Re: IH 304 Valve Noise

[jlandry@domain.elided (John A. Landry)]

The aliens commander decided "Chuck Welles" <cfw3@domain.elided> would make a
perfect specimen for dissection, and he yelled...

>Help!!!

Chuck,

First a couple of dumb questions...

Are you positive you have good oil pressure?  I mean through the use of a
mechanical pressure gauge connected to one of the oil ports on the block?
Of course *really* low oil pressure will cause lifter noise.

Are you sure the oil is at the right level?  Did you have any problems with
or swap the dip stick?  I had to ask.

If you're sure the oil level is correct, have you tried adding a quart just
to see what happens (running 7 quarts of oil instead of the regular 6).

Some thoughts on the oil idea...

If you don't have enough oil in the rear of the pan, air can get sucked in
and the air bubbles will cause problems in the lifters.  There are several
reasons why the oil in the rear of the pan can get low.  The obvious is too
low a static level in the first place.  The most common reason is using the
wrong dipstick or a broken dipstick.  Another reason for low oil in the pan
is partial clogging of the oil drain-back passageways from under the valve
covers through the heads to the lifter valley area.

Low oil delivery to the lifter galleries will cause clattering.  This can
happen because of clogged oil passageways or possibly because of camshaft
bearing shifting.  Probably very rare.

Assuming it's not something related to the oil (I think it is), then even
tiny amounts of dirt getting in the lifters will ruin them.  Internally
they rely on absolute cleanliness to hold the oil in order to lift the
valve.  A little shirt duration clatter at startup (of a couple of lifters)
in normal because of lifter leakage during extended shutdown.  But if they
all clatter, then something is definitely wrong.  One or two lifters
clattering all the time would indicate simple failure or contamination of
just those lifters.  If all the lifters clatter, then it would indicate oil
starvation or aeration of an entire group of lifters.

Personally I don't think shaving the rocker supports is a very good idea,
nor will it solve anything.  With old lifters it could actually cause more
problems and with new lifters it's not needed.  I doubt you need to spend
money on push rods either.  If I were you, I'd take the time to measure the
rise of the cam lobes just to make sure they aren't completely worn out.  I
doubt they are, but it can't hurt to measure with a dial indicator.  

Second, as long as any particular pushrod isn't loose when a valve is fully
closed (lifter on base circle of cam), then it shouldn't clatter if the
lifter is working properly.  You will be able to turn the pushrod with your
fingers when a valve is closed... that's normal, but there's no up and down
movement.

Try some more experimentation with the oil level and maybe even the grade
(try thicker higher viscosity oil) and see what happens before you commit
to more drastic measures.

Keep us posted,

John L.
-------------------------------------------------------------------------- 
jlandry AT halcyon DOT com      | 
Conservative Libertarian        |  "The road to  tyranny, we must never
Life Member of the NRA          |   forget, begins with the destruction
WA Arms Collectors              |   of the truth."
Commercial Helicopter - Inst.   |                     William J. Clinton
http://www.halcyon.com/jlandry/ |    10-15-95, speech at the Univ. of CT