I was just wondering if any one has some suggestions on the best oil to run in a slant six. I just rebuilt a slant six and its in my duster and it has 5300 miles on it. I just run 10w30 valvoline, but I was thinking of going to a full sythetic like mobil 1. any suggestions?

craig_o_connor88@hotmail.com

I have used Slick 50 for years and I have been very pleased with the results. When I had my shop, we installed it for a customer who was a rep. After changing the oil and putting in Slick, we let the motor warm up to adjust the valves. After a few minutes we heard the engine racing away, so we lowered the idle and let it continue to run. We had to lower the idle several more times because the idle speed kept increasing! Over time, we installed Slick in several motors and had the same thing happen every time. We realized that the reduction in friction was making the engine run faster with the same amount of fuel.

Many years later I had an '86 Dodge 600 ES Turbo that I had "slicked". At one point the head had trouble so I put in a new head, cam and lifters. A few months later it ran low on oil. I never figured that out because it had never done it before or since. The result was a scored cam and lifters. The bottom line is that all the moving parts that I had replaced that were NOT "slicked" were damaged. Even with the low oil, the turbo bearings (which HAD been "slicked") were NOT damaged. Made a believer out of me!

I have also used ProLong but don't have any great stories like this one to share about it.

Chuck


sl6@omnipages.com

I just pulled the head on my 80 Aspen. The engine has about 120K on it. I've always used 10W/30 Mobil I. The hone marks are still visible on the cylinder walls. There is a very small ridge at the top of the bores that I can feel, but I'd bet it's barely measurable. Maybe 0.001 - 0.002.

Mitch

I'm getting ready to rebuild a 225 in a 1970 Dart Swinger, and planned on using full synthetic oil afterwards. I use Castrol Syntec in my truck and love it, though it's not a 100% "true" synthetic (still made from an organic base). I hear Mobil 1's full synthetics are true synthetics, along with Amsoil, so I might switch to one of those two.

When starting a new engine I always use basic (mineral based) oil, non detergent if I can. basically cheap oil.

I know, it's a new engine but think about it, there is a bunch of special assembly lube(s) in there along with dust, lint and ???
And if there is some leak at start-up, no expensive synthetic on the ground.

Truth is that I run the cheap oil for a short while then change it to another "clean" batch of mineral base oil. After the break-in, switch over to the synthetic.
DD

Hi
I Have always used ND 30 or ND40 after rebuild run at 2-3 K RPM for Hr to break in cam. I then change oil filter and as ND30 is cheap I flush it ( fill with 2 quarts and drain ) Then refill with ND30 or ND40 and run 2-3K and change with syn. oil.


My 2c

_________________
Wild 1 AKA William Robertson
Owner Builder
65 Dart 270 2 door post /6 stock
89 dodge diplomat
66 Plymouth Barracuda
70 Challenger 451 ( Sold )
95 Chy New Yorker ( Stock )

i broke my engine in with castrol 20w50 and switched to syntech 20w50 mainly because i mistakenly believed the 10,000 miles between oil changes. car didn't use any oil at all with the castrol but used a quart every 600 miles with syntech. idle was a little smoother with syntech.i called castrol and they said syntech should be changed every 3,000 miles like any other oil. so i just went with castrol 20w50. the car doesn't use a drop between changes and the engine is clean as a whistle and it doesn't cost 40 dollars in oil every 3000 miles.

I run Mobil 1 in ALMOST everything I own. My F250 has 328K miles running Valvoline 15W-40. Why Valvoline? Because the engine already had 78K miles on it with Valvoline when I bought the truck. Point is, once you pick an oil, stick with it. Swapping around brands on an engine will, in my opinion, do more damage than anything else.

As for synthetic. If you already have an oil leak, you'll have an even bigger oil leak when you go to synthetic. As for the honing marks in the cylinders, I pulled the head off a 60K V6 and ditto, the hone marks still there (running Mobil 1). Make SURE the rings are seated before you go to synthetic or the rings will NEVER seat.

My $0.02

Gilly