What oil to use? 87 comp

[matt k]

Ok, so I tried to search, but "oil" is too short a search term, so hopefully this hasn't been discussed to death already.

Anyway, I know I'm supposed to use a "high zinc content" oil to protect the cams in my 87 comp (with 351w). What I don't know is WHAT oil has a high zinc content.

So, what oil do you guys use?

[matt k]

I found this particular writeup on a chevelle forum:


Approx 1200-1300ppm zddp is the stated minimum required for stock to mild perf flat tappet cam protection AND THE ROTELLA DOESNT CUT IT ANYMORE,PERIOD.

But the new cj delo 15w-40 i haD tested had approx 1350ppm zddp which matched the mfg's stated zddp lvl. Approx 1200-1300ppm zddp is the stated minimum required for stock to mild perf flat tappet cam protection.

When tested Pennzoils gt 25-50 gt racing oil had approx 1450-1500ppmzddp,valvolines NSL racing oils showed approx 1200-1250ppm zddp to name a few that er ok with flat tappet cams.

But the valvoline VR1 oils usually tested a smidge lower on zddp then valvolines NSL oils but the VR1 had better detergent pkg then the nsl oils that had sig less detergent. Yes the V1 may had more zddp the todays sm oils but less then the NSL oils on avg when i had it tested.

There are also some partial/full syn oils (Bradd Penn/Joe Gibbs/Royal Purple,etc that have good zddp lvls if you want to run them at 3x the cost in a stock to mild street motor that really doesnt need it with proper maint.

I think I can get the CJ Delo 15-40 at work, so maybe I'll try that...

[cadunkle]

Don't worry about zinc content even in these low zinc oils today. Your cam is already broken in so is fine with whatever off the shelf oil you use. Personally I run Valvoline 10w40. It has decent specs, but is low zinc compared to the good old stuff. Note that not only is zinc content important but phosphorus as well. Zinc lubricates and does well under very high pressure such as on a flat tappet cam. Phosphorus carries the zinc to where it's needed. Both are critical.

If you have a cam with a lot of lift, very aggressive lobe profiles, and very high valve spring pressures then you'll want to use an oil with a higher zinc and phosphorus content. If you just have the stock cam in there, run whatever oil you prefer or whatever is cheapest. These stock marine cams are very mild, and spring pressures on 20+ year old valve springs that weren't crazy to begin with are gonna be pretty low.

Unless I'm running a really radical cam I just run high zinc/phos oil for cam breakin. I used to use Shell Rotella, but they went low zinc without a warning on the jugs and I wiped a cam that way. Now I'm paranoid about cam break in so I use Valvoline VR1 (forget the specs but they publish them, quite high zinc/phos) and add a bottle of Comp Cams or similar cam break in additive.

[kvand347]

Don't worry about zinc content even in these low zinc oils today. Your cam is already broken in so is fine with whatever off the shelf oil you use. Personally I run Valvoline 10w40. It has decent specs, but is low zinc compared to the good old stuff. Note that not only is zinc content important but phosphorus as well. Zinc lubricates and does well under very high pressure such as on a flat tappet cam. Phosphorus carries the zinc to where it's needed. Both are critical.

If you have a cam with a lot of lift, very aggressive lobe profiles, and very high valve spring pressures then you'll want to use an oil with a higher zinc and phosphorus content. If you just have the stock cam in there, run whatever oil you prefer or whatever is cheapest. These stock marine cams are very mild, and spring pressures on 20+ year old valve springs that weren't crazy to begin with are gonna be pretty low.

Unless I'm running a really radical cam I just run high zinc/phos oil for cam breakin. I used to use Shell Rotella, but they went low zinc without a warning on the jugs and I wiped a cam that way. Now I'm paranoid about cam break in so I use Valvoline VR1 (forget the specs but they publish them, quite high zinc/phos) and add a bottle of Comp Cams or similar cam break in additive.


I agree 100%.

I wiped several lobes in my '75 corvette using Rotella as well. Since, I have switched to Valvoline VR1 and have had no problems whatsoever in the car (before I sold it) and my boat.

[matt k]

Great, thanks!

[haugy]

Yep, what's already been said. I have two Marine Supra engines. And both run on regular 10w40 or 15w40.