Reply to "Cam and lifter problems"

Mark,

Over the last half decade lifter / cam lobe failures have become far more common than they ever had been in the past. It was first suspected that quality control of parts coming from China was at least partially responsible for the troubles you and thousands of others have experienced.

However, the finger is now firmly pointed at modern oils designed for gasoline engines, because they are lacking in an additive that had been used in oil for 5 decades. "ZDDP" (zinc dialkyl-dithiophophate). ZDDP is a friction modifier used in motor oils and transmission oil. It coats the cam lobes to prevent the type of failure you are experiencing.

The phosphorus in ZDDP deposits a tenacious coating on the catalyst in catalytic converters, preventing contact between the catalyst and the exhaust gases, and leading to a gradual decrese in the effectiveness of a vehicles emissions system. So the automotive industry has been slowly specifying less and less ZDDP in the motor oil formulations for gasoline engines over the last 20 years. SG spec motor oil only had 0.15% ZDDP, SL spec motor oil had decreased that to 0.05%. The most curent motor oil spec is SM, I have yet to read how much ZDDP is specified in SM rated motor oil. But it seems to me, that the next step after 0.05% is probably none at all!

If you thought Ford & GM switched to roller cams in their OHV engines in the late 1980s to increase performance, think again. The move was made to allow lower levels of ZDDP in the motor oil without camshaft failure.

You have four choices to cope with the lack of ZDDP in motor oil:

(1) Switch to a roller camshaft
(2) Use an oil additive containing ZDDP
(3) Use an oil designed for diesel engines
(4) Use "racing" oil

Additives allegedly containing ZDDP include GM EOS, Bardahl 1 and Valvoline Synpower.

I see more and more enthusiasts switching to diesel engine lubricants. I've been recommending Castrol motor oil with additive, but the truth is I've never thought too highly of the quality or usefulness of "oil additives". I've been familiarizing myself with diesel engine lubricants and I am comfortable enough with them now that I will be recommending them in the future. Diesel engine oils include Rotella, Delvac and Delo. My favorite, Castrol, also sells Diesel oil. If you can, use a single grade oil as opposed to a mulit-viscosity oil. Finally, racing oils are "supposed" to contain as much ZDDP as was used in the good old (pre 1985) days. Probably the first racing oil that comes into everyone's mind is Valvoline.

Sorry to read of your misfortune.

Your friend on the DTBB