Projects Building My 34 B'Ville Coupe With a Potvin

So the next installment. I've decided to go the fluid damper route. it will be a 5" dia. unit that will be sandwiched between the crank hub and the drive gear. So to start with , how is a FluidDamper built? As you can see from the pictures (AND DON"T ANYBODY COME ON HERE AND SAY THEY HAVE A OLD ONE I COULD HAVE) There is a inertia ring that has been coated so there is no metal to metal contact. It sits in a cavity that has been filled with a VERY viscous silicon fluid. As can be seen the fluid in the cup, the puddle hardly moved in 5 minutes. So now to start building my own unit. I have the ring and the coating figured out but now I need to find a laser welder to weld it together and a supplier for the fluid, and then figure out how to fill it.
Cheers

 

I wonder what the camshaft retainer was for. Maybe just for a particular engine to act like a cam button. Should not be required on a hemi as they have a plate.

 

Ted,
I appreciate the concern on the slip fit crank coupler. I am building a "Potvin" for a Studebaker so I need to make the adapter also. I like your idea on the "gear to gear" connection. Are you changing the rotation direction of the supercharger and flopping the intake to the passenger side? A Stude is a gear driven cam so it's a bit different. I know a fellow with many street driven miles on a SBC with a traditional "slip fit" set up and no issues. I would like to chat sometime after the new year.

Jon

 

While we're on the subject.....

 

.....and some more..

 

Good stuff. Always fascinated by the Potvin blower set up.
Thought....over drive, under drive using quick change gear layout/set up between motor and blower???
Another thought... Crower or Carrillo had either a Nash or Hudson that I saw at Bonneville in 87 where the blower set up was divorced from the motor and driven off the crank by a drive shaft. Pretty kool.

 

Hey @earlymopar
Check this out.

 

Thanks Doug. I love that picture for obvious reasons! Would enjoy hearing (and seeing) it run.

 

Ted, have you figured out where to get the fluid? I am trying to dig up some info for you. I think it is the same stuff used by a bike mfgr. A guy I know did a ton of testing and found a source. It comes in different viscosities depending on app.

 

Now with the chance to see an enlarged copy of this picture, it sure looks like their primary sponsor must have been a hose-clamp manufacturer! On the other hand, I can't argue with rubber hoses being a simple, quick and effective way to mate the plenum to the heads (and the plenum to the runner).

 

They actually made gear drives for that type of setup. Made it longer but you could over or underdrive one that way.

If you had a sedan like an A or say up to a model 40 you could sit in the back seat. LOL

 

Are you still building this? Here is mine

Sent from my LM-Q720 using The H.A.M.B. mobile app

 

That is awesome

 

Hey Jon. With the gear drive the supercharger actually rotates in the stock direction because i'm driving the upper gear. My thoughts on the longevity of the slip fit has not changed mainly because nobody have used one for the miles i expect out of it (100,000 miles). If someone has, it would be nice to talk to them. Anytime you would like to chat just shoot me a message and we will connect.

 

Sorry for taking so long with the next installment so here goes.
I decided to try the having a hormonic damper route and the solution was building my own fluid damper that would fit inside the Potvin front cover.

Thanks Tman, I found a place in New Jersey that makes the silicone

 

So the latest installment
I had decided to build a harmonic Damper for my unit that fits inside the Potvin front cover. The largest I could go was 5 inches. What took so long was finding all the information needed to build it. I started with the idea of building a damper that sandwiched between the drive hub and the and the drive gear. After some sizing exercises I decided to build the damper and the drive hub into a single unit. This would allow me more room for a larger inertia ring.

