The case depth they are referring to doesn't sound right to me at all. .0002"-.0005" is a deposition depth that a plating would leave like a thin coating of chrome or TiN. Case hardening usually leaves a case depth of at least .020" or .030". I was machining some case ahrdened linear shafting the other day and the case depth was close to .070".

 

This zinc issue is of interest to many performance car forums. It has been covered in excruciating detail in this thread http://forums.pelicanparts.com/showthread.php?t=367300 on the Porsche 911 forum I spend time on. I now use Brad Penn racing oil in my 911. It is the old Kendal GT oil (green). Kendal is now a completely different oil. There's a lot of good unbiased information on that thread if you can stay awake.

 

I've heard good things about Brad Penn oil too, it can be hard to find though if you don't have a speed shop in town.

http://www.bradpennracing.com/

 

so after reading this thread im wondering if im doing more harm than good, my '79 has 33k orig. miles, stock motor accept for bolt on goodies. the last 3 oil changes Ive used royal purple 15/40 it says its safe for gas & diesel engines. is this acceptable or should i use a different oil?

 

I use the Valvoline VR1 that everyone loves to hate. Hey, they even have a sticker on the bottle that says its great for flat tappet motors because its got more zinc.

 

Read the Porsche thread referenced above if you want the facts. It seems these oils are constantly changing and what was good in 2007 may not be OK today. And yes, people are seeing increased wear and even failures in high performance engines due to this issue. As always everyone makes their own decision, but the info is out there and being discussed so this is something you should pay attention to.

 

If the bottle says it's OK it must be. I don't know anything about VR1.

 

Shell Rotella CJ-4 15W40 oil has been creeping up past 1350 PPM for zinc within the last 9 months.

Interestingly Rotella 10W30 CJ-4 has been rating slightly more than 1400 PPM zinc lately.

My company does over 100 oil samples A MONTH. We use Rotella exclusively in Diesel engines. In all our Gas engines we use Motorcraft Synthetic Blend 5W20 and 5W30.

Josh

Josh

 

Here's another good article...http://www.lnengineering.com/oil.html

 

Sarcasm Implied...

 

You mean that was only sarcasm???, i thought your bottle actually had a sticker on it that says it's "great for flat tappet motors because its got more zinc" how silly of me.

Imply sarcasam as you see fit.

 

Green type indicates sarcasm in forumland.

 

Cool. I've never seen that before. And I've been on lots of forums for a long time.

 

I have a 79 F150 302 that was overhauled over twenty years ago and was broke in on Havoline 10w30 and is still running Havoline 10w30 and was ran pretty dang hard when I was in my high school years and still no problems. I run havoline 10w30 in my 79 Bronco 400 that has probably 200,000 miles on it no problems. Would oil with higher zinc content in it be better for it? Maybe, but not enough for me to notice the difference.

 

Like most things on the internet this issue has a tendency to be overhyped and overanalyzed Ad infinitum, is zinc content important to a flat tappet engine? of course it is but the "sky is falling" crowd may be overstating their case just a bit, i haven't noticed a scourge of cam lobes being wiped out since the decrease of ZDDP in '07, have you?