Hi all
I have a 41060 distributor equipped with a Pertronix unit. My intention is to use it when I replace the Stromburg carbs and manifold with the triple HD8s and 4.2 manifold that I have sitting on a shelf in the garage.
But until I can get that ready to go, I’m wondering if perhaps I should replace just the distributor now? The car seems to run ok as it is, but I’m sure it could be better…
Thoughts?
Thanks
Robert
Hi Robert,
Yep, do it. It is always better to do mods, upgrades or replacements one at a time, in order to conform proper operation.
Get the Pertronix going to your satisfaction before going to the next item.
Regards
Chris
Cape Town
Seems like a reasonable thing to try and anyway, it is just one bolt.
I carry a spare distributor for easy resolution of ignition issues should they occur on the road, perhaps you will too as it seems you will have a complete functional extra when you’re done.
The advance curve may top out at a lower advance but that may be unnoticeable in daily driving. The curve may be steeper at low RPMs which you may like even with the Stroms.
What George said.
The early S2 (no adv or retard vacuum) distributor was to reduce emissions not to make the car go. Jaguar changed the dist. advance strategy several times after that. The old ebay come on for 3xSU’s was “bolt on 50 hp”. Not if you have the stock 68-69 distributor! The advance curve’s all wrong. Just make sure there’s no pinging . You may never put the SU’s on, it might run so well with stroms. Well 3xSU’s ARE hard to resist.
Before I restored my 1970 California OTS, I drove it for several hundred miles in it’s original condition with it’s Stroms and stock ignition. It drove ‘OK’. After rebuild, the rebuilder recommended I just run it with the stock ignition for the first 500 miles on the new 3xSUs before swapping in the Electronic vacuum advance Ignition (CSI in my case). There was a difference, but not earth shattering. When The CSI went in it made all the difference. What a car, as they say. Mine is the -9 high compression engine, and running on one of the middle maps using 94 gas, there is no pinging, even in the mountains with a heavy foot.
At the risk of being booed out of the building by those who’ve spent $5000 on “upgrading” the Strombergs to SUs, I have to reiterate that you can get close to the same performance improvement by simply removing the secondary throttle plates on the stock Stromberg setup. You won’t get quite the horsepower at WOT, and you won’t get the same bling when you open the bonnet, but you will get to spend the $5K on other things, like filling the tank to generate all those smiles…
-David
You make a point. If the money matters, then do the rest first, like pay off the mortgage or buy your partner a small diamond. Having done both with the Jag, I do find that the SU’s are better behaved than the Zeniths with the secondary’s hard wired open (which is what I did initially), especially in mixed mode ferry traffic. Not that one has to, but if you are a fan of double clutching the down shifts just because, the SU’s are more fun and predictable in 4 lane traffic across the low to mid range, not just the wot performance stuff. Just my butt dyno opinion, so no facts were destroyed in the text.
David
I have made the “5 minute mod” on the secondary throttle plates already. Actually did that before I got the on the road for the first time, so I can’t comment on any “ improvement “. I picked up the su carb and 4.2 manifold set for $2000 so it seemed worth it, if for no other reason than I am completely comfortable working on SU carbs, where the stroms are alien creatures.
Robert
Before going with the triples, and in case you havent, try a good dizzy, coupled with deactivating the secondary throttle plates: it makes a WORLD of difference.
What was the purpose of the secondary throttles originally?
Emissions control. How and why exactly I’m not really sure.
I agree with David. I removed the secondary betterflies and shaft, l plugged the shaft holes and then sleeved the carb bores with thin aluminum rolled into the carb bores. Next I added Joe Curto’s adjustable jets. Total outlay about $100; difference, amazing. I also installed a Petronix distributor. The car starts easily, runs great.
John what Pertronix distributor did you install ? I already have Pertronix installed in my stock 68 distributor but does what you have give you the better advance curve ? I too think the ZS set up with secondary butterflies removed and adjustable needles in mine run great for me at least compared to Weber equipped 68 that I got to drive a few years ago.
David
68 E-type FHC
I do not think Pertronix or clones (e.g. Hot Spark) change your advance curve, they are simply an electronic trigger in place of mechanical points. Of course the curve built into the Pertronix diizzy may be better.
The curve on the stock distributor used with the ZS carbs can be tweaked by substituting different springs - possibly a slightly weaker thin spring. Its a trial and error process but I think it worked for me.
I put in the Petronix for the vacuum advance and hopefully (knock on wood) maintenance free aspects. I’ve not checked the advance curve, pure apathy on my part. I did call the Petronix company and spoke to their technical department. They told me the advance was the same as the Jaguar distributor.
I can’t find my receipt but I’m about 100% positive it was a Part Number: D177600
The ‘expert’ in eastern Idaho modified my 20 degree original distributor (40 degrees at the crank) by welding up the ‘tab’ to limit the advance to ~10 degrees. The engine he rebuilt didn’t last long enough for me to be able to say if this was an improvement in performance.
Cheers,
LLynn
I saved this from a thread many years ago. Everyone’s car is different by now, having different timing requirements (so no recommendations are being made). Jaguar seemed to have a lot of choices. My car works well with the curve I made up with a Mallory spring kit.
I still wonder about Terry Sturgeon’s assertion that the XK engine needs 45 deg’s (crank, all in) to make high rpm power.
XKE-dizzy-compare-2-10-11.pdf (13.8 KB)
That’s the chart that inspired me to fiddle with mine – looked like 41207 (the black line) just needed a lighter thin spring to get more advance in the lower RPMs.
The 45° is what 41207 (S2, no vacuum unit) would get using 5° static if you take it to red line.
I couldn’t find springs, George. So I wound up with the Mallory. Where did you get your springs?
I remember crawling under the car trying to check “all in timing” at 4500 rpm. Unnerving with your nose inches from all that whirling metal. I installed an XJ sedan timing marker on the side shortly after. Ironically, I haven’t even looked at timing, under the diz cap in years. Gotta love electronic ignitions!
Moss (and others) sell an assortment. No specs or guidance, just 5 different springs:
https://mossmotors.com/spring-set-auto-advance-universal-replacement?assoc=41558
Thanks Geo. I think I will buy a set of those springs to play around with. Which ones did you put in your car ? It looks like they are color coded.
David
68 E-type FHC
