From:Gene Harper e-mail:gharperxman@gmail.com
Subject:RE: Doug's stuck exhaust valve and engine oil Date:Thu Apr 6 10:23:55 2023
Response to:7890
Perry Ruiter sent me an email with an interesting thought:
What about the gears and such in the transmission, as the oil
is shared in all compartments of the Henderson? In my simple
mind, I would think the clutch would release better with a
thinner oil, but I'm not sure about the gears, would they
need a heavier oil? As I told Perry, I'm a V twin guy, so I
don't think like a needy 4 cylinder.......

----- ORIGINAL MESSAGE FOLLOWS -----
OK here comes a bomb, which will probably start the endless
oil debate!

Doug, regarding your stuck valve: I would guess one of two
things happened.

1. The fit between guide and stem was simply too tight.
Running a bit lean (hot) could have easily stuck it.

2. Burning oil builds up carbon deposits on the stem and
sticks the valve open.

So, what clearance was used when fitting valve and stem?
Depending on guide material, I prefer fitting them about
.004-.0045". This is on twins, I've not built or run a 4 but
they should be similar I would think.

However, my experience (again with twins only) has shown that
burning oil is often the culprit. In addition, burning oil
causes carbon buildup in the cylinder, hence the need to
remove the cylinders (or heads) and de-carbon, every season,
as the owners manual suggests! What a pain!!! I have had
endless debates with George Yarocki and many others about
using, or not using oil control rings in total loss motors.
Granted, the Henderson is not a total loss system, but other
than that, it's basically the same, a hot running air cooled
engine. Georges argument was that "these engines are designed
to burn oil because that's the only way the top end gets
lubricated". I disagree, if burning oil was such a good
thing, then why do engine designers today go to such great
lengths to keep oil out of the combustion chamber?!!!
Because burning oil leaves carbon deposits on the pistons,
heads, valves and rings and eventually can break off and
cause severe damage as well as stick valves open due to
carbon build up on the stem. That's why I'm a firm believer
in installing oil control rings on these old bikes. THEN,
I've always added a bit of 2 stroke oil to the gas as bit of
a lube for the intake valve at least. I was told by a
chemist that Marvel Mystery oil when added to the gas will
drastically decrease octane and cause a very hot burn. I've
seen this damage first hand, so I would not recommend Marvel
oil in the gas.

OK, so what oil to use? My good friend Hans Coertse from So
Africa is an amazing engineer, restorer and vintage rider. He
has successfully competed in 3 Cannonball rides and 15 plus
So. African DJ runs and more, all on pre 1930 machines. I
saw a JD Harley that he pulled down after 10,000 miles. There
was absolutely no carbon on the pistons, AT ALL ! No
nicotine stains under the rings, no sign that the engine had
been run for more than just a few minutes! He said there was
a light dust on top of the piston which he simply blew off. I
was amazed and inquired about what oil he was running. His
answer shocked me! He runs Castrol full synthetic 2 stroke
oil, straight in the crankcase on all of his vintage bikes,
and has been doing this for many years! His thinking was that
if this stuff, diluted 50/1 with gasoline will work on a 2
stroke engine at 10,000 RPM, why will it not work on these
old tractor engines? Any full synthetic 2 stroke oil would
work, but he has always used Castrol. This oil is designed
to burn, and burn clean, which it does! It pours out like
water and has no viscosity rating at all, thus it's counter
intuitive to even think about using it, as we've all been
trained to think that these old machines need heavy oil
because they run so hot! Hans' theory on the old bikes is
this: Regardless of how well these things are built, and
even with oil control rings, they will burn some oil, a
little at least. So any oil that does get burned will burn
clean and leave no carbon deposits, and our recent experience
has proven that, again.

So, I was skeptical, but Hans and I just completed a 3500
mile cross country ride on our early 20's Excelsior's. More
info here if you want to read a lot of stuff about our ride:
https://forum.antiquemotorcycle.org/bboard/forum/general-
amca-forum/parking-lot-chatter/301197-the-lindbergh-ride-2022

We both used this oil, straight in the crankcase plus 1 oz /
gallon in the gasoline. Our engines were built almost
identically. We both used HD EL pistons with single piece
cast iron oil control rings. The only difference is I had
Nikasil bore linings in my cylinders and bronze guide liners
both intake and exhaust, where Hans was running the original
cast iron bores and guides. We had absolutely 0 engine
troubles. Plugs were checked every night and showed no signs
of carbon deposits, just a dull grey haze. Oil consumption
was amazingly low! I never saw any smoke from my exhaust, or
Hans' either. Our longest day was about 300 miles and I used
just over 1/2 quart of oil total, and most of that I dumped
out and recycled in the waste bucket. We drained the
crankcase at every gas stop and reset the level. I was
consistently removing about 2 oz of oil into the waste can.
Hans used a bit more oil than I did and I attribute that to
the Nikasil bore lining on my bike. The 3rd rider in our
group was using 50W Harley oil and used 1 quart or more per
day, but to be fair his mechanical pump was not working so he
was forced to rely solely on the hand pump and may have been
over oiling a bit. On occasion, his bike would puff some
smoke but that could have been due to some leaks as well.

When I returned home, I did a lot of clean up on the X and
fixed a transmission leak, new tire and chains and generally
went over everything. I put a lighted scope into both
cylinders for a peek. I was amazed, NO CARBON at all! Just a
dull gray haze on the piston dome, exhaust valve head and
plugs. No cylinder wall scoring at all, looked virtually new
in there! So, I'm sold on this stuff!

For comparison, my 24 Chief hauled my wife and I plus the
giant Princess sidecar on the 2018 Cannonball, running
original cast iron bores and late model Indian pistons with
oil control rings. We used conventional oil, Brad Penn 50 W.
Oil consumption was about 1 qt per 250 miles, but a peek
inside shows some carbon deposits forming on the piston,
cylinder head and valve heads.

I'm also of the belief that a thinner oil is good for these
old motors anyway. Plus a full synthetic 2 stroke oil is a
great thing, as it burns clean and is still very good
lubricant. I've experienced a huge difference when running a
40 W oil in my 39 HD sidecar rig. It has noticeably more
power and the oil seems to run cleaner. I don't see that the
engine runs any hotter either.

If I had a 4 cylinder running, I would give the full
synthetic a try, but that's me. I would think it would be
even better than in a twin, as there is a gallon of the stuff
sloshing around in there as opposed to only a few ounces in a
total loss twin.

Anyone care to give it a try? I'm ready to hear your
replies.......

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