The 'E' Type Forum

Mark, yes it was put up as one of the possibilities. My thinking is that the Jag should remain fully analogue as I already have the ultimate digital machine covered off by my seriously over muscled, piezo injected, twin turbo'd integrated everything BMW with all the M Performance bits.

There's something elegantly raw about having to choke and coax the Jag into life by feel and instinct knowing that there isn't a single ECU or nanny around to help pretend that you are good at what you do. I'll try to keep it that way.

The Car is coming along nicely. It’s completely apart and the body is on the rotisserie for final cleanup. It’s been a fun research exercise so far..

Per discussion earlier in the thread, The California version of the 4.2 litre engine has 2 wimpy Stromberg carbs with reduced HP and torque. (As dubbed in jest above, apparently some call them “Strangle-bergs” - very apropos).

Based on advice here so far, I'll first restore the car to historical accuracy with the stroms and the complicated secondaries for whatever shows it might go to that matter in future, then do driver friendly reversible mods to make it friendly crossing the Rockies and thru the high altitude passes . My practical interest is in driving it, not trailing to any shows. The next caretaker can do that. After all, we are just the temporary custodians passing thru on the car's ever evolving history.

The carb consensus seems to be for SU's with smoother response at the low end and better mid-range coming on in a linear fashion. Based on that, I found a friendly shop in jolly old to build me a suitable 3 SU setup that was used for Europe and Canada. So, for the driving emphasis, the shiny SU's will get an electronic fuel pump without those annoying points, and Electronic Ignition. With the 3.07 diff it should do the job.

thx all for the input so far.

The bodywork is happening. Car is straight, as are all the panels. Work on the drivetrain is happening in parallel, no surprises. As discussed on another thread I started here, the Diff is indeed 46/13= 3.54 and is in the process of getting revised to 3.07 as the rear assembly gets disassembled for new coil overs, fresh paint and so on.

The UK "stuff" ordered is starting to arrive. This is my first experience in dealing directly with the British speciality shops from afar. Nothing but praise for the professionalism with the ones I've engaged to date. Thought I'd try the rubber and Rims order; a triple SU Kit to replace the Strombergs; and a new steering wheel and associated bits.

On this side of the world, here is the baseline parts order (SNG - the US supplier) based on a combination of my requests and his expertise. The US Supplier is very good also.

Initial Misc Parts Rebuild Order

Being a California Car, it didn't have a heater, and that was a must have for the run thru the Rocky Mountains. I also want the drive train and associated suspension and steering to be as new. The Rad has been re-cored, just because, and the engine has been run on a test stand to decide how much needs to be done there. It has a small vibration @ around 2000 rpm, looks like it's limited to that range, so I've asked the mechanic to figure out what it is. The Ring gear seems to be a bit worn and perhaps uneven, - could be from the High Torque starter it has? If necessary, and he has to pull the crank /flywheel to get it dynamically rebalanced at one of the mid island engine shops, I'll make a decision on how much further to go. The compression is good, - 160 +/- 3 across the line.

The full interior upholstery has arrived from the US also, as has a new wiring harness.

If you have a vibration problem, the very first thing to check critically is the front crankshaft damper. Failure of these with an engine this age is very common, the usual failure mode being that the rubber between the inner and outer annular sections starts to delaminate, and in an extreme case the outer will twist on the inner, giving amongst other things totally false ignition timing ! ( which of course in itself can cause vibration)

christopher storey wrote:If you have a vibration problem, the very first thing to check critically is the front crankshaft damper. Failure of these with an engine this age is very common, the usual failure mode being that the rubber between the inner and outer annular sections starts to delaminate, and in an extreme case the outer will twist on the inner, giving amongst other things totally false ignition timing ! ( which of course in itself can cause vibration)

Thx for this Christopher. I'll pass it on.

Meant to post these earlier. These phone shots were taken just after the blasting of the body, with the residue still on the body. They are untouched, and it's first look at the raw metal. They named the Job "Honest Jag". Whatever that means.

A previous owner resprayed the engine bay, and in the process, blasted the painted lettering off the serial tag, leaving only the 4 numbers on the aluminium tag. To sort that out, I created a full scale CAD PDF that can be laser printed on All weather waterproof copier paper from Tacoma, WA (we use it for engineering projects). Using a box cutter on the printout, cutting out the 4 windows, the original number stamping shows correctly in situ on the plate, undisturbed.

The resulting waterproof overlay is held in place by rubber cement. If anyone has a similar problem and would like the correct actual size pdf to do the same, let me know by PM. I can probably also do a series 1 pdf with all the extra stuff if there is a need.

The journey back begins ..

The re cored rad is done..

