Jerry E. Howell Model Project Plans & Kits
Outpost Enterprises, LTD - 695 Godfrey Road - Hollansburg - Ohio 45332 - USA
(World Wide Supplier of Quality Model Project
Plans & Kits Since 1992)
"Howell V-Twin" Engine Revisions Page
November 1, 2007
Plan sets up to and including SN-225 - The Panasonic 6848 Hall
Sensors have been discontinued and are no longer available. The
only known available replacement Hall Sensors are smaller in size
and of a slightly different configuration and require a slightly
modified Hall Sensor Housing design. If you order ignition modules
or replacement Hall Sensors, ask for a free new Sheet #39 (Revision
"C") with your order.
Plan sets SN-226 and up - If you are ordering ignition modules
or Hall Sensors, you will automatically get the new Hall Sensors
and your plan set already contains the revised Sheet #39. (Revision
"C")
November 28, 2006
Beginning with plan set SN-201 all the following revisions
have been made.
Valve Tappet Bushings
Sheet #12, Valve Tappet Bushing, an improvement is to change
the .300" length dimension to .350".
On Sheet #17 as shown below, the bolt circle dimension of 2.475"
in Step 8 is not correct and should have been 2.525" instead.
The tangent dimension of 1.210" is correct. An easier way
to locate these tappet bushing set screw holes is shown on the
revised Sheet #17 below.
Cam Nose Radii
The Exhaust cam nose has (2) .032" radii, one on either side
of the nose. The drawing may look like just one radii to some.
Beginning with plan set
SN194 the cam nose radius was changed to .097" which was
incorrect. This error resulted from the twice size drawing........
I did a 10 times size cam profile CAD drawing for maximum nose
radii accuracy once and for all!
The correct cam lobe nose radii is: Intake = .020" and
Exhaust = .054".
5-40 Tap Drill
Pertaining to Sheet #42 Construction Notes at 15 to 17, last paragraph......
The tap chart I started out with nearly 50 years ago showed 3/32"
as the 5-40 tap drill. I have been using that all this time in
aluminum with no problems, but it really is tight. More recent
charts show a #38 (.101") drill. Even if the drill dosen't
drill oversize as most do, that only gives an actual 65% of thread.
You may want to consider using a #40 (.098") in aluminum.
September 18, 2006
Compression Ratio
You may increase the compression ratio by lengthening
the connecting rod (Sheet #23) from the 2.135" length to
a maximum length of 2.200". If the rods touch the bottom
skirt of the cylinder, make the 20 degree taper a little larger
in diameter and about .156" long instead of the .125"
length.
Valve Cams
The .045" dimension to the right of the cam lobes
should be .040" instead.
Cam Gear Cutters
The gears are 14-1/2 degree pressure angle. Gear cutters can be
purchased from KBC Tools (1-800-521-1740) or Travers Tool Co.
(1-800-221-0270). Specify that you DO NOT want Chinese
cutters. They are JUNK. The ones made in Poland are just fine......
2004
Assembly of crankcase vent check valve.
Insert the Check Valve Seat into the Vent Body. Insert the Check
Valve "Disk".
Insert the Check Valve Travel Limiter. The "Disk" should
have freedom to lift
approximately .025" to .035" off the seat when it is
stopped by the travel limiter.
On my engine I then inserted a .480" dia. 80
mesh brass screen disk followed by a
loose wad of clean coarse delrin lathe turnings as a trap to prevent
small droplets
of oil from getting into the air cleaners. The screen disk is
to prevent any of the
delrin turnings from interfering with the action of the valve
disk.
© Copyright 2003 - 2006 Jerry
E. Howell - All rights reserved