Hello everyone,
I started a new thread from my last post on the car stalling on hard right turns. I determined the problem from that was a needle valve seat that was improperly installed that threw off the float adjustments. With the problem solved, a new one began.
I have a vacuum leak problem of which I am suspicious of the gaskets between the manifold and the throttle body. I attached some photos of mine from the throttle body down, so starting with the stainless steel shim, the gasket, and then the bakelite insulator. Can anyone verify these are (1) the proper order and (2) the proper orientation?
While I am at it, I photographed the date code on my intake - it is 3N3. My '62 was "born" on March 9, so the 3 and the other 3 make sense, but the N does not. Any input on how to decode the intake manifold numbers?
Thanks!
Matt
I could not fit all the photos, so here are the other two. Thanks!
Looks correct to me. I was remiss in that the tab on the Bakelite plate is on the Driver's side--it is as you have it here. All the tabs line up, so that's good.
Is the Bakelite plate flat? They can warp over time. You can sand them down with a wood block and sand paper to get some of the warp out. If it's cracked, which also happens, replace it or try some JB Weld. The intense heat of the manifold could destroy the epoxy, though.
Is there any gunk on the bottom of the carb itself, preventing a tight seal to the stainless plate?
Walter,
Bottom of the carb is nice and clean, as I just rebuilt it a couple months ago before I start having these issues.
The bakelite appears flat, but I do have a spare one that I can use. I know the car came with a Rochester and I switched it with a 1962 period Carter AFB. Are the Bakelite insulators between the two identical?
You mentioned before without the stainless steel plate, the car will not idle correctly and the fuel will boil in the bowls. On the test engine I have been using, I did not put in the stainless steel plate and it idled poorly. I also noticed smoke coming from the top of the carburetor when I shut the engine off - is this indicative of boiling fuel? I just want to make sure I am comparing apples to apples to evaluate which components are good and which ones are not so I can figure this darn thing out.
Matt
I'm pretty sure the Bakelite plate was the same for years and is the same regardless of which carb is on the car. I do know of someone who had a '61 with a Carter and missing plate and his car acted like yours--ran fine until it got hot, then came the black exhaust and the car croaked. Smoke from the carb could also be boiling gas vapors. That is NOT GOOD! So put out the cigar!
How about the top of the intake--is that all clean or is there a little bit of old gasket stuck on it? Are you using NEW gaskets or reusing old ones? Is the cab torqued evenly on all 4 studs?
Try this: put it back together and disconnect ALL the suspect vacuum sources--booster port, advance port, the dash pot, and plug them. Eliminate all those from the vacuum equation. If it runs, then add the other stuff back one at a time. How is your vacuum advance? If the diaphragm is shot, there's a vacuum leak... Dash pot plunger work, or does goosing the engine make it die and the plunger is stuck out?
Quote from: Walter Youshock on January 02, 2014, 03:03:11 PM
Looks correct to me. I was remiss in that the tab on the Bakelite plate is on the Driver's side--it is as you have it here. All the tabs line up, so that's good.
Is the Bakelite plate flat? They can warp over time. You can sand them down with a wood block and sand paper to get some of the warp out. If it's cracked, which also happens, replace it or try some JB Weld. The intense heat of the manifold could destroy the epoxy, though.
Is there any gunk on the bottom of the carb itself, preventing a tight seal to the stainless plate?
Walter -
In the previous thread you referred to the tab on the right side. I guess you agree Matt's picture looks like it is on the passenger side (left). Maybe you were calling the passenger side the left looking at the engine from the front? The right side is from the driver's perspective.
Jon
Walter and Jon:
I think we confirmed the bakelite is right side up and correctly positioned. All of the gaskets are new, but I am going to take Walter's suggestion of inspecting the bakelite for squareness and cracks and then putting everything back the way it was and plug up all the accessories - vacuum advance, power booster, power door lock reservoir, A/C module vacuum, windshield washer, and firewall dashpot. With all of these disconnected, I can start to troubleshoot which one is the gremlin.
Vacuum advance is good - it is new and has been dialed in to provide the 32 degrees of advance at 3,000 rpm in conjunction with the centrifugals.
Let's talk about the dashpot plunger. What exactly does that do? I am tell with the engine off, the plunger is out and pushes the idle up. However, with the engine running, the plunger retracts because it is pulling vacuum. The only time that plunger comes out is when there is no vacuum, so any information on what it does or its operation would be helpful.
Matt
Matt -
Dashpot is designed to prevent engine stalling upon rapid release of the accelerator like in a panic stop. It gently slows the retraction of the accelerator linkage. Yours appears to working correctly. With engine running, if you rev the engine (momentary vacuum drop) the plunger should come out and as you release the linkage it will retract slowly and gently return the engine to idle.
Jon