Carburetor for 1957 Series 62

[Dan Koser]

I've got the Old Lady running....pretty much started right up after the rebuild, and then sitting for about two years. Happy about that.

I did not rebuild the carburetor, but am now considering purchasing a new Edelbrock . The carb that is on the engine now is a Carter AFB with 1 7/16ths primary bore and 1 11/16ths secondary. The manual shows it should be a Rochester with 1 7/16ths primary bores and 1 1/16ths secondary....so I'm assuimg the Rochester got swapped out for the AFB at some point in the last 50 or so years.

Does anyone have a recommendation on this issue? The carb I have isn't original to the car; I could rebuild it I presume, or I could buy a entirely new carb; I could search on Ebay for an original Rochester...then rebuild that, but am not inclined to do that.  From the research I did, the carb I get should flow about 500 CFM.   Regards,  Dan

[Walter Youshock]

All the early '57's came with Rochesters.  They were very troublesome and there were at least a dozen modifications--from accelerator pump and choke adjustments to float drops.  The Carter was introduced mid-year and a lot of later '57's came with them.

I had the Rochester and found the correct Carter.  The Carter is far better.

If you're looking for a rebuilder, Daytona Parts Co. in FL is about the best.  http://www.daytonaparts.com/

[Dan Koser]

Feedback from Daytona is rebuild costs $400 plus shipping, a rebuilt kit is $40 plus shipping....so I think I'll try the kit first and see how that goes. I also checked with Edelbrock, and they have a 600 CFM carb (#1400) that should fit this application. I looked at one at O'Riley's and everything looks like it should line up, but may have to use a piece off the old carb to get it all hooked up correctly with the auto trans and down shifting. At O'Riley, the cost is about $400. At Summit Racing, the same carb sells  for $324 plus $12.95 for "handling"....with free shipping.

[Walter Youshock]

I tried that as well.  When all was said and done, I finally paid the $400 and sent it to the pros.  Had I done that in the first place, I would have saved a LOT of time, money and aggravation.

The carb came back flow tested and adjusted with all the linkages replated to NEW condition.  Overall, a bargain! 

If you're looking to keep the car original, this is the best way to go!

[Dan Koser]

Here's my latest question on this...I've read all about adjusting the air/fuel mixture screws, but no one ever talks about the big 'ole....obvious...screw in the middle of the base between these two. What the heck am I supposed to do with this screw? So far, I'm ignoring it. In the mean time, the carb seems to be running rich. Any help would be appreciated. Regards,   Dan

[Walter Youshock]

The big one in the middle is the idle air adjustment screw.  That's the first one you need to tweak to get the rpm's at 450 in drive.  Once you get that set, you fiddle with the mixture screws, then recheck the idle and adjust the center screw if necessary then recheck the mixture screws.

If you don't have a vacuum gauge, get one.  I plug the gauge into the vacuum line from the intake manifold to the wipers.  Adjust for highest vacuum.

[Ralph Messina CLC 4937]

Dan,

First, I agree with Walter that a Carter is the better choice of the original carbs. They are much simpler and give the same performance.

The procedure for these carb adjustments is pretty much the same regardless of year. The ’57 Shop Manual will give you the exact numbers. I’m using the ’66 numbers for this example because I remember them. Let the engine come up to full operating temperature. Start by checking the timing which should be about 5 BTC. The large screw is the air adjustment screw and controls the idle speed. Backing the screw out (counterclockwise) raises the idle and leans out the mixture.  With a helper holding the brake on, put the car in Drive and adjust the idle to about 500RPM. You are trying to get the highest RPM with minimum fuel…..best performing leaning mixture. The two smaller screws adjust the air/fuel mix and compensate for changes made by “leaning” the mixture with the big screw. Turn one of the screws (clockwise) to obtain the highest RPM. Continue turning until the RPM decreases about 20-25 RPM which is the lean idle speed fall off. Reverse rotation ¼ turn. Repeat this process with the other air/fuel mixture screw. You may have to adjust the large air adjustment screw again to get back to 500RPM. If so, repeat the air/fuel mix adjustment again. It sometimes takes an iteration or two to get everything just right.

It’s best to do this with a tachometer. Real mechanics can do this adjustment by ear or feel. I’ve tried that and can’t even come close……Some of us still need training wheels.

HTH,
Ralph

[Walter Youshock]

Very concise, Ralph.

You do need a tach as well.  Set your dwell and timing first, then do the carb.  The original setting was 420 rpm in drive for the '57 then they upped it to 450 mid-year.

1200 rpm cold with the choke closed for start up.

