my 1997 Chevy Pickup with 350 cid and 110,000 miles taps/ knocks when cold(
goes away after a minute or two) and when under hard acceleration. A dose
of valvemedic helped the situation for a week or so and then returned.
The engine does not burn a drop of oil and still runs like the day I
bought it new. Oil pressure is not a problem cold or hot, running >40PSI
all the time. Is this a valve/lifter problem or some other sign of
Thanks for your help
My 97 does the same thing, it started around 105000 miles and it has 145000
now, I changed all the bearings and timing chain and it didn't help at all,
a mechanic told me it was piston skirt slap and said it won't hurt anything,
so I just keep driving it.
"Reck" < email@example.com> wrote in message
A friend of mine just had a similar problem. It was the Cam. Had to be
: my 1997 Chevy Pickup with 350 cid and 110,000 miles taps/ knocks when
: goes away after a minute or two) and when under hard acceleration. A
: of valvemedic helped the situation for a week or so and then returned.
: The engine does not burn a drop of oil and still runs like the day I
: bought it new. Oil pressure is not a problem cold or hot, running
: all the time. Is this a valve/lifter problem or some other sign of
: catastrophic failure?
: Thanks for your help
HOLY COW... lets see..
Drain & remove oil pan, drain radiator & remove. Remove Valve covers &
loosen rocker arms, remove pushrods.
Remove water pump & timing chain cover. Take three bolts out of the cam
sprocket, and remove
timing chain. Three long bolts as a handle, remove cam.... 4X4 is MUCH
harder. To get the pan off you would
A.) hoist the motor about 2 to three inches off the motor mounts. or
B.) drop the front diff out of the way.
Should only take about a hour to remove the cam otherwise. 2 hours to have
it running again.
Tell your friend to dial 1-800-different-shop.com next time.
For sure set the valve lash. Back 30 yrs ago you set the valves almost as
often as you changed oil and gapped your points. Modern cam/lifter design
and metalurgy along with roller cam's makes valve adjustment needs almost
nil but it still is part of proper maint. As for the post about 3K for a cam
replacement, I'm in the wrong buisness. I'm thinking (a guess) parts should
stay under 650 easily and that is with OEM parts. That leaves2350 in labor.
30 Hrs to do a cam change!
With wear things losen up. I have seen high rail style heads with the
rocker arm retainers so lose, the engine will not start.
Valve lash settings are proper maintaince. Not the 3K mark like older
engines, more like the 80k to 100K mark.
Heck some people think they shouldn't change the spark plugs till the
engine barely runs if the vehicle is fuel injected.
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