Oil Recommendation

Tavalin

Tavalin

Florida Mike (again)
My 1986 X has started to smoke after setting the timing and sitting for about 10 months. I have read several threads about what the proper oil should be but there doesn't seem to be a consensus as to which one would be good for my type of situation.
Currently, she has 10/30 in her. I just purchased 10/40 (recommended by Tony in a past thread). However, I read that 20/50 would be better for older engines.
Please, let me know if I should use the 10/40 or change it to 20/50?
V/r, Mike


Nebraska Mike
 
Oil is an never-ending discussion.... But it could be worse.... Just for grins, take a look at the forum at bobistheoilguy.com where the REAL oil crazies hang out.....

Bad news: If you're getting smoke whatever is wrong is not going to be fixed by changing the grade of the oil. But you'll have to tell us more about the smoke - oil/water/rich fuel, when does it smoke, all that. There's no Italian magic here.... These engines make smoke or not for exactly the same reasons that a thirty-year-old chunk of Detroit iron will smoke or not.

There's no particular reason to go to an oil heavier than xW-40 unless you have real oil pressure problems. If you can get hold of a mechanical oil pressure gauge (Harbor Freight sells an OK one cheap, but it's usually possible to borrow one) connect it in where the oil pressure idiot light sender connects, see if you're getting 10 psi per 1000 RPM or better. If you are, the oil is fine. And if I were placing a bet, sight unseen, I'd go for better than 90% odds that the oil is fine.
 
Thanks EricH. I just need to fix the clutch and get her out of the garage. Sitting this long can't be helping her. Maybe tomorrow after work.
See ya,
Mike


Nebraska Mike
 
20W50 is what I use in my '74. Fiat owners manual recommends 30W or 20W50 when living in climates where it is above freezing temps.
 
Agree - mine only smokes on start up if it's been sitting for a few days, but doesn't really use any oil while driving. I'm sure mine is related to valve seals.

I use 10w30 semi-synthetic "high mileage" oil from Castrol. "Apparently" It has reasonable levels of ZDDP. My engine doesn't leak any oil (it's so clean for a 34 year old!!) I could use something better, but for now it's fine. Previously I used Castrol GTX 20w50.


Tavalin - when does your car smoke? all the time, only during start up? Check if your crankcase breather is not plugged (although, not sure if that really would cause a huge issue, but it's good to check).
 
I run the thinnest oil possible. It seems logical that a thicker oil will stay in the head/valve train longer and provide better protection, but like most Italian vehicles, the oil passages are relatively small. Thick oil like 20w50 can't flow through them as well when cold (start up) as a thinner oil will at the time when you need the most protection. Thinner oils and modern synthetics have smaller particle structure which also allow the oil to penetrate into the cylinder walls, pistons etc... better then older heavier weight conventional (semi synthetics) oils . Yes "conventional" oils is in fact a semi synthetic and has been since the 80's.
 
Thanks for all the advice. I changed the oil and used Mobil 1 full synthetic 10/30. After I got her on the road, she quit smoking. I think either the rings just needed some exercising or I dropped antifreeze in the head when I changed out the intake runners. Either case, she runs great and is timed right.
Now on to the suspension... I am thinking new poly bushings front to rear and new struts.
Then the lights all around then on to the interior.
She should be done by then.
Thanks again everyone.
V/r, Mike


Nebraska Mike
 
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