5w40 in 350?

[carpart67]

Looking for some opinions on oil grade.

I've picked up a 1986 K1500 with a 350CID engine. The owner before me used Mobil1 10w30 in the truck. I'd like to stick with the Mobil1 oils.

Here's my issue, I'm concerned about the levels of zink and phosphorus. I've been reading the newer GF-5 certified oils may not protect flat tappet cams as well. I live in a small town, in a small province in Canada so the only other option I have in the Mobil line for increased zinc and phosphorus is Mobil1 Turbo diesiel truck 5w40.

I know that lots of people in this area run 15w40 in HP 350s. I'm just wondering if the 5w40 would protect properly.

Any thoughts?

 

[chengny]

The latest Mobil 1 Product Guide - April 2013 - shows their 15W-50 as having the highest ZDDP levels in that product line (1200 ppm Phosphorus/1300 ppm Zinc).

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This concentration is quite high by todays standards - about the same as the ZDDP content of Shell Rotella T.

If you can't easily source the 15W-50, you should be able to find either Mobil 1 0W-40 or 5W-50. Either of these is acceptable - ZDDP content is 1000/1100 in both.

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[77 K20]

After replacing my camshaft because it had some lobes ground down I looked into this also. Once it is fully broken in I'll be running Mobil high mileage 10w30 and use a bit of lucas zinc plus in it. Can't remember the link offhand... but lucas oil has a massive amount of zinc in it. Some suggested just add 1/3 of the bottle to your oil after an oil change and it will bring levels up. (the stuff I think was around 6000ppm of zinc).

http://www.lucasoil.com/products/display_products.sd?iid=82&catid=9&loc=show

 

[jake wells]

if you go over 1800 ppm of zddp you risk camshaft damage because to much is not a good thing it will weaken your cam if you go over 1800 ppm in a stock or mildly built engine anyways a oil with high amounts of moly are great too pennzoil contains large amounts as it is a anti wear component just like the liquid titanium found in kendall gt 1 oils.

 

[77 K20]

if you go over 1800 ppm of zddp you risk camshaft damage because to much is not a good thing it will weaken your cam if you go over 1800 ppm in a stock or mildly built engine anyways a oil with high amounts of moly are great too pennzoil contains large amounts as it is a anti wear component just like the liquid titanium found in kendall gt 1 oils.

I've heard that too much can be bad. Seems the oil in the old days had around 1200ppm or so of zinc and that was good. By pouring in 1/3 of a bottle of Lucas into it (assuming 5,500ppm of zinc) and I will be using the Mobile 1 high mileage oil (1000 ppm) is averages out to 1151ppm of zinc.
Could go higher I guess... but need to find how much that lucas acutally has.

 

[77 K20]

Finally found the article... and it is from 2011 so much better than other things I had read online from 2006 or whatnot. They say lucas oil break in additive tested at 6427ppm.
So when I add 1/3 the bottle to Mobile 1 high mileage I end up with 1195ppm.

http://www.carcraft.com/techarticles/ccrp_1108_camshaft_break_in_guide/viewall.html

 

[MrMarty51]

I do`nt know if it still holds true but, I remember about not going over a 25 points spread between the low and the high number, such as 15-40 would be 25 difference.
Also, I remember GM losing cam/crank and rod bearings when they was still recomending 10-30 oil so that is why the oil fill caps on the 87 and newer engines all says 5-30 wt. oil which is still 25 points in the spread.
I have been using 5-30 wt. Valvoline oil in My 93 GMC 350 and now have 248,000 miles on that engine, replaced the timing chain/sprockets and oil pump, just because I had the waterpump off and it was too easy to get to the timing chain and figured I`d screw up the pan gasket while trying to force the timing cover back on so I pulled the oil pan and whilst I was in there poked a new oil pump at it.
I am not saying that Valvoline oil is superior to any other oil, nor do I want to start that controversy in Your thread. What I use is what is readily available wherever I go and, Valvoline seems to be stocked in all of the states I have been in so that is what I use, in My motorcycles and vehicles too.

 

[dhamp]

It's high, but I've been running the VR-1 Racing oil in my Chevelle because it supposedly has the proper zinc in it (according to a bunch of very anal people on my Chevelle forum)

 

[Driver4r]

IMO, 5 is way to thin and it wont protect much. And i stay away from mobil. I run valvoline 10w-40 in all my stuff.