Randall: Thanks for taking the time to explain the lube proces for the
rocker shaft. What you say here is proably not common khowledge among
TRactor owners. I'll find another use for that braided feed tube.
Bob Roberts
----- Original Message -----
From: "Randall" <tr3driver@comcast.net>
Cc: <triumphs@autox.team.net>
Sent: Sunday, November 28, 2004 1:06 PM
Subject: RE: Puff of smoke when upshifting...
>> Randall: You remark about the external oil feed to the valves, when I
>> rebuilt my TR4 engine, I found that the rocker shaft had grooves
>> where the
>> rocker bearings rotated from a total lack of oil over a period of time. I
>> installed an external feed to correct this. I haven't truly run
>> the engine
>> except for running in place (tub not installed yet), There is not
>> evidence
>> of exhaust smoke at this time. Also had the block dipped and decked.
>
> Bob, this is my opinion, which obviously not everyone agrees with.
>
> Unless the area was actually rusty, most likely the excess wear was due to
> dirty oil (or simply old age). Unlike the rod and main bearings, the
> rocker
> bearings do not require a constant flow of oil under pressure for normal
> operation. They really only require a drop or two on occasion, which the
> original oiling system was quite capable of delivering.
>
> It's really not fair to expect the rocker bearings to last forever, and
> yet
> some people do seem to expect that. Such a simple thing to do, and yet
> it's
> frequently overlooked during an engine rebuild. Just like the crankshaft
> and it's bearings, the rocker shaft & bearings do wear and need to be
> replaced occasionally. I believe that will happen no matter how much oil
> is
> forced through it.
>
> Also, since there are no seals on the intake valves, there is obviously
> some
> air movement through the space between the valve stem and guide during
> periods of high intake manifold vacuum. If only oil is found at the top
> of
> the guide, then it will suck oil rather than air. Again, a drop or two of
> oil on occasion is beneficial (lubricates the valve guide) but a constant
> flow results in excess oil burning.
>
> Oil has an extremely low octane rating, so any oil that finds it's way
> into
> the combustion chambers can induce knock. I ran an external oil feed for
> awhile, which it turns out was causing knock during cruise conditions
> (when
> I couldn't hear it), which eventually broke a piston. Not wanting others
> to
> share my experience, I now recommend against the external oil feed (as do
> many others that have tried it).
>
> The original design is somewhat prone to getting clogged with sludge,
> particularly if a poor grade of oil is used, or the oil is not changed
> often
> enough. As part of my yearly lubrication routine, I now check that oil
> flows the length of the rocker arm with the engine running. If it doesn't
> within several minutes of starting the engine and letting it idle, then I
> remove the rocker shaft and clean it. I've never actually seen the
> problem
> on my engines, probably due to the oil I use, but I have seen it on almost
> every engine I've bought, or seen others buy.
>
> From personal observation, Quaker State, Pennzoil, and STP are all very
> apt
> to form sludge. I no longer use those products in my engines.
>
> Randall
|