304 Carburetor spacer

[mriplaybass]

I didn't get any answers to my problem by adding to my other MC2100 thread, so I guess I'll try starting a new one.
I recently had to replace my MC2100 carburetor because the old one had 2 of the bolt mounting lobes break due to the deterioration of the phenolic spacer below it. I rebuilt another MC2100 and purchased a Crown spacer to replace the phenolic spacer. When I put the thick gasket between the carb and the spacer, there is a considerable gap at all the bolt holes. I am a bit wary of torquing down the carb for fear of destroying the new carb. I don't know if the gasket will compress sufficiently when tightened down, or if I should possibly put some washers between the carb and the spacer to avoid stressing the carb mounting points. I have 3 of the thick gaskets, and one of them is a bit thinner than the other 2. Are there various thicknesses available? I have not found anything indicating that there are. I included some pictures showing the gap. Any insite would be greatly appreciated. I have rebuilt many carbs over the years, but the AMC 304 is the first one I have come across with this kind of spacer.

 

[Posi]

I missed your previous post on this.
I'm assuming the spacer isn't straight but did you check the intake and carb?
What torque spec did you use on your last install.
I can't see the pics now but assuming it's the spacer is it straight on one side or both sides are not level?
If only one side is level I'd return it. If both sides are uneven in the same way it should level out when tighten down.
I can check the spacers I have as well when I get a chance.

 

[lutry]

When I rebuild my 2100 last summer, I have to admit, that I did not check if the spacer is even.
Nevertheless I used the specified torque from the FSM which worked perfectly.
I would assume that the spacer will bend but not the carb.

 

[Lumpy Grits]

Put a known straight edge on the carb's base and ck for flatness, then ck the spacer.
Since you said the spacer was a 'Crown' part. Think I know were the issue lies.
LG

 

[lutry]

Sorry, I overlooked the Crown spacer, I used a NOS AMC part.
For comparison, I got one NOS carb and one NOS space (both AMC)
and took pics, the fit perfectly flat, so maybe a NOS spacer would be better...

 

[mriplaybass]

I missed your previous post on this.
I'm assuming the spacer isn't straight but did you check the intake and carb?
What torque spec did you use on your last install.
I can't see the pics now but assuming it's the spacer is it straight on one side or both sides are not level?
If only one side is level I'd return it. If both sides are uneven in the same way it should level out when tighten down.
I can check the spacers I have as well when I get a chance.

Put a known straight edge on the carb's base and ck for flatness, then ck the spacer.
Since you said the spacer was a 'Crown' part. Think I know were the issue lies.
LG

Sorry, I overlooked the Crown spacer, I used a NOS AMC part.
For comparison, I got one NOS carb and one NOS space (both AMC)
and took pics, the fit perfectly flat, so maybe a NOS spacer would be better...

I checked flatness on everything before I posted this thread. Manifold, carb, and spacer are all true. Here is what I found out today. I decided to see how the spacer would fit the intake manifold. With each of the 4 "mounting posts" on the spacer firmly making contact with the manifold, I could easily fit a feeler gauge between the carb base and the manifold. I turned the spacer over and noticed that there was a deformation on the bottom that looks as if someone brushed a hot soldering iron over it. Even with this leveled off, there was still a gap where the gasket needs to seal. Same problem with the top. The "mounting posts" are too low to allow the carb to make contact with the adapter. As you guys have said, it may well draw down and compress the thick gasket, but after breaking one carb, I am a bit hesitant.

LG, CROWN!

Even though I bought this spacer a month ago, Morris is going to send me a new one. Can't really say I am holding my breath for better results though!

Posi, let me know if you come across a decent spacer. I'm starting to think that might be the best route to take.

 

[Hedgehog]

THe new one will be the same. This is what I did.

In the other thread I mentioned the over all poor fit of the two spacers. I first opened up the corners of the 1/8" spacer to fit over the thicker spacers corners without interference. This helped. I think the smaller one was bowing up a little. Then I glued some quality sand paper to a flat board and went to sanding the spacer flat. You will find that the rubbery coating is thin and quickly you'll see the surface is a harder material. I did a lot of sanding ... sand some, put the two spacers together and look for a gap I looked for light coming through ..... sand some more .... eventually you will see the high spots going away .... Once I felt the gaskets fit well together I started paying attention to the surface that fit the carb. ..... once that was smooth and fit the carb well I put the two spacers together. and worked on the posts a little. ..... The doing really didn't take long ..... in the end I found that good old gasket sealer was good for fuel, so I put a VERY thing layer both between and on the mounting surfaces and bolted them together. My leaks stopped right there. You know about working meticulously and with considered care so I don't need to preach about taking it easy and not ruining anything. In the other thread I knew that without both gaskets/spacers in hand it was difficult to explain what I was talking about. I be now you see what I meant by the spacer not fitting well together.

 

[Posi]

Bass, I have a straight spacer you can have if needed.

 

[mriplaybass]

Bass, I have a straight spacer you can have if needed.

Thanks Posi, the replacement spacer came yesterday afternoon, and like the first one, the mounting posts are not symetrical. It is better, but there is still a deformation on one of the barrels as if someone dragged a hot soldering iron over it, and 2 of the 4 mounting posts are still too low and have a fairly large gap. I am going to try using one of my body block sanders to level things off, but if I can't make this work, I'll call or email you for the spacer you have.

 

[Hedgehog]

It will work, worked for me. First open the corners up to fit on the posts. Then like a carpenter squares a piece of wood, start on one surface of the 3/8" spacer, level it until it fits the big spacer ... nice and flat. Then proceed to fitting the carb and manifold. For good measure I used a small amount of good old form a gasket on the flat surfaces to make up for slight uniformity issues.

 

[Woolyworm]

I use permetex hi-tack on mine.


Wooly