67StingrayRdstr

Hey Kids!
I am having one hell of a time with my '67 L-68! The fuel line for the front carberator backs out every three weeks or so causing a severe fuel leek onto the manifold. Yesterday I noticed that the rear carb is starting to seep from the fuel inlet.
Is this a common problem? Is it caused by tension from the steel tube fuel lines? Has anyboby had this problem and fixed it successfully?
My brother says to "shelve" the tri-power and replace it with a new manifold and Demon carb. Although it will probably improve performance and reduce carb wrenching, I am torn about eliminating the tri-power.
Any suggestions greatly appreciated... I have considered lock-tight, but am not sure about using the stuff on carbs.
Thanks!
Matt... 1967 L-68 Roadster :confused: :mad

63Corvette

On my 67/427, the threads in the carb float bowls eventually were stripped out by the fuel line nuts. I would check that. I have no opinion about what to do about it, because I haven't owned one in Thirty years. However, THEN, I just bought new stock float bowls and bolted them on. Does anybody know if Holley still makes parts (or whole carbs) for these cars?

67HEAVEN

I wonder how many times the fuel lines have been in and out of the carbs. The metal is fairly soft, so any signs of weakness in the threads....line or carb? Have they maybe been over-tightened at some time?

I'd be tempted to fabricate a temporary replacement fuel line to look for improvements. Also, wrap the connector with some thread wrap.

Whatever you do, carry a fire extinguisher with you (at least until you solve this problem). Photos of burning Corvettes are really unpleasant. :cry

Dave's '67

"I feel your pain". Actually, I felt this way a year ago, until I found a 1 1/8" Holley wrench that would tighten the Inlet fitting sufficiently tight to let me then use a line wrench on the fuel line fitting. By the way, I did change the Inlet fitting on two of the carbs, because "Bubba" had tried to tighten these with Vice grips, or something in the past, and I knew that I could not get on them with any thing now to get them tight. Don't throw that Tri-Power set up away! They can be fixed, and they will give you incredible performance when set up right!

Dave

396 RAT

Tough call!
Is it a driver? (go with a 4bl)
Do you show it? (Tri pwr)

achapman

I have used the teflon plumbers tape with great success, just becareful that you don't cover over the end of the line and block the flow.... :smash:

Dave's '67

Matt, "ditto" '67 Hvn on the Fire Extinguisher! Also, be sure your Inlet fittings are not completely shot, and therefore, even the teflon tape won't do much good. If you do use it, use it as Andy says, and not too much of it.
Let us know

Dave

midyear

You can get a rear float bowl for a 3310 holley and it will work on the end carbs, just did it on mine, I think they were around $40 each

67StingrayRdstr

Hey Kids!
I have to tell you... a fire extinguisher was the FIRST accessory I added to the car! I had the carbs rebuilt about 6 months ago... maybe I will take them apart again... New carbs are about $300 each. Maybe I will try another rebuild... with new float bowls.
Although, I am tempted to just buy new carbs... The car is a driver, but a REAL CLEAN one... I am just kind of caught up in the tri-power charisma!
Still looking for insight!
Matt '67 L-68 Roadster - Black w/red :flag :rolleyes: :eek:

Ih2lose

I have a 1966 and NO tri power.I am sure there is a cure for your problem I just dont know it.I know how frustrating a leak can be.But I had a rebuilt carb on my cadillac that used to back out and get loose not on the gas line but on the carb fitting.my brother in law removed the fitting and we put on a sealer (simular to teflon tape but liquid and blue in color non hardening ) Only 1 drop on the tip of the threads.He used a wrench only 1/8" thick not a normal looking wrench (I think it was especially designed for carb fittings) he tightened up the carb fitting ,then same liquid sealer on the gas line and we tightened with a flare type wrench on the gas line.Using the other wrench as a back up wrench and have never had a problem since. I was using a adjustable wrench that between my opened end wrench and the adjustable I could never really torqe them down enuff.If yours are not stripped or as chuck would say bogered try the correct tools

427435

There are 2 possible sources for the leak. The first is between the flare on the end of the fuel line and the fitting in the fuel bowl. Couple of things you can try if that's the leak source. First, make sure that the tube flare hasn't been dinged or scratched. Then get an open end wrench (I think 1") that fits the fuel bowl fitting---you may have to buy a cheap 1" wrench and do a little grinding to clear the bowl but's that cheaper than an engine compartment fire (or worse, the whole car). Then, with the fuel bowl fitting firmly held with the 1"wrench, tighten, loosen , and retighten the fitting on the fuel line . As a last resort, I solved a leak like this once by first loosening the fuel line at the 3-way "T" fitting off the center carb and then retightening it after I had the other end tight at the end carb.

