Wednesday, July 26, 2006

Brand New Carbs, further tweaks!

Got my tyres. Bridgestone RE720 185/55/14. £96 to the door...My local place quoted £140 a pair so after fitting i'm saving dollar.

They came from Germany!

The carbs brand new old stock, DHLA40-C non-emission. They are identical to my last set but they have a more advanced progression setup. More progression holes, larger sooner and run on later. I call these C models miracle workers the DHLA40-45-48C is a very very good carburetor. I had no issues at all on my previous engine with 30-32chokes using 3 holes DHLa40. This engine is a bit fussy and I want perfection from it, don't get me wrong it very very good before but just a few points it was hard to tune on the race-cam and 33 chokes.

James C has some DHLA40 with 4 progression holes, kind of middle road.

Pic shows new carbs ready for test run and setup. I set the float levels, or levels in the bowl to my favoured 26mm, removed the lighter 7 gram floats fitted in favour of my favourite spansil 10grams versions from E models and some F models. Fitted the viton valves from my last set. Set the pumps up. These have a different lever to my last ones, the last development of lever, this operates the same at low TP but can give a squirt much higher into the TP (throttle position)...Not sure if thats of any use -I can cut it out by fitting harder springs under the diaphragms if needed.

I always find you balance them once after fitment, do about 15miles and they go out of balance and you need to reset them again later on..I did that on the roadside testing them earlier.

I was hoping to not use these as they are worth a fair few quid and I wanted the cash! I have an odd carb that is a perfect factory match for my other two I removed, so making a perfect triple set.

That set is for sale, ideal for 6 pot engine.


All ready to go.

After the test run they are truely superb. I had adjust my jetting a bit but after two road side stops they were far better than the old ones. Almost as good as my old smaller choke setup on the 3 hole versions which was faultless.

They balance to perfection, they idle like a clock, even better than before! near perfect. There is a shed load more torque at lower throttle positions and off idle for some reason, the car leads itself on much easier with virtually no throttle use at all...It drives itself even more than before, following traffic on flat road or slightly downhill you almost have to brake to avoid running into the car infront when using no throttle!

Mid range cruise is more lively and active and I am much less into the throttle to make progress, much more like my last engine, carbs and cam was.

I expect to find some things to improve on but after only 1hr playing the improvement is pretty impressive. Also the cooler air tonite helps only 25c!

Much more crisp and smooth in low ranges as to be expected...I am happy with them, very much so!

These are the very last carbs Dell'Orto made with over 30years of development they didn't really change much on the carbs till the earlier 80's.

Then fuel injection killed off carbs on Alfa-Romeos and Lancias and Dell'Orto stopped production as market for racing versions was small, tiny around 2% of all production.

These carbs were only born as a result of production cars use. The ammount of carbs Dell'Orto made for the italian cars was simply vast, Weber and Solex couldn't hack the pace. All 3 companies were making carbs for the same models of car in the late 60's and early 70's, them Dell'Orto took over the whole shabang.

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