Thanks for the information about the restricted pushrods. Interesting concept. Are these commonly used in non-raced engines? Anyone on this site using them, cause you just have to? I would think that under higher-than-idle rpms, whether racing or everyday driving, a leak down problem would not be a concern. At least on the Bonne, lifters are too easy to replace if they do wear excessively, but I don't know that this problem is common at all to Bonne'*. I'd say if you can hear the chatter with the doors closed and windows up and the sound lasts for more than 30 sec. then you might want to consider replacement lifters, or another alternative. From the noise the 3400'* and 3800'* make in this family, it is really quite unnoticeable on the few occasions it does occur. Don't know why the condition is soooo sporadic.
I've noticed that running 10w-40 year round seems to limit the number of cold starts on a hot day that my old Bonne exhibits this problem (notice I said hot day). I've never experienced chatter with a cold start on a cold day. Guess that'* because the oil thickness when cold tends to keep the oil in the lifters. Also, I've never experienced chatter after an oil and filter change. One thing I do know: a little sporadic lifter chatter on start up seems to have no long-lasting effect on the overall integrity of pontiac v6 engines. Just go ask about any Bonne or Grand Am owner on this site. These engines are freekin' tough. Bring on them so-called long-lasting Toyota and Beemer iron!!!!!!!!!!!!!!!
I believe I used the term "thinner" when referring to synthetic.
I run synthetic in my rediculously babied '95 C4 Vette and I swear by the stuff because I run her hard and change the oil only seasonally (after about 3,000 miles per year during spring and summer). I would not run it in my Bonne because I am not hard on that engine and standard oil works just fine. Maybe "thinner" is the wrong term but it definitely flows easier when cold and hot. And it seems to "stick" to surfaces and stays there after shutdown ensuring a nice lubed startup the next time. Also it is proven that synthetic oils will work past seals and gaskets where standard oil of the same viscosity will not. Of you petroleum experts out there
, "why does synthetic of the same viscosity under the same temperature conditions flow as if it has a "thinner" viscosity. Hmmmmm?