[Dan Koser]

Thanks Walter and Ralph. I've got a ways to go then.....I'm told the vibration dampener has rubber in it and is likely deteriorated; as a result, I'm unable to time the engine correctly in the first place. So, I'll probably have to start there...get it rebuilt...and then move on to the other steps. Thanks again for the advice...much appreciated. Regards,   Dan

[Dan Koser]

So I orderd a rebuild kit from Daytona and have just got the rebuild done. When I ordered the kit, they asked me if I had the stainless steel spacer.....if I didn't have one I'd need one. I ordered one, and now wonder just how this fits into the overall assembly. I now have a phenolic spacer of about 1/2" and the stainless steel spacer. Does anyone know the order in which the stainless steel and the phenolic spacers go? Also, in my way of thinking, I need three gaskets for this to work without leaking. Any thoughts would be appreciated.   Regards,   Dan

[D.Yaros]

I bought/used a Daytona rebuild kit.  In the process I had a question about a part, emailed them with it, and received a quick reply with my answer.  Shoot 'em an email, or give them a call.

[Ralph Messina CLC 4937]

Starting at the manifold the sequence is: gasket, spacer, gasket, stainless shim. The engine will not idle without the stainless shim.


Ralph

[Dan Koser]

I bought/used a Daytona rebuild kit.  In the process I had a question about a part, emailed them with it, and received a quick reply with my answer.  Shoot 'em an email, or give them a call.

You were right about this...The folks at Daytona are very helpful. I gave them a call, spoke to the tech and got the same order of spacers as Ralph mentioned. I received two new gaskets with the kit and spacer, so will have to re-use the one I had on the car to make this work, but I believe it will be OK. Thanks for the advice. Regards,   Dan

[Walter Youshock]

The stainless shim is only used on Carters since they have the aluminum bowl.  Without it, there will be too much heat built up in the warming passage under the carb and it'll cook the gas--not to mention the carb itself.  Even a pinhole will cause trouble once the car is warmed up.

On the fiber gaskets--MAKE SURE the port for the brake booster port is punched out or you wont have any vacuum going to your booster.  I speak from experience...  It's a triangular hole between the secondaries.

The stainless plate and bakelite plates have a tab on the primary side.  The tabs have to line up and the tab on the bakelite plate MUST be on the bottom, closest to the intake manifold toward the passenger side of the car.  Flipping it over will restrict the passage to the secondaries.

The photo shows how it should be installed looking down.  The tabs of the plates have to line up. 

The shop manual says to put gasket cement on the top surface of the stainless plate.  Daytona says don't do it.  I did use cement on mine since there is really no sealing mechanism between the plate and the carburetor bowl.

[57flw]

Hi Guys,
I know this post is a little old BUT.
I am now ready to fit the Carter Carb, I had overhauled at Daytona and I am a little confused on the gasket order.

I have seen the order from Ralph......(Starting at the manifold the sequence is: gasket, spacer, gasket, stainless shim. The engine will not idle without the stainless shim.)

My confusion is I have THREE gaskets + Spacer + Stainless Steel Shim.
Does the other gasket go on top of the shim and then the Carter or does the Carby sit on the Stainless Steel Shim.

Thankyou.

Ken

[Ralph Messina CLC 4937]

Hi Ken,

I don’t know why the kit has three gaskets other than the vendor supplying a spare. I don’t usually bother to read, much less follow, instructions until I can’t get something to work properly or I’ve broken it. But the sequence I posted, is directly from the Shop Manual and know that it works correctly. I would start with that method using two gaskets. I’ve seen posts about Carter’s not running properly and the issue is usually related to the stack sequence in question. The explanation that Walter provided (the shim acting as a heat sink to protect from carb overheating) is the usual explanation for that sequence.


HTH,
Ralph

[Walter Youshock]

You got an extra gasket.  MAKE SURE the second gasket has the opening between the secondary barrels opened.  The gaskets, bakelite plate and shim go on with the tabs lined up and to the passenger side.  The bakelite plate has vacuum passages bored into it on the secondary side.  These have to be to the top.  This is the vacuum feed for the brake booster.

[57flw]

Ralph and Walter.

Many thanks for the replies.
A spare gasket.... Who would have thought that? Something for nothing!
I will fit it today.

Ken

[Walter Youshock]

One extra isn't going to help you much.  If you ever have to take it off, you'll still need one more...  I've rarely had luck recycling carb gaskets.

[57flw]

Hi Walter,
I agree. One extra gasket is really not much use.

I also got a reply from Daytona. See below.

Ken!  Originally Cadillac factory installed the gasket on the manifold, then the spacer, then another gasket and then the shim.  The carburetor goes directly onto the shim.  Remember to not overtighten the nuts; then retighten after a couple of startups and warmup of the engine.  It will settle down, and prevent vacuum leaks, and the nuts will never fall off.  We include a third gasket, in case there is severe warpage present on the carb base, but you do not have to use the third gasket.  Keep it as a spare. Hope this helps.

It was nice of them to reply.
Same as you and Ralph.
Once again. Many thanks.
I am sure I will still have some more questions before I am finished.
Ken