitting a couple of years with some minor use here and there. As I understand the valve stem seals are rubber arn't they? I've never really replaced/adjusted anything internally on an engine any deeper than the valve cover. However I'm eager to learn more about engine and plan on one day building an L28 turbo. Any advice recommendations would be greatly appreciated.

Oh and the oil lever hasn't seemed to drop much either. I will keep checking it though.

Gav:classic:

[halz]

Smoke on startup sounds like worn valve guides to me. This is job for machine shop so while the head is off you should consider anything else you might want to do to it... port and polish, skim, cc'ing etc.

[Zpeed]

gavin, i think its turbo time... build that L28turbo hehe..

the blue smoke is what HATZ said, to bad your engine still is pretty strong, i wouldn't worry about it unless u got the cash to fix it, around 300 or so, if its pretty simple to do thou, just gotta take the head off and give it to a machine shop, then u gotta put it back on,

but when u got the head off might as well do the rings, and get new bearings, timing chain, get a larger cam ,port and polish the head, and while ur at it, get tripple's hehe... if you need any help, call me, i've done a few engines, including my L6 so i've got some experiance..

have fun... hehe..

[2ManyZs]

A little blue smoke at start-up is usually caused by the valve seals, they are rubber and over time harden and lose their ability to seal properly. It could also be worn guides, but they usually last a lotlonger than the seals.

Not a difficult job to change just the seals, but the easiest way is to remove the head, so a thorough check of all the components while the head is off would be a good idea.

[Royce]

It is most likely both the valve guides and the valve stem seals. However, replacing the seals will probably make it go away and unless the guides are heavily warn you could probably drive for years without any issue. Unless it is smoking heavily I wouldn't worry about it. To change the seals you would have to disassemble the valve assembly- rockers, springs, etc. Then you would need to do something to keep the valves from falling into the cylinder, ex. fill with compressed air or rope. I have only done it with the head off the car but I have heard of people doing it these other ways.

Hope it helps!

[Royce]

Oh yeah, a tune up and a compression check would still be a good idea to find out if there is anything wearing out!