Vintage Jag Works' logo

E-Type Engine Enhancements

Stock 5.3 litre engine.

This 1973 E-Type ran okay when it came in but had some oil leaks and the oil pressure was a little too low. The car only had about 70,000 miles on it so we decided to freshen the motor and add some performance at the same time.

Our goal was to end up with about 10.5:1 compression because the car is from Salt Lake City and some compensation must be made for the altitude of 4,000-plus feet. Pulling out the calculators, we figured that increasing the stroke 3/10 of an inch and increasing the bore 1/8 inch would increase the cubic inches to about 375. This required a new set of pistons and connecting rods. A set of special rod bearings, rings and some big bore head gaskets completed the modified parts necessary to install the crankshaft, special rods, pistons and cylinder liners.

Stock pump showing excessive clearance.
Stock pistons and liners

In addressing the low oil pressure issue, we found that the original oil pump was too worn out to save. We located a good used 6.0 liter oil pump and cleaned and checked it. It had no appreciable wear so we bolted it in the engine.

The cylinder heads were in good shape so all we really had to do was go through and swage all the valve seats with a blunt punch just to help keep them from falling out like they sometimes do. The guides were still within tolerance. We replaced the springs, seals, valves and installed a pair of Isky XM-2 re-ground cams. The ports only needed a little careful clean-up.

Assembling with high-volume 6.0 litre pump.
Ready to install stroker crank and pistons

There are a few areas that always receive special attention when we assemble an engine. We polish the crankshaft journals by hand to a mirror-like surface. We have the rod bearings race coated with moly disulfide. We take great care to get the correct fit on the rod to journal and the rod to crank check clearances. Because we run 20W50 Valvoline Racing Oil, the clearances are not tight but rather "just right."

Slightly modified head.
Oversize pistons and liners.

We decided to help the breathing with a set of HIF S.U. carburetors offered by Burlen in the U.K. We purchased a set of the carbs and their associated mounting kit but it was by no means a trouble-free install to get them adjusted and working together. Eventually we discovered a broken bottom casting and bent main jet tube. The manufacturer was less than helpful when queried by e-mail and we had to buy our own repair parts. The end result was good but it was a rough road getting there.

Engine bored and stroked to 373 cubic inches.

The ignition was also modified with a 700-series Crane kit. We have installed many of these over the years and find that they prove much more reliable than the ancient OPUS. With rebuild suspension all the way around and the upgrades to the engine, the car is really dynamite to drive. It is noticeably quicker than a standard Series 3 E-Type.