Need help with stalling problem

[irishman]

When my Avanti R2 gets hot it stalls when I slow down for a light or stop sign. At first it will restart after a few tries accompanied by splutters and a backfire or two. But once the problem starts it gets worse and worse until finally I have to wait for the engine to cool completely. Then it restarts and runs well. Engine has been freshly rebuilt and the carb just came back from Dave Thibeault.

I have heard that the problem is fairly common since so much ethanol has been added to gasoline and that the ethanol causes the fuel to vaporize at a relatively low temp. Have also heard two possible solutions. One is a mod to the manifold to close a heat conducting channel. The other is to add about a gallon of diesel to each tank of gas to elevate the fuel boiling/vaporizing temp. Does anyone have any real knowledge on this? Thanks in advance.

[Gunslinger]

Has this been a problem only since the rebuild? It could be related to the carb rebuild. THe carb could be properly rebuilt but the jetting may need to be matched to your specific engine if you live in higher altitudes, or a float or the accelerator pump is out of adjustment.

I do remember that Studebaker Avanti's had a hesitation issue when the temperature got high...the R1 I used to own suffered from that...in cool temperatures it ran fantastic but in hot, humid temperatures it would hesitate and stumble. Studebaker even put out a service letter on the problem and it was carburetor related. There was a modification for curing it and my R1 apparently never got the modification.

Overall, it does sound like vapor lock. You might try re-routing the fuel line to the carburetor or wrapping some header tape around it to help insulate it from the heat. You could also install an electric fuel pump and bypass the mechanical pump altogether.

I've never heard of adding diesel fuel to the gas tank...that does not sound like a healthy thing to do.

[avantifred]

It's hot where I live but my Avanti does not suffer from vapor-lock like your car obviously does. I have a fix....BUT you have to promise NOT to laugh when I tell you the fix. I'm old, a lot older than my '64 but here goes: go into your wife's laundry room and grab a handfull of the clothes pins with the springs on them. They MUST be wooden. Next open the Avanti's hood and clip them onto the fuel line running to the carburetor. You should clip them before & after the in-line fuel filter. Put them on about every 2 inches or so......well. that's it. Give it a try, it SHOULD work.

Fred

Edited June 13, 2011 by avantifred

[Stan Gundry]

I also have an R-2. For years I had the same kind of stalling problem when it got really hot. Over the course of 15 years or so I tried a number of things such as changing the jet/metering rod combinations, replacing and adjusting the accelerator pump, repairing a leaky float, adjusting float levels, several new carb kits installed, and so on. Nothing solved the problem.

Finally, I installed the Edelbrock 1406 knock-off the the Carter AFB, including the electrical choke. I have never had the problem again. No, I have not had to seal the carburetor for use with the supercharger, though I have a marine style accelerator pump with the seal for shaft ready to install if I start getting leakage there. It is not pure stock, but it improved driveability and I no longer fear the car stalling and not being able to restart at a busy intersection.

[Billy Shears]

I experienced a vapor lock problem with my Avanti just a couple of hours ago. I just took the car back yesterday, after a very, very long delay, from having one of Nimesh Solanki's R2 engines put in it. The delay was caused partly by the first mechanic I got (someone recommended to me) being incompetent and a procrastinator. I turned the job over to a very good mechanic, but he had the car longer than expected because getting it to run right proved something of a problem. I ordered the engine from Nimesh with one of his performance-oriented camshafts, and am now wishing I hadn't. Cars with radical cams never really idle well, but getting this engine's idle adjusted has been a real pain in the butt -- if you get it to where it idles smoothly, it wants to stall out when you drop it in gear; but if you get it to where the engine won't stall when it's idling in drive, it races in neutral. Nimesh has a similar camshaft in his car, but likely doesn't experience the problem because he's got a five-speed manual. I'm going to put one in my car as well (in fact I just bought a used Tremec TR3550 whose arrival I'm awaiting as I type this), but until then, I have to drive the car as a "two-footer," (left foot on the brake and right on the gas pedal) else the engine will quit when I'm slowing down to make a turn or stop at an intersection.

