[Argess]

Tinkering with my car yesterday I noticed that a fuel inlet fitting was loose where it screws into the carb. It wouldn't tighten up and I presume the bowl threads are stripped. Not sure why, although I either partially stripped it many years ago during instsallation, or over those years the weight of the fuel line rocking back and forth under vibration stripped the threads. Maybe some of both.

Looks like the P/N for a replacement bowl is 134-101, but I notice they also sell an aluminum bowl, P/N 134-76C. Holley doesn't say much other thna there's a weight savings, but I'm wondering if it stronger and will hold up better than the zinc based bowl. Any thoughts?

Below is a picture of my installation:

 

[2old2fast]

I wonder if there's an oversize/ repair fitting available ? Something like a Dormant 55124 .
Q jets were known for folks stripping the inlet fitting , I'm sure I put in a couple dozen repair fittings in them back in my shop days , never had a problem .

 

[RWENUTS]

I don’t see evidence of a leak!
Usually loose fittings on fuel lines always result with a leak and fuel staining.

 

[BogiesAnnex1]

The aluminum is lighter and has a color difference to the Zamac cast parts.

Bogie

 

[2old2fast]

I don’t see evidence of a leak!
Usually loose fittings on fuel lines always result with a leak and fuel staining.

I do see Teflon tape on a flare nut ,that's a no- no !
How long does it need to last , the float bowls on my Holley's are 40+ years old ?

 

[Argess]

T-Y for all the replies. There is no evidence of leaking as this was an older picture. The teflon tape is yellow, commonly used with propane. Looking into it at the time I found it is also gasoline proof. I always had a slight leak there because the fuel log (Summit) doesn't have very good flares on the ends. They look almost cast. I doubt they are, but it didn't look good for cutting them off and re-flaring. After using the tape, no more leaks. Oh, and I did the original install back in 1996, although I had it out once since then.... maybe 15 years ago.

I htink there are repair kits, but one has to be accurate using them and keep the fitting perpendicular to the inlet hole. It turns out that a new float bowl may be not much more than a kit. I intend to look into that some more, but at this point a new bowl seems like the best solution.

I need to take things apart. It may be that the float bowl input fitting boss cracked underneath. I noticed it the other day when my hand brushed the fuel log and it moved. The fitting moves up and down and when I tried to tighten it, it just kept turning.

I was really wondering if the aluminum float bowl was stronger and less susceptible to having the threads strip.

 

[RWENUTS]

Sometimes a copper flare washer will help sealing the fitting back up.

Copper Flare Gasket - JB Industries

1/4"

www.jbind.com

 

[Argess]

Now that's a good idea. Thanks for posting about it.

It seemed familiar so I looked in one of my books and found this:

I just now checked the fitting and carb and the fitting is fine, but the carb is stripped. No cracks that I could see. In the pic below you can see the stripped threads (from me continuing to turn it when I thought it was only loose).

You can see the stripped area and good threads further in.

At first I thought that if the fitting was longer, it would be stronger, but if it was any longer it would cover up the transer tube. That's the funny looking gray area to the lower right of the good threads.

 

[2old2fast]

That washer will to you no good , your problem is between fitting & carb bowl , the washer is line flare to fitting .

 

[Argess]

That washer will to you no good , your problem is between fitting & carb bowl , the washer is line flare to fitting .

Yes, we got off topic for a moment discussing the poor quality flares on the Summit fuel log.

 

[eric32]

If you need some new float bowls go to www.allcarbs.com and they have both aluminum and zinc bowls in shiny finish or the gold finish on the zinc ones. Plus they are way cheaper then Holley from Summit or Jegs etc. I get all my stuff from them and there center hung bowls or side hung bowls are on average about $35 on average vs about $60 or even higher from Holley.

 

[Argess]

Thank-you for the link. I checked a few things and their prices went from quite cheaper to "way" cheaper. Good to know. T-Y.

I've done a bit of research and it appears cast zinc is stronger than aluminum, but I couldn't find anything on thread strength, although is does relate to shear strength which is stronger for the zinc. On the other hand, aluminum sort of "smooshes" over when stripped. The zinc threads fracture and came out looking like fingernail clippings. In the end, I don't think it matters much about the material.

If the inlet fitting worked back and forth after years of vibration (and then stripped when I tried to tighten it), one answer might be to use blue loctite on the threads when installing it. That might also help when tightening the compression fitting as holding a wrench on the inlet fitting without letting it move is touchy when you torque the compression fitting down.

One Youtube video demonstrates that subsituting the inlet fitting for one with a AN-6 male fitting solves a lot of leakage problems. My issue with that is finding an AN fuel rail that is adjustable as they all seem to be the length that suits a single carb with inlets on both the primary and secondary float bowls. I have a greater distance to span with the two carbs. I could make something up but my flare tool is for 45deg, not 37deg. I'll keep looking.

 

[eric32]

I like to stay away from those flare fittings as much as I can as they take so much to seal and end up putting a lot of stress on the bowl threads and thus is why I invest to one, an attachment that I can just hook a rubber hose up to or get a high price AN hookup as they don't have to be cranked so tight to almost strip things and only take a snug and they seal up well without issue. Honestly both bowl types have there pros and cons but I like the aluminum since they don't seem to corrode as bad as the zinc bowls do over time with ethanol fuel at least in my experience.

I used to use the flare fittings on the center hung bowls for years but hated the part when holding a wrench to keep the inlet nut from over tightening while tightening up the flare line and I finally went to AN fitting hookups for rubber hose and never looked back. Yeah its nice to have all solid lines but at times it can be a pain. Nice setup by the way and looks cool with the dual carb setup.

 

[65panhed]

Eric32 Thanx for that link!!!

 

[Argess]

I now have a plan. In fact two plans.

1/ New bowl(s) and new inlet fittings. The ones I have were used when I originally installed them. New ones with fresh threads and a good inverted flare might be wise.

2/ If I get leaks, I can go to AN fittings. See the picture below. Just cut the flares off my existing fuel log.

One other issue is the vibration of the fuel line and log. I used to use ty-wraps to support the fuel line to the overflow tank bracket where the line crosses over the engine before dropping down to the fuel pump. When I switched from a copper line to a steel line and added silicone tubing to stop vapour lock (which it did 100%) I didn't replace the ty-wraps. I'll add them again.

If I continue to get leaks from vibration and probably metal fatigue, I'll have to go to flexible hose for a fuel log.

I think I better carry a fire extinguisher too!