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Spark plug tube seals

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DaimlerDave
Posts: 30
Joined: Tue Mar 21, 2017 7:53 pm
Location: Wiltshire

Spark plug tube seals

Post by DaimlerDave »

Hi all, I can now report my findings having replaced the spark plug tube seals with the kit from J&E Engineering Services. I have now done a couple of hundred miles since replacement and the new seals have not allowed any oil through. The tubes were very tight to remove and to aid removal I made an extractor with a large raw bolt inside an aluminium tube, same principle as the tool from J&E but I think their tool would be a better choice I just wanted the challenge of making my own, I did have to remove a carb on one side to get a bit more access though. All in all a good mod to do.
1967 Daimler V8 250
1979 Honda CBX1000z
1974 Suzuki GT750M

Ian Slade
Wise Man
Wise Man
Posts: 792
Joined: Sat Feb 13, 2016 9:54 am
Location: Sevilla Spain

Re: Spark plug tube seals

Post by Ian Slade »

There is nothing wrong with using a copper washer of round section of the diameter of the internal head thread diameter, the J&E blurb is good marketing but it's a simple engineering process, annealing the washers before inserting even if new, to remove the tubes screw on one of the alloy nuts inverted then screw on another the correct way and tighten against each other then unscrew using the lower ring with your preferred wrench.
Owner since the 70's, Genghis is slightly to my left.

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wally999999
Posts: 58
Joined: Mon May 16, 2016 10:01 pm

Re: Spark plug tube seals

Post by wally999999 »

Hi,

I made a series of 7 videos when I fixed my leaking spark plug tubes a couple of years ago

Getting the tubes out is relatively straight forward using a Rawl Bolt (i.e. expanding masonary anchor bolt) - as noted by DaimlerDave above (but see the second video)

One thing that I hadn't expected was that my two cylinder heads are different. At least one head must have been swapped in the past because the lower tube ends and washers are different. I assume that Daimler / Jaguar (probably Jaguar) must have improved the design to address issues with leaks. I annealled and reused the plain copper washers on one head but bought replacement washers for the second one. The (more recent?) washers have a 'crushable' design that probably won't seal if used a second time

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