Autolite 4100 fuel filter help

[bryancobb]

Originally Posted by Jays66gt

I called my local Ford Parts Department. Got a very nice Rep on the phone. He took the part number and put me on hold. It took him a minute to get back on the line. The fuel filter would have to be ordered and would take 2 - 3 hours. Not days. He called me when it got there and I drove right over. It's perfect. Reverse flare and everything!

Best part? It was cheaper than thru mail order. 15 minute drive and less than $9.00 later I have the filter. I did find it a bit disappointing that it's labelled as "Made in China". Oh well.

What that parts person did is pick up the phone and called AutoZone and their delivery guy drove it to the dealer.

It is not a REAL Motorcraft filter. A real one will be marked like this and be in this kind of box and say MADE IN AMERICA.

[22GT]

Originally Posted by bryancobb

Do what you want...BUT...if you don't get a Motorcraft FG-15, It WILL leak.

Not that I'm sticking up for the Chinese filter, but why would a non-Ford filter leak?

[bryancobb]

Originally Posted by 22GT

Not that I'm sticking up for the Chinese filter, but why would a non-Ford filter leak?

The 2 off-brands that I tried, one U.S. Made, (Hastings)
and one Chinese, both leaked.

When the depth of the threaded portion with the reverse-flare inside, was almost 1/16 shorter than the Motorcraft one. The hex portion bottomed against the carb at least 1/2 turn before the flare bevel touched. That's even without the gasket. The gasket made it 1/32 worse and I couldn't stop the leak. THE GASKET IS NOT SUPPOSE TO DO THE SEALING, THE BEVEL DOES.

[Jays66gt]

This is going nowhere fast. I'm going to give it hell and see what happens.

Wish me luck.

[jmd66fb]

Originally Posted by Jays66gt

This is going nowhere fast. I'm going to give it hell and see what happens.

Wish me luck.

Yeehaw!!
Dont give it too much hell or youll be changing the carb out

Joe

[Gene_J]

Originally Posted by bryancobb

The 2 off-brands that I tried, one U.S. Made, (Hastings)
and one Chinese, both leaked.

When the depth of the threaded portion with the reverse-flare inside, was almost 1/16 shorter than the Motorcraft one. The hex portion bottomed against the carb at least 1/2 turn before the flare bevel touched. That's even without the gasket. The gasket made it 1/32 worse and I couldn't stop the leak. THE GASKET IS NOT SUPPOSE TO DO THE SEALING, THE BEVEL DOES.

The original filters have a reverse flair inside. If you look inside the carb inlet you will see why. Later filters from parts stores (even the good parts stores) will not have these flairs in the screw in portion. It is completely flat. Some genius at a manufacturing plant must have thought the chamfer was not required and eliminated it to save on costs. This is easy to fix with a drill press. If you don't do this the filter will not screw in all the way. Then the filter will stick out a bit and the gasket will not seal.

Incidentally the 66 Mustang carbs and Lincolns have different threads for some reason.

[Jays66gt]

My filter that I just bought from Ford has another issue. It does have the reverse flare. But the threaded portion is too short. Weird I know, but I tested it with a few marks from a Marks-A-Lot. The reverse flare does not "bottom out" inside the carb fitting. I plan on trying a few options today and see what happens.

Option 1: plumbers tape on the threads with no gasket.
Option 2: plumbers tape with the gasket in place.
Option 3: I haven't considered option 3.

[bryancobb]

Originally Posted by Jays66gt

... newly purchased 4100 carburetor...

Ok, I suppose the FIRST step should have been to identify EXACTLY what carburetor body you have and compare that to the Bob Mannel book to see what's correct.

[22GT]

Originally Posted by Gene_J

Some genius at a manufacturing plant must have thought the chamfer was not required and eliminated it to save on costs. This is easy to fix with a drill press.

IIRC, the inverted flare is machined to 47°.

[bryancobb]

Originally Posted by Jays66gt

6Z A is stamped on the foot...

According to Mannel's book, That is a C6ZF-A which is the the earlist revision of that C6ZF. It is definitely the correct carb body for a 289 4V without smog. Appendix C says in #16, All 67-69 had "pipe threads" on the in-line filter. Prior ones had "tube-type" threads and refers to page 7-10 photo # 7C4. In THAT picture, if you look at the "c" one, YOUR carb body is definitely the one like mine for the in-line Motorcraft FG-15. (the right-hand one in picture (e), with "1966" printed above it.

I don't know what to tell you. Either the threaded part of your filter is too short, or a PO has "monkeyed" with the bevel inside that carb body, which I doubt.

All I know is, I had leaks with 2 locally purchased filters, due to the same issue you are having, and then I bought an NOS Motorcraft one off Ebay that was made in the 70's and it fit right on the bevel and the leak stopped.

Now about Teflon tape... YOUR threads don't taper like pipe threads. Pipe threads get tighter as they go deeper and teflon tape works real well on them.

YOUR threads are uniform diameter all along and if you put tape on them, the threads won't SQUEEZE the teflon into the voids like pipe threads do.
You MAY be able to get it to seal, who knows?

If you screw it all the way in WITHOUT a gasket, will it bottom out?

My thought is...you still haven't got the filter that is made right. If it were me, I'd chuck the filter in the lathe and remove 1/16 of the hex-area flat, so it would screw in deeper.

My gut tells me that if you got an NOS one off Ebay, it would seal, but I can't prove that.

[67t5ponycoupe]

Thanks for all the info on this post. I'm going through the same thing right now and it is helping out a bunch. Just ordered a Filter.

[Jays66gt]

Originally Posted by 67t5ponycoupe

Thanks for all the info on this post. I'm going through the same thing right now and it is helping out a bunch. Just ordered a Filter.

Good luck to you. I have to admit that I was hesitant after going thru all this post had to offer.

I put a little plumbers tape on the threads, installed the filter, and started the car. After around 500 miles or so, not a drop of fuel. Nothing. She runs perfectly. There is no gasket. Maybe the plumbers tape will go the he!! someday. Maybe not. For right now I'm happy.

Regards,

Jay