20w50??????

[guy_geo]

Ok, the car mechanics who did the inspection on my Z worked a lot on old Datsun (he owned a 510 and a 260Z).

Remember, I asked you advice on the blue puff of oil that was coming out of the car...

I saw it today (so did the mechanic) and the diagnosis, was worn oil ring piston...The bill might be heavy (around 1500$US he told me.. (I'm skeptical) and Datsun garage don't show at every corner in Montreal...

His recommendation was to try an oil treatment for the segments, and to run my car with 20W50 (I did use that on my GTI16V 1990) to cure athe same kind of problem, and it was working well.

Any recommendations, denying, or should I follw his recommendation?

[Dan]

I can't imagine anything on an early Z costing 1500 to replace even with service charges, i mean msa sells brand new engines for 1700. I would go with the oil treatment first. I once had a Nissan garage tell my wife that my 72 needed brand new carbs that would cost 1300 bucks. I was on a training hop with the navy at the time and had only had the car for a few days. I called her and asked if she could just have them check it and tune it. Long story short nothing wrong with the carbs. However i did end up buying ZTherepy carbs probably the best out of the box SU's on the planet for under 600. After that i will never never never again trust a professional mechanic with my Z, there is nothing on that car i can't learn how to do. I mean come on a modern toatster has more technilogical sophistication than an early Z. Ok breath....red haze subsiding pulse.....returning... to.... normal. I know i didn't help you a bit but your post just brought it all back to me. Anyway someone on this site will give you the right info soon. No offence to any pro mechs out there i'm sure there are some good ones.

[guy_geo]

OK, Merci dan. I was in the same boiling mode yesterday afternoon, but as soon as I took the car for my 1st OWN RIDE, the boiling water went off.!!

Yes, I will definitely try the the oil treatment.

I might not be bad.

[2ManyZs]

Try a product called RESTORE, I used it in an old 200sx I had and it did help to cut down on its oil useage, not a lot but enough to notice. It didn't cure the problem, but it didn't hurt. They have a can for 4 cylinder, 6 cylinder or 8 cylinder engines and you should put a can in with every oil change. The 200sx had over 160k on it when I bought it, and it was still going at 210K when I got rid of it. The engine had never been taken apart.

But, if the rings and cylinder bores are that bad, the only true cure is a good honing, and new rings if it doesn't need to be bored.

Like we said before, a compression check and leakdown test is the only truly accurate way to find out how bad (or good) condition the engine is in.

And there still is the possibility this could be in the valve seals, if one or more is almost completely gone, it could be causing a lot of the smoke. Is the smoke heavier when you first start the engine and then lessens after it has be run a while?

[guy_geo]

No, it is faint, not a big blus puff of smoke, but sometime when I lift the gas to slow down, I can see it (faintly, but still visible), and between each shift I can see it also.

I will run the car like this and see how it evolves this summer, and wait for the loooooooon winter.

I'm not gonna use the car everyday, so I can wait, and merci for the nice advice again!

[240znz]

I had a similar problem on a A14 engine. When I got off the gas it puffed blue out the back...it was a combo of bad seals and too much slop down the valve guides.

Took the head off and send it off to a machine shop to get it refaced and changed the guides. Cleaned up the values and lapped them. Put it all back and no smoke at all.

I'm not saying that it will work for you but I'd try replacing the seals before ripping into a full rebuild. Also a compression leak test would be a very good idea too. It will give you a idea about how bad the ring is.

Additions and corrections welcome.

Zed not ZeeROFL