Progress Update ...
Have been out of country for a month, but back home now. So far things are progressing well. Here's a couple of pics of the bodywork and painting progression.

On the drive train and engine side of things, looks like the engine was rebuilt approx 5,000 +/- miles ago, so I asked the mechanic to pull the head and the pan to tell me what kind of job/shape he thought its last restore was and whether we should do anything on it while it is out of the car. Considering that I am taking it to a more European spec verses the Strombergs and wanting the most out of the engine with the 3.07 upgrade to European IRS, it was important to look at the nail holes for ourselves.

The Engine number says it was originally high compression (9). Turns out that the pistons used for the restoration are the lower compression low domes, but the overall restoration job was a good one, ending up at 20 thou oversized. The bores and crank journals as well as the interface head to block plane work are excellent from the original rebuild, the oil pump was replaced and is like new. The block studs were replaced with new last rebuild. Looks like one or two of the chrome rings showed some (break in?) issues, but the valves, guides and so on are good. So we'll go ahead with another rebuild and dynamic balance (with a new Crank Damper) back to high compression with new pistons, rings, bearings and so on now that they've gone this far into the engine. The triple SU's should arrive from England by the end of January, so it should all work out fine for timing. The tranny will also get a full rebuild while we are at it, although it looks pretty good to me. No broken synchro's, some minor wear/chipping on one of the chrome shafts, so might as well get the bearings reworked with a new shaft at the very least. This car is meant to be driven.

Some engine pics:

Just before you go for 9:1 pistons, first ensure that neither the block nor the head has been shaved, both of which are quite common to repair corrosion in the case of the head, and cracks in the case of the block. Then you need to consider whether with modern fuels you really want 9:1 . The XK engine is usually prone to pinking in any event, and was even when new with 100 octane fuels . One of the reasons is that although the nominal compression ratios are quite low by modern standards, the effective ratio is quite high because these engines operate on only 30 degrees of valve overlap . I have one car with 9:1, and one with 8:1 , and the 8:1 is both smoother and more powerful !

Thx Christopher. . I'll pass this on to the re-builder, and hand-wring with him over a beer on what to do. :)

I do see that carbon has built up on piston tops, which could easily cause some after glow and pinging, but I was thinking it had more to do with the torturous arrangement the combustion mixture has to follow off the Strombergs to the intake valves and associated standing waves moving around in the manifold at various operating rpms and secondary operation. Or maybe the last owner was a bit too soft on driving / babying it. Was hoping the SU's would help out in that department.

The block hasn't been cracked or repaired, I'm not sure about how much milling was done on the first go around on it or the head, but the gasket wasn't leaking anywhere, so I'd assume some light levelling might have been done. The Engine re-builder said it was minimal. He also said he was going for a bit less valve gap with the 9:1, which would make some sense to widening out the overlap some for better overall breathing. He has done quite a few 4.2 engines, and is an experienced old cotton top on this particular engine version.

Here's the valves as they came off the engine.

christopher storey wrote: ↑

Sat Dec 30, 2017 8:39 am

Just before you go for 9:1 pistons, first ensure that neither the block nor the head has been shaved

The compression test ran around 155-160, so that seems to be in line with 8:1, implying that not much shaving was done on the original rebuild?

Sounds like you have a pretty good engine.

I agree with Christopher. Fuel is not like it used to be at the pumps, and these engines can ping? (pink) easily nowadays.

8:1cr can suit these old motors better, with no adverse effect on performance for a road car. Your engine might just last longer.

politeperson wrote: ↑

Sat Dec 30, 2017 7:41 pm

Sounds like you have a pretty good engine.

I agree with Christopher. Fuel is not like it used to be at the pumps, and these engines can ping? (pink) easily nowadays.

8:1cr can suit these old motors better, with no adverse effect on performance for a road car. Your engine might just last longer.

Yeah.. I'm torn on this now. Could use the extra grunt in the high Rockies, but I can see that the compromise is in the smoothness of lower pressure and backing off the advance or whatever at sea level. A first world Sea-to-Sky highway issue I guess. We do have 94 AKI here, so I think that availability mitigates things a bit.

The Original matching numbers Engine is a 7R variant, not 8x, so it should be fine.

To be continued...

Parts are coming back from the refurbishing, right down to the smallest nuts and bolts. A small sampling:

The engine is into the rebuild/refresh/restore to new stage, and the rebuilder asked what I would like for Electronic Ignition. I see the 123 thread is active, and there are a number of opinions on what works and doesn't but nothing definite in the voting trend on preferences there.

The rebuilder's preference seems to be for a CSI system with Vacuum advance , appropriate high tension leads and matched coil, etc. Unless someone has a horror story on it, I will tell him to go ahead with that.