Hello forum,
I have a 72 E. I have a question regarding the timing.

My local jag mechanic passed away recently. He told me that he set the timing on my car by retarding it until it missed… then advancing it just until smooth. It runs fine BUT exhaust is way rich and it does not have the silky-smooth idle of a double six.

i would like to improve these two things. So does Raul’s (my former mechanic) method make sense? Can I do better by trying a factory setting?

I entertain your responses please!

Chemosabe!

 

You haven't said, but I assume this is the V12 engine.
I would think the Jaguar engineers knew what they were doing when they decided on the advance/retard settings ! Of course you need a stroboscope to see what is happening at the timing marks.

However, I wouldn't think the richness is due to wrong ignition settings, more to do with the carburettor settings

 

Frazier Mitchell, indeed the ‘72 is a v12. I intend to try the factory spec setting and have the strobe with which to do it. Thanks for your insight and recommendation. Perhaps I should check the carbs. Thanks, Chemosabe!

 

The carbs aren’t a mystery. In fact they are about as simple as a carb can be.
Problems tend to be one of 2 things.
Most likely is the rubber diaphragm has cracks in it. They typically only last about 5 years. ( time not mileage) are very simple to replace. Remove the 4 phillips head screws from the top of the dome. Pull up the rubber diagram. Replace with new, put in screws and retighten. Now one by one go after the other 3. Once you’ve replaced the domes don’t forget to add back carb oil. It’s pretty thin weight. Around 5-15? Weight oil.
2nd most likely. Is the Jet is leaking or stuck.
Remove the 6 straight slot screws on the bottom of the carb. Drop off the float bowl. There are 2 plastic floats and one side touches the jet ( you can swing the floats out of the way to check the jet). Rarely ever needs replacing. May be stuck open or closed. A little carb cleaner should solve that problem.
While spraying carb cleaner clean both sides of the throttle shafts. Really flood them. You want to float away any dirt or grit. Then flood that same area with clean engine oil. The vacuum from a running engine will suck in enough oil to lubricate and seal the throttle shafts. ( saving you from having to replace them in the future)

 

Mguar, your reply is both timely and well-placed. . I definitely have more than 5 years on my diaphragms! I just sent off two 1.75s for rebuild by Joe Curto from aTR250. They look great and fired right up… although fuel gushed out of the top hole and had to go back. I can change the diaphragms. I know what you mean about removing the bowl, etc. I don’t have clarity on the jets though… how to check, change, adjust, etc. My carbs need oil each time I crack up. What is my issue there? Curto suggested ATM for the oil. Thoughts? Thanks!
chemosabe

Current vehicles:
‘72 E Type
’68 TR250
’09 XJ Super V8 Portfolio, Astral
’89 BMW 325iS
’17 Mini Countryman