Restoring a 1962 Jaguar E-Type

March 10, 2008

The dark path

Filed under: 1962, auto restoration, E-Type, Jaguar, restoration, XK-E, XKE — Penforhire @ 7:15 pm

While I continued working on the carbs I also managed to remove the left rear bumper, now that the gas tank is out. No photos because construction was no different than the right, already covered.

Carburetors are peculiar devices. In one way they are fairly simple. You see a bunch of parts but with a little assistance from a manual you can identify everything and you have some idea what their purpose is. But on the other hand, there are always details that make the difference between running okay and — hard or non-starting, rough or racing idle, hesitation under acceleration, fuel efficiency, fuel overflow onto the ground, and spark plug fouling.

I have more experience than I ever wanted to have with what can go wrong when I rebuilt the Bing carbs on my old BMW motorcycle. But when I research service costs to have others rebuild the XK’s triple SU HD8 carbs I choke (ha, ha) on the prices, from $800 to $1500. Okay, so we’re giving it a go on our own, right? To slant the odds in my favor I ordered a recommended DVD on rebuilding SU’s from Moss Motors. I also bought three complete British Superior rebuild kits from an e-bay seller (Atkinson Classic Jaguar). Price was about $170 with shipping, about 20% less than the usual mail-order shops. I also ordered a specialty SU tool kit from another vendor for about $28 with shipping. This has the jet centering tool and some wrenches. Seems like a couple of the SU hex-shapes are indeed Whitworth size. Aargh! Otherwise a good use for my English crescent wrench.

Hmm, these are my first actual Jaguar-specific purchases beyond repair manuals. Well what can a person do while waiting for these purchases? I don’t think I can get into TOO much trouble if I disassemble and clean the carb bits. Famous last words, probably.

Let’s put up a bunch more reference images so you can see what I’m up against. Might even help me reassemble the bits later. Here is an exploded view of the main piston section.

2585-main-needle-exploded-view.jpg

Here is the main body of the carb. The main jet, where the needle rides, is the brass bit in the floor of the body.

2586-carb-main-body.jpg

Here is the inside of the “bell” that is the top of the carb. A smaller piston rides in oil down the center of this to dampen the motion on the needle’s piston. The oil fill point is the brass hex-plug at the very top of the carb.

2588-inside-bell.jpg

Got a little varnish built up in there but none of the nasty corrosion we saw at the carb intake and output. Gives me some hope.

Here’s the top of the needle piston. Not sure yet what purpose that multi-holed brass bit in the center serves.

2589-top-of-needle-piston.jpg

Grimy but again no scary corrosion. Here is an exploded view of the float bowl shut-off, the bits that prevent overflow.

2590-overflow-valve-exploded-view.jpg

These are the bits I mentioned I might replace with something better. That would be called a Grose Jet. Should cost me another $15 or so per carb.

The front carb is unique in that it has a port that feeds vacuum to the distributor advance mechanism. Here are the bits.

2591-vacuum-advance-port-exploded-view.jpg

The hole is tiny, maybe 1/32nd inch or so. There has to be an intentional delay in vacuum transmission to the advance unit because the coiled tube after this hole is at least a foot long. After solvent soaking I used some electrical wire to safely clean it up.

2597-cleaning-vacuum-advance-port.jpg

The carb’s butterfly is screwed to the throttle shaft. That shaft has the most bizarre end-cap arrangement. I’m sure it is all necessary but it smells Rube Goldberg to me. Here are the outermost bits, a press-fit brass cap and spring.

2593-throttle-pivot-end-cap-spring.jpg

It is difficult to pull the caps off without damaging the caps. Hopefully they will be part of the rebuild kit. The next bits are a dished brass washer and a cork seal.

2595-throttle-pivot-dished-washer-cork-seal.jpg

I read somewhere that later carbs use a Teflon insert that lasts forever but requires some sort of accurate boring to retrofit. Accurate? Me? Guess we’ll try the original cork system.

Here is a curious little bit. This is a guide (or maybe just anti-rotation?) for the main jet piston.

2596-needle-piston-guide-split-screw.jpg

The screw has a split tail same as the two butterfly screws, spread like a cotter pin to never back out, because “very bad things” would happen if these bits got loose and were sucked into the cylinder. This guide extends slightly into the open throat of the carb but I’m thinking the piston never rises high enough for it to interfere with air flow.

Here are more images of the linkages of the middle carb as mounted on the engine. The links look tricky, like I’ll never get them exactly right again!

2601-middle-carb-reference-linkages.jpg

2602-middle-carb-more-linkages.jpg

And now some more angles of the middle carb as removed on my bench (I was not thorough enough with the front carb photos) —

2604-middle-carb-on-bench-butterfly-view.jpg

2605-middle-carb-bottom-view.jpg

2606-middle-carb-other-side.jpg

2608-middle-carb-float-side-view.jpg

2609-middle-carb-intake-view.jpg

The choke shaft is a wicked-looking assembly all by itself —

2607-choke-assembly-detail.jpg

Here is where we veer off into obsession and madness. Think back to Return of the Jedi where Yoda says to Luke Skywalker, “Once you start down the dark path, forever will it dominate your destiny.” Well I’m here to tell you that once you learn how to polish metal that looks unrecoverable, as I did on my motorcycle restoration, forever will you toil.

