Weber Carb on Chevy SB

[Jim L.]

Re: Weber Carb on Chevy SB

Jim,

Great video!!!!!!
Is the DeWitt's painted silver? How much diff did it make as far as heat rejection capacity.

Joe

Joe, thanks for the kind words.

The radiator is bare aluminum, per my request when I ordered it from Tom and it's an early 396 core (note the straight inlet). ( The engine is bare aluminum and I just happen to like the look of the metal, hence the bare radiator.) The total engine cooling package also includes a correct, original Harrison oil cooler that slightly impedes airflow at the left edge of the radiator.

The cooling system has been sufficient to keep my water temp gauge to the left of 180 under all track conditions I've so far encountered. I really don't know how the heat rejection would differ if the radiator were painted, say, black. Any thoughts on the matter?

Regards,
Jim

[Joe C.]

Re: Weber Carb on Chevy SB

Joe, thanks for the kind words.

The radiator is bare aluminum, per my request when I ordered it from Tom and it's an early 396 core (note the straight inlet). ( The engine is bare aluminum and I just happen to like the look of the metal, hence the bare radiator.) The total engine cooling package also includes a correct, original Harrison oil cooler that slightly impedes airflow at the left edge of the radiator.

The cooling system has been sufficient to keep my water temp gauge to the left of 180 under all track conditions I've so far encountered. I really don't know how the heat rejection would differ if the radiator were painted, say, black. Any thoughts on the matter?

Regards,
Jim

I like the bare aluminum too, but think it might develop a white Al2O3 "patina" after awhile. Maybe you should have it "clear" anodized.

Somewhere, way back in the innermost corner of whats left of my mind, I'm thinking that light colors with shiny surfaces, such as bare aluminum, would reflect any radiated heat from the ambient air away from the radiator, rather than absorbing is as a dark, dull finish would do. This refers to radiation, the third transport method of heat, the first two being conduction, and convection. But alas, I have forgotten more of my University thermodynamics than I learned in the first place. Maybe that radiation principle would only apply if the ambient air temp is hotter than the surface temp of the heat exchanger....................

[Stuart F.]

Re: Weber Carb on Chevy SB

For what it's worth, without getting into the dynamics of it, I worked for Young Radiator Company at two different stints in my early career designing cooling system products for various fields incl. Industrial, Agricultural and Transport. I don't recall any product, regardless of it's metaleurgical construction, that ever left the factory without at least a coat of protective primer paint on it. Many, specially those for trucks had bolt on aluminum tanks (Kenworth, Peterbilt), or were repainted by the customer for their particular corporate I.D. (Allis Chalmers, Catapillar). The cores at least had a mist coating, even those with many fins/inch, fins with louvers, flat and round tubes. No matter what metal is used (those with best heat transfer characteristics), there is one form of corrosion or another that will attack it in one environment or another. Of course, like any product destined for inclusion in an assembly, many times they were held in storage until needed and were not attended to by the eventual user.

Stu Fox

[Jim L.]

Re: Weber Carb on Chevy SB

Joe and Stuart,

Thanks for the information. I took thermo but my degree is electrical, so not much of what I "learned" has stuck around. That said, I'm pretty good at doing "parasitic engineering" to get what I need. I see something that works and I can frequently figure out why it works to the extent that I can adapt what I see to my application.

Such is the case with the bare aluminum radiator. I did, at least momentarily, wonder about heat transfer. Then I noticed the old Harrison oil cooler had nothing more than a gold alodine finish and it seems to work well enough. The finish on the oil cooler was probably for corrosion protection that I don't think I need on the radiator. So, bare aluminum wins out.

And it looks so purdy......

Jim

[Stuart F.]

Re: Weber Carb on Chevy SB

Jim;

What ever does it for you. The thing is, you are living with your car I'm sure. That is, it is something that you are very close to. You probably know every nut and bolt. You maintain it and it speaks to you. Well, you know what I mean. At the first sign of any corrsion or unusual appearance or operation, you'd attend to it. Not many typical applications of equipment would get that attention, and sooner or later the elements and neglect will get the better of it. In this day and age in America, the average car owner wants the Toyota perception, i.e. get in, turn the key and go until it stops years down the road. Dispose of it, get another one and tell everyone it is just a car.

