Boiling fuel in 1960 Buick Stromberg 2 brl

[Dave@Moon]

Please see my posting on this subject in the BCA performance forum for background on my problem. I fixed my 1960 LeSabre's habit of boiling dry the carb and fuel line at shutoff with an electric fuel pump. Are there any alternatives?

[Guest]

What's causing the problem? Do you need to insulate the fuel lines better?<P>Cheers, 3MP

[Dave@Moon]

This is going to be a long story. I've had this problem for years and noone seems to be able to help. I'm geting no response to the BCA posting, so I'll repeat it here.<P>In essence, my problem seems to be that, until I modified it, the fuel in the carb and lines along the engine was boiling as shutoff. When I shut the car off after it was up to temperature, gas would begin to seep out of the bowl vent AND through the gasketed surfaces of the carburator. This seepage was rapid enough to create a drip rate off of the carburator linkage of 1-2 drops per second until the bowl was dry. This was a huge fire hazzard, and I was having to run out to the hood each time and put absorbant pads under the carb to soak up the gas. The fumes were so bad I had to let the car cool off outside before putting it in the (in house) garage.<P>It's important to keep in mind that absolutely no leekage would occur until shutoff. Not a drop!<P>Gas was also found in increasing quantities in the crankcase oil, which I eventually attributed to boiling gas being forced down the carburator throat at shutoff. In fact, this is where the gas first began to appear, the external seepage came shortly afterward.<P>This problem was only minor in nature when I bought the car in 1995. Within a year and a half, however it became very serious. I'd not seen this on any other car, and I still haven't to this degree yet. If gas had not been forced out of the carb, I'd have blamed the fuel pump for the gas in the crankcase. Also if the crankcase wasn't vented by the road draft tube, i.e. if I had a stuck PCV, the fuel pump could've been allowing crankcase pressures (bad rings?) to push the fuel out via a blown diaphragm. Unfortunately, neither scenario applies. Therefore I never tried replacing the fuel pump (with a stock type replacemnt). <BR> <BR>I first blamed the carburator, a WW-2 Stromberg 2 barrel. I figured that it had to be the problem since that's where the fuel is comong from. After 2 different carbs were rebuilt 2-4 times each, the last one a professional rebuild, I gave up and bought a NOS rebuilt carb, figuring I was dealing with carb body warpage. Still no success.<P>I then learned about the low boiling point of today's "gas" from a professional carburator rebuilder in Missouri. I was told that today's fuel will begin to boil @ 150 degrees F, and boil dry at about 225 degrees F. He advised me to install a thick insulator between the carb and manifold. I did, no real improvement. I couldn't find a heat insulator kit for a 2 brl. carb, so I started to make one out of 1/8" aluminum plate, a very complicated task for this car because of linkage interference. I was about to install this UGLY insullator when I talked to an engine rebuilder locally who suggested using an electric fuel pump.<P>I finally fixed the car by installing an electric fuel pump in the rear. Using this, and re-routing the fuel line away from the engine, did the trick. The car now functions perfectly, albeit with a noisy pump in the rear and a decidedly non-stock looking fuel line in the engine compartment. <P>You should understand that the 1960 Buick 364 engine is a huge piece of metal, and generates tons of heat. 8-10 hours after I park the car in the garage the room is still noticably warm from engine heat. Also the Stromberg WW-2 is a tiny carb for such a large engine. My car has the (very expensive) optional low compression motor for regular gas (in 1960), the only combo which used a Stromberg in a Buick by 1960. (They are quite common on Buicks as late as 1956). <P>With this odd combo, I'm sure my car is especially vulnerable to fuel percolation or boiling. It is such a rare combination (I'd say less than 1% of 1960 production) I can get little or no advice on the subject. Also the earlier cars, which have a taller, more exposed intake system, probably aren't as apt to have this happen as mine is.<P>The only suggestion I've gotten from the BCA posting was to check for a stuck bypass valve, the Buick has an exhaust passage under the carb in the intake for heat. The valve is not stuck, it's quite free and I assume it therefore still functions. The passage in the manifold was found to be completely blocked with carbon from leaking valve cover and manifold gaskets in the middle of all this. Clearing the passage did not affect the problem. <P>My question is very simple, what am I missing? The car runs great! It has 175 Lbs compression in each cylinder and gets 17 mpg on the highway. I am, however, badly fouling plugs (black carbon) after only about 1000 miles (I've put about 10K miles on the car in 5 years). This with the carb set as lean as possible w/o stumbling at idle. <P>I love this car, and I could probably drive it indefinately with the electric pump and periodic plug changes. But I want to fix it. Besides, the electric fuel pump does make quite an annoying racket. At the 1999 Buick Nationals I saw about 15 similar cars, one with a Stromberg (the first I've seen besides mine). None of them needed this fix. They all had the same minor fuel staining of the carb that you typically see on any drivien car these days.<P>Somebody, somewhere knows the fix for this. I hope they read this posting.

