facts zink is used/sacrificed in verry small quantaties at time,so toatle amount present in your oildoes not change the wear protection the oil provides,as long as you do not run out of zink. wear testing confirms that more zink provides Longerwear protection ,not more wear protection. also of interest zink is not a lubricant until heat and load are applied. and finaly to much zink erodes cast iron. acording to the tests i am refering to the actual spec printed on the jar is far from acurat,best safest info is actual load tests. ones quoted wher byals tribology (formerly)staveley labs in sparks nevada. usa. the others fav saying is ther is noshortage of snake oil salesmen, and folklore about aditives,and most oilcos specify no aditives required to ther products and eve mixing brands can defeat ratings.

the coments that modern engines have roller cams is not factual. the cuming engines used in dodge trucks are flat tappet in all 2 valve engines. i am nor sure of the 4 valve cumins.

the coment re the 460 ford raises some questions,as they have flame hardend cams and failures ar very rare and when usually other isues.have some bearing.

tto hell with any more,i ame tired from my 1finger typing.

I'm with Ted. The zinc has nothing to do with viscosity , it is a friction modifier which helps to lubricate the cam and lifter faces. In this case more is better. Later modern oils have removed the zinc as it plays up with catalytic converters. This is why oils today generally have some message like "for modern gasoline engines" etc.. New engines have roller cams/lifters and rockers. This zinc is most important when fist starting up with a new engine - the cam and lifter faces are soft. As the engines gets used dyring its lifetime, its dependence on the zinc decreases as the two surfaces harden.I have seen a 460 with the old hydraulic lifters chew a cam out in two hours of use due to using the wrong oil.

Rick - West Australia
Do Y Blocks Downunder run upside down? Gravity Sucks!!

((5w30 oryly house brand has api sn=91433psi (3.99pr us quart) zink is992ppm

motorcraft 5w30 api sn=68782psi zink is796ppm

10w30 royal purpel (high perf street)=66211psi zink=1774 ppm

5w30 castrol gtx convent. api sn=95392psi zink880ppm.

my point is high zink does not add to api sn ratings as a mater of tests re wear.more zink does not insure of no cam isues or bearing wear etc. high viscosity #s do not give better wear results tho they may plug loss of oil pressure for short time, till engine is temp and under load,then it looses any advantage. yblock engines will live as long as most, but due to rocker lube isues need a low viscosity especially on start up,so as to keep the small lube supply clean and lubricate the rockers and valve train. also less strain on the puny oilpump drive. The info i have is not for race cars, tho the reasercher claims he runs a verry radical bbchev with no isues.

my coments re 90gear oil wher to rais some factual discusions, not to be a smart ass.ihave passed on the info to other posters,and it is factual.

Any API rated multi-weight oil with 30W or less in the classification will have less than the recommended amounts of zinc/phosphorus for regular use with flat tappets camshafts. A good quality API rated 10W-40 oil has the old SJ levels of zinc/phosphorus and works well for most streetable Y engines without the use of additional additives.

Lorena, Texas (South of Waco)

Because that would be ridiculous. I run 20w-60 but it doesn't get very cold here, never below freezing.

I think constructive debate is better than cynicism. That's just my personal opinion.

why not 90wt gearoil

20W40 with zink is best I think.

"The Bat" out of hell

50's & 60's hotrodder

retired speed shop owner,built and design hotrods, racecars

airbrush t-shirts, engine balancing

Miami fl.

now all you hve to do ischange oil and filter and use a good 10/30 oil,motorcraft checks out verry good. then make sure your therm is at least 180. just my thoughts.

Picked up another complete 292 Y the other day,it had a outdside oiler hooked up to the right side only. After doing my checks of all other stuff,an then a short test start,it passed those with flying color,even 60 PSI oil too,so now to fix the rocker oiling.I pulled all the sparkplugs,an the right side rockershaft off,put a wire down the head hole to be sure it was at lest clear down as far as the block,spun it up with the starter tell it showed 50# on my gage,but no oil coming out of head hole. Nexted filled the head hole with carb cleaner and let it soak for 30min. refilling now and then. A bit more wiring it out and then fill again with carb cleaner. I pumped up my aircomproser to 110pis and with my airgun with its pointy end,stick that into the head hole that has the carbclear in it,be sure I'm stand off to the side{saftey so ya don't blast your self with carbcleaner,and being sure to hold it so the pointy end of airgun is sealing the head hole good,pull the triger pumping 110 psi into that hole,after about a min or so,I can see I'm starting to get oil moving in the semi clear oil gage plastic line=its now getting through into inside block oil lines{BINGO].
Next spun engine tell I saw oil coming out head hole like it should of,this took some time because the air PSI going the wrong way had push most of the oil out of block lines. Replaced rocker shaft an readjusted valves. One last note/were the outside oiler had been added it had to be removed and seal again like Ford did. The rocker arm shaft oil blockage is nearly always the slot in the headgasket fills up with junk on one or both sides of motor,.
The old aftermarket outside oilers are one way to fix,but I don't like them,and another way is the long one of taking a head or heads off,replacing the headgaskets after cleaning the the oil hole down to the cam and the one in the head too.
Hope that helps some one out.

"The Bat" out of hell

50's & 60's hotrodder

retired speed shop owner,built and design hotrods, racecars

airbrush t-shirts, engine balancing

Miami fl.