Stainless steel baffle plate needed for carb!?! Help.

[Guest middleman]

Running a Carter AFB 4 barrel on the Riv and mechanic says I am need of a stainless baffle plate that will keep intake from damaging base of carb.

Any more info that you guys can offer on this? Is this a need based on the design of the Nailhead intake manifold???

If so, do I order one from YearOne?

Clueless but ready to learn,

JB

[RivNut]

Your mechanic is correct.,

There is an exhaust passover that goes up to the carburetor to heat the base. This is (was) necessary to make the car run smoothly during cold weather operations. The problem is that the exhaust gases will corrode the aluminum base of the AFB carb. The stainless gasket was put between the fiber gasket on the manifold and the base of the carb. This would let the gasses circulate, and heat the base of the carb, but the stainless plate would protect the aluminum.

These can be obtained from almost any vendor who handles Buick Parts. CARS, Inc., Classic Buick, or on ebay you can find a vendor who goes by Buickrodder. (I think his plates are a little thicker than normal.) You can also secure them from any carburetor supply or rebuilding company. You can probably get them from places like JEGS or Summit Racing. Before going to any of these places, I'd first check your local jobbers: NAPA, Car Quest, Advance Auto, etc.

Here's what your looking for: The stainless gasket is on the left, the fiber gasket is on the left. The heat gets to the stainless, and it in turn heats the carburetor.

Probably a lot of places cheaper than year one. You should be able to get both and change from a ten-spot.

Ed

[Guest middleman]

Thanks Ed. Good to know about this. I wondered why the intake had that little "ditch" in it. I found the plate and gasket on eBay from Buickrodder. My local NAPA did not carry it.

I appreciate the help,

JB

[RivNut]

JB

Buick Rodder is a guy named Russ Martin. Russ on the west coast and Tom Telesco on the east coast are THE nailhead gurus. Russ is most active on the Yahoo Group for Buick Nailhead guys, and Tom's expertise can be found on the V8Buick.com fourm. Tom's signature line for his nailhead engine rebuilding services is "If I can't get it, you don't need it." Both are good sources for parts and information.

I don't think there's a question about the nailhead engine that one or both of them couldn't answer.

Ed

[Guest Rob J]

I second Tom Telesco. I just got my carb back from him from being re-built, and he is also going to rebuild the engine and carbs in my 65 GS. Tom is the authority when it comes to Nailheads. The man knows his stuff.

I also second on getting the carb baffle from CARS. I just ordered a replacement, and received it yesterday from them for my 401 65 Riv.

[Jim Cannon]

Your mechanic is correct. I would say he is a "keeper" if he knew that about your nailhead.

[Jolly_John]

Hi, Middleman. I sent you a PM through the forum, regarding some parts I have. John

[Guest Greg Gessler]

The parts for carburetors are getting harder to find,

I have 100's of parts for Rochester and Carter carburetors.

Check out my website:

Quadrajet Carburetor, Rochester 2G Rebuilding & Tuning Parts & Tools

[NTX5467]

In addition to Buicks, Chevrolets of similar vintages also used the "heat track" intake manifold, plus the composite/stainless plate carb base gasket set. The last set I got were made by FelPro, and from NAPA. A key is finding a vendor with a catalog that goes back that far.

Happy Holidays!

NTX5467

[RivVrgn]

Here is a picture of my carb and baffle plate I took off my 65. You'll notice the plate has the holes just like the base of the carb and the gasket, the ones I have seen offered don't.

Like someone else said other cars used these also.

Try a site called paragon corvette. The plate is for a 62-65 corvette. The part number I have is 669. (GM part # 3799354)Thats where I got mine and it fits and works perfect, just like original.

Joey #12735

[RivNut]

Joey,

The base of your carb shows some burn through too. Without the stainless plate to block the exhaust gasses from contacting the aluminum base of the carb, it won't take too long for the aluminum to corrode completely through to the bowls and venturi area.

[RivVrgn]

Joey,

The base of your carb shows some burn through too. Without the stainless plate to block the exhaust gasses from contacting the aluminum base of the carb, it won't take too long for the aluminum to corrode completely through to the bowls and venturi area.