[Guest]

Dave:<P>A couple of things come to mind when I read your posting. I will assume that the timing, dwell and spark plugs are all correct for this car. <P>Now, If I were checking out this car, the first thing I would check is the Thermostat and radiator cap for proper operation and more importantly, proper temperature. Do not use the dash gauge for temp measurement. Use a thermometer. You might also want to check the radiator (visually) for proper flow. Why? An engine operating above its designed range will vaporize fuel which could be why you are leaned out and still running rich. The cap could also be contributing if it is not holding pressure.<P>The 2nd place I would look is the mechanical fuel pump mounting. Was there supposed to be a spacer between the block and the pump? Is this the correct pump? Why? If the pump was designed for a spacer (keeping block heat away) and it was removed, the pump could be overheating causing your condition.<P>The 3rd place is the carb. choke system. Is the choke pulling off when the car is warmed? If this car has a snorkel on the air cleaner (I'm not familiar with 1960 Buick) with a temp flap inside, check the operation of that too. <P>What you might have here is a combination of factors contributing to your problem. Check all of the above out.<P>Good Luck<P>Chris <P>

[Dave@Moon]

Thanks Chris. I haven't tried replacing the radiator cap yet, but I can assure it holds at least some pressure. The thermostat is new, and the cooling system seems to function perfectly. There is no guage.<P>I've not noticed any spacers on Buick fuel pump mounts, mine doesn't have one. I'll put a posting checking for any on the BCA forum.<P>With all of the carb trouble I had, when I finally got one that ran right it was an NORS rebuilt carb I bought @ Carslile. The damn thing works great but has no vaccuum to the choke thermocoil (this car has a thermocoil pull off attached to a stovepipe). Therefore, I've been running all this time w/o a choke, closing it manually when I needed to warm up the motor on cool days.<P>Finally, I would hardly say the car is running rich. I do have the carb leaned out to where it will stumble, but at that setting the car is running great, with a normal exhaust odor and (except for briefly after it's been sitting a long time) no smoke.<P>There's no flap in the air cleaner's snorkel.<P>I'll try the cap and see if it helps.

[Dave@Moon]

This is the old thread I started on this subject. There is also one on the BCA forum.

[Guest]

Dave:<P>I am assuming since you posted this that the problem is not solved. If you checked all of the previously posted recommendations and it is still happening here is what I would check next. (assuming fuel pump pressure is correct).<P>Check the needle/seat assembly and the float. My Packard had a needle made of steel and would allow fuel to leak past. I replaced it with a rubber tipped one and it worked, not leaking of fuel. Second, check the float level. If it is correct, then I would lower it. For example, mine is spec'd for 5/32", but I set it at 6/32" (or 3/16"). A slightly lower float setting will probably not have an impact on performance but will mean less fuel in the bowl and less of a chance of boiling out.<P>Chris

[Guest]

@Moon -<BR>As hvs once pointed out, 90% of all carb/fuel problems are electrical. This one may not be because it sounds like two problems. But if your plugs are fouled constantly with a leaned carb setting and no oil blowby, then the spark is probably weak or the plugs are either wrong for that engine or not gaped correctly. One way to check the source of plug fouling is to take off the intake maniford to see if it is loaded with wet gasoline residue. If the manifold is OK, then I would suspect some kind of electrical problem in addition to the carb problem. I don't know about the carb problem, but along with checking the jets and float setting, I would also make sure that all gaskets and fittings are sealed (carb to manifold and manifold to block). Use modern sealers and gaskets to compensate for warpage.

[ply33]

On some cars there is an insulating spacer between the carb and the manifold. If that is missing the carb will overheat particularly when the engine is turned off. (When running the expansion of air in the venturi throat will tend to cool the carb.)

