75 S to R Homage

[haasad]

Gary, good call. I'll have a think, perhaps a couple of slits across the diameter to allow some expansion , nobody wants stuck throttles. I know the replacement couplings are basically stepper motor couplings. Might be worth getting a couple from RS and boring them for a 5mm shaft. I can buy the "proper ones" from Paul but I like a project.

Keith...I don't do cooking, its too scary ....(often)

[sladey]

Awesome work Andy

[haasad]

Bought a couple of couplers off amazon for peanuts....turned down the o/d counter bored the ends and fitted, quite an elegant solution.





Zero throttle shaft play now...

[haasad]

Final part of this carb overhaul was new throttle butterflys, I found that DCOE 40 , 78 degree butterflys are easy to get , the same as those for our carbs and only about £6 each so I abandoned making them and bought 6.

The shaft screws are M4 by 0.7 threaded and staked in place, once out they're not really useable again. Luckily Weber type ones are still easy to get as are suitable screws from any fastener supplier. My carbs had cheesehead screws originally not c/s as some. Some folks just loctite new screws in but I wanted to re stake mine. I needed to drill out the screw ends to make this work. . It is possible to centre punch the screws to stake them but I was worried about bending the newly refurbed shafts. The solution is to press the flare into the screw end reacting only against the screw itself.

I made a little tool which is adjustable for stake depth ...worked a treat.







What was obvious on setting up the new butterflys in position was how leaky the old ones were due to edge wear, I used a little torch shone up the carb bore to get the minimum of light passing the new ones, I achieved a nearly perfect seal all around. The old ones had really big gaps.
I set the air by pass at 1 1/2 turns the idle mixtures at 2 turns set the throttle stops and bolted it all up synchronising the mechanical linkage as it was fitted. Started first time...... If its dry tommorrow I'l sort balance and idle mixtures and we should be good to go.

[Lightweight_911]

Clever stuff Andy !

[Gary71]

Great stuff. It's great when you finally achieve that position of the butterflies when they all line up and seal! Took many hours on mine, but worth it for the low speed throttle response and smooth running.

[KS]

I think you're ready to have a go at cooking now... (in joke!).

[911SE]

Andy, I really enjoyed the article of your car in the latest Classic Porsche, it's a very very nice car with amazing craftsmanship!

[haasad]

Thankyou so much.I just got a copy to read, crikey how did that happen..glad I was able to acknowledge at least some of the help and support I got.

[Darren65]

Congrats on a great feature Andy......no doubt a build to be very proud of.

[haasad]

Couple of things I've been meaning to do. The car had a tendency to backfire on overun so part of the work to try to remedy was the re-ebushed webers. I also knew my original and temporary megaphone caps leaked a lot of air in so they were also a candidate for attention. Obviously it is very noisy on open pipes and still will be I'm sure, but I wanted to tone it down a touch.

My answer has been to make some baffled inserts copying a few well known designs meant for Harley pipes and to reduce the effective outlet diameter which also adds some back pressure helping torque(apparently) when I run it open. An ex Penske exhaust guy helped me with my plans so I hope there's some skill and knowledge behind this even if its not all mine. Next I made some simple caps to blank the new outlets and hopefully stop the air leaks and backfires.. The assembly was welded up today and just needs a bit of fettling and paint.





I also fitted two bungs and bushes to help setting AFR's.



And finally a bit of bling in the form of a wheel centre recycled as a horn push the picture makes it look shonky but it has a nice used look in the flesh.



Cheers Andy

[Darren65]

Very clever!

I take it you were pi**ed when you fitted the gauges!

[sladey]

Nice stuff Andy

On the backbox - was mine no use after all then?

On the horn push - did you cut down the wheel centre? Mine is bigger than that

[haasad]

[quote="Darren65"]Very clever!

I take it you were pi**ed when you fitted the gauges! [/quote]


Very.....

[quote="sladey"]Nice stuff Andy

On the backbox - was mine no use after all then?

On the horn push - did you cut down the wheel centre? Mine is bigger than that[/quote]

I have done some work with the M&K but still need to make and fit two new tail pipes and inlets, its a work in progress. I think youd be very surprised to see how little one gets in an M&K for the money, a bit shocking really I'm sure later newer ones are a bit more ..."complicated" , I'll post a snap of its internals at some point.

You spotted that I turned down the badge and had it re-anodised , I preffered the smaller diameter on my wheel. Its mounted on a common moderm momo push button.

New LED oil warning lamp next.

[haasad]

Fitted the exhaust this morning, certainly much quieter when capped since the leaks are gone . Without the caps it sounds much nicer too, kind of crisper...Must get it out for a run to see if the backfire is cured.