i use 15w40 Shaffer diesle oil in mine. its free from our horse farm,but they use it from Big john Deeres to 4 cyl chevy colorados and everything in between.

mobile 1 in the GT tho

 

This is whymany people don't recommend switching to synthetic on an older engine. But after 10k mi you shouldn't have all of those pinhole leaks for the synthetic to uncover.

 

No, it's not "IMO." Those of us that actually have done the research don't feel like finding and citing all of our sources because it would take a ridiculous amount of time.

If you go through the MSDS sheets for all of the oils we're talking about, you'll see that they have high Zinc/ZDDP and manganese contents. If you read the product description for the Valvoline VR-1, you'll see that it states this very specifically. And if you do a little digging, you'll find that many diesel oils are going to be cleaned up to prevent these additives from clogging up and destroyingcatalytic converters. It has to happen, otherwise all of the newdiesel owners would be returning to their dealers for warranty cat replacements.

If you doubt that these additives are important, call Comp Cams and ask them about it. They have enough statistical data about the removal of ZDDP and manganese from modern street oils and the related cam break-in failures that they thought it wise to include a flier with all of their cams explaining the problem.

 

http://www.mossmotors.com/Shop/ViewP...69&SortOrder=1

for those of you unfamiliar with moss they have as good a rep as any mustang vendor.

 

Yeah, emissions on deisels will remove the deisel oil from the list of useful for flat tappet cams. In California they're going to be running MAF sensors on deisels for emissions, to give you an idea of how tight emissions are getting. And yeah, zinc annhilates cats. Solution....switch to roller cams like all the manufacturers did.

 

A car rolls off the assembly line,gets shipped by train and then truck to the dealership. Sits on the lot until some one buys it,then they hop in it and once they have it home for a day or two ,they light up the tires. Break in LOL. Average temperature for the location of operation determines the pour point and weight of the oil. it doesn't matter if its man made or dinosaur goo. If it's 5w 20..it's 5w 20.My 38 year old 351W has had nothing but Dino goo 10w 40. Let's see how many space aged synthetic machines last that long...

 

I have a question. i have heard lots of people use synthetics or regular oil. I have a 68 302, what Weight and type of oil would you suggest?
I have in it now 5w-30 Castroyl with Slick 50 and its a rebuilt engine.

Thanks!

 

Lots of good information. Thanks for your comments. I'm still reading up on the synthetics, the different types and what I should use.

 

Well sent in an email to AMSOIL this afternoon, 30 minutes later my phone rings and its one of their reps. After a length discussion he recommended that for the original 289 I should go ahead and use the Rotella oil for the break-in and first 3k to 5k miles. After this break-in is when he said the change over to a synthetic should be done. What did he recommend?
He recommended using the 'Ea Oil Filters' AMSOIL part number EAO15.

Thats the word from the AMSOIL Rep who called me today.