Yeah, that's what I thought too but,with some cleaning and scraping it was okay. But, if had gone much longer it would have burned through. I caught it just in time,even though the gasket burned through the base was saved. I dodged a bullit on that one. After cleaning and rebuild it's working just fine. At least it was a good surprise.

Joey

Edited November 29, 2011 by RivVrgn (see edit history)

[RivNut]

Hey, it's one of those times that two wrongs make a right 1) no stainless heat shield, and 2) the wrong AFB gasket (no exhaust passage). The wrong gasket worked as a shield until you discovered the error. As you said, luckily you caught it in time.

[msthing66]

Your mechanic is correct.,

There is an exhaust passover that goes up to the carburetor to heat the base. This is (was) necessary to make the car run smoothly during cold weather operations. The problem is that the exhaust gases will corrode the aluminum base of the AFB carb. The stainless gasket was put between the fiber gasket on the manifold and the base of the carb. This would let the gasses circulate, and heat the base of the carb, but the stainless plate would protect the aluminum.

These can be obtained from almost any vendor who handles Buick Parts. CARS, Inc., Classic Buick, or on ebay you can find a vendor who goes by Buickrodder. (I think his plates are a little thicker than normal.) You can also secure them from any carburetor supply or rebuilding company. You can probably get them from places like JEGS or Summit Racing. Before going to any of these places, I'd first check your local jobbers: NAPA, Car Quest, Advance Auto, etc.

Here's what your looking for: The stainless gasket is on the left, the fiber gasket is on the left. The heat gets to the stainless, and it in turn heats the carburetor.

Probably a lot of places cheaper than year one. You should be able to get both and change from a ten-spot.

Ed

Hi Rivnut, I just ordered the gasket and baffle for my 1966 Riviera (Carter 4bbl Carb). Thanks for confirming the order of the gasket/baffle assemblies.

 

I have seen references to "square bore" on the intake manifold? How do I determine if I have a square bore or not? Do the same gasket/baffle still work on square bores or is it a different part number?

[RivNut]

Square bore vs. spread bore.  The spread bore carbs are the Rochester Quadrajets and its clones. Because of the enormous diameter of the rear butterflies, the rear bolts on the carb are spread farther apart than the front bolts.

 

 

Square bores include the Carter AFB and its clones, most Holleys, and Rochester 4GC's.

[msthing66]

In addition to the metallic baffle and four hole gasket on "SAM 0409" pic attached. My 1966 425 with Carter Carb also had a non-metallic shim between the carb and metal gasket - on the left in pic "SAM 0408" . Is this shim recommended? Is this additional shim necessary?

[RivNut]

Oh yeah!  The "shim" is actually a heat shield.  Exhaust gasses are channeled to the base of the carb to assist with cold weather carb operation.  The heat shield is necessary to isolate the exhaust gasses from the aluminum base on the carb.  You place the heat shield, usually made from stainless steel next to the bottom of the carb; this allows the shield to be heated and transfer the heat to the base of the carb without the corrosive exhaust gasses coming into contact wtih the aluminum carburetor.  You then need to put a regular carb gasket on the manifold.  Set the heat shield on top of it and the carb on top of the heat shield.  The fiber gasket that sets on the manifold needs to have the same 'horse shoe' channel in it as you see on the manifold.  The exhaust gasses need a passage and the manifold groove and the channel in the fiber gasket are this passage.  Both of the gaksets you pictured are toast, and the fiber gasket does NOT have the necessary channel.  Find the gaskets from one of the vendors who knows about which he speaketh.  CARS, Jon at the Carburetor Shop in Eldon, MO, or any others that know Buicks and how their engines are designed. Dont' use universal gaskets (as you pictured.) Unless you really know what you're after, DO NOT get your parts from your local jobber.  Russ Martin, www.nailheadbuick.com , has the right stuff.

 

Ed

[XframeFX]

I'm bringing this back as I'm still confused.

For my AFB, I have .060" smiley gaskets and the .017" heat-shield all on the left in the image below. My observation has this sealing well around the perimeter. But what about in-between the 4 holes? The gasket will compress more around the perimeter then in the center. Would the center section of the gasket be sandwiched or flap in the flow?

