Well, by definition gasohol is lead-free, so I don't put it down to alcohol alone. And I've had no problems with gasohol and hardened seats on subsequent trips.

 

Well right now my truck is barely drivable around town, let alone highway worthy, so I'm not quite there with what my concerns really should be now. My truck had about 80k on it when I got it and there was a rebuild done in there somewhere, so I wonder if hardened seats were put in at any point. I think the octane-raising properties of tetraethyl lead are kind of moot in our trucks considering how relatively low the compressions are, and hardened seats should help with valve recession, (I say should because it still can happen with lots of use.) Basically, to answer OP's question, if you're planning on lots of miles, get the hardened seats or plan on buying the lead additive, or both, if you want to be really careful.

 

just my ten cent

but the lead additives also help lubricates and prevent surface deposits on the small little details in the carbs, that can occure from the "new" "dry" gasohol.

helping out keeping the carbs in good shape, steady idle etc

 

Wasn't this the result of the run out of gas on the country road scheme we played on our girlfriends

 

Yep, a lot of guys were used to using and recommending the diesel oils specifically for the zinc that was still in them. But as Ross points out, new federal standards have greatly reduced or removed the zinc from most diesel oils. You can still get oils with zinc, but they are limited to break in and off road racing oil and those are usually very costly. When I got the new rebuilt engine for Edith, I wanted to get some good high zinc oil for the break in and so I did some homework and found a really good deal at Summit Racing. They carry Lucas 30W 'Race Only' Break In oil... "It features higher levels of zinc and phosphorous to offer maximum protection."
They sell it in 5 qt containers for $21.97 ($4.40 qt) +shipping or in a 3 pk for $63.97 ($4.26 qt).

 

FYI Cam grinders are "requiring" Rotella to protect cams/lifters. That warning was in big bold letters on my new Comp260

 

Hmmm, that is interesting. I never heard that before. Good to know.

 

Interesting, they don't mention that in the link below. Do they identify a specific Rotella spec, like CI-4 (older spec that still had ZDDP)?

http://www.compcams.com/Base/pdf/Fla...chBulletin.pdf

 

I guess I've always used Rotella in my pickup cause the P.O. used it. He is a farmer and I s'pose he got his in a 30 gallon drum. My truck has almost 260,000 on it, doesn't smoke or knock . Runs great. Plus the rotella is cheaper too. I figured the diesel would be good for the old trucks due to the extras added. A most informative thread.

 

A diesel rated oil would have a better EP additive package? Rotella is good stuff.

I remember a study by one of the major auto mags and seems to me they found the "lead" substitute additives work, but only at two or three times the recommended concentrations, for every fill. Makes for a pretty expensive tank even before any fuel. Another study found that hardened valve seats are important at extended high speeds/RPM and heavy duty use e.g. towing &c. For Farm&Fleet runs and Sunday cruise, don't worry about it.

I like Marvel's in the fuel on solid lifter Y blocks.

 

I've been using Valvoline VR-1 racing oil. Has all the zinc/phosp. you need for the older flat tappet cams. No detergent, but I don't leave it in the engine for more than 6 months. My local NAPA stocks it. I've also seen it at O'Reily's.

 

Shell rotella still has over 1000 ppm of zinc in its oil, one of the industry highest for the price point. Chevron has a little more.
"Rotella T with Triple Protection 15W-40 (new API CJ-4) has approximately 1200 ppm zinc. This is 50% more zinc than current passenger car motor oils (SM, GF-4) which typically contain approximately 800 ppm zinc."
This is quote is from blueprint engines. I had another site I thought I bookmarked that actually showed the real breakdown numbers but can't find it.

 

Hard to get a straight answer! The Rotella Triple Protection 15w40 is rated for BOTH SM and CJ-4, how can that be?? From what I've read, SM limits zinc to <800 ppm

 

Another question - why would zinc cause problems with catalytic converters in the first place? At parts per million levels, it doesn't make a lot of sense.

 

Diesel-spec oil has some other features, like additives to suspend particulates, that are a benefit on older engines. The biggest thing is they seem to be cheaper by a significant amount.[/QUOTE]



Interesting about the particulate suspension. I've changed oil on a number of different diesel vehicles and every one was as black paint coming out of the pan. Is that from blow-by being caught up in the oil. Too small of particles to get picked up by the filter? I am by no means as savvy on oil as you guys, I just know what works in my vehicles. This Valvoline VR T, what does that cost per quart ? I've seen it a few times but thought it was out of my price range {cheap}.