PDA

View Full Version : Worn out 289 with sticking intake valve??



Studebaker Johnny
09-16-2006, 03:32 PM
I have an Avanti R2 with recently rebuit AFB carburetor with new leaner metering rods & jets, new coil, plugs, plug wires, original Prestolite distributor OK as far as centrifugal advance weights and vacuum advance, on a 98,000 mile untouched original 289. I rebuilt the fuel pump a few years ago and think it works OK. My local Montana mechanic tells me that it has a sticking intake valve on cylinder #6 which causes it to backfire through the carburetor and stall. It will run fine on an idle, but will backfire or stall when put in drive or under a load. Held on a fast idle (2000 rpm) it will fluctuate regularly in speed down to 1500 up to 2000. It is virtually undriveable as it is, although it can slowly be teased up to speed at the risk of being stranded. It also has a tendency to flood after stalling. I could try to further lean out the idle screws, but I wish I knew where I could get better advice. I also have a home in SoCal and used to take it to Jon & Mike Meyers when it was newer, but hope to get the problem resolved without hauling the car to CA or OH. Where can I get the 289 rebuilt? Does anyone have any advice on how to procede further? I will be in Omaha for the meet on the 26th.

wagone
09-16-2006, 05:56 PM
I'm far from the expert others on this forum are, but I can't imagine one sticking valve making a car undriveable. Let's see what the experts have to say. Sounds like carb issues--but again we need the experts. Rebuilding AFBs "ain't" rocket science. If it tends to hunt up and down in rpm it might already be too lean.

wagone

JDP
09-16-2006, 07:22 PM
Check yhe metering rod springs. If they are too strong you don't have enough vacuum to pull the rods down at low RPM.

http://stude.com/sig.jpg
Studebaker On The Net
http://stude.com
Studebaker News Group
http://groups.google.com/group/alt.autos.studebaker
Arnold Md.
65 Sports Sedan(sold)
64 Daytona HT
63 R2 4 speed GT Hawk
63 GT Hawk
63 Avanti R1/AC
63 Avanti R2/4 speed
63 Daytona HT
63 Lark 2 dr.
62 Lark 2 door
62 GT(parts car)
60 Lark convert
60 Hawk
52 Starliner(sold)
51 Commander

Roscomacaw
09-16-2006, 08:47 PM
I'm having trouble with the "sticking valve" thing too. Too what degree did this guy tear into this engine to make such a determination?
Was it running OK before all this work was done to it or has it been setting for sime time prior to this?[}:)]

Miscreant adrift in
the BerStuda Triangle!!

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

JDP
09-16-2006, 08:54 PM
My thoughts were around the Carb becuase rebuilders often use too strong a spring for the low vaccum on a R2.

http://stude.com/sig.jpg
Studebaker On The Net
http://stude.com
Studebaker News Group
http://groups.google.com/group/alt.autos.studebaker
Arnold Md.
65 Sports Sedan(sold)
64 Daytona HT
63 R2 4 speed GT Hawk
63 GT Hawk
63 Avanti R1/AC
63 Avanti R2/4 speed
63 Daytona HT
63 Lark 2 dr.
62 Lark 2 door
62 GT(parts car)
60 Lark convert
60 Hawk
52 Starliner(sold)
51 Commander

Mike Van Veghten
09-16-2006, 11:28 PM
From the "flooding" & "tease it up to speed" parts of the statement...my bet would be in the carburetor and or timing (distributor problem in general) also.

A "stuck" valve would cause all kinds of racket (noise), it would run like crap at all rpm's, and would NOT cause a carburetor to flood over!! Wouldn't idle hardly at all.

Back fire, yea....but all the time, not just when trying to rev it.

You did say one thing correct....find a better machanic!!

Mike

64V-K7
09-17-2006, 07:38 AM
"New leaner metering rods & jets???!!... popping from carb??!!! " I'll bet that what you're experiencing, is detonation, from too lean a mixture. How did this "mechanic" determine you needed a leaner carb, on an R2? If anything, the jets and rods should have been replaced with the original sizes. This engine is designed to run rich, to compensate for the blower pressure and fuel demand.
The flooding is being caused by the fuel pressure boost with blower pressure. You have to tease the RPM up, because the mixture is too lean. Backfiring starts to occur, when your spark advance get near peak and preignition fires the mixture...
Tell the "mechanic" to RTFM and hope you didn't burn a hole in a piston

Mike Van Veghten
09-17-2006, 12:27 PM
55prez said -

quote:This engine is designed to run rich, to compensate for the blower pressure and fuel demand.

Where did you come up with that one?

Please enlighten me/all of us, how a Studebaker (any engine for that matter) can be designed to run rich?

Carbureted, mechanical fuel injection, electronic fuel injection, belt driven or gas driven blower, nitrous oxide all have their differeing fuel expectations.
It ALL goes to the amount of air going into the cylindres.
A blown engine and nitrous oxide injected will need a little more fuel because of the extra air being forced into the engine. That does NOT mean they are running rich.
Any fuel (gasoline, nitromethane, alcohol, nitrous) needs it's own particular amount of air to run right.

