Oil wieght for turbo motors

[Caliturbo88]

Alright. I just got an 88 turbo supra and the whole motor was rebuilt with new forged pistons and freshly machine block and head so everthing is "tight". The guy we bought it from is a master toyota tech and he runs 20w50 oil in it right now. I was wondering if this thick of oil is really nessicary for winter time. I was thinking somthing more like straight 40w. Also, do synthetic oils work fine for these turbo motors? What brand oil does everyone like? Im a firm believer in castrol oil for toyotas. I searched but couldnt really find anything, so dont nag on me too much.

[Murd]

20w50 sounds off, I think most people run either 5w30 or 10w40

[mrnickleye]

10w-40, dino or syn is what you want. 5w-30 is too thin for this motor (unless you are in frozen places like Fargo).

20w-50 is good for engines with over 100k miles, because it will fill up those big worn gaps in the engine, and can help it last many k miles longer. And its good for those higher mileage motors in the summer time, where temps are consistantly over 100*, like where I live.

[Caliturbo88]

so 10w40 isnt too thin for the turbo? Im thinking next oil change run 10w40 synthetic. as long as synthetic is ok for a turbo.

[IHateHacks]

The recommended viscosity oil changes with ambient temperatures. If you don't know what ambient means go look it up in the dictionary.

As far as putting in heavier oil to mask problems, thats hack sh!t.

TSRM recommends 5w30 for temperatures of 50 degrees F to below -20 degrees F. Perfect for winter. I run 5w30 in the winter with no problems because my engine is not worn. If you have problems with running 5w30 in the winter, you better start saving for a rebuild.

TSRM recommends 10w30 for temperatures of 0 degrees F to above 100 degrees F. Perfect for summer.

TSRM recommends 10w40 for temperatures of 50 degrees F to above 100 degrees F. TSRM does not recommend running 10w40 in below 50 degree temperatures.

TSRM recommends 20w50 for temperatures of 80 degrees F to above 100 degrees F. TSRM does not recommend running 20w50 in below 80 degree temperatures.

I don't see any reason to run 20w50 in a MK3 supra unless the main bearings are excessively worn or the clearances are too big.

5w30 in the winter and 10w30 in the summer, period.

[Caliturbo88]

Yea, i thought it was too thick BUT the guy we bought it from has been a tech for 25 years so i dont htink its hurting it if he doesnt htink it is. Next oil change ill probably be going to 10w40 amsoil full synthetic.

[scruffboy]

This is not a "dis", as you have given me good advice before, but I've used Mr.Nickleye's high mileage formula of 20w-50 summer, 10w-40 winter, and I think the man knows his stuff. While my engine is not about to drop out of the car, I would have to assume that tolerances when new are now slightly off. Anyway, I've run this formula for a year now and have had no problems whatsoever. I change my oil every 3 months and do not seem to be losing any. Now the guy with the rebuilt motor is another story, I'm sure he'll have tighter tolerances and won't need to go with the 20w-50, but for me it works. Thanks Mr.Nickleye.

Scruffboy

[mrnickleye]

Originally Posted by Caliturbo88

so 10w40 isnt too thin for the turbo? Im thinking next oil change run 10w40 synthetic. as long as synthetic is ok for a turbo.

10w-40 should be just right for your car. I see you are in sunny s. cal., where temps stay up above freezing, and hardly ever get over 95*.

Amsoil makes a GREAT product, and will serve you well. I know many people that have run it for years, and swear by it.

I run their gear oil in my diff.

It seems to be commonly known that putting syn oil in an engine with high mileage (like 100k+) can start to leak oil.

It appears the syn oil cleans away the varnish and sludge that builds up around seals(crank, rear main, cam, etc), which has been helping those old seals to keep sealing (with continued dino oil usage).

I'd say, if you start to see some leaking develop, replace the offending seal(s). (a good thing) And see if you can keep using the syn oil. BUT ... "Feeding" a leaking motor with syn oil can get expensive.

On my JDM motor with approx. 100k miles, I use dino oil and change it every 2-3k miles. I don't a drop of oil leaking.