What oil should I use? 00' Miata, 74 TR6, 74 F250

[Angstrom42]

First post so be gentle, I figured I'd start with a pretty common n00b post and get it over with

What oil should I use?
I'm coastal California so I almost never see freezing. My commute is 13-18 minutes including an 5-8 minute dash down the highway. I have a tendency to let almost everything idle to nearly operating temp before I leave the driveway (I like my cars!)

1974 Ford F250 Camper Special.
Manual trans, 2wd, 390cid FE series engine, 4v carburetor, 70k miles. All stock internally but heads were rebuild less than 500 miles ago, plus I replaced the exhaust manifolds with headers. It sits a lot but I try to drive it at least once every couple of weeks. I've been running Shell RotellaT 15w40 & WIX filters for the last 2-3 oil changes, 3k or 3 month OCI. Oil was selected based on random ZDDP information found on the internet. No clue on the factory recommended weight or change interval.

1974 Triumph TR6
Manual trans, 2wd, 2.5ltr I6 engine, dual Zenith Stromburg carbs, flat tappet cam. Stock rebuild on the engine but has not run since 2003. I need to flush and change the oil in the old girl, but I have no idea what to run. There is less than 1,000 miles on the rebuild so I doubt its even finished breaking in yet. Converted to spin-on oil filter rather than the "reusable" 70's vintage "cartridge style" filter. I plan to use WIX or M1 filters (once I figure out what size fits!)

2000 Mazda Miata
Manual trans, 2wd, 1.8ltr DOHC 4cyl, C30-74 rotrex supercharger. This is my daily driver, believe it or not. Add a tire change and she becomes the autoX beast and open track abuse car. I've been running Mobil 1 0w30 and M1-110 filters for the last 3 oil changes. Currently 3-5k OCI but it always gets new oil & filter before any track event, not so much with the autoX. I've driven this car on multiple 300-400 mile trips in this configuration for track events. I'm running Redline in the LSD diff and some sort of AMSOIL product in the trans (but its getting notchy

) Oil was selected based on the recommendation of the guys in my car group. I believe the factory recommends 5w30, but I don't have an owners manual. The rotrex uses its own lubrication circuit with a proprietary "Traction Fluid" ($100/ltr, 50k OCI) so the engine oil system is not feeding it like a turbo.

So, what does BITOG recommend? You folks seem to have a much better understanding about these things than most of the documentation I've read on the internet.

Cheers!

 

[Donald]

Amsoil sells some engine oil for flat tappet cams and also storage situations. Their guide does not go back to 1974. Maybe call and ask. I would use a 10W30 HD oil in the truck, maybe a gas and diesel rated oil. Amsoil does have a recommendation for the Mazda. If you don't mind ordering Amsoil products go with their stuff. A M1 or Bosch D+ filter would be fine for all applications if available.

 

[expat]

For what it's worth, I have a 74 spitfire modded to about 100hp, After loosing a cam and lifters once (possibly due to low zinc oil?) I have used 15w-40 HDEO. it has worked well for 20k.

Ever considered switching to SU HS6's on that TR6?

 

[semaj281]

Originally Posted By: Angstrom42


What oil should I use?
I'm coastal California so I almost never see freezing. My commute is 13-18 minutes including an 5-8 minute dash down the highway. I have a tendency to let almost everything idle to nearly operating temp before I leave the driveway (I like my cars!)

1974 Ford F250 Camper Special.
I was going to say Pennzoil 10w40 HM, but that Rotella you've been using is a good oil. If you don't have issues with oil consumption or oil pressure I wouldn't change a thing.

1974 Triumph TR6
I can't say much about this car. I don't know much about flat tappet engines besides the fact that they do well with a good dose of ZDDP, which can be found in HDEOs like Shell Rotella and Chevron Delo.

2000 Mazda Miata
I'm pretty sure the Mazda BP engines call for 10w-30. And since you never see freezing temps, it would be best to follow this recommendation. I would not use a 0w on a car that sees track duty. They tend to have too much NOACK volatility.