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avantibngrant
09-07-2012, 02:21 PM
I am looking to change my springs which open the step rods as they seem to be opening too early. I bought the 5 differnt combinations from 2 in of hg to 8 inches I believe. I was wondering what the original ones should be in terms of in of hg as mine may well have been changed. Also, what whould the jet and needle diameters be stock? Mine may well have been changed over the years and I am wondering which springs and rod/jet diameters it came with originally as a good starting point.

Regards

Neil

Gunslinger
09-07-2012, 04:17 PM
The parts manual doesn't give the specs of the stock needles and jets...only the part numbers. You might give Jon Myer a call for advice on that since he rebuilds these carburetors routinely. If Jon doesn't have the parts you might want, give Edelbrock a call with the specs as their carburetor is an updated clone of the AFB and many parts interchange.

bezhawk
09-07-2012, 09:57 PM
I use the orange springs....I believe they are listed as 5 in of HG. .095 jets. , and Edelbrock 1456 metering rods- .073 x .047 @ appprox sea level.

KOOL R2
09-08-2012, 07:52 AM
Factory main jets were .101.5 and secondaries were .089 Metering rods were .076 X .055 with "orange" springs. With today's fuel containing so much ethanol I am using .071 X .047 metering rods. Also for track use I have my secondaries set at .095

Neil, do not attempt to try to lean out a supercharged engine. Bad things happen.!

Peter Sant

WCP
09-08-2012, 12:24 PM
Neil, it is good to start by identifying what you have. The carb should be a 3507S, 3588S or 3725. Mine is a 3588S and would have been supplied with 16-263 rods, 120-162 primaries and 120-159 secondaries. These numbers should be stamped on the individual parts. Carter listed the 16-263 rods at .076x.049, 120-162 at .1015 and 120-159 at .089. Later replacements for these jets would have been numbered 120-401 and 120-389 respectively. My 3588S has 16-263 rods, 120-162 primaries and 120-392 secondaries (.092). As Peter says, you don't want to go lean with the secondaries open.

avantibngrant
09-08-2012, 05:58 PM
Thanks folks for the feedback. I took the springs and step up rods out today when I came back from a car show at a local fair on "Drive Your Studebaker Day".
The findings are as follows
Step up rods measured .045 and .079 with my vernier
Springs were the silver ones - the 8 in hg per my measurements.
I did not take the cover off the carburetor to take out the jets. I put the orange springs in an put it together. I took it for a test drive. It is a little better, but still not the power I would expect. It will not squeal the tires with a hard first gear take off - R2 - 3.73 rear end and 205/75 tires with power shift.
I checked the timing and found it was a little advanced per R1 specs which I am supposed to set it to per Dave T whom I bought the distributer from. I set it back to the 4 degrees from the 6 or 7 it was at with the vacuum advance disconnected and taped at idle. Net result is it is even a little less responsive.
To be clear, it is about as fast on the take off as my 63 GT was with the 2 barrel and 3.54 rear axle - still respectful, but I don't think up to its full potential. My next move is the get my son to hold the gas pedal to about 1600 rpm and see what the timing says.
When I think about it more, I am not getting full vacuum at the vacuum advance at idle. It does go up a little when I rev it up off idle, but I would think it should be full vaccum at idle? It is routed to the front of the caruretor via a rubber hose to a steel line. At no load, how should vacuum at this port vange with rpm?
I think the step rods are in the ball park for size, but I will need to take the top off the carburetor to get at the jets. Before I do, I will get new ones to have on hand. I have a lung disease and I don't relish messing with the stinky gas any more than I have too.
What do you experts think about the step rods and the timing?
Regards
Neil

KOOL R2
09-09-2012, 10:01 AM
Neil, I think that your Carburetor is OK with the metering rods that you have provided that the main and secondary jets are at factory sizes.
They say that timing is everything!! I am running at 30 degrees at 1600 rpm with vacuum line disconnected. At the track I bump this up a bit more. The vacuum advance should show zero inches of vacuum at idle and increase to about 15-20 degrees at cruise speed. If you set the timing as I describe you will end up with "basic timing at around 15-17 degrees advance at idle. My Avanti seems to like this setting and the power is adequate.


