AFB Carb on a 425 Nailhead

Evening. Got a 65' Wildcat Deluxe being pushed by a 425 Nailhead w/an AFB Carb and an electric choke. The car runs great... for about 20-30 mins and then stalls. From what I can tell, the carb butterfly will not close once the car's up to running temp, thus allowing too much oxygen into the carb. I disassembled the electric choke, cleaned out a ton of carbon buildup, replaced the gasket and reassembled it, thinking that may have been the problem. I've also cleaned the carb really good and all the linkages move easily and or do not bind or stick.

It idles ALOT better now, and purrs like a kitten (no pun intended) for about 20-30 mins, then stalls repeatedly. Once I remove the air filter and "push the butterfly closed", she'll fire back up, go down the road but then stall again w/in 1-2 mins. Had to do this about 4 times just to get her home and back in the garage.

Is is the bimetallic coil at fault? I know it works because when I disassembled it, I used a heat gun (on low) to warm it up and I can see it uncoil and then coil tighter once it started to cool.

Any suggestions or advice?

 

That carbon build-up in the choke assembly tells us that the steel shim gasket that goes under the carb. is missing or rotted through. It either needs to be replaced or plug the exhaust outlet holes in the manifold. I would plug the holes as they are not really needed any longer. DO NOT block the holes in the heads. But, you would need to take the intake manifold off to do this. Exhaust is being sucked into the choke housing & you have a BIG vacuum leak. Old cars don't run very well when they such exhaust into the intake.

 

If it doesn't run properly after it warms up, but runs better with the choke partially closed, I'd say it's too lean for some reason.
Could very well be the carb base gasket/shield causing a vacuum leak.
Here's one source:
http://www.ebay.com/itm/Buick-1966-...Parts_Accessories&hash=item1e86384b81&vxp=mtr

 

Removed and disassembled my AFB carb... it definitely needs replacing. Rather not go thru rebuilding it. At least not any time soon.

Any suggestions?


65' Wildcat 4 Dr Deluxe w/425 Nailhead

 

Take some pictures of it, especially the bottom. Or, send it to myself for rebuilding.

 

WKILLGS, you were right!!

There wasn't even a steel shim gasket present when I removed the carb.

 

TELRIV: I appreciate the offer, but after watching a couple of YouTube videos, and talking to a few guys, I realized it wasn't very difficult, just time consuming and tidious. So I purchased a rebuild Kit from a guy here in TX, disassembled, cleaned and rebuilt it myself.

I attached a few pics:

Before:






AFTER:

 

TELRIV: Again, I appreciate the offer though.

 

Nice Job on the Carb JD. It looks Great. :TU: I just got a kit for mine and am going to get at it One of these Months.

PONCH

 

Thx PONCH. Learned some "hard lessons", as this was my first (& hopefully last) time doing something like this. Admittedly, I was a little intimidated as I'm a metric motorcycle guy. So I initially thought it best to just replace the whole thing til I saw the price difference between rebuilding versus replacing. Not to mention my wife did too LOL... Nuff said... GIT ER' DONE!

 

I've seen a lot of "aftermarket" air filter and filter housings. Would anyone recommend replacing the stock filter housing (see attached), or keeping it?




There's nothing wrong with it from what I can tell, and I believe it functions just fine. I just wanted to know if there was something out there that help my Nailhead perform better...?

Any suggestions other than just replacing the filter with a K&N element?

 

I've found the stock '66 air cleaner to be very restrictive over 4000 rpm. Taking the stocker off and putting on an open element style on improved performance significantly.....both on the street and on the track.

 

I figured as much. Like I said, this is my first real "automobile" (had plenty cars 1990 and newer), and I'm learning the old technologies so bear with me.

Admittedly, I have come to like the older technology versus say, my 2013 Ford F-150. Too many systems relying on computers and what not.

My 65 Buick, mmmm, not so much!

Thanks WKILLGS, I shall make it happen!

 

Does anyone know where I can get replacement lenses for my 65' Wildcat (backup, front turn signal, and curb lenses)... at a reasonable price?

 

Not to be picky JD, but if you go back to post #2 you will read that I talked about the steel shim gasket before Walt did.


Tom T.

 

You did Sir... My apologies Mr. Tom T.

It's not like this old Soldier to not pay attn to detail.

 

Might either of you be able to tell me what this fitting is on the top my transmission housing just above the tranny dipstick?

I don't ever recall seeing any type of line connected to it.

Should there be?

If so, what should be there and where/what does it connect to?

 

That's just a vent for the transmission. It doesn't connect to anything.

 

Thanks WKILLGS! I was worried I'd forgotten to reconnect something...

 

Another question: When I got this car, there were rubber lines running from the PCV Valve to a coupling on the back of the carb, that had another hose continuing on to the brake booster (see attached pic).

Is this common for these engines?



I only ask because a friend of mine is suggesting I get an air cleaner that has a fitting to run a line from the air cleaner to the PCV Valve, & to block off the original PCV Valve connection on the fitting at the back of the carb, and keep the line to the break booster. This doesn't sound right.

Your advice...?