MOTOR car modifications. It doesn’t matter what it is, unless the whole deal is really thought through in terms of how the mod will affect everything might suddenly have a disaster. Happened to a bloke with a tasty Mark 2 compact manual Jaguar that was really well looked after and not many kays. But he had never been happy with the heavyweight steering, so he finally decided to install a power steering rackand-pinion. There’s not much room around Mark 2 Jag twin-cam engines, particularly down the left front where the Lucas contact-point distributor lives. But the bloke found a steering set-up that would fit in that cramped engine bay, along with a compatible belt-driven hydraulic pump, so he got out the tools and an angle grinder. Took heaps of hours to get this new set-up just right, and finished it off with a string-and-wheelstand tyre alignment. He knew his stuff to do this, and after testing it out on the tar he was smiling.
All was going real smooth with this bloke’s Jag for a few months, until that day came when the long-stroke, 3.4-litre six suddenly missed and stopped. This attracted a small crowd of Jag club rally people, who looked into the dark depths until somebody noticed, when the starter motor was working, that the distributor was wobbling about. A hand down there soon confirmed that the thin alloy housing was broken.
Somebody came up with a spare distributor; after all, if you drive around the country in an old English Jaguar, it pays to carry lots of spare pieces. Should have only been a matter of undoing two bolts and a wire, lifting the old dizzy out and resetting the ignition timing. Not so fast now – remember that power steering rack conversion? Didn’t matter how hard they pulled and twisted the now-unbolted dizzy, the damn new rack had been installed too close, and there was no way the finest from Lucas was going to pull up past it. Tow truck time.
It was the new rack that had broken the distributor. With no clearance between its housing and the rack body, every time the engine jumped forward on the rubber mountings when the clutch was dropped, it shoved hard against this spark generator, until it finally broke. So the bloke had to get out the tools and angle grinder again, to relocate the rack to where it should have been with a bit more forward thought!
Talking of Jaguars, I know an independent young guy called Neil, who inherited an slinky XJ6 from his father. Most of this cat was okay, including the beautiful dash panel, but the engine was really, really tired. So Neil managed to lift the double-cam alloy head to see piston-ring ridges in the six-cylinder bores, and big mobs of corrosion that had savaged the cooling system passages. Turns out Dad hadn’t believed in filling the radiator with expensive Tectaloy, and reckoned rain water was the way to go.
So it was crunch time. Neil did research and added up different amounts of dollars, discovering that a Chevy 327 transplant would be much cheaper than fixing the Jag six. And he knew a mate who had one in a dead Bel Air. Got that, ripped it apart for reconditioning, plus a few go-faster tweaks like pop-top pistons and a mild hydraulic cam. With these pieces back inside his shed, the block was carefully assembled and two big-valve heads dropped on.
With all that done, a conversion kit bought and with a new coat of paint, Neil slotted the 327 and ’box into the wide-open engine bay. Fired this classic eight into life and it sounded a little odd, but he figured that was just the cam and his new twin-pipe exhaust system, combining with the big-hole Holley.
He had a few short test drives early, not using more than 3500rpm to break in the new stuff. But when he ventured out on the freeway and lifted the engine to just under 5000rpm to see how it went, there was a noise from the engine bay and major misfiring. Bugger! He managed to limp home and found three cylinders had gone out to lunch, and his compression gauge said: “Son, you had better lift those heads off.” Did that, and found three bent inlet valves. He didn’t know why, but figured the piston pop-tops were too high.
So Neil extracted the Chevy and had 60thou machined off those new lumpy pistons, and he was even more assembly-careful this time around. But out on the road the mongrel thing did the same trick gain. More bent valves and marks into the pistons.
Then he thought about me. He arrived after lunch with samples, and asked if I knew why his engine was doing this.
“Well,” I said, “my crystal ball isn’t working yet, so let’s go look at your engine.”
This was out on the floor with the sump off, and I asked if he had set up the cam timing with a degree wheel.
“No,” he said, “I just went by the marks.”
“Okay, can you take off the timing cover, so I can check?”
And there it was. Wrong cam timing. Chevys have two silver links added to their cam drive chain, which must line up with the single scribe marks on both sprockets. What Neil had done was to run a straight line through the centres of this. crank Which and cam stuffed and up line the up cam the scribe timing! marks s with this. Which stuffed up the cam timing!