Oct 162015

Default 4.2 ignition mapping

The EDIS Megajolt electronic ignition kit for the 4.2 engine was supplied with an ignition mapping that closely replicated the advance curves of the original Lucas 22D6 distributor.

The aim is to produce a mapping tailored to my actual engine by taking it to a professional outfit with a rolling road. Although I’ve been told it’s not for the faint-hearted. The engine is taken through its paces with sustained running all the way up to the red line!!

For now, I’ve followed a suggestion from the E-Type forum to load different mappings into the Megajolt controller to compare. A number of owners have produced maps for their engines and uploaded them to the forum for others to try. As the controller can store two different maps at any time, a discreet switch has been mounted in the glovebox to enable switching between two maps.

Checked into the Jaguar specialist
for further investigation

Although the final tuning and mapping is some way off as neither the garage that did the MOT nor Powerbell, a local independent Jaguar specialist, had been able to tune the carburettors to get the engine running smoothly. The latter suspected there might be either sticking valves or valve clearance issues which would require further investigation.

The engine had sat without being run for quite a long time since being reconditioned by VSE, which is far from ideal. The plan was to run the car for a while to see if the layup had resulted in a slightly sticking valve which might clear with use …. ever the optimist! Alas it didn’t! So the car was returned to Powerbell to get to the bottom of the rough running.

The first task was to perform a compression test and measure the valve clearances. The manual indicates that the expected compression pressures are 150psi for 8 to 1 compression ratio and 180psi for 9 to 1. The test showed mine were way off and in some cases almost non-existent:

Cylinder: 1 2 3 4 5 6
Pressure: 125 130 125 120 65! 10!!

The thicknesses of the valve adjusting pads under the tappets were miles out so everything was far too tight. The guys at Powerbell were shocked that they could be so far out in a newly reconditioned engine. Had I not decided to get it resolved now, they said the likelihood would have been burnt valves and a much bigger problem to resolve.

The compression test revealed very
low pressure in cylinders 5 & 6
Calculating the correct thickness
for the valve adjusting pads

I was relieved but at the same time not impressed with VSE who had rebuilt it. Unfortunately it’s way past the standard one year warranty they offer but I’ll not be using them again. It really shouldn’t be necessary to correct a simple measuring job that could have had expensive repercussions.

Removal of the camshafts to correct the valve clearances … on a newly reconditioned engine!

It was with some anticipation that I headed off to pick up the car when the call came to say it was ready. I really didn’t know what to expect but it had been transformed! It was now able to idle at the intended 700rpm, the rockiness had gone and it was running so smoothly.

They did recommend putting on another 1000-1500 miles on the clock, so the engine is properly run in, before mapping the ignition on rolling road.

 Posted by at 8:45 pm
Aug 312012

When I first contacted Hutsons, I was warned that they estimated it would be 10 months + before I would get the completed, painted body shell back, such was their current work load. So my aim was to get all the other components completed for its anticipated return in May 2011.

I tend to be rather optimistic (read extremely optimistic!) in the time it will take me to completed things. Even so I knew I wouldn’t be able to tackle everything in that time. The plan was to get the engine and gearbox reconditioned by reputable companies. In the meantime, this would give me the space and time to renovate and restore the other components.

I chose VSE to recondition the engine, based both on recommendations from others and price. I wanted to see their operation first, mainly out of interest, and to discuss the rebuild in person. So I headed off to see them in mid-Wales. It the last place you’d expect to find an engine reconditioning firm – it really was in the middle of nowhere in converted farm buildings with sheep for neighbours!

VSE offer a number of performance levels for their rebuilds and those that had recommended them suggested to go for maximum torque rather than headline BHP, which made good sense.

I think it’s all too easy to go over the top seeking greater performance with loony cams and excessively lightened clutch plates at the expense of drivability. So I opted for mildly tweaked performance which is in between their VS1 and VS2 levels, a 123 Electronic Ignition distributor and adapted to accept a modern oil filter.

