BAB PROJECT PHOTO JOURNAL
TRIUMPH ENGINE OVERHAUL
1970 Triumph TR6 Engine Overhaul commissioned by client on 12/10/05.
Received engine on 12/18/05 and promptly photographed every aspect of disassembly
as notes were taken of all significant wear tolerances.
Prioritized and recommended replacement of all gaskets, seals, main bearings, rod
bearing shells & bushings, pistons, pins & rings, valves & guides, primary chain &
tensioner, clutch plates & springs, alternator rotor, sludge trap, carb overhaul kit, lock &
tab washers, oil pump, patent plate and all missing hardware including head bolts and
Ordered all parts and supplies, sent engine covers out for polishing, and head,
crankshaft & cylinders to machine shop.
Head proved to be extensively damaged in one valve guide bore as well as one exhaust
port spigot thread. A replacement was taken from BAB spare stock and a complete valve
job was performed including replacement of the guides.
Cylinders were bored to .020 oversize and pistons & rings were optimally matched and
Crankshaft rod journals were undercut .010 and oversize bearings matched and fitted.
Sludge trap was completely fused in place with overheated sludge, resulting in eventual
removal in pieces. Sludge trap plug threads were reworked, and new trap was inserted
with plug loctited and peened in place.
Thoroughly cleaned and polished all internal parts, installed all bearings & seals,
reassembled engine, overhauled carburetor, and assembled a "test mule" from a BAB
spare stock 1973 Triumph rolling chassis project bike. Constructed a basic wiring
harness and athoroughly flushed out the oil-bearing frame, fittings, and sediment trap
On 2/03/06 installed engine in frame, kicked the starter to promote oil flow to top end,
then started on the 4th kick after tickling carbs. Performed extensive testing including
alternator output, oil pump main gallery pressure, top end lube pressure, and leak testing.
Leakage was noted from the upper pushrod tube seals, and smoking exhaust from
seepage into cylinders. Drilling of the pushrod tube seats on the replacement head was
required for the proper depth with the tubes to be used.
On 2/17/06 the head was replaced, the engine was again started and all areas tested
leak-free and smoking from exhaust was completely remedied.
A wooden support cradle was built for the engine which was then crated for return to
the customer. Total overhaul project time was 48 hours in 22 shop days, over 60
Born Again Bikes