I could use some help with this

[MagikDraggin]

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?


1962 GT Hawk 4sp

[sbca96]

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]

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]

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.

[Guest]

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]

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?


1962 GT Hawk 4sp

[MagikDraggin]

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


1962 GT Hawk 4sp

[Alan]

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.

[Guest]

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]

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]

"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


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

[Guest]

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]

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


1962 GT Hawk 4sp

[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.


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

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

[mapman]

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