American oils are not that easy to come by here in England.

I used 20/50 mineral classsic motor oil to do the first 1000 miles.

Whats the best oil. I can possibly get our local US parts man to obtain the right stuff.

By the way, the first 1000 miles passed without incident.

I didn't realise that diesel oils contain the required zinc.

I just bought some Comma Classic 20/50 and according to the bloke in the auto parts shop iot is meant for older style engines and includes some anti shearing agent to aid the flat bottomed tappets.

Is he lying to me? I can punch fairly hard.

      Don't think we have that brand Stateside, I've never seen or heard of it here. What you're looking for is Zinc, or a zinc substitute. Diesel oils have it, some racing oils or additives like Lucas (no, NOT the Prince of Darkness) or STP, also have it or a substitute.   

      I think the SE is ok, You can tell by the designation. Or you could if you can remember which is which, and I forgot!  They changed the designation after they removed the zinc.

Mike

I downloaded this sheet on the Cat oil today at work it is a Gasoline rated SL oil and has 0.146 of zinc which I think = 1460 ppm

http://www.cat.com/cda/files/199221/7/pehj0059-02.pdf

Our oil lab guy says its good for flat tappet Y blocks, being Cat its available worldwide too for all Y blockers and it comes in 1 Gallon or over here in my paddock 5 litre packs.

15w40 DEO 5 Litre Pack part number 3E9901 or 248 7518 for a 1 US gallon pack

http://catmsds.cat.com/MSDSSearch/servlet/cat.cis.ecs.msdsSearch.controller.SearchResultsDisplayServlet?MSDSNO=8962&LANGUAGE_CODE=en_US&searchString=MSDSNO

I'm going to give it a run in my rebuild, cheers

Mike

           Add to the comments what SAE specs to AVOID. The ones with the reduced zinc content.

Here’s the link to a previous thread regarding the API classification and how it affects the zinc / phosphorus content of the oil.

http://forums.y-blocksforever.com/Topic9285.aspx

Not all API rated oils with the ‘SM’ classification are low in zinc/phosphorus. Doing a search for ‘zinc’ on this site will bring up several different discussions regarding oil for the Y.

Seeing as how this thread has gone into detail on oil, I’ll add some additional info that doesn’t get passed along very often.

On multi-weight oils, you’ll have an oil with basically two different temperature ratings.  For a 10W-40 oil the ‘10W’ refers to the equivalent oil weight of this oil at low temperatures (ie. 32°F or lower) while the ‘40’ refers to the equivalent oil weight or grade at high temperatures (ie. 212°F).  On a single weight oil, the weight or grade is rated only at 212°F but is assumed that the viscosity equivalent of the oil is the same grade at 32°F due to not having additives in it to alter the viscosity at various temperatures.

A 5W-30 oil will have better oil flow and startup characteristics than a 10W-30 oil due to the 5W-30 weight oil having a reduced viscosity at lower temperatures.  This might be a player in the Northern States where the temperatures gets considerably cooler in the winter months but not as much as a player here in Texas on the older vehicles where it rarely gets to the freezing temperatures in my part of the country.  For this reason, I typically always recommend a 10W-40 oil for year round use in the older engines as this provides a sufficient viscosity at the higher summer temperatures while also insuring adequate zinc/phosphorus levels even if the oil has the newest SM API rating.

The other item to remember on multi-weight oils is that the greater the difference between the low and high temperature ratings, then the greater the propensity for the oil to break down over time and not actually retain its rating.  For example, a 5W-30 oil or a 10W-40 oil will break down quicker than a 10W-30 oil.  But if the oils are changed out at regular intervals, then this breakdown issue is a non-event regardless of the grade being used.

Rick.  Thanks for the additional info.  Regarding the posting of links, the pasted in links need a space behind them in order for them to work.  Using a hard return without the space keeps the link from working.  I believe this will fix you up.

Here’s the link again.

http://forums.y-blocksforever.com/Topic9285-3-1.aspx

And here’s the text:

The latest API SM classification now means some variability in the amount of zinc and here are the rules as I interpret them. If the oil is 30W or less (ie. 5W-20, 10W-30), the zinc/phosphorus content is reduced to 800ppm max. But if the oil is greater than 30W (10W-40, 20W-50), the zinc levels remain at 1200-1400ppm. If the oil is classified as SM but has “Racing” or “High Mileage” on the label, then it will have the 1200-1400ppm zinc regardless of the oil weight or viscosity.

When in doubt about the amount of zinc in an oil, just pull up the manufacturers MSDS or technical sheet and you can pull the actual zinc/phosphorus content information out of that.