TR6 Engine Repair

By 1975 Triumph had lowered compression to meet emissions standards to a lowly 7.5:1. Horsepower had been reduced to 101 HP. In the early winter of 2000 the head was shaved to increase the compression ratio to 9.5:1. At 9.5:1 we should still be able to burn pump gas and realize a marked improvement in performance. Shorter push rods may be required as the valve cover will touch the rockers when really tightened down. This really needs to be checked out carefully before the car is put on the road again. An aluminum valve cover is in order anyway. The cast valve cover was ordered nearly five months ago and is still on back order (as of 11-30-01)!

Update: It arrived in January of 2002. Very nice.

Update: May 5, 2002. The new cover is installed and looks great but there was a small glitch. The tube for the oil filler stuck down inside and touched a couple of rocker adjusting screws (caused by planing the head to raise compression). Quite noisy until the tube was trimmed back a bit.

At the same time compression was increased, the ignition sytem was upgraded by removing the points and installing a Crane XR3000 photo cell conversion. The stock Lucas coil was upgraded to Crane’s high energy coil (looks like a GM High Energy Ignition coil). The wires are custom from NAPA Belden, 8mm with silicon boots.

The mechanical fan, including shaft extension, was removed and a 14″ electric unit (Flex-a-lite Trimline fan from NAPA, #827-8016) installed behind the radiator. A new balancer washer (pictured) from my friend Ken was a perfect replacement for the shaft extension. Ken’s kit included the new machined spacer washer, the proper short bolt, and a lock washer. (Update 2004 – Ken will no longer be supplying these spacer kits so I will offer them.) For more info see: Spacer. Soon an adjustable fan control will be added.

Since those changes, the car has had little running time and virtually no road miles. The body work must be completed first. Unlike body work, I look forward to engine work.

Future engine mods include an S2 camshaft, possibly headers and overdrive, and quite likely conversion to electronic fuel injection. Yes, I like complicated high performance stuff like that. In the dead of winter I started construction if a fuel injection manifold. The manifold is on hold until the car is once again roadworthy or winter temperatures force me to store it. I’ll post a picture of the manifold soon. I think 150 HP is easily doable from this engine.