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MagikDraggin
03-24-2007, 08:29 PM
Have been tinkering with my recently acquired 62 hawk, 289 4sp 4bbl (WCFB).

I notice when the motor is idling at 800 rpm, it idles smoothly....but the service manual says it should idle around 600-650 rpm.

However, when I set the idle at 600-650, there is a "rocking" motion going on, which gives the impression that one cylinder weighs 5 lbs more than all the others. Motor mounts are tight. Spark plugs and wiring all good and gapped correctly.

When sitting in the drivers seat, it actually makes me "bounce" up and down.... wobble back and forth....not really severe or extreme, but noticeable.

There are no accompanying weird noises, like puffing exhaust valves, or ticking and the exhaust is smooth on the palm of my hand. What could be causing this and how would I remedy it?

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/IM000987-reduced.jpg
1962 GT Hawk 4sp

sbca96
03-24-2007, 08:52 PM
I think its 800 rpm out of gear, and 650 rpm in gear for an auto?? Set
your parking brake and block the wheels.

Tom

'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires

GTtim
03-24-2007, 09:04 PM
One cylinder may have lower compression due to a valve or ring issue. If all the tune up items are in order, then the next step is to check the compression.

Tim K.
'64 R2 GT Hawk

Mike Van Veghten
03-24-2007, 11:50 PM
Have you run the valves yet?

Valve lash on only one or two misadjusted rockers will also do what you are refering to.

My preferance...adjust'em cold.
Save yourself the heartach of doing it "correctly" when hot. I've tried all the ways in my 56 years....cold is my prefered method.
And no mater what anyone says...a running engine, rocker adjustment is for "hydraulic" lifters ONLY....in my opinion!

Mike

P.s. - do a compression test. You may have a leaking valve.

1961HAWK
03-25-2007, 08:21 AM
Use a vacuum gauge and set your carb to peak vacuum. it could be an issue in your carbs idle circut . that issue could be it is set wrong.

Erin Hays
1961 Hawk
1962 Lark
1963 Wagonaire

MagikDraggin
03-25-2007, 09:17 AM
quote:Originally posted by 1961HAWK

Use a vacuum gauge and set your carb to peak vacuum. it could be an issue in your carbs idle circut . that issue could be it is set wrong.


Now that brings me to another question. But first, it "appears" that the carb is functioning as designed, in that it shows no outward signs of fouling by way of "varnish", and that it is readily responsive to adjustments of the choke and idle/air circuit screws.

The service manual is rather vague as to how to make the final adjustments with the air/fuel ratio screws. It says to fiddle with them until a steady idle is obtained and then continue turning them until the idle speed drops 50 rpm and that's it.

In the old days when I used to do this sort of stuff, I recall that the screws are to be turned clockwise, until the idle begins to drop (50 rpm) and then turned back counterclockwise 1/2 turn.

Is that how Studebaker intended for their WCFB carbs to be adjusted? Or does it not really matter WHICH direction the screws are turned, as long as you end up with a 50 rpm drop in idle speed?

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/IM000987-reduced.jpg
1962 GT Hawk 4sp

MagikDraggin
03-25-2007, 10:16 AM
quote:Originally posted by Mike Van Veghten

Have you run the valves yet?

Valve lash on only one or two misadjusted rockers will also do what you are refering to.

My preferance...adjust'em cold.
Save yourself the heartach of doing it "correctly" when hot. I've tried all the ways in my 56 years....cold is my prefered method.
And no mater what anyone says...a running engine, rocker adjustment is for "hydraulic" lifters ONLY....in my opinion!

Mike

P.s. - do a compression test. You may have a leaking valve.


In response to you and GT Tim, no I haven't done a compression test as of yet. And I was told by the PO that he had just recently done a valve lash adjustment......and I am confident that he knew what he was doing.

However, I suppose, just to be on the safe side, that I should recheck it to make sure.

Regarding there being a possible leaky exhaust valve, wouldn't I "feel" that with my hand over the tail pipe, like a rhythmic "puffing"? I mean, if it were burned to the extent that it would make the entire motor rock, I'd think I could feel that in the exhaust gasses. But I don't feel any kind of uneveness whatsoever.

I find it hard to believe just how much of this "old school" kind of stuff I have forgotten over the years. It's almost like starting out all over again.

Karl

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/IM000987-reduced.jpg
1962 GT Hawk 4sp

Alan
03-25-2007, 12:39 PM
What we used to do for a bad exhaust valve check was to put a piece of paper at one side of the pipe. If there was a bad valve it would suck the paper back toward the pipe, it would slap. Hard to tell by hand.

