:doh: I was wondering if changing to synthetic oil was a good idea for my 81...When I changed over to synthetic it had 39k. Ever since then I have a slight ticking from the lifter on the (#8)cylider closest to the passenger. Would it be wise to put in a zinc additive or to tighten the rocker arm ?

NEW C3 Guy

:doh: I was wondering if changing to synthetic oil was a good idea for my 81...When I changed over to synthetic it had 39k. Ever since then I have a slight ticking from the lifter on the (#8)cylider closest to the passenger. Would it be wise to put in a zinc additive or to tighten the rocker arm ?

NEW C3 Guy

what viscosity did you use? synthetics don t need additives and zinc will affect your sensor. just pull cover and w/motor idling, tighten down til it quiets then 1/4 to 1/2 turn more

You haven't hurt a thing by changing over to a synthetic oil, but don't add any additional additives. Because the synthetic oil already has all the additives you need. To adjust the valve lash, bring the piston up to the top of it's stroke, then tighten the rocker arm nut JUST ENOUGH to make the pushrod snug (the rocker arm won't wiggle). Then tighten the rocker arm nut an additional 3/4 to 1 turn.

switching to a synthecic is NOT advised: you have a flat tappet cam. all new oils do not have enough zinc and other chemicals in them that prevent shear wear. All oil that has the API donut on the label is bad for flat tappet cam engines, they are designed for roller engines, like ALL new engines. You should go to the hot rod shop and get brad penn 10-30 or joe gibbs or royal purple, its oil designed for race engines, but its purfect for your engine. New oil has kept me very busy for the last few years, I build engines and see a ton of good looking engines with worn cams. Do not just put aditives in standard oil either. The new oil has detergents like tranny fluid that works on a molecular leval to make zinc and sulfur a larger molocule so it gets trapped in the filter. So in 100 miles all that additive is in your filter.most synthetic oil will break loose any crud and send it through your engines bearings and causes lifters to "tick" with crud stuck in new places that it wasnt before. hopefuly this has been of some help.

switching to a synthecic is NOT advised: you have a flat tappet cam. all new oils do not have enough zinc and other chemicals in them that prevent shear wear. All oil that has the API donut on the label is bad for flat tappet cam engines, they are designed for roller engines, like ALL new engines. You should go to the hot rod shop and get brad penn 10-30 or joe gibbs or royal purple, its oil designed for race engines, but its purfect for your engine. New oil has kept me very busy for the last few years, I build engines and see a ton of good looking engines with worn cams. Do not just put aditives in standard oil either. The new oil has detergents like tranny fluid that works on a molecular leval to make zinc and sulfur a larger molocule so it gets trapped in the filter. So in 100 miles all that additive is in your filter.most synthetic oil will break loose any crud and send it through your engines bearings and causes lifters to "tick" with crud stuck in new places that it wasnt before. hopefuly this has been of some help.
i disagree, i ve had 3 engines . go 250.000 plus miles each on only Mobil One synthetic without a single mech failure and all had flat tappet cams i let engine break in for 3.000 miles and then used synthetic and maybe you don t know this but GM puts Mobil One in every vette out the door, has for many years but why don t you call them and tell them its bad for motors

:doh: I was wondering if changing to synthetic oil was a good idea for my 81...When I changed over to synthetic it had 39k. Ever since then I have a slight ticking from the lifter on the (#8)cylider closest to the passenger. Would it be wise to put in a zinc additive or to tighten the rocker arm ?

NEW C3 Guy


The zinc additive they used to put in motor oil was there to combat friction (zinc is a soft metal) between the flat tappet camshaft and lifters. Now that most engines use roller cams, they discontinued putting the zinc in. If you have a slight ticking coming from one lifter only, the lifter may have a leaking check valve in it. Or you might be hearing a ticking coming from one of the rocker arms/guide plate/pushrod.