Peter Sant

WCP
09-09-2012, 12:30 PM
Neil, just a thought - do you have the proper higher rpm stall torque converter in that car? You can check that out by putting in "drive", holding the brake on, and flooring the accel pedal. You should get 2100-2200 rpm as I recall. Don't hold it at full throttle for more than a few seconds and have an open foreground. If that checks out, drop it into 1st, put into stall and release the brake pedal. I'm sure you will light up the tires. You need to have the blower speed up to achieve the power you're after.

avantibngrant
09-09-2012, 09:09 PM
Peter. I think you are right on more advance. My experience with my tractors is advance as far as possible withjout pinging on a hard pull and no startert binding.
Just looking at the centrifugal advance curve int he repair manual for the R2 - 1600 RPM shows an advance of 18+/-2 deg and and the same for the R1 at 1600 rpm. My Malory is to set up per the R1 curve which is a little different as at 2000 RPM, the adavnce peaks out at 20 +/-2 deg. So with the 30 degrees, the idle no vacuum advance basic timing would be 30 - say 16 to 20 which would be 10 to 14 if my math is right? It seemed to run better at 6 degrees than 4 so I would well amagine another 10 degrees or so will help for sure. It is exactly what I would do if I was working on one of my tractor engines. A by product will be it will run cooler also. I am going to try to set it to 14 at idle and try that. It will make it a one person job and more importantly, how would you set it to 30 degrees as the numbers end at 24 degrees btdc?
Thanks again for all your help. BTW I really enjoyed the visit with you in Kingston.
Regards
Neil

avantibngrant
09-09-2012, 09:13 PM
WCP, I will try that for sure after I get the timing set a bit better per Peter's good advice. I suspect it is ok as I think it has never been apart.
I am not looking at burning the rubber, but I just am trying to get it to not stumble on take off as it does some times.
Were you one of the folks at the Kingston event?
Regards

Neil

KOOL R2
09-10-2012, 07:51 AM
Neil, Use a "dial back" timing light. Set the dial on the light to 30 degrees and run up the engine to 1600rpm with vacuum line disconnected and the timing mark should point to "zero" on the timing plate.

Peter Sant

avantibngrant
09-10-2012, 08:52 PM
Peter and WCP - thanks for the advice.
Peter, I see what you mean about the set back timing light. That is a feature of the $149.00 Candian Tire one. The Scottish blood in me made me buy the $49.00 one instead which does not have this feature. I set the idle timing to 14 degrees with the vacuum advance disconnected. That sure livens it up at the lower end. No binding on the starter and no pinging as of yet. I had a visit from a Scottish collegue from the UK today and was describing the situation and he was saying a couple of pings on acceration is "the sound of fuel economy" I don't hear any yet, but I think I will drive it for a while like this and check the mileage and operating temperature. If it is ok, I may advance it to 16 degrees.
I do find it interesting it runs so much better at 10 degrees over the stock setting. What do you other guys set the timing too?
WCP, I tried the stll speed and it is about 2200 rpm. It will definetly break the tires loose with a rev up in low with the brakes being released. I did not want to do it to much around my house, but it seemed to break the tires loose in low also if I am percieveing it right. I am just glad to get the stumble put to bed which seems to be so far. There still is a little change in engine speed through 1500 rpm as the carbureter changes circuits, but I will live with that to be sorted out later.
Thanks again.

Neil

ronhusak
09-11-2012, 10:04 AM
avantibngrant (http://forum.studebakerdriversclub.com/member.php?731-avantibngrant) ..
Be very careful with too much advance on a supercharged car.. You won't have the "sound of economy" but will have the "sound of destruction". With all the other noise of full boost loud exhaust and all it can be very difficult to hear the sound of dentonation.. Err on the side of being conservative.. This can damage an engige quite quickly..
Ron Husak


