0w-40 Mobil one

[flyinlow]

I have been using 15w-50 Mobil one in a 446 street engine for the last 9 years (40,000 miles). This oil has a lot of ZDDP. So far the engine seams to work well with it. Good oil pressure, good compression and is not burning oil. I looked at the cam and lifters when I upgraded to Comp Car rockers last year and they looked good.

I would like to run a lighter oil ,sticking with a synthetic. Mobil makes a 0w-40 , but the ZDDP levels are lower and I would need to add a supplement. The 0w would help with start ups and maybe pick up a horsepower or two.

Recommendations ?

[Scaregrabber]

That's whats in my Viper.

Sheldon

[c00nhunterjoe]

Unless you drive in winter, the dual viscosity is not as critical to you. Fwiw, the 40w, is measured at 212 degree oil temp.

[alfaitalia]

I tried the zero in my Jeep....according to Mobil it was a recommended oil. Only used it for one change. The extra mechanical noise from the top of the motor when cold or hot (more when cold) was quite worrying. Just a bit too thin when cold IMO. Wont be using it again. Back to the 15 and all was silent again.

[c00nhunterjoe]

What were your oil pressures cold and hot at idle, 1500 and 3000 rpm in both scenarios? I would almost bet a 10w40 would be plenty for your engine and high zinc oils are plentiful in that weight

[flyinlow]

I do drive in the winter some. However the car is stored in a heated garage so it's starting at 45* or warmer.  I sometimes get lifter noise for a few seconds on a cold start and forged piston noise for a minute or so. I don't know if lighter weight oil would help?

I just changed the oil in our Accord which uses 0W-20, which pours like 3 in 1 oil compared to the 15W-50.  Just got me thinking about options.

[flyinlow]

What were your oil pressures cold and hot at idle, 1500 and 3000 rpm in both scenarios? I would almost bet a 10w40 would be plenty for your engine and high zinc oils are plentiful in that weight

I still used the factory electric oil pressure gauge and a separate idiot light normally. I had a mechanical gauge on it when it was first installed for the break in and again after I switched to Comp roller tipped rockers.

75-80 psi on start. Warmed up , 45-50 psi at idle 70 psi at or above 2000 rpm. Melling HV pump.

[cdr]

I run 10/30 VR1 in my 512.

[c00nhunterjoe]

If you are 70+ hot, the pump is in full bypass, 50 weight is too thick in my opinion. A 10/30 wpuld probably yield good numbers and free up horsepower.