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View Full Version : Avanti Fuel Pumps, Carburetors, and Sealers



jnfweber
09-02-2010, 01:51 PM
Some of you may have read my recent posts, which have discussed a poorly running R-2, which admittedly, is due for an engine rebuild at 95,000 + miles. After working most of the summer, which I'm afraid lasted July 1-August 15 in Montana, I have both of my Avanti's running well enough to DRIVE to a rebuilder I've found in Butte, only 25 miles away. I posted compression tests I did in a previous post:

http://forum.studebakerdriversclub.com/showthread.php?43810-Avanti-Diagnostic-Testing but later discovered that the cheap on-line ($35) "Pit Bull" compression kit was about 25 psi low compared to pressures measured by my local "professional" technician, who I assume had a better and more accurate gauge. Adding 25 to the pressures I got in my "sickly" R-2, and comparing the two Avanti's, the pressures were very similar. Not surprising since both engines have about the same mileage.

Both cars have had distributors removed, centrifugal advance weights checked and lubricated, points filed and gapped, distributors checked (length of spark arc from distributor to ground) all seem to be equal and reasonable. Both carburetors taken apart, cleaned, inspected, and reassembled. The R-1 has always driven well enough to be driven to a shop, but up until now, I could barely get the R-2 to drive back up the incline into the garage. It would not idle, and would conk out after running a variable time on fast idle. Not any more. I can actually drive it!

THE PROBLEM: The carburetor was plugged with SILICON sealer. Here is how this came about. Back in the 1970's I found the pivot arm on my 289 Sky Hawk fuel pump was always dripping oil, so after cleaning it thoroughly with gasoline and soap and water, I applied silicone sealer to both ends of the pivot arm, and it HASN'T LEAKED SINCE.

The Avanti shop manual states that the R-2 carburetor MUST BE SEALED and recommends Permatex #2 or similar non-hardening sealer, which should be applied sparingly to various threads. Not having Permatex # 2, I used silicone sealer applied sparingly, which with use, was eventually distributed throughout the carburetor! It did run well for a while, but got worse and worse with time.

Blame the SILICON, or blame the ETHANOL? I don't know. But most gas now contains 10% ethanol, at least in the summer when we put the most mileage on our [sic] rust-free cars. But to get on to the first subject: FUEL PUMPS.

I believe the original Carter "Super Pumps" for Avanti's and Jet-Thrust Cars are better than replacements available from most Studebaker vendors, so I would rather "rebuild than switch". I replaced the diaphragm in my R-1 fuel pump with a kit from a well-known secondary Studebaker vendor (after S.I.) in September 2007, and it appears to be pumping gas into the crankcase even though on visual inspection the diaphragm appears appears to be intact. http://forum.studebakerdriversclub.com/showthread.php?43242-Pumping-gasoline-into-crankcase.

I could not get a guarantee from any of the Studebaker vendors that the new diaphragm would last any longer than three years, so I have decided to order a fuel pump kit from "the cellar" http://www.maritimedragracing.com/antique_auto_parts_cellar.htm as recommended by N8N. Nate seems to have quite a bit of experience, judging by his number of posts and his web site. When I called "the cellar, "Then & Now Automotive", the guy said their diaphragms were "guaranteed ethanol resistant."

THE BONUS: The fuel pump rebuild kit from "the cellar" is only $37.50, which is $22.50 less than most Studebaker vendors sell it for (S.I. seems to set the price). Besides, they will ship it in a Priority Mail Flat Rate Box for $6.50. They said they can ship 2 for the same rate, so I ordered 2, it never hurts to have 2 when you have 2 Avanti's.

Another thing I discovered, thanks to Jeff, were the Edelbrock pages http://www.edelbrock.com/automotive_new/mc/carbs_acc/access_calibrate.shtml
where one can buy jets, metering rods, piston springs, etc. for calibrating the AFB carburetor.

And finally, when I get the fuel pump kits, possibly in 3 days, I will use SBCA96's excellent description http://forum.studebakerdriversclub.com/showthread.php?737-R1-fuel-pump-rebuild-proceedure-w-pics of how to correctly rebuild the Avanti R-1 fuel pump. BTW, the kits are the same for both the R-1 and R-2 fuel pump. Does anyone have the flange number for the R-2 pump? The R-1 number is 35085. Thanks guys! Sorry for the long post!

Jack in Montana

StudeRich
09-02-2010, 04:39 PM
Jack, if you look closer, I think you will see that it is 3508S for the R1.

Good but lengthy description Jack, I do like that you provide references though. Unfortunately, it only verifies what I have been saying here for years, but sometimes those posts get buried, and frankly I am a bit tired of saying it, so I am glad you did!
You know the old saying...you can lead em to water, but...! :D

Only one thing I might add, about the ethanol eating the diaphragm thing, you simply did not speak to a knowledgeable person at the Studebaker Vendors, because all or MOST, are the same kits as you bought. If not ALL the kits, (since NOS are 99.8% gone, only private parties with closets to clean, would have any).

jnfweber
09-02-2010, 05:17 PM
Jack, if you look closer, I think you will see that it is 3508S for the R1.

Only one thing I might add, about the ethanol eating the diaphragm thing, you simply did not speak to a knowledgeable person at the Studebaker Vendors, because all or MOST, are the same kits as you bought. If not ALL the kits, (since NOS are 99.8% gone, only private parties with closets to clean, would have any).

Rich, you are correct! I called my recent Studebaker vendor, thinking that he might have an Avanti fuel pump lying around, and never got a return call. I got the above number from the last url I posted http://farm5.static.flickr.com/4096/4914785122_d4fb0c80e8_m.jpg which has a nice photo of the flange and number = letter S. The lady at "the cellar" said the kits she were sending cross-referenced for both the R-1 and R-2, so I hope she realized what I reported as a "5" was really an "S". Next time I will look more closely. She also said that she knows of no Studebaker vendor that uses their kits. So, either they get a different synthetic rubber for their diaphragms, or there may be several sources. I hope this is "ethanol resistant".
I don't look forward to changing diaphragms every 3 years. I replaced the diaphragm in my R-2 in the 1980's when I lived in California and probably got it from Studebaker of California, now Studebaker International of Indiana, and it is still working. I doubt if it was NOS even then.

Jack