I'm rebuilding the Carter AFB from my '65 Wildcat parts car as a back-up/spare. The number is 4053S which I believe means its from a '66 401. There's a 5/16ths passage drilled from the bottom of the base that looks like it should be plugged. It connects the vacuum tube at the front (to dist. advance?) to a port in the primary bore below the throttle plate. The outer edge of this passage has a slightly larger counter bore machined in it like a plug should be installed here. Is there something special that ought to go here, or would I be OK to press in a welch plug and epoxy it and sand it flat? The car didn't have the metal plate between the carb and manifold, and this passage was packed full with hard baked on sludge. Also, where can I get that plate, and which side of the gasket does it go on?
Plugged hole or not to plug Kevin, I checked three different carbs that I have and 2 two of them had the same hole that you have. What it is for is the exaust crossover. The carb pulls vacume and heat for your choke from that port in your intake manifold. The third carb that I checked is from a 1964 dual quad set-up the exaust cross over is not machined through from the factory. Are you planning to block the intake ports between the intake and the heads? I would sugest to block those ports, either way I would not be concerned. Dale Jenne 1966 Buick Skylark GS Ragtop
Thanks Dale, I really appreciate your efforts. The choke housing gets its vacuum from the hole centered between the primary throttle bores (the lower one in the shallow channel in the picture above). There's a cross passage drilled all the way over to the choke housing on the right. This draws heated air through the choke housing from a pipe going to the exhaust manifold. This passage was also completed plugged with sludge before I cleaned it out. The carb gasket that came with the rebuid kit is cut out to closely match the exhaust cross over on the intake. The hole I'm asking about is located part way over the cross over. The gasket partially covers it. The choke housing port and the larger one would both be drawing exhaust from the cross over if only the gasket was installed. Both of these ports would have vacuum "leaks" to the exhaust crossover and wouldn't provide vacuum to the choke housing and vacuum tube. I'm now thinking o No: that the metal plate is required to isolate both of these passages from the cross over exhaust gasses. The plate would seal off the larger hole, so a plug wouldn't be required. It gets vacuum from the hole drilled into the primary bore, on the vacuum side of the throttle plate. The choke housing port is exposed to vacuum through the shallow channel going to both primary throttle bores. I think I might put a plug in that 5/16 inch hole for insurance, unless some one can tell me why it's a bad idea. If I can't find the correct metal plate, I'll make one, it shouldn't be too hard. I wasn't planning to block off the exhaust passages at the intake gaskets, I was going to keep the exhaust heat to the intake manifold. If I was going to block it, would it be better to plug the cross over on the intake? Pipe plugs fit nicely into the holes at the ends of the cross over passage. This would then be very easy to un-do if I wanted. If I'm all wet in my thinking, some one please tell me. Thanks.
Yes, very thin stainless steel isolator plate and gaskets on each side are required. If the plate/gasket combo isn't used, there will be an internal vacuum leak not easily found. Most people lose this plate when they trundle the carb off to the auto parts store, and then go round and round with the parts guy as to why the new carb doesn't work. We used to let new techs in the dealerships take this plate off, not tell them it was needed, then sit back and watch how long it took for them to find the problem, usually long after the tech goes nuclear crazy trying to find the vacuum leak.
Kevin, I'm certainly no expert on anything :gt: but your post got me thinking. I took a look at the bottom of some of my spare carbs. Unfortunately all I have to look at are some dual quad carbs. :Brow: I found that the rear (primary) carb had that hole plugged and the front (secondary) carb didn't have that hole at all. Now I don't know if that plug is only found on the dual quad carbs or not but perhaps someone else who's running a single quad motor could take a look and post their findings.
Some carb even take that hole a little further--there is a notch in the bottom of it that goes over to the throttle bore so that vacuum can be pulled on that hole from the main throttle bore. The carb for a '65 300 is that way. I actually plugged that hole and drilled a hole into that passage from just above the throttle plate so as to convert the vacuum advance port from manifold vacuum to ported vacuum. I made the mistake one time of putting it on the car with the wrong gasket and it got exhaust gases up into all those passages--definitely doesn't work like that. If you can't find the SS plate (I have never found one yet), you can use a solid gasket that doesn't have the exhaust crossover area open in it (like you would use for a Holley carb.) and it will work fine.
I'm a little curious about this isolator plate. When I rebuilt my motor there was no plate or gasket between the original afb and the intake. The new edelbrock 600 I bought came with no gasket, it seemed a bit odd but I just bolted it on. I don't notice a vacuum leak - but maybe I don't know what I'm looking for. Would this plate be available aftermarket? And I wonder why the edelbrock didn't come with gaskets... Thanks, Zach
Still more guestions on the spacer plate . . . . The 66 Electra I recently purchased was missing the plate. I did not realize this plate was needed when I removed and cleaned the passage ways. On reinstallation I just used a gasket which made the car run bad (those typical vacuum leaks!). I read here that the two holes from the exhaust heat risers to the carb crossover could be plugged and the metal plate NOT used. I experimented with this and the car does run much better but not just as smooth as I would like. I have ordered and recieved the metal plate but have not installed it. My questions: 1. If you plug those exhaust riser holes SHOULD the car run fine without the metal plate? 2. Is it recommended to go exactly as the factory supplied with the gasket and the metal plate? Or.... 3. Is it recommended to plug the exhaust riser holes AND still install the plate? Thanks, Robert
In my 300 with the original Carter I use Mr. Gasket steel shims with gaskets in between. It helps the motor restart easier when it's hot because it insulates the carb from the manifold (slightly). It does start MUCH easier warm now and they are just plain 4 hole steel shims...
carter lovers hey fellas im reading this post and see a number of you have spare afbs im wondering if one of you would part with that little piece of linkage that connects the choke assy(the one with the coil spring) to the choke itself ///does that make sense? anyway i picked up a carb but it is missing that little rod and the kits dont come with it ill be willing to pay for one thanks in advance pete
hey Pete, call Carmen Faso, I just gave him a carb thats not rebuildable, he should have the extra bit you need 716-693-4090 :3gears:
thanks ted illltry tomorrow ever heard of a barney kitsel guitar lol i probable spelled it wrong i had a 57 f hole hollow for 10 years then the org owner asked me to sell it back could say no to a friend but it hurt lol pete
Sorry to repeat the questions, but . . . . My questions: 1. If you plug those exhaust riser holes SHOULD the car run fine without the metal plate? 2. Is it recommended to go exactly as the factory supplied with the gasket and the metal plate? Or.... 3. Is it recommended to plug the exhaust riser holes AND still install the plate? Thanks, Robert
To answer question 1) Yes it is O.K. to plug the exhaust holes in the riser passage, they are ususally plugged with carbon anyway. 2) With the holes plugged there is no need for the metal insulator, just a regular gasket. 3) If you decide to leave the holes open, a metal gasket is necessary to prevent vacuum leaks. Hope this helps, Ian
brian i have 2 of these stainless steel spacers/gaskets in the orig. buick parts bags. I'll check around and see if the can be reproduced for a REASONABLE price. al
Al, reproductions are available from CARS www.oldbuickparts.com Price is $14.50 and part number is BP-576. However, their delivery time is ?????? (I've been waiting 2 weeks so far...) So I think you would have some customers here, if you decide to make them! We DO need reproductions of the '66 Q-jet heat shield plate! The Chevelle ones do NOT fit! Al????