It occurred to me that whenever I see under-the-hood photos of other series one E-type restorations my eye is drawn to the bright trio of SU carb tops, then to the two shiny cam covers, and finally to the golden sheen of the painted block. I dunno about you but that’s how MY eye first takes in the XK motor. I suppose that makes it a foregone conclusion that cleaning the grease off would not be enough. No, I feel the need to polish.

Here is my primary tool, a sewn polishing wheel on a Shopsmith arbor capable of running up to about 5K RPM.

2598-polishing-wheel-emery-grit.jpg

Here you see the coarsest common polishing grit, black emery. This is not coarse enough to remove dings or deep pitting. You must start with actual sandpaper, running from coarser to finer grits, if you want flawless bling. But the emery compound is good enough to remove fourty years of surface oxidation.

Here are the carb bell’s bolts before and after polishing the heads. Note that polished surfaces are hard to capture with a camera. They reflect all nearby surfaces and pick up visual defects or texture that isn’t there. So they always look better in person.

2599-bell-bolt-before-after-polishing.jpg

Here are the floats before and after polishing.

2611-floats-before-after-polishing.jpg

Polishing is one of those jobs where you can get in a groove and hours fly by. Good thing because this next comparison of carb bells, before and after polish, took at least eight hours. For that one bell!

2610-carb-bells-before-and-after-polishing.jpg

I probably should have started with some sandpaper but I stuck to emery compound on the wheel and just worked it… and worked it… and worked it. Then I switched to a different wheel and a finer white compound, skipping a possible brown “tripoli” compound, and worked it some more. Then I finished with an unsewn buffing wheel and Wenol metal polish. There are probably a dozen metal polishes I could have gotten the same final shine with (e.g. Simichrome, Mother’s Aluminum, Autosol,…).

Note I did NOT remove all the deeper scratches and grooves. I need to ruminate on whether to sandpaper or not before tacking the second bell. The thing is, once you start with a coarser grit you force yourself to work back in several steps toward the finer grits. If you skip over too many grits you make even more work for yourself to remove the marks from the coarser grit steps. On this I might have to go all the way back to 320 grit if I wanted perfection. To knock out most of the deep scratches (not all) would require 400, 600, and then 1000 grits, worked over every square inch, before getting the bell back to the polishing wheel. And then I’d still have to run at least the same three wheel steps. I am describing a several-day effort. For one carb bell.

Madness, right? But the parts I’ve done so far sure look good! Maybe I can get Monster Energy drink to sponsor me. Speaking of which, let’s talk about this weekend’s Tivo! The AMA motorcycle races at Daytona had unusual drama this year.

I had no idea Neil Hodgson, who qualified on pole in Formula Extreme (Daytona 200, 69 laps!), lives on the Isle of Man. That is a strange little island where one of the world’s craziest races takes place, the Isle of Man TT. Full-on racing around the island and through the streets of a quant village with sidewalks and solid walls to either side as you scream through it at 180 MPH. Someday I hope to race around the old Nurburgring track in Germany but at the Isle of Man I just want to watch. You think I have a deathwish? Sadly, Neil’s bike self-destructed in this race with only about 5 laps to go and his position was somewhere around 4th.

Then there was Jake Zemke whose Honda had a big wheel mounting issue at the first pit stop, riding in 2nd place at the time, so he took off his leathers! His team-mate Josh Hayes was in first place but HIS pit stops were perfect. He won the race.

But you have to feel even worse for Miguel Duhamel. He had a clutch problem on the second lap, came in for his back-up bike, and worked his way back up to 5th place. There were 40+ riders ahead of him when he came out of the pits! And then with only a dozen or so laps to go the officials black flagged him because although his bike change was early enough it was not also under a red flag. He risked life and limb for HOURS pushing every limit before the AMA made that decision and black flagged him. If I were him you’d have to shoot me with a tranquilizer gun to calm me down.

BMW had a four HP2 Sport bikes in the field for the first time outside of a BMW cup race. Why was it that TWO of them ran off the track on the first lap? This was sort of an exhibition since the engines were stock. In theory they had no chance against the veteran Formula Extreme bikes. Would you believe they came in 5th and 6th (Richard Cooper and Brian Parriott)? Unbelieveable. How cool would it be if they decide to develop the bike and run the season?

But wait, there’s more. Did you see the Supercross race in heavy rain? That was the most gnarly stadium riding I’ve ever seen. Water was up to the axles and that was only if you found the shallow line. One bike got stuck, front wheel in the air looking like a dinosaur in a tar pit, and he couldn’t get it out even with one corner worker’s help! Nobody’s goggles lasted to the end. Chad Reed rode an incredible race, getting OVER a 60 second lead, despite falling over a couple of times and running off course a lot, over Kevin Windham in 2nd place. Oh, but if only Chad’s bike didn’t die just two turns away from the finish line on the LAST LAP! See Kevin, that’s why you never give up.

That’s all for now. Check back for more the good, the bad, and the dirty as it happens.

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1 Comment »

  1. You could do the Isle of Man TT course on Mad Sunday when it’s open to the public… but there’s a reason they call it Mad Sunday 🙂

    Comment by Go Mann — March 11, 2008 @ 6:18 am


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