 

Getting the inertia ring coated with nylon wasn't too bad but trying to machine it to size afterward was a bit of a challenge. When they put the coating on they cannot control the depth of the coating so there was trouble figuring out how to grab it. With the input from some very smart people I think I have it ready for the next challenge, filling it and welding it up. i did find a company that makes the silicon fluid. I need to explain, finding the right fluid is very important. Fluid Damper says their fluid is 45,000 more viscous than 30 weight motor oil. When you measure the viscosity of a fluid the unit of measure is Centistokes. 30 wt motor oil is about 130 centistokes x 45000 times more viscous is about 600,000 centistokes. Are ya still with me? so I went looking for silicon fluid of the 600,000 centistokes variety. The good people at Clearco LLC. have it in all, they sure made it easy. the next question was How does temp effect it? Luckily the people at Clearco said it was unaffected by temp up to 300 degrees. So now the only issues are how to fill it and how to weld it without melting the nylon inside and making the thing useless.

 

What a beautiful car and great detail in the build. Where can a guy find out more???

 

I thought about using quick change gears to allow for changing the ration but I did the calculation and at 1:1 it should make 6-8 lbs of boost which is just right for the street.

 

You're way outta my league, but a Hemi-powered street car (I got one) doesn't need 6 to 8 pounds of boost to keep up with traffic. I couldn't get mine to run worth a shit for a few years until I got electronic fuel injection. I'd had Donnie at Herbert's grind my cam – ("300 grind or something a little hotter?" – Oh, go a little hotter). I don't think I'd worry how much boost I was getting at 35 MPH. I also know that I chose too low a gear – my little 354 has a lot of grunt and I now wouldn't mind having a higher ratio. That electronic fuel injection will make a wonder to clean up the low end.

 

Thanks Stan. Nobody Needs 6-8 lbs boost but with the 1:1 ratio that’s what I get. I’ll need to play with it I’m sure. I’m just starting with the manifold. Cutting up a brand new hot heads manifold to get the runners I want took some hesitation before having at it with the saws all.

 

I am planning on a solid roller cam for mine but not sure of the specs I want yet. I just ordered a set of H beam rods for it after getting a stroker rotating assembly with stock rods. I now have this idea to run it at the USFRA meet in one of their 130 or 150 clubs. What EFI did you go with? I will use the MegaSquirt unit as I use it on the RMR and I'm comfortable with it although, if I have to wait another year to run the car I might forget how to. The head work on this thing is causing some concern with rockers, valves, porting. I hear ya on the cam going a little hotter, a little hotter. I can't loose site of "this is a street car"

 

Very slick work!

 

I went with FiTech after years of stalling at intersections, etc. Part of that fault was the automatic transmission. I have the Hot Heads 4-barrel manifold. I ground off the nitrous bosses (or whatever they were there for) and took it to my old chrome shop and had them polish it. "How much? Just give me a hundred dollars worth." I got to know the FiTech guys pretty well and one of the owners said he could run the roadster on the dyno. We'd have discussions about how much advance was best. We made a half dozen or more runs (in 3rd gear) and got some very impressive numbers out of the 25-year-old Batchelor motor. Sure made a lot of noise . . .

www.youtube.com/watch?v=nNoVYDO8_xg

 

Great looking engine bay. It must be a hoot to drive. The roadster sounds great on the dyno. 25 years old!!
I'm going to hide the injectors under the runners thats why I started with Hot Heads manifold as it has the runners standing more vertical.

 

OH what a beautiful Noise

 

Can someone EB weld it for you? It may minimize the heat transferred internally if they can do it correctly/quickly. Melting metal requires heat so it'll likely be tricky.

 

Yes, that's what I was thinking or laser but trying to find a shop that does it up here in the sticks is really hard. I found one place for laser but they said no thanks as the job wasn't big enough. I found another but it does jewelry repair. EB so far I can't even find a place. I'd hate to have to do it with TIG. Boy would it take a long time (one tack at a time then cool)

 

Those are some expensive-looking flanges. Sure look a lot different than my 4-barrel one. What was that originally -- a blower manifold? Might be easier to start with some steel flanges and go from there. I know you guys have the skill.

 

It started as their 2 x 4 manifold. I am going to fishmouth them and add a log onto each runner set then build a top and bottom to try make it look similar to the Potvin unit below.