Quote:
Originally Posted by Jeff/Illinois
ZDDP additive in our '69 Mach 1 with 10.5:1 compression
Nothing added to the Model A or '36 Flathead and all is fine.
Been running Motorcraft 5W-30 in the Flathead, changed it the other day during winterizing the vehicle. Oil came out looking very good after about a thousand miles, no evidence of sludge in the pan, and this motor was kinda dirty when I got it she is running clean now after several oil changes with detergent oil  |
Instead of adding ZDDP to my '69 Mustang oil, I instead, use Valvoline Racing Oil which already contains the zinc.
From what I have already learned about A's is that their valves don't require the zinc since apparently the mineral oil that they were designed to run on didn't contain zinc.
Re: STP That product sure does produce a lot of discussion on both sides of the issue! People either love it or hate it, there never seems to be anyone in the middle! 😂