1961HAWK
03-25-2007, 04:57 PM
I always use a vacuum gage. set to peak vacuum works easy and you aren't waiting to hear the engine respond. it was also let you know if you have low vacuum from a possilbe leak or tight valves.


Erin Hays
1961 Hawk
1962 Lark
1963 Wagonaire

pete
03-26-2007, 05:23 AM
also check dwell angle about 29 degrees to 31 wwhich gives you the proper points gap eg. i did but points had to be 12 thou but i put in a new dizzy and then to get 30 degrees the points become 18 thou you see wear and tear othe wise wats been said above wouldnt be far wrong by the other guys pete

Roscomacaw
03-26-2007, 03:05 PM
"In the old days when I used to do this sort of stuff, I recall that the screws are to be turned clockwise, until the idle begins to drop (50 rpm) and then turned back counterclockwise 1/2 turn.

Is that how Studebaker intended for their WCFB carbs to be adjusted? "

Yes. Engine must be FULLY warmed - idle adjust screw turned back completely. Engine SHOULD be able to idle like this even if a bit roughly.
Then do the mixture adj screws as you decribe above. first one - then the other. then repeat at least once to prove that they're both at optimum.
MY rule of thumb with a carb that I've never adjusted is to turn the two mixture screws in until they bottom - being careful NOT to tighten them TIGHT! - just tighten them until you realize they've reached bottom. Then turn them out, at least two full turns before warming the engine and doing the final tweak as mentioned above.
Once you have the mixture screws set, go back and turn the idle adj screw in until you bring the idle up to the RPM you're happy with.;)

Miscreant adrift in
the BerStuda Triangle
http://images.andale.com/f2/115/106/906179/2006/12/7/truckonhill3.jpg

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

1961HAWK
03-26-2007, 03:30 PM
It can be done either way. The use of vacuum gage takes out some guess work. if you set your carb to peak vacuum. it is functioning at its best.
you should try it a couple times. you will find it is a very easy and accurate way to set a carb.


Erin Hays
1961 Hawk
1962 Lark
1963 Wagonaire

MagikDraggin
03-26-2007, 09:08 PM
Man, if it ain't one thing it's another. I managed to check out the distributor. Points are new; cap is new; rotor is ehhh, ok, but not fantastic; plug wires are new.

No play in shaft, dwell is right on the money and a steady reading. Timing is right on the "mark". Was suprised that there are no BTDC and ATDC markings on the crank pulley. I guess they wanted it timed right on that little mark and that's it.

Anyway, while test driving the rascal, I noticed when accelerating moderately through the gears, when I was in 3rd gear about 2800 rpm, the power went down as if one or two spark plugs had suddenly fouled out and began misfiring.

I let up on the gas momentarily and then went back to accelerating and all was well again. It does this every once in a while....not every time. I also notice that while in first gear, and slowly accelerating, sometimes the motor will suddenly "buck", as though just for an instant, all spark shut off, then came right back on again.

I re-inspected the insides of the distr, thinking it might be a bare spot on the secondary wire grounding out when the mech adv plate moved and found no problems.

I'm at a loss here as to what I should be looking for. Any ideas from some of the resident experts?

Oh and also, after shutting the engine off, I noticed a rather strong gasoline smell, and found that fuel was "hissing" into the intake manifold from the carb jets. Would this be a carb problem or something caused by excessive fuel pump pressure? (could possibly be part of the reason I have so much black sooty carbon being blown out of the tailpipe at start up, as well as the rotten fuel mileage I am getting).

Checked spark plugs and while they were showing signs of carbon buildup (rich mixture) and were gapped at .042, there was no signs of anything else amiss....and I regapped them at .035 before reinstalling them. The peculiar misfiring problem was still there, as well as the off and on "bucking" at lower speeds.

I am really trying hard to get this Hawk ready to make the trip to South Bend in June, but it seems like the more things I fix, the more things I find need fixin'.

All suggestions appreciated.

Karl

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/IM000987-reduced.jpg
1962 GT Hawk 4sp

showbizkid
03-26-2007, 11:11 PM
Sounds like time for a carb rebuild for sure - that's easy. But the bucking... that sure sounds like a partially clogged exhaust system to me. I've experienced that symptom many time with various cars, and it's always turned out to be clogged mufflers (or catalytics, with newer vehicles).

If it was me, I'd take the car to my friendly local muffler shop and ask them to inspect the system.


