Stinky 63 340hp

[Stuart F.]

Re: Stinky 63 340hp

Just an update on my Stinky 63; I took my drain oil from my last change to the local auto parts store and they refused it because they said it smelled like it had gas in it. To verify this, I took a sample in to a local lab that does oil analysis and it does indeed have gas in it.

Now, I never was able to detect any dripping in the carb after shut down, but it is obvious that that is one of the sources for my strong odor in my garage, and it is where I will expend my first efforts to remedy the situation.

For any of the members with 63's or other years having a similar problem, that has to be one place to look. Pull your dip sticks and smell the oil for any sign of gas.

And so you ask; how will you get rid of 6 quarts of contaminated drain oil? Well, how about using it for Tiki Torch fuel? Should be easy to light, and God help those skeeters!

Stu Fox

[John D.]

Re: Stinky 63 340hp

Stu, Very dangerous situation. If a fuel car dumps gas in the engine it is typically short lived. Hydraulic lock up is around the corner. A troublesome FI unit can cause this. That's why I (we) push siphon breaker kit shut off solenoids for the 57 to 62 FI's. As you found out a carb can dump gas too. If your engine is hard to start and you keep cranking and cranking you see what can happen. Thinned out rotella. I am glad you discovered this problem before you had major damage. John

[Jim T.]

Re: Stinky 63 340hp

Stuart your gas cap does two things, lets air in and fumes out. When you come back from a drive one thing you could try is remove the gas cap to relieve any built up pressure that could be pushing gas. Another thing that can be done is a fuel flow shut off valve. Also to save on the starter you could install a inline electric fuel pump with a manual fuel shut off vavle. The one GM sells looks like a cannister type fuel filter and comes with a mounting bracket part # 6472657. Flows 30-40 gph at 6-9 psi. This electric pump has hard line fittings and one wire electrical hook up with ground wire. Can easily be connected to the IGN terminal in the fuse block and work only with the ignition key on. I assume your 63 has similiar fuse block as my 68/70.

[Louis T.]

Re: Stinky 63 340hp

Hi Stuart,

Don't forget to also check your fuel pump if you haven't already. I had noticed some increased residual fuel odors coming from my '65 L76 after each run for months that I dismissed as a typical characteristic of the breed (and some hard driving) until I one day found a puddle underneath the engine compartment in the garage. The fuel pump had been leaking and venting through the weep hole all that time until it finally just failed completely. A new service replacement pump solved the problem, but the house reeked for days until the odors dissipated. I don't remember if I checked the oil for fuel contamination but I changed it immediately just to be on the safe side.

Good luck!

Louis

[Duke W.]

Re: Stinky 63 340hp

Just an update on my Stinky 63; I took my drain oil from my last change to the local auto parts store and they refused it because they said it smelled like it had gas in it. To verify this, I took a sample in to a local lab that does oil analysis and it does indeed have gas in it.

Now, I never was able to detect any dripping in the carb after shut down, but it is obvious that that is one of the sources for my strong odor in my garage, and it is where I will expend my first efforts to remedy the situation.

For any of the members with 63's or other years having a similar problem, that has to be one place to look. Pull your dip sticks and smell the oil for any sign of gas.

And so you ask; how will you get rid of 6 quarts of contaminated drain oil? Well, how about using it for Tiki Torch fuel? Should be easy to light, and God help those skeeters!

Stu Fox

If you paid for that lab analysis, they should have documented the percent fuel and the normal expected range. Did you get actual numbers?

If you do have above normal fuel contamination in the crankcase you need to evaluate your driving habits and do a complete configuration audit and functional check of your PCV systems.

"Short trips" -when the engine is operated for less than 30 minutes before shutdown and a complete cool down before the next cycle can cause fuel contamination in the crankcase as can an improperly configured or malfunctioning component in the PCV system.

One solution to the "hard cold start" after a week of sitting is to use a syringe to fill the fuel bowls through the bowl vents because much of the fuel will evaporate during the week of non-use, particularly the light fraction, which is critical to good cold start performance.

It's also possible to use the syringe with some thin nylon tubing to extract much of the fuel from the bowls if you anticipate not using the car for a week, which should help reduce fuel odor and improve cold start performance by injecting fresh fuel into the bowls prior to the next cold start.