The first thing to do was to build a suitably sturdy trolley which was low to the ground to avoid the problems encountered during the engine removal. The trolley base was made from two sheets of 22mm wooden boarding with castors that could be bolted directly to the base.

Even this wasn’t strong enough partly because I had used a coarse resin chipboard. Additional sections of wood were attached to the underside to stop it bowing in the middle.

It was far easier to get the engine delivered rather than trek out to mid-Wales again. In due course the engine arrived wrapped in cellophane, strapped to a pallet.

Unfortunately the body shell hadn’t even been started at this point which was annoying. My regret is that, if I’d have know how long it eventually took I’d probably have taken on the rebuild of the engine myself, farming out the machining tasks.

Below are a few more photos of the reconditioned engine, more for interest than anything specific to mention …..

Aug 312012

The two tried and tested methods for the engine removal are either lifting it out from above or lowering it onto a trolley and then lifting the body sufficiently until the engine is clear of the sub frames. Although I’ve heard of people, doing full restorations, who have lowered the engine onto a trolley and then removed the surrounding engine sub frames.

The difficulty with the removal from above is that the engine and gearbox come out together as a single unit and this requires it to be tilted at the same time as it is being lifted clear. I didn’t have a controllable method of tilting and wasn’t too keen on having such a weighty item dangling at such a height.

All the ancillaries had been removed and the lifting frame ready to drop the engine. The off-side front suspension still refused to come off!I was also doubtful that my home-made lifting frame, scaffolding cut to make a cross beam supported by A-frames, could raise the engine/gearbox unit to a sufficient height to clear the sub frames. So my only real option was to drop the engine.

The bottom out approach is documented in the Haynes manual and required the removal of all the engine ancillaries, the exhaust and inlet manifolds, alternator, oil filter etc. Once these had been removed I was then ready to lower the engine. Gulp! So far, so good.

At this point I must have taken leave of my senses when making some key decisions and the removal process descended into more of a farce!

I had some 1″ square Dexion speedframe lying around which included a set of castor wheels so I set about making a makeshift trolley. I’d lower the engine and gearbox on to the trolley, lift the car and then pull clear.

The first issues were the length of the 3-pronged corner connectors and that a length of 1″ square would be required between the connector and the castors. This resulted in a considerably higher platform that I’d originally envisaged.

The knock on effect was that, not only would I have to raise the front of the car even further, I would have to raise the rear of the car to reduce the body angle when the front was raised. This would allow the engine & gearbox to be dropped without hitting the sub frames. At this stage I should have reconsidered my approach to how I was dropping the engine.

The car was already supported on axle stands so once the ancillaries had been removed, the hoist could be used to lower the engine onto the waiting trolley. The castors were already showing signs of giving way, as can be seen in the photo above! I really should have reconsidered whether it was wise to continue. However, again, I ploughed on. Dooh!

The ridiculous height of the makeshift trolley caused no end of trouble! Not only that but it shows the first signs of the castors giving way under the weightThe front and rear were then raised alternately, supported by axle stands on building blocks. The rear was just about within the range of my trolley jacks but the front needed to be lifted via the lifting frame.

Once the front sub-frame was clear of the engine, the lifting frame was used to take the full weight of the front of the bodyshell. The supporting blocks were then removed to provide an exit route for my wobbly trolley. The trolley castors didn’t approve of being moved and their jaunty angle worsened severely as the trolley was delicately pulled clear!

At this stage I would have been in all sorts of problems had the trolley collapsed “mid-extraction” as the only lifting gear I had was in used supporting the bodyshell!

I did have to realign the trolley legs several times, taking the weight by an extended crowbar. It was very close but fortunately the trolley lasted just long enough to pull the engine clear. It was then mounted on a proper engine stand.

On a positive note, the lesson learnt for the rebuild is to use a more substantial trolley which is as low to the ground as possible and to have a backout plan in case something does go wrong. Even with the self-induced problems, I still think dropping the engine is the way to go!