[Guest BillP]

Some thoughts on the preceding:<P>Fuel pump spacer. If this a conventional (i.e., mounted low on the block, diaphragm-type, operated by a arm riding an eccentric on the camshaft) type pump, a spacer will move the pump away from the eccentric. Then it won't work. <P>Carburetor base spacer. Dave mentions having begun work on a 1/8" aluminum spacer. This is very thin and more crucial, aluminum is an excellent conductor. Installation of this item will be futile. If a spacer is proven to be required, thicker is better, as is construction from a non-conductive yet heat resistant material. Phenolic may be a good choice. <P>Plugs are fouling. The mixture is gas-rich, either from too much gasoline or too little air. From the factory, this is a large engine with a small carbuetor. At some time, someone may have opened up the main jet orifices to improve performance. If this was done, it may have been an unscientific modification, resulting in too much gasoline being delivered compared to the paltry amount of air available. Can you verify the jet size with what it is supposed to be?<BR>If the jets are correct, maybe the stock aircleaner(if that's what is on there) is restrictive. See if you get an aftermarket aircleaner (I hesitate to use the phrase 'HotRod') with plenty of open area to use for a brief test. <BR>Boiling gas. This is curious. The first conclusion would be to blame today's fuels as having a lower boiling point. The answer there would be to dump in a gallon or so of diesel per tank. Yet, a cure was effected by installing an electric fuel pump. Now we get into speculation. Perhaps the electric fuel does NOT hold a pressure head on the fuel line, thereby NOT blowing gas past an already marginal needle/seat and NOT overflowing the carburetor. Or, maybe the electric fuel pump DOES slighty pressurize the line and fuel bowl, raising the boiling point of the fuel therein, preventing it from churning out. <BR>Maybe a pressure regulator with integral guage mounted in the line would help in solving this question. <BR>Noisy fuel pump. There are silent ones on the market, check with your more knowledgable local parts guys. Then you'll have a spare, albeit noisy, pump on your shelf.

[Dave@Moon]

Thanks guys! I really only called this one out of the dusty recesses to try and help "Avavtey" in his/her thread on a similar problem with a '31 Huppmobile. Using the electric fuel pump , and especially isolating the fuel line and the directly attached mechanical pump, seems to have pretty much got this one licked.<P>For the record, the problem persisted through 3 carburators, each one rebuilt in several ways. Even custom-made viton needle and seat didn't help. The car was constantly being tuned up, as the plugs fouled so quickly. (They still foul much faster than they sould, probably the valve guides are starting to go although there's no oil smoke.) <P>The 1/8" aluminum was being made to build a tiered heat sink below the carb, with the fins conducting the heat away. Thank God that ugly thing never made it on the car! I was totally unsuccessful in finding a phenolic insulator, and for reasons I don't remember it would be very difficult to make one. <P>The intake was pulled 2 years ago. The exhaust passage was corroded shut with crud from sucking in oil from a leaking valve cover gasket, but otherwise eveything was normal. Clearing out the exhaust passage did not improve or worsen the problem.

[Guest]

I thought we were talking about a Buick, now it's a Hupp? You might get straighter, more useful answers if you asked specific questions about a specific problem. Save people's time and brainpower, too (both limited). Not trying to be a smart aleck, I just recognize the value of straight talk in both directions.

[Guest]

Dave.Fix your boiling fuel by installing a 3 port fuel filter between the mechanical fuel pump and the carb.the 3rd port has a very small orifice and pipes back to behind the pump.this relieves all pump press as soon as you shut off the engine.Some late 60's thru mid 70's chevys used this but the return line went clear back to the tank.Works either way.also,leaning out the idle mixture has little effect on the high speed circuit.these are fixed jets although some carter and stromberg used tapered metering rods which can be adjusted.

[Chacheska]

What kind of pressure is your pump operating at and do you have a regulator after the pump to regulate a specific pressure?

[Dave@Moon]

The fuel pump is an internal regulator (cheap) type, that provides 7 lbs. pressure (as I recall). I paid about $30 for it at Pep Boys. It beat keeping the absorbant sheets next to the battery and sopping up the dripping gas every time I stopped the car!