Peter and WCP - thanks for the advice.
Peter, I see what you mean about the set back timing light. That is a feature of the $149.00 Candian Tire one. The Scottish blood in me made me buy the $49.00 one instead which does not have this feature. I set the idle timing to 14 degrees with the vacuum advance disconnected. That sure livens it up at the lower end. No binding on the starter and no pinging as of yet. I had a visit from a Scottish collegue from the UK today and was describing the situation and he was saying a couple of pings on acceration is "the sound of fuel economy" I don't hear any yet, but I think I will drive it for a while like this and check the mileage and operating temperature. If it is ok, I may advance it to 16 degrees.
I do find it interesting it runs so much better at 10 degrees over the stock setting. What do you other guys set the timing too?
WCP, I tried the stll speed and it is about 2200 rpm. It will definetly break the tires loose with a rev up in low with the brakes being released. I did not want to do it to much around my house, but it seemed to break the tires loose in low also if I am percieveing it right. I am just glad to get the stumble put to bed which seems to be so far. There still is a little change in engine speed through 1500 rpm as the carbureter changes circuits, but I will live with that to be sorted out later.
Thanks again.

Neil

avantibngrant
09-11-2012, 12:16 PM
Ron, I agree with you as the exhaust is pretty loud. What do you run for timing with the R2? Does the 14 sound out of the ball park? It seems to make sense per the 30 degrees petter is using at 1600 rpm, albeit on the high side of the range. I could put it in the middle at 12 degrees. I do not want to harm the wonderfull piece of history I get to drive to cruise nights.
Regards

Neil

ronhusak
09-11-2012, 12:44 PM
avantibngran (http://forum.studebakerdriversclub.com/member.php?731-avantibngrant) Neil..
Can't go by what I use as I live at 9000 feet and mine can tolerate and in fact needs more advance..
Check the manual.. Then maybe a touch more..
Ron

KOOL R2
09-11-2012, 04:00 PM
Neil, If the distributor is set up to give 20 degrees mechanical advance and you add another 14 degrees on top of that you are pushing the nevelope to the extreme. At the track with 112 octane racing gas I will run a total of 32 degrees. This is as far as I am willing to push it. I know other guys have gone further but I drive my Avanti to and from the track a round trip of 1100 miles.
I would go no further than 30 degrees mechanical if you are using the 91 octane available in Canada.

As mentioned in an earlier post, detonation cannot be detected in an Avanti at full throttle. Your only evidence of detonation is the aluminum deposits on your spark plugs which means your pistons are not doing well at all.
Peter

avantibngrant
09-11-2012, 09:23 PM
Peter, Ron et al. You folks have saved my bacon. I looked at the the info I received from mallory. The total advance is 24 degrees coming in at 3000 to 3200. When I plot it all in excel, I get some interesting timing happening at different rpm's - assuming fulll load and the vacuum advance is not part of the equation. I see why it accelerated better with 14 initial (it inear where it should be between 1000 and 2000 rpm) and I also see why it would have cooked itself with much runinng over say 2500 rpm at full load - way too much timing as in 38 degrees at 3100 rpm. I set it back to 6 degrees tonight and when I tightend it up, it was at 7. I will get the mallory kit to set it up to match what it should be.
Thanks very much for putting the flags up for me to see.

Regards

Neil

bezhawk
09-12-2012, 08:34 AM
The jets I used stated I used was not a shot in the dark, but rather dyno tested under full load, and 7 lbs boost, never went lean, in fact showed 12.4:1 air/fuel.
They are the same jets you will get if you purchase a new 1406 Edelbrock.

64V-K7
09-12-2012, 10:40 AM
What kind of file is in that zip package. It unzips fine but I get an error in trying to read the file. It's not a BMP, as the header says 'BMF'

WCP
09-12-2012, 12:28 PM
Neil, in following your progress, I've been puzzled why you were trying to make an R1 setup suit an R2 - like putting a square peg in a round hole. However, I guess by your last post that you have come to that realization. I assume that you have ordered advance curve change kit #29014 or something similar. You want 20 degrees max. mechanical advance. That needs to be verified and use a matched set of the lightest springs to yield full mech. advance at 1200-1400 rpm. Check the vacuum advance with a hand vac pump - no advance at 8" Hg and 16 degrees at 16" Hg. Although I'm not familiar with the Mallory unit, with some improvisation of a distributor degree plate, verify that you have max 10 degrees mech advance and 8 degrees vac advance at 16"Hg on the distributor. Set initial timing at 4 degrees and then verify that you have 24 degrees at 1600 rpm. or adjust accordingly.