[Stuart F.]

Re: Stinky 63 340hp

Thanks guys for some good ideas - can always count on you.

My oil analysis was a freeby through a friend at our local auto parts store. He has the spec sheet which I hope to pick up tomorrow.

Today I changed back to my older carb which I recently rebuilt. It's the 3720SA that was put on my car when they stole my 3461S. I do have new jetting of .104" primary w/ 16-389 rods and a little sweeter secondary at .070". I have eliminated my low speed stumble and can finally realize the full advantage of the 236 VAC. However, when I again put her away wet, 15 minutes later she smelled to high heaven. I checked carefully to see if this one was dripping and it was not. BTW, I changed to a new PCV and Fuel Filter as well.

The 3721SB I took off only has about 12 years and 3000 miles on it, but OH! was it cruddy inside. The gas looked like muddy water with tur** floating in it, yet the outside looks like brand new! My first thought was "What kind of crappy gas are they selling out there, or is this long sitting sludge"? Whatever happened to good old Blue Sunoco?

After a thorough cleaning, some new jetting (back to 3461S+ specs) and some Tomco Inlet Valves, the 3721SB will go back on and represent the best I can do to curtail the stink in that department.

Guess I"ll have to work quick between the storms (Gustov's coming!).

Stu Fox

[Stuart F.]

Re: Stinky 63 340hp

Recent updates/progress (+ and -) on my efforts to reduce fuel smell in my garage after hot shut down;

I've switched back and forth between my 3720SA and 3721SB carbs. I have them both jetted to original 63 AFB specs (3461S) in the mains and secondaries, but I only have one set of 16-389 metering rods which I share. My latest version of the 3721SB was tried today, complete with Tomco Inlet Valves in place of standard n/s's. When I took off the 3720SA I found gas puddled in the manifold ribs beneath the primaries. The car had only been sitting about 6 days, so I realized where I must concentrate my efforts. I set the floats in the 3721SB with the Tomco valves down to 9/32's, instead of std. 7/32's. On my test drive it ran like a bear, pulling 6500 rpm in 3rd with ease. But, after putting it in the garage it stunk like crazy! I pulled the Air Cleaner and used a bright light to look into the carb and, sure enough, the primary venturis were puking fuel like faucets.

1) When I installed the Tomco valves, I pressure tested them with air and soap bubbles to be certain the gaskets were holding and they were.

2) I still have the heat riser butterfly wired open.
3) I have an electric choke installed to eliminate the hot air tube to the choke as a heat source.
4) I have a fuel hose installed in between the filter and carb to eliminate/reduce the heat soak through the chrome steel fuel line.

I am literally going backwards! It is worse than ever now and I must change the oil again too as I am sure it is contaminated. I hate to say it, but I guess I have to look at more drastic measures, including siphoning the fuel out at shutdown and back in before startup (easiest). Also, I'm thinking about a fuel shutoff valve and perhaps an Electric pass-thru pump for startup prime.

The jury is still out, but right now I'm thinking these Tomco valves don't live up to their claims. The symptoms they claim to control are exactly those I have back now in spades. They certainly do flow more fuel, but unfortunately they do this with the engine shutdown as well as when its' running!

Stu Fox

[John D.]

Re: Stinky 63 340hp

Stuart, You better be careful my friend. Next thing that is gonna happen is hydraulic lock up and then good bye engine or at least a couple of rods.
Scrap the carbs and put on a nice 1st class FI like the rest of the 63 owners. At the shows the only carb car I see is Pappy's. Good luck though in solving your problem. Stu I wouldn't run the engine any more if I were you. Get somebody to look at the carbs. JD

[Stuart F.]

Re: Stinky 63 340hp

John;

As always, thanks for the good advice. Guess though I'm a lot like you; when faced with a problem, I can't stay away from the challenge to solve it myself. This has cost me dearly over the years, but few good lessons are ever free.

Little under the weather down here in the swamp today. We had a brief cold snap and I just can't handle the temperature swings like I used to. You know; sweat in the garage, then go into the air conditioned house, then go back out and sweat some more. That 63 will be the death of me yet - one way or another.

Stu Fox

[Michael H.]

