Hi. I was hoping to fit Dellorto DHLA 40s to my S2 type 26 Elan but it looks as if they will not fit under the standard S2 bonnet. It appears that the bonnet cross bracing will foul the enrichment device tower on the front carb. Has anybody come across this problem and found a solution? Did the Sprints originally fitted with Dellortos all have the Stromberg bonnet bulge bonnets?
Any thoughts much appreciated.
I have DHLAs on two other cars and find them much more accurately tuneable than the type 18 DCOEs, understandably as they are a later development of the design, hence the attempt to change
Thanks
Vernon
I’ve been running 45 DHLA’s on my S1 for many years without issue. But it may be just down to variability in how the bracing was bonded on.
The DHLA with 5 hole progression circuit really helped tame my ported/cammed 1720 engine for the street. So I would be inclined to mod the bonnet bracing before forgoing the Dellorto’s.
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Vernon,
By the time Dellortos were fitted to Sprints, around May 1972, the design of the bonnet had changed, bracing being achieved by dint of a steel rod around the inside lip. There were therefore no clearance problems.
Tim
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Many thanks to you both. Modifying the bonnet cross brace would not be that difficult but not sure whether the Dellortos will actually give a noticeable improvement on my big valve Sprint spec engine. Decisions, decisions!
I would say there will be no apparent improvement in power, but a notable improvement in drivability, especially just off idle and low throttle openings. The down side is you will need to dial in the settings on the Dellorto’s, which will require time and money to swap out the various jets and air bleeds. Dellorto parts are generally not interchangeable with Weber, though the tuning concepts are very similar.
Thanks, I’m with you absolutely. Going for Dellortos was not for power but for exactly what you describe, part throttle driveability. The others cars I have on Dellortos, a Ford Crossflow powered Seven and an Alfa are both much sweeter running on part throttle. As for the jetting, my engine is standard big valve Sprint, so I can follow the factory spec for Dellortos, which should get me close if not exactly there. I’m wondering whether to cut down the height of enrichment tower on the front carb rather than mod the bonnet - I’ve never used the enrichment function on either Webers or Dellortos, just a few pumps for a cold start. Thanks again for your input.
Regards
Vernon
My first two sprints were on Webers. The latest one came with Dellortos. There was a noticeable difference in mid throttle sresponse. So much so that I replaced the Dellortos on the late one with Webers and am happy with the result. Horses for courses…