Well, after getting the car up on the interstate this morning (where it cruised along quite well), I got off at the ramp nearest my house, drove the half-mile or so to my street, and the engine died right at my driveway. I couldn't get the car restarted until I waited for it to cool down. I think the problem was that after that cruise, with the engine heated up, when I got off the ramp and had to wait at several lights, in 90 degree heat, with one foot on the gas to keep the engine idling above 1500rpm so it wouldn't stall out with that lumpy idle, the temperature climbed just enough. The engine never got close to overheating or anything, but it got hot enough to cause vapor lock.

I'm not going to get much enjoyment out of driving this car this summer until I find a solution to this. The five speed will help, I think, since I won't have to worry about a sudden dip in rpm going from neutral to drive the way an automatic does. But I think I'm going to go back to the stock camshaft. I like extra horsepower, but I am not liking what this cam is doing to driveability. The stock cam will probably be good enough, and should allow the engine to idle smoothly at lower rpms, which will help sitting in traffic, I think.

[Gunslinger]

When an engine is built and the components are selected they have to match one another's characteristics or the whole will be less than the sum of its parts. No matter how good the quality of the components are, unless they're well matched the engine simply won't run to its potential.

I used to own a '78 Corvette L82...the hydraulic lifter version of the LT-1 engine. A previous owner installed a higher performance camshaft with no other changes...it wouldn't idle for crap but ran strong otherwise. I took the car to a carburetor guy who re-jetted the carb and it ran great after that.

The carburetor could be running very lean...it makes for a hotter temperatures...running rich makes for a bit cooler running, at the expense of fuel economy. Your idle circuit may need richening. I'm no carburetor expert...carbs are voodoo to me...just going by past experience.

Making any changes...intake, camshaft, carburetor, etc., and it throws out of kilter the balance designed into the original setup. That needs to be addressed by further changes...even minor changes to bring everything back into balance for best performance.

Your carburetor probably needs to be jetted to match the new cam profile. You could also have a dashpot out of adjustment or it could need replacing. There could be a vacuum leak. The distributor could also benefit from being curved to match the cam profile. If it's the original Prestolite distributor, it may have worn bushings...a common problem. Some of what I'm saying may have little to nothing to do with your immediate problem, but addressing all these more or less minor things can result in a noticeable increase in drivability and performance.

Edited June 17, 2011 by Gunslinger

[Billy Shears]

Your carburetor probably needs to be jetted to match the new cam profile. You could also have a dashpot out of adjustment or it could need replacing. There could be a vacuum leak. The distributor could also benefit from being curved to match the cam profile. If it's the original Prestolite distributor, it may have worn bushings...a common problem. Some of what I'm saying may have little to nothing to do with your immediate problem, but addressing all these more or less minor things can result in a noticeable increase in drivability and performance.

We did all that. In the two months my second mechanic had the car, he checked everywhere for vacuum leaks; checked the distributor; rebuilt the sealed Carter AFB with a kit from Myer's Studebaker; replaced the sealed Carter AFB with an Edelbrock 1406 (with marine grade seal installed in the accelerator pump), which helped a little; adjusted both carbs extensively, looking to get it just right. We really left no stone unturned We've got it about as good as we can get it. As I said, I expect the transmission change will make things a little better, since the car will either be in neutral, or I'll have my foot on the gas. And it has a lumpy idle, but in neutral it doesn't tend to stall out.

I still think the cam, in my case, is a little more radical than I want to live with for what will be almost entirely a street car. Aside from the rough idle, the engine only makes 5 inches of vacuum, for example, so I had to put a vacuum pump and vacuum reservoir on the car to get my brakes back. And even in neutral, when the transmission's not putting a load on the engine, the engine has to be set to idle a little faster than a smoother idling car would in order not to stall out, which makes vapor lock a little more likely. I imagine a rough idle will make starting and running in cold weather a bit more challenging as well, at least until the engine gets completely warmed up.

[Avanti83]

We did all that. In the two months my second mechanic had the car, he checked everywhere for vacuum leaks; checked the distributor; rebuilt the sealed Carter AFB with a kit from Myer's Studebaker; replaced the sealed Carter AFB with an Edelbrock 1406 (with marine grade seal installed in the accelerator pump), which helped a little; adjusted both carbs extensively, looking to get it just right. We really left no stone unturned We've got it about as good as we can get it. As I said, I expect the transmission change will make things a little better, since the car will either be in neutral, or I'll have my foot on the gas. And it has a lumpy idle, but in neutral it doesn't tend to stall out.