[ARUCKEY]

TO: DAVE MOON<BR>THOUGHT I WOULD THROW IN MY 2 CENTS SINCE I HAVE SOME EXPERIENCE IN THIS AREA. IS OF ALL WHEN THE CAR WAS NEW IT RAN OK ! THIS MUST BE REMEMBERED WHEN ONE THINKS OF MAKING NON PRODUCTION MODIFICATIONS. THESE TEND TO CREATE NEW PROBLEMS. THIS NO DOUBT ONLY HAPPENS WHEN THE OUTSIDE TEMPERATURE IS ABOVE 80 F. HOW MANY MILES ON THE CAR? <BR>MY FIRST SUGGESTION IS TO OBTAIN AN OFFICAL BUICK SHOP MANUAL OR BORROW ONE FOR YOUR YEAR. THIS WILL GIVE YOU THE "CORRECT " FUEL PRESSURE WHICH IS CRITICAL ! SECOND, THE MANUAL USUALLY HAS PHOTO'S OF WHAT THE CARB, GASKETS,AND FUEL LINES LOOKED LIKE WHEN NEW.<BR>ALSO, IF THE MECHANICAL FUEL PUMP HAS WHAT RICHARD MAUNNEY CORRECTLY POINTED OUT AS A SIGNIFICANT HELP IN REDUCING FUEL LINE PRESSURE AT SHUT OFF. IT MAY HAVE AN APPROX. 1/8 INCH DIA. LINE THAT BYPASS'S FUEL BACK TO THE FUEL TANK. WITH A MECHANICAL FUEL PUMP THE CHECK VALVE WITHIN THE PUMP TRAPS FUEL BETWEEN THE PUMP AND THE CARB. NEEDLE AND SEAT. DURING SHUT OFF THE HEAT CAUSES THE FUEL TO EXPAND , INCREASE IN PRESSURE AND FORCE THE NEEDLE OFF IT'S SEAT. IF WOULD SUGGEST THAT THE BOWL IS NOT "BOILING DRY". THE FUEL COMING OUT OF THE CARB. IS SIMPLY WHAT IS BEING DISPLACED OUT OF THE LINE BETWEEN THE MECH PUMP AND THE CARB. <P>MY NEXT SUGESTION IS TO OBTAIN A PRECISION FUEL GAGE IN THE RANGE OF ZERO TO 10 OR 15 PSI. DO NOT USE A ZERO TO 40 OR 50 PSI, THE INCREMENTS WILL NOT BE SMALL ENOUGH TO READ THE PRESSURE YOU WANT TO MEASURE. INSTALL THIS SOME WHERE IN THE LINE BETWEEN THE MECH. PUMP AND THE CARB. MAKE SURE THE I.D. OF THE FITTINGS DO NOT RESTRICT THE FUEL FLOW. I AM GOING TO GUESS THE CORRECT FACTOR FUEL PRESSURE IS FROM 4.5 TO 5.25 PSI.<P>I ASSUME YOU BY-PASSED THE MECHANICAL PUMP WHEN YOU INSTALLED THE ELECTRIC PUMP. BILL P. WAS CORRECTED WHEN HE INDICATED THAT THE ELECTRIC PUMP DOES NOT TRAP THE FUEL IN THE LINE, IT LETS IT RELEIVE ITSELF BACK INTO THE FUEL TANK. HENCE, NO TRAPPED FUEL TO EXPAND ! TRYING TO ADJUST THE FUEL MIXTURE WITH THE IDLE MIXTURE SCREWS WILL ONLY LEAN IT OUT FROM IDLE TO ABOUT 15 MPH. AFTER THAT THE MAIN RODS AND JETS TAKE OVER. IF YOU USE AN INCORRECT MECH FUEL PUMP (TOO HIGH PRESSURE) OR AN ELECTRIC THE RESULT WILL BE A RICHER THAN NORMAL AIR/FUEL MIXTURE. IT WILL CHANGE WITH AS LITTLE AS A 1/4 PSI INCREASE. WITH YOU ELECTIC PUMP RUNNING AT 7 PSI THE RESULT WOULD BE A RICHER IDLE AND EVERYWHERE ELSE. THIS IS BECAUSE THE OPERATING FUEL LEVEL IN THE BOWL IS RAISED BECAUSE OF THE PRESSURE INCREASE. IF YOU KEEP THE ELECTRIC, YOU WILL HAVE TO GET AN ADJUSTABLE REGULATOR AND USING A PRECISION FUEL PRESSURE GAGE YOU CAN ADJUST IT TO GET THE CORRECT FACTORY PRESSURE. <P>MY EXPERINCE WITH REBUILT CARBS IS THAT THEY GROUP THEM TOGETHER AND OFTEN "ONE SIZE FITS ALL" AND YOU END UP WITH A LESS THAN SATISFACTORY CHOICE. IT WOULD BE BEST TO REBUILD THE ORIGINAL. OR IF YOU HAVE THE ORIGINAL, INSTALL THE ORIGINAL JETS AND RODS IN THE EXISTING CARB. BE SURE TO SET THE FLOAT LEVEL TO EXACTLY FACTORY SPEC'S.<BR>THE PLUG FOULING IS NOT ELECTRICAL, IT IS EXCESSIVE FUEL. <P>IF YOU HAVE A HOT AIR CHOKE (VS ELECTRIC) YOU ALSO HAVE TO MAKE SURE THAT AFTER THE ENGINE WARMS UP (5 MILES OF NORMAL DRIVINGS)<BR>THAT THE CHOKE BLADE COMES TO FULL WIDE OPEN<BR>POSITION. IF IT DOES NOT, THIS WILL ALSO CAUSE EXCESSIVE RICHNESS. ONCE AGAIN, MAKE SURE THE CHOKE IS TO FACTORY SPECS.<P>I DON'T BELIEVE ADDITIONAL INSULATORS WILL HELP. THE UNDERHOOD IS LIKE AN OVEN WHEN IT GETS HOT. DO YOU THINK YOUR THANKSGIVING TURKEY WOULD BE COOLER IF YOU PUT INSULATORS UNDER THE ROASTING PAN ?<P>THE THERMAC ON THE AIR CLEANER IS CRITICAL. IT IS ONLY SUPPOSE TO SUPPLY HOT AIR FROM THE EXHAUST MANIFOLD WHEN THE ENGINE IS COLD. IT THEN SHOULD SWITCH AND THAT GET THE NORMAL AIR FROM THE FRONT OF THE INLET AIR SNORKLE. SOME TIME AN EXTRA COLD AIR DUCT EXTENDS OUT THROUGH THE GRILLE. THIS MIGHT BE A GOOD IDEA TOO ADD THIS. THIS WILL TEND TO KEEP THE CARBURETOR COOLER. <P>FEEL FREE TO CONTACT ME DIRECT VIA E-MAIL AT<BR>ARUCKEY@YAHOO.COM WITH ANY ADDITIONAL QUESTIONS.