Come to think of it, if you ever notice the radiator in a NASCAR race car - they are all aluminum finish, right?

Good Night;

Stu Fox

[Joe C.]

Re: Weber Carb on Chevy SB

Jim;

What ever does it for you. The thing is, you are living with your car I'm sure. That is, it is something that you are very close to. You probably know every nut and bolt. You maintain it and it speaks to you. Well, you know what I mean. At the first sign of any corrsion or unusual appearance or operation, you'd attend to it. Not many typical applications of equipment would get that attention, and sooner or later the elements and neglect will get the better of it. In this day and age in America, the average car owner wants the Toyota perception, i.e. get in, turn the key and go until it stops years down the road. Dispose of it, get another one and tell everyone it is just a car.

Come to think of it, if you ever notice the radiator in a NASCAR race car - they are all aluminum finish, right?

Good Night;

Stu Fox

What an appropriate way to put it! Thanks.

Up until the mid seventies, I could always be found under the hood of my car, responding to it after it had "spoken" to me. For me, the fun of ownership was the "quirkiness" of the car, the amount of tweaking that it demanded, and the degree of difficulty required in driving it.

When the American auto industry went to sleep in the early-mid seventies, I lost faith in American cars, and bought the first of my Datsun 280Z's and was in foreign cars until the Industry began to wake up in the mid eighties. BORING. I had been reading Car and Driver magazine for a long time, by 1985, and was used to hearing Pat Bedard and Don Sherman constantly singing the praises of Porshe, and trashing American makes. In 1985 the Magazine began RAVING about a new, revolutionary car that was about to wake up the American auto industry. That car was the 1985 Corvette, and the "powerful" and revolutionary engine was the L98. I had to have me a 1985 Corvette, bought it, and have been "in" it ever since. Of course, the Industry has come a long way since 1985. I can attest to that fact from what I see at the track. Stock C4 Corvettes are consistently in the low to mid 14 second bracket. C5's are in the high 13's, and ZO6 C6's are in the high 12's and low 13's.

But, there is still nothing like the sound and smell of a vintage American V8 thundering down the strip. Yeah, modern cars are fast, clean, efficient, comfortable. The C5-C6 Corvettes "moan" or "wail" as they speed down the strip, lacking the sweet thunder of the vintage cars. They certainly don't "speak" to me like the vintage beauties from the fifties, sixties, 1970 and 1971.

Joe

[Jim L.]

Re: Weber Carb on Chevy SB

That is, it is something that you are very close to. You probably know every nut and bolt. You maintain it and it speaks to you. Well, you know what I mean. At the first sign of any corrsion or unusual appearance or operation, you'd attend to it.

OOOoohhh, yes. I know every bolt, nut, weld, Heim, hose end, caliper, rotor, bearing, and wire on that car. Every time I strap in, I'm betting my life on how well prepared it is.

Jim

[James G.]

Re: Jim, what is that disc-shaped gizmo

The ribbed gizmo is the power brake booster, mounted on a 90 degree offset bracket for Weber clearance. The access door leads to the master cylinder.


Steve asked for more pictures. Here's a link to a moving picture (a talkie, even....):

http://www.youtube.com/watch?v=7Mfw7Jjd97s

Jim

Jim , is that THUNDER HILL? That is one track I never raced. My MS got me before I had a chance.

Joe Freitas and I met Jim Castle there after Jim bought Joe's 57. I loved the area and everyone says it is a real neat track.

Thanks for the ride. Got my morning Goose Bumps. Now for more coffee.

[Jim L.]

Re: Jim, what is that disc-shaped gizmo

Jim , is that THUNDER HILL? That is one track I never raced. My MS got me before I had a chance.

Joe Freitas and I met Jim Castle there after Jim bought Joe's 57. I loved the area and everyone says it is a real neat track.

Thanks for the ride. Got my morning Goose Bumps. Now for more coffee.

Hi Jim, yep, that's Thunderhill. It's definitely a good track with some challenging turns and plenty of run-off room. If you and I are ever there at the same time, let's go for a ride, OK?

Jim

[Robert I.]

Re: Jim, what is that disc-shaped gizmo

" The hood catches a LOT of air, actually. I keep it loosely tied at the rear to relieve pressure that builds up underneath. It pops up at approximately 100 MPH air speed over the vehicle."

