best oil for the old bomber

[blackbomber]

Hey guys.  in walmart yesterday  and could not find the conventional oil in the 5 quart jug.  Still have it in the 1 quart bottles.  They have a high mileage  synthetic  blend in the

5 quart jug.  Its cheaper than buying the single quarts..  So is it   ok for me to go to a  synthetic oil blend ???  never have put synthetic  oil in the truck ever...    really don't know

???   motor is at   284000  miles.   Thanks ......     PS   Is  5w=30  just  a  little  thinner than   10w--30?   I put a quart of   5w---30 in the truck  yesterday,  its all I  had at the time and it was pretty low so I used it..   

[wayno]

I say stay with conventional oil, synthetic oil may be good for newer vehicles, but it can leak thru the seals of our older truck engines(front and rear crank seals).

I was there a few weeks ago and bought a 5 quart container of 20/50 and some antifreeze.

[DanielC]

Old engines need old engine oils.

One additive used in older engine oils is a Zinc and Phosphorus compound, ZDDP.  This additive sticks to metal surfaces and protects them from wear, this is a concern where parts slide across each other without being pressure fed, like the contact between the rocker arms, and the camshaft.

The oil I use that has this additive is Valvoline VR-1 racing oil.  Amazon had it.

More modern engines have roller rocker arms, and are also designed with closer tolerances, and can use modern thinner engine oil.

The ZDDP additive can poison catalytic converters in modern cars, that is why it is greatly reduced in modern engine oils.  But modern cars also have more sophisticated catalytic converters, that are more sensitive to this additive.

 

[datzenmike]

I put synthetic oil in my 620 and within weeks had an oil droplet on the front crankshaft seal where there had never need any before through years of driving. Synthetic is just too slippery and thin for our old technology engines. The clearances and seals are for the 60s. Oils have definitely come a long long way in almost 50 years and are much better than back then but as mentioned ZDDP is slowly being reduced, if not being phased out because modern engines simply don't need the protection and it's poison for the new catalytic converters. Oil manufacturers claim the new lower levels (down to about half what they were) are reverse compatible and the old levels were simply excessive to begin with. Rather than slowly grinding my cam lobes and rockers away I simply switched to an oil that still has the same levels. Diesel oils still run 'flat tappet' oils and probably will for the foreseeable future. I just run Shell Rotella T4 15w40 as I only drive in the summer although it also come in 10w30 as well and found universally found everywhere. Chevron Delo 400 is similar and Esso also makes one and I think any oil marked R (for racing?) but may not be as easily available. Running conventional oil as an emergency top up isn't going to cause any problems. The wear is accumulative over years of running the newer lower levels. Diesel oils are higher in detergent so it will clean your engine insides and you may notice the oil darkens quickly after the switch. This should go away after several oil changes.

 

Are the newer lower levels of ZDDP injurious to our cams? I'm simply not about to find out and have switched to an oil with the old levels in it. Look up this controversy on line and decide for yourselves. For me it's as easy as reaching farther over for the right bottle of oil.

[Madkaw]

I run Rotella T-4 in the truck . Run T-5 in my Z . Cheap and extra ZDDP helps 

[canon3383]

Rotella T-4 15w40 in the summer, Rotella T-4 10w30 in the winter, I reduced tappet clack, runs better. New oil without the ZDDP clacked so loud I couldn't turn up the radio loud enough.

[blackbomber]

Ok  guys   cool   .    Ok guys  I will stay clear of anything synthetic.. I will look for  old stuff.  I ran Pennzoil for  like  29  years.  I am lucky I still have a license.  I got a 14 point ticket in the middle of a blizzard going to work!!!  I had the truck in 4 wd and I was having a blast in the snow!  guess officer  wasn't as exited as me...boo hoo...

Young  cop.  funny thing is I was driving my truck  five years  before he was born.   well , I probrably    deserved it. My driving   sucks.  I need to start driving like a old man.  

PS  [ tranny,    axles,  cv joints are all original on truck]   .   

[datzenmike]

You can certainly run a synthetic just beware of any disadvantages using it is all. Conventional oils are low in anti scuff additives so try for any oil high in ZDDP.