The 'E' Type Forum

Following many attempts by a good and respected jag mechanic our 1969 E-type is still running poorly. The engine has approximately 15,000 miles since a complete rebuild. All engine stats are good. My mechanic rebuilt and tuned the two SU’s with new appropriate needles. The engine now starts and runs better but it continues to “surge” while driving and backfires when the engine is turned off. Am I being unreasonable to expect a reasonable smooth running car? Can anyone recommend a good experienced Jag mechanic in the Southern California area?

Hi....sorry to hear that you havent resolver your running issue with your non original E type SU set up discussed here http://forum.etypeuk.com/viewtopic.php? ... 40c541134b i suggest you post on the US Jaglovers forum im sure you will get some local knowledge and reccomendations Steve https://forums.jag-lovers.com/

Do you mean backfires, or do you mean it runs on ? Neither of these are in any way normal, and the latter in particular points to the possibility of acutely weak mixture which if allowed to continue may well burn holes in pistons. What are the needles which are fitted - that at least should tell us what jets the carbs ( which in any event are too small for the engine ) have been built with ?

If you've still got the Strombergs, maybe you'd be better off putting them back? Swapping strombergs for 3 SUs perhaps makes sense, but not sure about the two?

My experience is limited to the HD and HS series SUs so can someone please clarify the following on Allen's setup:-

Both carb jet linkages appear to be mounted on the middle of the rear shaft. This can't be right, surely. This would mean that when the accelerator pedal is pressed and the shaft turns, the jets are pulled down in addition to the throttle disc opening. This would not only limit the opening of the throttle discs but also mean the mixture is totally over rich at anything above idle.

In addition the carbs are not a matched pair-the rear unit has a much "fatter neck and piston cap. Chances are the jets aren't matched either.

If I'm right I think Allen needs a new mechanic..

Cheers

Alan