Carlo,
…and all great questions too! My answers may disappoint…!
A little background: Jaguar made several changes in the 1968-70 period to meet the evolving emissions regulations in the US. These changes generally resulted in poorer engine performance in one way or another but allowed them to continue to sell the cars. Over the years, owners have often attempted to get back the original performance of the S1s by removing some/all of the changes with various levels of success.
My recommendation would be to first determine what you’ve got. How does it differ from what Jaguar shipped in 1970? It seems that, as a minimum, a previous owner has disconnected some of the hoses. Once you know what you’ve got, you can decide whether to try to return it to stock, or make improvements. Some of the original emissions components, if defective, are probably difficult to find replacements for, as they were only produced for a short time. So, it may be necessary to deviate from stock anyway. To determine what you’ve got on your car I would start by comparing it with the following documents:
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Section Q (Emissions) of the Jaguar Service Manual - this describes the early version of the emissions controls used on the Series 2s. Some of it is still relevant to your car (e.g. the dual Stromberg carbs, and secondary throttles), but some was superceded by 1970.
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Service Training Notes SSJ1 - this describes the changes made in 1970 which should apply to your car. This includes a new air filter system with a temperature controlled valve, vacuum retard distributor etc. You should find a downloadable source in the archives somewhere, but I’ve attached a pdf to save you the search.
1970 Specs-emissions.pdf (2.6 MB)
Try to determine what you have, and what is missing, and we should be able to help with recommendations. If you have doubts about what you see on your car, posting photos may help.
-David
David
I ran the car over the weekend for about 150 or so miles. New plugs, new air filter and the air filter box hoses hooked up like they should be. The car starts right up like a champ, but is still with a rough idle when cold. Once the car has a few miles on it, the idle is quite smooth and nice, and runs really strong. I’ve heard that the rough idle is normal, and maybe it is, but to me, a rough idle doesn’t sound normal. Am I looking at this idle thing correctly? If a rough idle is normal, then so be it- I’m okay with it. Should I even care?
Carlo
Without knowing (a) how rough it is, and (b) how close to stock your ignition and carb setup is, it’s difficult for me to comment. If the idle smooths out after a few minutes when the engine warms up I probably wouldn’t worry much. When you get a chance I suggest checking to see what mods have been made the the car (eg. removal of the secondary throttles), and look into the setup of the temperature compensators on the Stromberg carbs. These compensators lean out the mixture when the carbs are warm by opening a bypass passage around the throttle plate. They have been known to stick in the open or closed position and probably have most effect at idle. For details of the Stromberg carbs and their idiosyncrasies have a read of a document written for Triumph owners (but still applicable to our Series 2s with a few differences) downloadable from Carburetors — Buckeye Triumphs
-David