[img=left]http://members.cox.net/clarknovak/lark.gif[/img=left]

Clark in San Diego
'63 F2/Lark Standard
http://studeblogger.blogspot.com

mapman
03-27-2007, 02:00 AM
Also check your spark advance systems. Both mechanical and vacuum. Make sure there is no leak in the vacuum advance or hose. check to see that it advances correctly and holds as engine speed increases.
Rob

MagikDraggin
03-27-2007, 09:13 AM
quote:Originally posted by showbizkid

Sounds like time for a carb rebuild for sure - that's easy. But the bucking... that sure sounds like a partially clogged exhaust system to me. I've experienced that symptom many time with various cars, and it's always turned out to be clogged mufflers (or catalytics, with newer vehicles).

If it was me, I'd take the car to my friendly local muffler shop and ask them to inspect the system.


Clark in San Diego

Okie-dokie, a carb rebuild it will be. Hope that helps. Regarding the exhaust system, I have already had both turbo mufflers replaced due to clogging and collapsed baffles inside.

My intuition tells me the "bucking" is electrical in nature, but so far I've been unable to locate the cause.

Has anyone replaced that old WCFB carb with a newer style Edelbrock/Carter AFB, and if so, is it a difficult modification and worth the time, effort and money?

Thanks to all for the helpful input so far. I'm gettin' there, "one piece at a time", heh.

Karl

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/IM000987-reduced.jpg
1962 GT Hawk 4sp

N8N
03-27-2007, 09:30 AM
WCFB to AFB is not a bolt on, the bolt pattern on the carb baseplate is different. Jeff Rice is your man for AFB intakes, if he's back up and running yet.

good luck

nate

--
55 Commander Starlight
http://members.cox.net/njnagel

1961HAWK
03-27-2007, 10:49 AM
an eldelbrock fits on the wcfb intake no big problems. it uses the inner bolt holes on the carb.you need a small spacer under the carb to get the linkage to clear. and will have to drill out the mount hole alittle where your linkage bolts on. i run one on my lark and used my wcfb intake until the hawk needed it. then had a two barrell intake modified for the lark.
it is possible you have float issue. a pinhole in a brass float will gradually get worse over time letting the carb over fuel.
so be cure to check your floats well when rebuilding.

Erin Hays
1961 Hawk
1962 Lark
1963 Wagonaire

sbca96
03-27-2007, 02:10 PM
The bore spacing and size is different between the WCFB and the 600
CFM Edelbrock carb. The linkage requires a spacer as mentioned. The
bolt pattern is the same as mentioned. I think that the 500 cfm is
similar to the WCFB, but I am not positive. To use the Edelbrock (or
the Studebaker Carter AFB) on a WCFB manifold, you should have the 4
holes bored out to improve flow. Or you can end up with some jetting
issues and drivablity problems. One of the best upgrades I did to my
60 Hawk was going to an AFB (from a junkyard Caddy), and than later
to an Edelbrock AFB.

Tom

1961HAWK
03-27-2007, 03:30 PM
http://www.chevyhiperformance.com/howto/45638/

here is a good site on setting idle mixture.
if anybody wants it.

Erin Hays
1961 Hawk
1962 Lark
1963 Wagonaire

PlainBrownR2
03-27-2007, 05:38 PM
Another source for the "bucking". This will probably appear in the glass fuel filter as a lack of fuel or a great deal of sediment. If there is any sediment in the tank, and it gets into the line, it will plug the line, thereby starving the car of fuel. This also happens if you run out of gas(dont ask how I know this :) ). The sloshing of the fuel will cause the car to buck and surge.
With the former, its a simple matter of popping the line off of the tank. There should be a pinkie diameter stream of fuel coming out of the tank. If its only a trickle or none at all, the outlet is plugged. I solved this by sealing the fill hole and running compressed air, into the fill hole to push the sediment out of the tank. That and maybed using some pipe cleaners to clear the outlet. Haven't had any problems with this since then.


1964 Studebaker Commander R2 clone
1950 Studebaker 2R5 with 170 turbocharged
[img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00003.jpg?t=1171152673[/img=left]
[img=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00009.jpg?t=1171153019[/img=right]
[img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00002.jpg?t=1171153180[/img=left]
[img=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00005.jpg?t=1171153370[/img=right]

jpvill4th
03-31-2007, 01:35 AM
"I think its 800 rpm out of gear, and 650 rpm in gear for an auto?? Set your parking brake and block the wheels."


I think you may be correct on this. Ted suggested that I do this with my OHV6 Lark and it seemed strange when I consulted the shop manual (shop manual is not clear with automatic equipped cars), but I have changed it in this fashion - setting the idle with it in drive and it has made a big difference. The OHV6 engines I have had have always had a bit of a lope at idle and under load but not moving which I think may have something to do with the intake manifold runner lengths.