My engine builder recommends 15W40 Diesel oil instead of a synthetic or dino gas oil.

He says it lubricates better, has zinc in it, and generally cleans better. He uses it in all his motors.

Any thoughts on this?

 

Won't hurt a thing. It has different additives than syn or dino and is low ash. Have run it in some of my builds but found no advantage with it over Kendall GT-1.

 

That is on the thicker side. I assume he builds with older style tolerances...?

 

Well older style it may be, but if anybody bothered to check with Clevitte they will see that 2.5-2.7 rod bearing and 2.7-3.0 main brg clearance is what they recommend for the "H" series brg and 7000RPM's.
I have been using those kinds of clearances for a LONG time on built engines.

 

Some are low ash and others are not. Which diesel oil are we talking about here?

Either way, I'd check to see if this oil meets the API SL service classification before I used it.

Also keep in mind that high levels of ZDDP, which many diesel oils have, can be harmful to catalytic converters. At least this is what GM was saying a couple of years ago. In case you're still running them.

-Mindgame

 

Dude,

There are alot of different practices out there (surprise) for building engines. There are success stories on each side of the issue.

I know a number of builders these days who like to use tighter clearances, standard volume pumps and lighter sysnthetic oils in their race engines. These guys are winning a lot of races too.

-Mindgame

 

Didn't say there wasn't tight clearance engines out there.
I said what CLEVITTE recommended for their "H" series brgs and what I have used-- "from the Old School"
Races are being won by loose clearance engines also so it's a matter of preference.
If ya want to argue clearance's call CLEVITTE and tell their engineers that design their products.

 

He recommends Quaker State and yes he builds his motors a little on the looser side. He has a circle track car that races against other guys' whose motors only last one or two races. His last the whole season.

 

Your builder has the right idea. My dirt track sprint car engines last a season also.

 

Nah, don't want to argue with Clevite. It's not a bearing "brand" thing anyways... clearance is clearance and oil film thickness is oil film thickness no matter which brand you prefer.

My point was only to say that whichever way you build it, make sure you get the right oil and oil pump for what you're doing.

By the way, have any of you guys performed an oil analysis on your race engines comparing synthetics to some of the better dino oils?

Let's just say..... I won't run anything but synthetic anymore....

-Mindgame

 

I'm still torn between synthetic and dino. Thats why I made this thread.

Does Mobil 1 make a 15W40? I know they make a 20W50.

 

I'd also only recommend real sythetic, not the mineral oil stuff Mobile 1 uses. I use Castrol Syntec German version, which was green a long time ago, I think it's brown again

The 0-30 version I use built in Germany is aparently a real good race oil and for it's price it can't be beat.

Did a lot of research a while back, but things changed, like the last time I bought it, it wasn't green anymore so I should do so more digging around to see what's up with that.

 

care to elaborate on the mobil (1 ?) deal?

 

I say as long as you keep oil in your motor who cares. EVERYTHING is preferance no matter what way you look at it. Somebody will have awesome experiences with one type and others will have very bad ones witht the same oil. I refuse to use anything but Mobil 1 in my "Hot Rod Cars" or Valvoline in my regular ones. Why? Because I have used all other brands and those are what seems to work the best, I don't have a lab so I can't test to see which brand is better.

Keep in mind research is ALWAYS going to make one brand look the "best" out of others.

I thought that Mobile 1 didn't make a 20W-50 but a "Racing" 15W-50 ??? Just my 1/64 of a cent.

 

I was more concerned about the comment that it wasn't fully sythetic. I just finished an expensive powertrain swap in my daily. Its been dead nuts reliable for 4k miles (not a check engine light since I swapped!) and I love it. Gas milage improved too. I'm running mobil 1 oil and filter. If I spend an extra $120 a year on oil and filter that does nothing so be it. That money would be squandered off on women and booze anyway.


I thought that Mobile 1 didn't make a 20W-50 but a "Racing" 15W-50 ??? Just my 1/64 of a cent. [/QUOTE]


well, at least youre not on the metric system!