That's very cool to watch the hood pop up!

Reminds me of how my 65 used to get "power steering" at about 120.

[Stuart F.]

Re: Weber Carb on Chevy SB

Bob;

I know of what you speak. Back in 63 in Navada we would cruise my convertible at 130 plus. It was not only like power steering, but felt a little south of rotation and take off. One day it began to look like rain so I popped open the headlights and experienced my very first aero effect as the front end pulled down and the car became much more stable. It was no substitute for a lower air dam and air relief vents in the hood and/or fenders, etc., but it then became the norm for my high speed runs. C-2's love to fly!

Stu Fox

[Robert I.]

Re: Weber Carb on Chevy SB

" One day it began to look like rain so I popped open the headlights and experienced my very first aero effect as the front end pulled down and the car became much more stable. "

Never experienced that or thought about it.

Good idea.

[Duke W.]

Re: Weber Carb on Chevy SB

Webers may look cool, but that's about all they offer - bling! In most Chevy V8 applications they won't make as much power as a suitable for the application manifold and 4-bbl. carburetor.

The trouble is that an individual runner system may have 1600 CFM total flow capacity at 1.5" Hg, but only one-eight of that is available to each cylinder and each throttle bore is only flowing air for about 180 degrees of the 720 degree four-stroke cycle.

Some early F5000 guys used 48 mm downdraft Webers (the largest downdraft size available), but quickly transitioned to IR FI systems with at least 2" throttle bores and no restrictive "choke" (venturi) - just a straight throttle bore with suitable length velocity stacks. I think the Kinsler system used on Can Am big blocks had 2.5" throttle bores.

The basic design goes back to the fifties and most of them are designed for smaller cylinders than even a small displacement small block. The Grand Sports used the 58 mm side draft version, which are very rare because only a few sets were built for the 2.5L F1 engines of the fifties.

The next biggest size - 48mm - is too small for a racing small block were maximum specific output is required to be competitive. A single plane manifold with even a modest 600 CFM carb. will make more power, all other things equal, but the Weber engine will make greater peak torque.

I went around and around with the Cosworth Vega guys on this issue. Converting to Webers was popular for a while with the claim they made "more power", but to get reasonable street performance and throttle response most used the 42 mm versions with a fairly small choke.

The OE EFI system has short runners, a generous sized plenun, and two 1.75" straight through thottle bores that flow 500 CFM plus (total for both) at 1.5" Hg and each 500 cc cylinder sees it all. It's a speed-density fuel metering system, so no venturi signal is required to determine fuel flow. The throttle bores merely modulate air flow to the engine.

I admitted that Webers would probably make more peak torque due to the longer overall inlet runner length; and it took a few years, but I finally got enough comparative dyno test data to show that Webers did make better peak torque, but lost a lot of top end power with a very severe rolloff beyond 6000 revs compared to the OE EFI system, and many have now been converted back to EFI with my reindexed cam sprocket design to get decent low end torque while still making more top end power than the OE cam indexing with no significant rolloff until well beyond 7000.

Webers look cool, but that's about it. The other issue in most road applications is configuring a decent air filter system. Most just run the open velocity stacks and get a nice continuous dirt hone in the process.

Duke

[Robert I.]

Re: Weber Carb on Chevy SB

"Webers may look cool, but that's about all they offer - bling! In most Chevy V8 applications they won't make as much power as a suitable for the application manifold and 4-bbl. carburetor."

A friend went to the R66 Reunion last weekend and sent me a picture of a 62.

It had what looked like sidedraft Webers, but they turned out to be Dynatek fuel injection units on a crate engine.

They're too pricey for my tastes and I don't care for the look of a crate engine, but they sure do look great!

[Jim L.]

Re: Weber Carb on Chevy SB

Webers may look cool, but that's about all they offer - bling! In most Chevy V8 applications they won't make as much power as a suitable for the application manifold and 4-bbl. carburetor.

No argument about that; I lose some drag races between Laguna's turn 11 and turn 1 for that reason.

When I first started vintage racing with the car, Bob Paterson counseled me: "When you are ready to get serious, put a Holley on it."

Good advice, I'm sure, but that'll never happen as long as the car is in my custody. I like the Webers.

Jim