5W wt base stock oil is way too thin,yam rec's 20w40/20w50 depending on yr so you want to reduce
yami's rec from 20w base stock oil to 5w?
The R* motors bottom end and or general mechanical clearcnes are designed/setup for a 20w base stock oil with cold motor and 40-50 wt oil when oil reaches full op temp.
Dont forget a 5w40 oil starts out a 5w base oil when could then chemicals in the oils additive pkg increases the oil from its base 5w to 40w when it reaches norm op temp.
But the larger the dif betwen the base 5w to upper end 40w there it the more additives it takes to get the oil up to the full op tem 40 w oil. Oils in that case are more prone to shearing/visc breakin down then oils that have less diff between cols base wt and hot full temp wt like for ex 20-40 vs 5-40
Dont chince out when
ti comes to great ptotecttion ,keep running the amsoil or run mobil 1 both syn 20w-50 oils that both have proper zddp lvls for safe Flat Tappt cam/lifter operation and no friction mods that can poss cause clutch issues in some cases too.
BTW,sheel rotella 5w-40 syn or there convetional 15-40 doesnt have the proper zddp lvl for best protecting the flat tappet cam/lifters in a R* motor and have friction mods too not good for wet clutches either leading to clutch slippage in some cases but not all.
I am beginning to wonder/if not believe that's why we are seeing more issues with lifters going bad & or vlves neeing adj and still being noisey post adj in the R* over past few yrs when people are running pass car/truck poils without enough zddp in them to properly protect the lifters/cam/valetrain in general from premature wear.
The whole concept behind a hyd lifter valvetrain is not valve adj over srv'c life of the motor or at least maybe only 1x valve adj and people are having a lot more issues with noisey valvetrain or bad/worn out lifters .
BTW,The few times i bothered to ask questions when i saw bas lifters here in RSC they were running oils with low zddp lvl's that can significantly reduce FT cam/lifter srv'c life.
That issue had been happening to the ft cam'd motors in classic cars too over past 4-5 yrs untill people got on board with the low zddp issues in most pass car/truck oils sold over the counter today.
That was due to extended cat converter warrantee's mandated by Fed Gov/EPA and the higher zddp lvls in older gen oils could over time/miles foul/clog cat's at approx 90k-100k miles and Fed's wanted cats to be warrantee'd past 100k miles . So car mfg's requested oil mfg's reduce zddp lvls so tey could extend warrentee wituout having to spend $ replacing cats if clogged by zddp . They felt it was ok because most motors mfg'd today have overhead cams with lighter spring rates and or roller cams in v8's not having scuffing issues flat tappet setup can that arent installed in todays motors anymore that have issues with oil that had low of zddp lvls.
But they dotn care about the millions of classic cars/trucks/motors/motorcycles left in the word today still running flat tappet cams/lifters,the oil mgf's never told the gemeral bublic thaey had reduced the zddp lvls in the oil ther were selling us which has led to many a trashed v8 musclecar motor when 4-5 lobes/lifters wear out seining a ton of metal particles into the motors oil system .
When that happens the metal contam trashes the crank/all bearings/scratches cyl's etc and the oils mfg's felt they didn't need to tell the genral public buying thier oil that BTW,donjt run it in FT cam'd motors esp hi perf motors running higher valve spring rates for hiperf ft cams.
Scott
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