Rich is rich in any combination. The best power will NOT be gained, the best milage will not be gained, oil milage and spark plug milage will also suffer.

Just a suggestion...if you've got your engine tuned rich...you might try leaning it down a bit.

Now...if you mean with a supercharged engine, you need more fuel...you are correct (see above). But the "rich" statement does not work correctly.

Mike

64V-K7
09-17-2006, 06:54 PM
"Please enlighten me/all of us, how a Studebaker (any engine for that matter) can be designed to run rich? "

Here's your enlightenment...

You ever check the jet sizes on an R2 vs an R1 ... or a 57 GH Ww carb vs a standard 2 bbl.

The overjetting was established to have the engine run properly when the boost comes in. Failing to run a richer mixture, than a normally aspirated engine, will result in detonation, because the ratio would be too LEAN* It doesn't happen magically, it has to be there, so the mixture is statically richer on an R2, than it is, on an R1.

>>>"Now...if you mean with a supercharged engine, you need more fuel*."<<<

*I think this equates to running richer. Could you enlighten us, as to where the "more fuel" is going to come from, in this instance?

Studebaker Johnny
09-18-2006, 07:15 AM
Thanks guys for the advice. I do need a new mechanic, as this one here in Anaconda, MT (population 7,500) is stumped. Part of my problem is than few in this town know anything about Avantis. He did RTFM which I provided. I doubted his diagnosis as he did not check compression in cylinders. Problem started because of "backfiring" and killing, with carb as originally equipped, which led to checking distributor centrifugal and vacuum advance, followed by new coil and plug wires (didn't change dual points) and tuning to specifications for R2 (18 degrees before TDC @ 1800 rpm). Mechanic said distributor was "only getting 1/2 voltage". This apparently was fixed.

Talked to Jon Meyer, and after a lengthy discussion where he was skeptical about changing jets & rods, which I had bent in my rebuild of carburetor, I decided to try leaning down mixture with leaner jet and metering rods, using original springs, because of the persistent flooding and fouling of plugs. I guess the engine is "leaned to the max" and it usually starts and idles OK now, but problem is running at speed. I will try the advice you have given me to make it run richer.

BTW, the problem persists even with supercharger disconnected from carb. I will do one thing at a time, then possibly try setting timing back a little. I do have an R1 which runs OK, I could try swapping carbs for diagnotic purposes. I did have a problem with fuel line blockage near the tank but that was fixed earlier by John Metzger in CA. Thanks for advice so far.

Dick Steinkamp
09-18-2006, 10:29 AM
quote:Originally posted by Studebaker Johnny
Mechanic said distributor was "only getting 1/2 voltage". This apparently was fixed.


It's supposed to get 1/2 voltage...approximately 6 volts. There is a resistor in line to the coil to drop the voltage. If he bypassed this resistor it will burn out the coil and/or points rather quickly.



http://thenobot.org/images/s2d/s2d_01.jpg

Dwain G.
09-18-2006, 11:43 AM
So many possibilities here.......is it hard to start cold? When you try to open the throttle from an idle it spits back through the carburetor and dies? That's typical of an inoperative accelerator pump in the carburetor.
Or is this a more rapid and less severe 'popping' as the rpm is raised, and that has been traced somehow to number 6 cylinder? That could be a broken valve spring.

http://home.comcast.net/~jdwain/9GQ2.jpg
Dwain G.

Studebaker Johnny
09-18-2006, 04:17 PM
I replaced the accelerator pump myself from a kit from SI. It appears both to me and the mechanic (visually) to work correctly. The ballast resistor is hooked up right to deliver only reduced voltage to the coil and points. It does seem to "spit" back through the carburetor when opening the throttle, especially when in gear. I can get it to drive only with a very light foot on the gas pedal.

Studebaker Johnny
09-20-2006, 11:04 AM
[:p]Fortunately I have two Avantis, a 64 R1 and the said 63 R2, both high mileage original engine cars. Taking advice from this forum into account, I felt the problem was fuel/mixture/carburetion, so I swapped carburetors yesterday. Then, with one quart of Risolone added to the oil, I ran it at 2000 rpm for an hour. If the intake valve ever was stuck, that seemed to unstick it. Viola! Problem mostly solved. Said R2 is now drivable, both with and without supercharger attached, and it does not drive badly. The problem was switched with the AFB to the R1, which at least runs better than the R2 did. I will pull the "bad" AFB and work on it, to find out the problem. It could be the wrong metering rods & jets, or the springs on the metering rod pistons, or possibly the accelerator pump. But not until after the trip to Omaha (in a Cadillac). Someday I may be able to have a car in such shape to present at an International Meet. (sigh) :)

46 M-5
48 Champ Starlight
56 Sky Hawk
63 R2
64 R1
64 Cruiser

hank63
09-21-2006, 10:11 AM
Only my opinion, of course - but if it runs it's in shape to take to an international meet. I reckon a running Stude beats a non-runner any day. Go for it and enjoy the ride.
/H