& Porter Traction Engine Mods - Part 2
Part of an article in the Maxitrak News of September
1995 - By Phil Scarborough.
Andy Probyn should be able to tell you when I bought
my engine, it must have been about 6 years ago and one day it may be finished,
but I keep seeing ways in which I can alter, improve or just change it.
So far, starting at the front axle, modifications have been as
- Centre pivot re-drilled and spacer fitted, engine sits 18mm higher
at the front. This helps water level over firebox crown and the engine sits
more "head-up", like the full size ones.
- Front wheels are now retained more positively and the brass hubcaps
are purely decorative. This was done by making new stub axles with larger
outer ends and hollowing out the hub caps.
- Large prancing horse ground off and a new, smaller one made by
casting in brass and fitting.
- Exhaust steam blast pipe cut in two where it passes through the
smoke box. This makes it easier to fit and remove as experiments continue
with blast nozzle dimensions.
- New regulator made to more adequately cover steam port to cylinder.
- New rear cylinder cover to give stronger construction where it
joins the trunk guide.
- New little end pins split-pinned in place to stop it unscrewing.
- Crankshaft main bearings clamped down with heavier bolts and
prevented from moving fore & aft by brackets either side.
- New gear change to move levers to right, over the gear guard to
simulate the real thing.
- New O/S bracket for steering chain roller, copy of the real thing.
- Steering roller fitted with needle roller bearings to improve
- Steering box created to keep worm & wheel firmly in mesh.
- New steering chain with smaller links of heavier build, a copy of
the real thing.
- Bigger balance pipe between belly tank & tender so that water
transfers more quickly.
- The second shaft is very close to the boiler back-head, so new
gauge glass fittings were made to extend the glass in front of the shaft.
This makes it much easier to keep an eye on the water level.
- Heavier gauge ash-pan made with modified mounting arrangement -
makes it easier to drop the ashes.
- New stainless steel firebars with adjustable spacing. This was done
during experiments to improve steaming.
- Differential fitted to L/H rear wheel, modified from Leyland mini diff.
- Longer back axle. Rear wheels now retained by collars and pins as
per full scale. Hubs & caps now decorative, having been hollowed out
to cover axle & fittings.
- Brake screw fitting altered to copy full scale more authentically.
- New top bracket to support steering wheel, similar to full size and
a bearing half way down the steering shaft to reduce whip.
- New brass whistle on cylinder top, thus giving modified mounting
for steam valve to blower pipe. This can now be reached easily when
- Steel shaft fitted through perch bracket into front axle yoke to
strengthen the castings, which gave way on some very rough ground.
addition, many dummy rivets have been fitted an many
casting marks ground away in the interests of cosmetic appearance.
conclusion, may I thank Maxitrak for unfailing courtesy and advice on the
occasions when I needed it.
By Phil Scarborough