Thru a conversation I had with Ron Iskenderian at Isky cams I learned that our US motor oils no longer contain zinc di-phosphate. This is a critical component for our engines. Seems the EPA figured the only cars left that needed it were old rust buckets so what the hell. The idea is that ZDP bonds to the metal and when the oil sheers, the ZDP takes the hit instead of the metal. For a solution he recomends General Motors E.O.S. Assembly Lube (GM part #1052367). It can be obtained thru any chevy dealer. He says to use 1.5 can for break in and .5 can every oil change. I called a family friend at GM who works in the Corvette division and he verified Ron's claim. GM still sells EOS for its antique Corvette owners who are in the same boat we are. Hope this helps out there.

Through a conversation with one of the representatives from Lucas Oil Products a few years back, I learned that their Heavy Duty Oil Stabilizer contains ZDP which I'd never heard of up until that conversation. He said that it was expecially necessary for older cars. That was some years ago and the next time I heard of it was in your post.

Been using Lucas and been quite happy.

Support Lucas Oil, and Lucas Oil Stadium, the future home of the Indianapolis Colts!

I sell all the Lucas line at my shop. The product does what it claims. Although the one negative I found was on an L28 that had a couple valve stem seals going bad. Tended to smoke a bit more on the Lucas. But, it did raise the oil pressure at idle by 9 pounds.

The folks on this site that ran STP Motor Treatment and saw what it did to a crankcase will understand what Lucas will do to a motor.

I personally dont put anything in my engine oil. I use Lucas in the gearbox and differential. They run cooler and quieter.

I'd be interested to know if the GM additive leaves such a heavy coating on internal parts.

FWIW,

Chris A.