I still think the cam, in my case, is a little more radical than I want to live with for what will be almost entirely a street car. Aside from the rough idle, the engine only makes 5 inches of vacuum, for example, so I had to put a vacuum pump and vacuum reservoir on the car to get my brakes back. And even in neutral, when the transmission's not putting a load on the engine, the engine has to be set to idle a little faster than a smoother idling car would in order not to stall out, which makes vapor lock a little more likely. I imagine a rough idle will make starting and running in cold weather a bit more challenging as well, at least until the engine gets completely warmed up.

Billy, I know this is stating the obvious but why not just replace the camshaft with one that behaves better. A lot cheaper than switching to a 5-speed and still having all the issues you described. I too wanted a five-speed in my 83 but finally figured a 200R4 AOD would serve better.

I also have a significant cam in it with a lot of duration and lead but it does not have the issues you are having with your R2. But mine is an SBC that has the stall speed and manifold to handle it.

Let me make a recommendation. Ask the folks at Racingstudebakers.com to advise you on a better all around camshaft or if you choose to not go that route on RS, there are several individuals on the SDC forum that can also help. Both Jack Vines and Mike Van Vieghten (sp?) have been building high performance Stude engines for a long time and you could email one of them. Jack and Mike are on both sites.

An Avanti that runs like yours takes a lot of fun out of the great experience of driving a well performing car. Mine is a blast as I can leave big long marks if I like or run down the road at low speeds or even sit and idle for long periods. I'll bet in the end you will lose little if any performance with a better stick.

Bob

Edited June 18, 2011 by Avanti83

[Billy Shears]

Billy, I know this is stating the obvious but why not just replace the camshaft with one that behaves better. A lot cheaper than switching to a 5-speed and still having all the issues you described. I too wanted a five-speed in my 83 but finally figured a 200R4 AOD would serve better.

I intend to replace the camshaft and put in the five speed. I always intended to put in the five speed. Before I ever contacted Nimesh to get the engine from him, I planned on putting in a five speed. Lots of owners have used Dan Giblin's kit to put Tremecs in their Studebakers, looking for better performance and driveability, just as lots of other muscle car owners have put five speeds in their old rides for similar reasons. I want the overdrive. I like to take my cars places, and driving several hours at a stretch at steady 3600rpm, with loud exhaust is fatiguing, not to mention the difficulty of hearing passengers or the radio. And it would also be nice to be able to pass by at least a couple of gas stations without having to stop and refill the tank. The overdrive will also mean less wear on the engine, in the long run, as well as the alternator, water pump, supercharger, and everything else attached to the engine that turns along with it.

The TR3550 will give me the overdrive, and is a good transmission, strong enough for the engine I've got. And I just plain like driving a manual better than an automatic, especially in a car like the Avanti.

I also have a significant cam in it with a lot of duration and lead but it does not have the issues you are having with your R2. But mine is an SBC that has the stall speed and manifold to handle it.

Let me make a recommendation. Ask the folks at Racingstudebakers.com to advise you on a better all around camshaft or if you choose to not go that route on RS, there are several individuals on the SDC forum that can also help. Both Jack Vines and Mike Van Vieghten (sp?) have been building high performance Stude engines for a long time and you could email one of them. Jack and Mike are on both sites.

An Avanti that runs like yours takes a lot of fun out of the great experience of driving a well performing car. Mine is a blast as I can leave big long marks if I like or run down the road at low speeds or even sit and idle for long periods. I'll bet in the end you will lose little if any performance with a better stick.

Bob

I've already spoken with Phil Harris at Fairborn Studebaker. I may contact some of the other you suggest.

[Gunslinger]

With only 5 inches. of vacuum, there is definitely something wrong. Even with the more aggressive cam it should still be pulling 12 inches or more vacuum. A stock cam at idle should pull 15-17 inches at least. There has to be some kind of mismatch going on or vacuum leak. It would be unheard of to find the camshaft was timed wrong when installed. Maybe even the valves are adjusted improperly.

An Edelbrock 500 cfm carb would be a better choice for a 289 engine than their 600, but that would have nothing to do with the poor idle, but could stumble on takeoff. If they've set the carb up correctly that shouldn't be an issue.