avantibngrant
09-12-2012, 08:28 PM
WCP, I guess it all started trying to get a stumble out of the car on acceleration. I was and still am to some degree getting a situation where the vacuum drops enough to cause the step rods to lift up and cause stumbling from a too rich condition. I have since changed to the orange springs from the silver ones which ahs helped. The issue is still on some occoasions the vacuum still drops enough to open the step rods. I have a Mallory Unilite which I bought from Dave Thibeault which works fine, but as per the paper that comes with it, it is set up closer to the R1 setup, but not even matching that set up. THe total mech advance is 24 degrees at 3100 and it starts to come one at 1100 rpm which is different thane the R2 or the R1 for that matter. I hope you can see the picture this time. The only way to get the curve to line up with the R1 even curve at 4 deg initial timing is to set the initial timing to 14 degrees. This gives better lower end start off without the step rods opening too soon. The downside is the upper area is off scale for advance. You are right. I need the kit to set the curve to get closer to the R2 curve. That will be done in the off season this winter.
Thanks for the tips on the vaccum advance settings.
Neil

WCP
09-12-2012, 10:03 PM
Neil, change the advance weights to give 20 degrees max and use the lightest springs for "all-in" advance at 1600 rpm. That combined with the 16 degrees of vac advance at 1600rpm yields 40 degrees advance at light load. You will have lots of vacuum. Match the R2 distributor curve and your stumbling problem will probably go away. Then you can tweak the jets, rods and springs for good spark plug color and reasonable economy and performance.

Jackson
09-13-2012, 07:17 AM
I have a 64 Avanti R2 that I drive daily. The original engine block has been bored .125 and uses Chevy 305CI dished pistons . The carb has the original carter top with an Edelbrock base and an electric choke, the jets are .095 and the rods are 73/42 with orange springs. The distributer is a Mallory from T-bow with the timing set at 14. The trans is a TCI 200 4R, the diff is a flanged 3.73, I get an actual 17.5 MPG highway, the Avanti drives great, turns 2100 RPM at 70 MPH, uses no oil and gets a lot of attention, I do not take it to the track.

avantibngrant
09-13-2012, 12:09 PM
I wonder if your dished pistons would have lowered the compression ratio which would tolerate more timing. I am assuming the 14 degrees is initial timing without vacuum advance and at idle speed. With the stock curve from mallory, you would have up to 38 degrees at 3100 rpm then not including vacuum advance.
I get about 17.5 mpg avg, but to the Canadian gallon or 14.5 to the US gallon.
The 2100 at 70 mph - you must have overdrive in the tranny. Must be nice!! Mine is powershift and 3.73 rear. I need 3000 rpm plus to keep up with traffic at all. About 2800 rpm for 60 mph.
Regards
Neil

bige
09-21-2012, 07:22 PM
I know a little bit about Jackson's set-up. The Mallory distributor was modified to limit mechanical advance to about 14-16 degrees so that full advance is not more than 28-30. The car has compression close to the original R2 spec. The heads are std. compression heads not R2 low compression style, it has thin head gaskets, and blocked exhaust crossovers to keep the intake charge cooler.

If you curve the distributor to limit total advance to 26-30 you can run initial at the 14-16 without detonation. Also it's important to check timing at rpm above 3,000 rpm. You may find that the advance continues in the aupper rpm ranges. In other words if you are seeing your desired setting at your desired RPM it doesn't mean you are done. Make sure that advance does not continue past that point.

I'm confused about the springs opening the jets " too early"? What symptom were you trying to cure? Unless you have a severe restriction somewhere any of the springs will push the rods up under full throttle acceleration as vacuum disappears. A weak spring may cause a flat spot under part throttle acceleration, keeping the rod down and too strong a spring will give you an over rich idle allowing the rod to rise.

If you have your timing squared away look to the accel pump for bogging issues, also float levels. I tweak the "s" clip on the accel pump linkage to remove play. If you move your linkage by hand and watch the pump rod itself you wull be surpised how much play there is before the pump moves in relation to the throttle opening.

Also, I highly recommend blocking the heat riser passages in the manifold either removing the heat riser or fixing it in the open position. The blower is heating the air as it comes in, the manifold is heating the fuel in the carburetor and in warm weather you end up with an over rich condition so the engine is effectively flooded before you even step on the pedal.

But in the end...I say "timing is everything".

ErnieR