Re: Stinky 63 340hp

Stu... are you sure you don't have a fuel boil problem after the engine is shut down hot? Does the carb do the same if the engine is cool?

The new fuel seems to have a lower boiling point than real gasoline.

[Stuart F.]

Re: Stinky 63 340hp

Michael;

I'm sure that is one way to call it (boil). I usually always run the engine to full warm when ever I start it, so it is "puking", "perculating" or "boiling" the fuel out of the fuel bowls in the carb every time. Now that happens with both carbs (either the 3720SA or the 3721SB). I just removed the 3721SB this morning that was doing the "puking" yesterday, and there was still pressure in the fuel line from the filter to the carb!

I'm dropping the floats even further on the 3720SA to 5/16" (from 7/32") and putting it back on with a L-75 SS plate and gasket to help insulate it a little. That's where I started this experiment and it was a lot better that way.

Thanks for your observations. I'll keep you posted. I know there are a number of other L-76 63 owners out there having same/similar problems and I hope I can find a livable solution, preferably one that isn't too obvious to the casual observer.

Stu fox

[Michael H.]

Re: Stinky 63 340hp

Michael;

I'm sure that is one way to call it (boil). I usually always run the engine to full warm when ever I start it, so it is "puking", "perculating" or "boiling" the fuel out of the fuel bowls in the carb every time. Now that happens with both carbs (either the 3720SA or the 3721SB). I just removed the 3721SB this morning that was doing the "puking" yesterday, and there was still pressure in the fuel line from the filter to the carb!

I'm dropping the floats even further on the 3720SA to 5/16" (from 7/32") and putting it back on with a L-75 SS plate and gasket to help insulate it a little. That's where I started this experiment and it was a lot better that way.

Thanks for your observations. I'll keep you posted. I know there are a number of other L-76 63 owners out there having same/similar problems and I hope I can find a livable solution, preferably one that isn't too obvious to the casual observer.

Stu fox

Just for giggles, try allowing the engine to cool completely, then run it for just 30 seconds or so, enough to fill the bowl.
My guess is that no fuel will be dripping out of the boosters.

I wonder if trying 100% AV gas would make a difference? Not supposed to be any alcohol in it.

Seems like a LOT of folks are having this problem these days and not that much has changed on the cars. Only the fuel.

[Stuart F.]

Re: Stinky 63 340hp

Michael;

You're right. This only happens when the engine has been fully warmed up. In other words, it is as you say; it is boiling out. The fact that there was still pressure in the fuel line this morning indicates that the Tomco fuel valves were still holding back against fuel pump pressure - so it has to be just boiling of the fuel in the bowls.

Also, I usually use Max 2000 TEL fuel additive in my fill ups, but did not this last time as the tank was still half full. It is possible that I was running more straight 93 octane pump gas and the problem seemed to be worse. There may or may not be a correlation there. Perhaps I should try some Av Gas on my next fill.

Thanks again for your input.

Stu fox

[Michael H.]

Re: Stinky 63 340hp

Michael;

You're right. This only happens when the engine has been fully warmed up. In other words, it is as you say; it is boiling out. The fact that there was still pressure in the fuel line this morning indicates that the Tomco fuel valves were still holding back against fuel pump pressure - so it has to be just boiling of the fuel in the bowls.

Also, I usually use Max 2000 TEL fuel additive in my fill ups, but did not this last time as the tank was still half full. It is possible that I was running more straight 93 octane pump gas and the problem seemed to be worse. There may or may not be a correlation there. Perhaps I should try some Av Gas on my next fill.

Thanks again for your input.

Stu fox

Betcha Av gas will correct the problem. In the last several months, the formula for pump gas has been changing here in FL. (and likely all over the US)
Up until last year, several brands contained no alcohol and those that did, only had a small percentage. More recently though, almost all have gone to the full 10% that's allowed by the gov. That's when the problems got much worse.

I haven't run AV gas for many years but I may try it again soon.

[Stuart F.]

Re: Stinky 63 340hp

I guess we shouldn't complain too much. At least we can still get gas in Florida, unlike a few states just north of us. Any shortages down by you? I think my one son ran into a dollar limit here last week, but I don't know the details as yet. It was with his Tahoe. Now there's a tank.

Stu