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Ah! Roll bars! In the early days of SCCA, a roll bar was more cute than functional. Today, the simplest "broom handle" test is hard enough - without a full Duetto windshield, the top of his roll bar has to be pretty high, as the front end of the broom handle rests on the car's hood. They sure are ugly compared to the svelt things we drove in the 60's. I always thought it was so hard to flip a Duetto that you really didn't need one at all......

But I raced bicycles without any helmet back then too.

>:)

Robert
I think attitudes to safety have changed to, or maybe just with some people. I have a friend who at over 50 who started classic racing and he has every safety option possible, so much so that I could not race his car because of clostrophobia (spelling?) and the fact that so little of my body can actually move ... yes I have driven his car around the pits and to his trailer, awkwardly.

If I raced a Spider I would remove the screen and build a hoop in front of the steering wheel and another behind my head. The weight of a roll bar does affect the cars handling a lot because it is so far away from the cars roll centre, but one must build what one feels safe and comfortable with as confidence makes an even bigger difference to lap times.
Pete
 

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Thanks for the kind words, Bill. If I ever have a chance to race at Circuit of the Americas, I'll give you a heads up. OTOH, if you're ever in the PNW during a race weekend, shoot me a note and I'll put you on my crew list to get in to the races for free.

Yeah, double guns above is a bit much. Single gun would have sufficed. I couldn't help it, I was relieved of anxiety, overjoyed with results, and my Alfa cup runneth over. At least I had sense enough not to wink with the guns.
Quite an offer thank you, and one I hope to take you up on one day!
(The Circuit of the Americas is an OUTSTANDING course to watch from anywhere and one I hope to run on sometime)
 

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Discussion Starter #624
When my older brother's not helping out on the car, he's taking pictures. He snapped this interesting moment when I was up against two unlikely competitors.

The old Corvette, at over 4L displacement, is questionably placed in our small bore class. It's fast as expected in the straights, but slow in the turns, and takes up the whole track. It's one of those cars that has a PR poster next to it in the pits, if you can imagine (which gives me some ideas as well...)

On the other hand, that unassuming little green "Hippie" Sprite is the opposite. It's a momentum car that's driven very, very quickly, usually up front with the Porsches. Mainly because Parker Johnstone is driving it. If I can follow him for a lap or less, I consider myself lucky for the driving lesson.

So there I am, about to pass one and be dusted by the other, destined to complete the remaining laps mostly alone.
 

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Nice pic. You're well positioned on the track. Keep following the faster cars while you learn to take advantage of your car's new capabilities and you'll soon be driving in their group!

Your tall hoop doesn't look so bad on the track.

Keep us informed on how well you push your car!

Robert
 

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Parker Johnstone will be joining the Alfa vintage community in the future. He purchased a '66 GTV racecar that is undergoing restoration.
 

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You missed the whole point

40 lbs? Are you drunk? If I sectioned out 4" of tube from each side of the main hoop, what would that weigh?
You should cut the whole mess out and have a knowledgable race fabricator build a lighter functional roll cage.

There is no "sectioning" of roll bar tubing.
 

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Discussion Starter #628
If Richard is done perseverating about my cage, we'll move on to the next project...

After completing "sliding block madness," I felt a sense of relief that car development was complete, and that I could finally rest. But that was short-lived. Sometimes I'll just stand there looking over the car, looking for low-hanging fruit to modify. (Careful in my wording, I didn't say "improve.")

A lighter crankshaft pulley looked like an easy enough bolt-on project, so I bought one from England. I was excited by the weight savings which you can see below.

I was a bit discouraged to see that they weren't a perfect match in height; the misaligned pulleys would cause excessive belt drag (parasitic power loss) and fraying of the belt. I forgot to ask when I ordered it if this lighter pulley was compatible with my engine. It's not enough of a deal-breaker for me to send it back, since I'm able to make things like this fit.

I wonder if the difference between the two is because my stock pulley is made to operate a SPICA system, evidenced by the toothed part of that heavy pulley. That SPICA factor will bite me again in the next post...
 

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Discussion Starter #629
Even though the new pulley stands a bit short, it appears to stand proud when installed for a test-fit. That's because it's not fully seated; it's blocked by that shroud on the front engine cover for the original SPICA belt. Blasted SPICA! Exacting its revenge for my abandonment of that primitive mechanical fuel injection.

Man, that water pump pulley is ugly. It needs attention, too...
 

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One easy fix is to set the water pump pulley back a bit to bring it in to line. adjusting the alternator is just a washer or two. Or fit a 1600 water pump. You might even change the front cover....

The smaller pulley looks like the one from my 1600 Duetto engine. It is really nice, 'though you can get a machined aluminum one - I think from Paul Spruel - that is even lighter.

On my Duetto pulley, it suffered from a hairline crack along the keyway. I replaced it twice. Next time I'll get the aluminum one. Your old one looks like it has eaten a few crank seals. That's quite a groove.

