Opinion on oil in a L71

[Robert M.]

Over the years I have read all the threads on oil usage for flat tappet cams and don't need anymore arguments. I am more interested in those that own a car with a stock L71 435 HP motor, what oil brand and weight are you actually using? Do you put any ZDDP additives in at oil change? Thanks

[Michael W.]

Re: Opinion on oil in a L71

don't need anymore arguments.

My crystal ball says that's exactly what you're going to get.

I doubt that there are enough owners of this or similar engines that have put enough miles on them using current oils to say conclusively one way or the other. The exceptions would be gross neglect of minimum ZDDP requirements, and a caveat of one off failures that would have happened anyway and the ethanol uhh, OIL gets blamed.

[Jim T.]

Re: Opinion on oil in a L71

Do not have a 427-435 just old 1968 original engine L79 and 1985 Corvette that I use diesel oil 15w40, usually Shell brand. Switched to diesel oil for the ZDDP.

[Daniel S.]

Re: Opinion on oil in a L71

15W 40 diesel oil no additives in my L71. Brand doesn't matter

[Douglas L.]

Re: Opinion on oil in a L71

As long as the oil has the API rating of CJ-4 or SM(not SN) your'e good to go. SM is the rating GM recommended from the factory in the 60s. I think youll find most diesel 15w-40s(rotella, delo, etc.) have these ratings. There are also small label oils that dont have API ratings that work just as well also but use a SM rated oil and you cant go wrong.

[Gary P.]

Re: Opinion on oil in a L71

Brad Penn, The Green Oil.

[Robert M.]

Re: Opinion on oil in a L71

Thanks guys. I have used the diesel oil before. I currently have Valvoline 10w-40 VR1 with a 4 oz. bottle of ZDDP additive in the car. It might only get driven 50 miles a season so I agree it really is not an issue. Thanks again

[Duke W.]

Re: Opinion on oil in a L71

As long as the oil has the API rating of CJ-4 or SM(not SN) your'e good to go. SM is the rating GM recommended from the factory in the 60s. I think youll find most diesel 15w-40s(rotella, delo, etc.) have these ratings. There are also small label oils that dont have API ratings that work just as well also but use a SM rated oil and you cant go wrong.

The SM rating did not appear until about ten years ago. Back in the sixties the rating was MS, based on a different system. Current SM has less ZDDP. Primary category SM should not be used with one exception explained in the next post.

Primary category CJ-4s have a secondary rating of SM or SN. These are okay to use as they have 50 percent more ZDDP than primary category SM. The key is to choose the correct primary category, which is CJ-4.

It's all explained here:

http://stlouisncrs.org/news_files/St_Louis_NCRS_Chapter_July_2011.pdf

Duke

[Duke W.]

Re: Opinion on oil in a L71

Thanks guys. I have used the diesel oil before. I currently have Valvoline 10w-40 VR1 with a 4 oz. bottle of ZDDP additive in the car. It might only get driven 50 miles a season so I agree it really is not an issue. Thanks again

According to the spec sheet that you can download from the Web, the only available VR-1 multiviscosity ratings are 10W-30 and 20W-50. Both are okay to use in vintage engines as they have sufficient ZDDP based on the P and Zn analyses and no supplemental ZDDP additive is required.

The 10W-30 product only carries the obsolete SH rating. Why? Because the API service category rules state that any SM oil with a low end viscosity rating of 10W or less must comply with the 800 ppm P limitation for SM and SN oils. If the low end viscosity rating is greater than 10W, the P limitation doesn't apply, so the 20W-50 product can be labled SN/SM.

The above is explained in the oil article that is linked in my previous post.

Valvoline VR-1 is the only primary S-category oil I am aware of that has sufficient ZDDP for vintage engines.

Duke

[Robert D.]

Re: Opinion on oil in a L71

Brad Penn oil has everything our cars need usually run 10w 40

[Don H.]

Re: Opinion on oil in a L71

photo-211.jpg

wallymart

[Steve B.]

Re: Opinion on oil in a L71

I use Valvoline VR1 20/50, as Duke states, it has the right amount of ZDDP.

[Steve G.]

Re: Opinion on oil in a L71

I use Valvoline VR1 20/50, as Duke states, it has the right amount of ZDDP.

Why do you use such a heavy oil?

[Robert M.]

Re: Opinion on oil in a L71

According to the spec sheet that you can download from the Web, the only available VR-1 multiviscosity ratings are 10W-30 and 20W-50. Both are okay to use in vintage engines as they have sufficient ZDDP based on the P and Zn analyses and no supplemental ZDDP additive is required.

The 10W-30 product only carries the obsolete SH rating. Why? Because the API service category rules state that any SM oil with a low end viscosity rating of 10W or less must comply with the 800 ppm P limitation for SM and SN oils. If the low end viscosity rating is greater than 10W, the P limitation doesn't apply, so the 20W-50 product can be labled SN/SM.

The above is explained in the oil article that is linked in my previous post.

Valvoline VR-1 is the only primary S-category oil I am aware of that has sufficient ZDDP for vintage engines.

Duke

Thanks Duke. I had a senior moment. I had VR1 10w30 in it before I changed it last. It now has Brad Penn 10w-40

[Nick L.]

Re: Opinion on oil in a L71

Amsoil AMO 10W40 in stock 67 L-71. Mine is one of the few that get driven, 1000+ miles per year.