1978 Pontiac Bonneville 350 engine lifter

[57chevyragtop]

1978 Pontiac Bonny broughm, 18K Surviver car all original, always garaged.
Here's the deal..This just started by the way....Been a coulple of months since driven (summer..60+ miles highway) no issues at that time. Took it out a couple of weeks ago 30-degrees day warmed it a little then hit the road... once it got up to temp and hit 55-60 started getting lifter or rocker clicking, One only I think from the sound, brought it home and once got slowed for a time the clicking stopped. Parked it. Took it out next day, drove it around some in town no problems and did that for three four times. Tried getting it up to speed of 50-60 clicking starts again then again stops when it has slowed for a bit. no noise whatever at idle...other stuff to know, oil has about 400 miles but 2-3 years since changed (at purchase). Gets driven very little every couple of months or less. I am thinking it's a weak valve spring or oil starvation at that specific rocker (ie. dirt in oil hole or run) Haven't taken valve cover off yet, it is the right side of engine (pass side). Any ideas on this from you guys....?

[MrPbody]

An engine with old oil in it will sludge-up quickly. Change the oil every 6 months, even if you haven't driven it much.

Your noise could be an oil pressure issue. Put a mechanical guage on it to verify what the pressure actually is. Oil "return" in sludgy engines is a real problem. Pressure should be over 20 lbs. at a hot idle, in gear. It should also get to at least 45 before 2,000 RPM.

A bad lifter, bad valve guide, spring or rocker/pushrod are some of the things that will make noise. Connecting rod bearings in stock Pontiacs will make more of a "tick" than a "knock" when they're wearing out, too.

Change the oil, check the pressure, and get back to us.

Jim

[57chevyragtop]

Thanks Jim for your reply, This car belongs to my long time best friend and I have been unable to convince (so far) him of the necessity of the oil change every 6 months...He insists that it only has 500 miles at most and it should not be dirty. I tell him OK this may be true but like gas goes bad so does the oil and the additives within. I'll try again on that front and thank you again for the input.

Dave~