Robert

PS - love the alternator tension adjuster. Clearly too much free time and too good at machining.....
 

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C'mon... So how much material was removed, weight loss? :)

That spica blanking plate looks chunky
 

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Discussion Starter #633
...That spica blanking plate looks chunky
Yeah, what's up with that? I'll look into that later. At least it's alyoominium. Speaking of which, here's my stock of metals. That's a Stanley Vidmar cabinet, so each drawer can support about a teaspoon full of dwarf star. Near part of the drawer is all Ti, and far part is the plastics. Steel and Al loosely organized in the middle partitions.

I'm made mention before of my stockpile of Boeing aluminum sheet plate acquired just before Boeing stopped selling surplus to the general public. Well, I collected this mass of metal by similar means and luck from a Seattle metal supplier. They initially sold the Al lengths (even highly desirable 7075 and 2024) for a few buck a pound. Their main business is online orders for specific lengths, and also industrial supply. So the scrap and saw droppings they sold off the shelf weren't a priority.

Then, a few months back, to my surprise and delight, the last few trips I made there they just gave me whatever I wanted for free. So at first it was just few choice pieces, then with subsequent visits I started walking out with literally armloads of free metal; stainless, various flavors of Al, and even a couple pieces of Ti. I took whatever they had. They were just trying to get rid of the band saw droppings before the scrapper or recycler took over. Now, you can't buy the droppings anymore, not even under the table (I tried, even offered beer, because I got to know the guys).
 

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Discussion Starter #634
I reflect on my metal supplies because appreciate how nice it is to have what you need, when you need it. I used to have to order bits of material individually for each project, back when I got started doing this stuff for the racebikes some years ago. Same with fasteners, making frequent trips to the hardware stores for what I needed until I finally wised up and stockpiled excellent fasteners in a variety of shapes and sizes from McMaster-Carr.

So for this project, I'm faced with a pulley that not only is too short on the shaft, but has too much thread on the end showing for the stock nut to seat on the pulley body. See how dished that new pulley is? Too deep for the stock pulley nut. I turn to my metal supply to make the shims and spacers I need.
 

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I'll be very disappointed :))) if you don't notch that with 60teeth for a crank sensor and mount one (Hall effect sensor) in the SPICA flange... somehow.

How many teeth on the original SPICA pulley out of interest?
 

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Discussion Starter #636
This is nuts.

...How many teeth on the original SPICA pulley out of interest?
18 teeth. No crank-fired ignition allowed. Besides, my Marelli is Plexing with great fortitude!

So, I'm looking at that ridiculous cam pulley nut, and that stupid spacer I had to make for it, and thought why not make my own? I can make a longer nut that accommodates the protuberant shaft without using a separate spacer, and also incorporates a remnant of a sleeve that fits inside the pulley as the stock nut did.

I have a nice length of 2024 Al hex bar, which is pretty strong stuff. I used it to make my timing belt tensioner some time and many pages ago. Certainly, I can't torque down an Al nut as hard as a steel one, but this pulley is lighter, and working less (smaller diameter, no SPICA drive) than the stock unit which is more than 5X heavier. It will be fine when torqued to 90 ft/lbs.

That hex bar is about 45 mm, and I want to retain a 36 mm size. Not only does that size fit with a socket in the smaller pulley, but I don't want to have to buy more large sockets. So I had to shave down the hex by about .100". Drilled, threaded, etc. Installed. Underdriven.

Oh, and I painted that ugly water pump pulley. That's another thing fixed that had been bothering me since the start of this build six or so years ago.
 

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Sorry I did not see this mod earlier ... but if you are going away from standard, throw the V belt in the bin and instead run a toothed belt. You can get alloy pulleys and you don't have to run the belt as tight, saving hp and weight.

Did this to my last club car. V belts are for concours not racing ;).
Pete
ps: serious weight saving is often done by counter boring the ends of all bolts as that part does nothing, or drilling holes through large bolts ... lots of machining for you ;).
 

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Discussion Starter #638
ps: serious weight saving is often done by counter boring the ends of all bolts as that part does nothing, or drilling holes through large bolts ... lots of machining for you ;).
Oh, you mean like this bolt treatment on my KTM SMR? The whole bike is like that. The clutch basket is so drilled out, it looks like a spider's web. In the lower left, you'll see the titanium clutch bleeder screw that I made (has a rubber cap).

I thought about shaving down that pulley nut, but decided to leave some extra meat on it since I knew it would be subjected to an impact wrench.
 

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Hi Nader, first of all I want to congratulate you for this superb work you are doing to your spider.

Probably you have thought about this, but I see that the crank pulley is smaller than the original one, while you are maintaining the diameter of the cooling pump pulley, and increasing the diameter of the alternator pulley. As first sight this not make much sense, specially for a race car... or I missed something?
 
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