Just put new motor togeather and an deciding what oil to use, I have ran 20w50 in the past and have been looking at a 5w50 full synthetic racing oil with high zinc. Any thoughts?

Need engine details, bearing clearances, power level, steel or aluminum block and rods, etc

Gm 350 cast block scat forged 3.75 crank scat forged 6 inch rods .0027 bearing clearance aluminum heads running vp c12 racing fuel

quote:

Originally posted by tony palmieri:
Gm 350 cast block scat forged 3.75 crank scat forged 6 inch rods .0027 bearing clearance aluminum heads running vp c12 racing fuel

If it were mine I would run 10/30 full syn, no reason for 50wt with that type of engine

Thanks for the input I forgot to mention flat solid cam

Agree, don't need 50w. 10-30 or 10-40 will be good, use a zinc additive or high zinc oil because of the flat tappets.

I have not ran a flat tappet cam in like forever but I would think as long as it is a high zinc oil you would be fine. Personally I run full syn Redline racing and it has one of the highest zinc level out there but is very pricy. Lucas oil also has a very high zinc level plus they have a zinc additive you can add to any oil of your choice.
Just remember the low number in your oil viscosity, say the 5 in your 5/50 basically means nothing unless your starting your engine with the oil temp under 45*, at least that is my understanding of it.

10w-30 is what I would run with those clearances. Just about any name brand racing oil will have what you need even for a solid cam. All of the oils now are really good. Technology has advanced to a point that the differences are extremely small.

Curtis

I wanted to EDIT this to say that I don't agree with adding a Zinc additive to any oil. Buy one that has the amount of ZDDP you need and run it. The oil engineers spend a great deal of time getting their additive package the way they want it and home brew stuff can cause problems. JMO though.

I like Brad Penn 5/30. Great oil. You will only get approx 11- 1300 pp/m zinc so look for a good additive.

I've used Mobil 1 racing 15w-50 and Mobil 1 10w-30 with a 1/2 bottle of Lucas zinc additive. Solid flat tappet cam.

Thanks for the reply I know a guy that's a schafers dealer they have a full synthetic high zink 10-30 I was looking into

Tony, you mentioned you just put the engine together. I don't know what your experience is with regard to building and breaking-in new engines, so please don't take offense to this advice. Do not ever break in a flat-tappet cam with synthetic oil. Ever. Your lifters, cam lobes, and rings will not wear in and seat properly. I would recommend using one of the available break-in oils that are conventional (non-synth), such as Driven (formerly Joe Gibbs).
Also, most builders used to always recommend a straight-weight oil for break-in, (such as SAE 30 weight), rather than a multi-viscosity. I don't know if that is still the case, but if you choose to not use a specialty break-in oil, I do highly recommend the use of an extreme pressure additive for break-in, like Comp Cams P/N 159. Once you get the cam and lifters run-in for 30-40 minutes, (keeping RPM's above 2,000 with no idle time), then immediately drain the oil and change the filter. And use a long filter if you have space for it, not the shorty. Also, I don't recommend using a race filter for the initial run-in time, since they are designed to allow for higher flow, at the expense of allowing larger particles through the filter. Since you don't really need a high-flow filter for break in, (no need to spin it above 3,500-4,000), you want as fine a filtration as possible, to catch all of the metal particles the will be released during that break-in. Afterward, you can then run synthetic oil and a race filter if you wish.

quote:

Originally posted by stk 758 BP!:
I like Brad Penn 5/30. Great oil. You will only get approx 11- 1300 pp/m zinc so look for a good additive.

I was told yesterday Brad Penn is being discontinued.

I have always used RP 15W40 (S) with no issues at all. A friend of mine that sold his TS operation, gave me 10 gallons of (New) of Royal Purple 20W50
XPS. Oh don't worry it won't go to waste.I looked up retail on the XPS and about fell off the chair.