[ronbarn]

Time for Father Ron again! This is an excellent thread and we appreciate the excellent inputs. Please do not go to email with other details (unless they are personal) since that would deprive the rest of us of the good information. Thanx.

[Dave@Moon]

Thanks ARUCKEY,<P>The fuel pump I went to, which was a Purolator brand item, was rated at 4-7 psi. I presume the range is related to flow rate and line diameter. It's supposed to be for "most carburated cars". The Buick factory rating for the mechanical pump's pressure was 5.5 psi. Since installing the the fuel pump I've noted no more (excessive) leakage from the carb, so I must be well within the acceptable range.<P>The myriad of rebuilt and re-rebuilt carbs I went through before isolating the problem to the fuel pump and line were all original 1959 and 1960 Buick carbs. The carbs for those years (Stromberg WW2 types 112A and 113--<I> very </I> hard to find) differed only in float setting, and are physically identical. I went through at least 8 rebuilds of three individual carbs without result.<P>The choke mechanism on all three carbs worked perfectly, and were fully open at normal temperature. There is no thermac in 1960 for Buicks, only a silenced snorkel on the air cleaner can. Also a cool air duct to the carb wouldn't have helped, since there was <I> never </I> any fuel leakage while the car was running. Only after I shut the car off would <I> any </I> fuel begin to leak out, and usually within 15-30 seconds it would be dripping rapidly off of the linkages.<P>Since I last posted on this thread, I talked to Rick Shick, the BCA Technical Advisor for these cars. He told me that most of them were retrofitted to the Rochester 2 barrel (the stock carburator on the standard 10.25:1 engine) because these Strombergs were so troublesome. Apparantly today's gas makes them virtually undrivable in strictly stock form.

[Guest JT]

I was at a car show this weekend and did a survey of some the 40 era cars there to check out the carbs. I noticed most all of the ones I looked at either had fuel stains or were wet at the base of the carburetor. So is it the vaporization of modern gas or old carburetors?

[Guest]

Something of interest this past week that I thought I would pass on. My 48 Packard started fouling plugs, rough idle, gas dripping inside the carb from the nozzles and the temperature was slightly above normal. Checked timing, dwell and all the other specs and couldn't find anything out of sync. Was ready to take the carb apart when just by chance I checked the manifold heat riser and guess what? It was only opening less than halfway (bad spring). This was causing the engine to do all of the above, but most noteworthy was the gas boiling through the nozzles and into the carb just like described above. Replaced the thermostat spring, changed plugs and the car runs beautifully (and the heat riser opens fully now).<P>Just something I thought I'd pass on.