The second (and most likely) source is through the threads between the aluminum fuel bowl and the fitting in it. Teflon tape can help, but a new fuel bowl is again a lot cheaper than a fire!!! The last time I checked the Holley web sit, these carbs and parts were still available from them. Their prices were reasonable too.

clem zahrobsky

holley sells a thick nylon gasket( part # 26-102) for the fuel bowl gas line fitting that is more forgiving than the thin black ones for leaks :chevy

Cmacsvette

67StingrayRdstr, the guys have given you great advice. :yesnod: I'm going to add to it and probably repeat some of it. I think the guys are right, you can still get the bowls, I got a new center one from Holley 6 years ago, no problem. If those threads on the bowls are tired, you'll probably be fighting those fuel inlet fittings more then once down the road. Just don't over tighten the new ones. Clem brought up that nylon gasket, that one sounds like a good idea. Now to the fuel lines. I have used this trick more then once and it works, I'm sure someone else has too. I've used a fine lapping compound, coarse to start out with if need be and lapped each flare to its respective fitting carefully. When done, clean all pipes and fittings GOOD. Re-install all four pipes by hand and try to keep all four pipes in their most relaxed position, right down to the final tightening. You don't want to mix any pipes or "T"s up with each other, the same goes for your fuel inlet fittings. Now my 2 cents on fire extinguishers, DON'T leave home without them. Just starting at the first "T" fitting, you have 12 threaded connections, counting the fuel inlet fittings, not even counting the three carbs and what their capable of doing. This is why I carried two extinguishers in a bag in the back when my car had four wheels and made a lot of noise. :cool: Through the years, I have heard the same story more then once, when it came to car fires. (You grab your bottle, you start putting your fire out......almost out and BAM.....she's empty!) I have seen this happen, you probably have too. When I'm back on the road I'm going to have TWO Halotron extinguishers in the sack! Halotron is the agent which leaves no residue, from what I'm told. Vettedan on the forum sells them. His site is Vetteworksonline.com. Anyway, thats my opinion and just more food for thought. ;)

Good luck, Craig :cheers:
BTW, when you tighten down your fuel bowl screws, use a criss-cross pattern and slowly work up to the 40 inch lbs. If I recall, I think thats Holley's spec. I also like to put a little and just a little grease on the screw gaskets, so they don't dry out. Since I'm talking grease here, if you ever replace the two little cork seals(for idle needles) in your metering body, coat them also with a little grease. This will help to keep them from drying out and allowing the idle needles to change adj. on their own. Anyway more food. :)


[Modified by Cmacsvette, 11:38 AM 10/12/2002]

clem zahrobsky

use teflon tape on the threads of the nuts for the flare fittings as this will allow you to tighten them tighter because the teflon tape will reduce the friction in the threads. do NOT get the tape into the flare itself,just wrap it around the threads,one or two wraps is plenty. this works as i have done it many times with all types of flare fittings not just carbs. there is also teflon sealer paste that would do the same thing. :chevy

Dyna

Hey 67:

One other thing you might try that is really easy is to open the hood, slowly increase the engine idle rpm up through the typical road rpms and watch for any vibrations developing in the hard fuel lines, etc. The vibrations may show up at road speeds and not at lower engine speeds. Easy to try. Be careful not to overrev.

Dyna

Tom454

For what it's worth.. I have a 68 aluminum spreadbore GM manifold and a Holley 6211 spreadbore 800 cfm on my 70 454 and it doesn't come close to performing like my TriPower setup. Can't wait to get the trips back on the engine. When TriPower is set up and adjusted properly, it kicks the butt of a single 4. Direct experience.... my own.

Since I rebuild carbs... including throttle bodies/shafts.... I can put a TriPower setup in top condition & adjust it properly. One thing that cannot be repaired is "sour gas damage" where gas left in the carb eats away the metal including the INSIDE of the internal passages... this can't be fixed.

On the fuel leak issue... the above posts are right on the money, and there are various fuel bowls still available that will fit if the threads are messed beyond repair. The fuel inlet threads in the bowl are also one spot where sour gas does it's damage.

Tom

clem zahrobsky

2 things are big killers of the plating on the inside of all carbs,water and octane boosters as they will find the smallest place where the plating on the zink casting is missing and attack like crazy. that is why GM moved the seal on the Qjet fuel filter fitting from outside the carb to the insde to keep the fuel from the threads. :chevy

joe58

Do you have steel fuel line or Stainless Steel fuel line? I have read that the Stainless Steel repro lines have more trouble with leaks because the Stainless Steel is a harder material and does not form as well in compression as the steel does.

Solidlifters

Just one quick addition to the advice above: It's important to tighten the lines in the fuel blocks first. I snug the lines up in the carbs then tighten the fuel blocks. If the blocks are done last it stresses the carb ends in the loosen direction and the normal expansion/contraction from heat will make them have more of a tendency to come loose. I've never used tape or sealer in any of the joints on my tri power lines and haven't had leaks when they're installed properly. Two of my cars have stainless lines.

67StingrayRdstr

I just want to thank you all for your GREAT suggestions! I received very useful information and will be taking care of the problem.
I have decided to keep the Tri-Power and will be replacing either the float bowls or the the carbs themselves (may even get a little stronger cam this winter :reddevil )
Thanks again to all!