The heat shield on the right (I'd use just one, not the stack), will seal evenly on the entire flange surface. Wouldn't this be preferred?

Thanks

[RivNut]

You need the "smiley" gasket to allow the exhaust gasses to cross over and heat the stainless gasket. The Mr Gasket heat dissapator is an item used to keep heat from the carb. Most are made from some kind of phenolic resin.  You don't  want to use that  because it will act as a carb riser and disrupt the flow of the fuel mixture. Plus it may cause interference between the air cleaner and the hood.   You might look around and see if you can find a heat shield that is shaped like the gasket except for the "smile." 

[telriv]

In all reality the heat under the carb. is NOT nec. the way these vehicles are driven today.  We DON'T need the heat under the carb. because we are not, on purpose anyway, will be driving in inclimete weather conditions as when they were new & daily drivers when needed to perform in all weather & all conditions.  I plugged the holes in the manifold on my Riv. 50+ years ago & have had no problems even when driving on a daily basis in all weather conditions when the Riv. was newer. 

Just block the holes in the manifold under the carb. & not the heat crossovers in the heads. We still need some heat in the manifold to help vaporize the cat pee that's used as fuel today.

Just my thoughts.

 

Tom T.

[KRmanr]

1 hour ago, telriv said:

In all reality the heat under the carb. is NOT nec. the way these vehicles are driven today.  We DON'T need the heat under the carb. because we are not, on purpose anyway, will be driving in inclement weather conditions as when they were new & daily drivers when needed to perform in all weather & all conditions.  I plugged the holes in the manifold on my Riv. 50+ years ago & have had no problems even when driving on a daily basis in all weather conditions when the Riv. was newer. 

Just block the holes in the manifold under the carb. & not the heat crossovers in the heads. We still need some heat in the manifold to help vaporize the cat pee that's used as fuel today.

Just my thoughts.

 

Tom T.

I agree with Tom T.  I "plugged" the holes under my '67 Q'jet carburetor 30+ years ago simply by using high-temp silicone. Especially living in Texas, this is not necessary at all.  Also, consider the fact that by 1969 (possibly 1968 too), Buick did away completely with that under carb heat tunnel, so it must not have been providing the positive results they anticipated.  

Edited June 21, 2021 by KRmanr (see edit history)

[XframeFX]

13 hours ago, RivNut said:

You might look around and see if you can find a heat shield that is shaped like the gasket except for the "smile." 

Exactly. In addressing flange-to-flange seal, I'd use just the top plate of that Mr. Gasket #98. It is .07" aluminum  but has the same area as the flange. I think I'll use it instead of that 'Square SS Shim'.

Thanks for the response!

[RivNut]

That #98 Mr Gasket heat shield is 1/2” thick. 

[XframeFX]

15 hours ago, RivNut said:

That #98 Mr Gasket heat shield is 1/2” thick. 

Ed, with the 3 plates and gaskets, that #98 amounts to 1/2". I'd use just one plate with smiley gasket.

Question is if the soft .07" aluminum plate is good enough to set the carb on directly. Or, use a 4-hole gasket in-between thus defeating the heat transfer in favour for a positive seal around the perimeter and between holes.

Lots of discussions on this. But, I'm addressing the seal over the entire flange area.

https://www.corvetteforum.com/forums/c1-and-c2-corvettes/1978466-q-jet-carb-base-gasket-tech-info-the-hot-slot-manifold-problem.html

 

[RivNut]

@XframeFX If you read the description for the Mr Gasket #98 heat riser, it says right on the package that it’s 1/2” thick. It also says it’s to be used only on race engines and that it is not to be used on the highway.  These fishers serve two functions. They let a racer run a cooler (more dense) charge of fuel, and they’re supposed to increase runner length which supposedly increases horsepower.

 

If I were you, and I will on my 64 as I reassemble the engine, do as Tom T. suggests and plug the crossover holes at the top of the manifold then run just the “smiley” gasket between the manifold and carburetor.  Because of the way we drive our cars, we don’t need the heat to the carb on those bitterly cold mornings, for which the stainless plate is designed.

[OldGerman]

I also used just one of The 3 Mr. gasket 98 steel plates. I need to grind a small cutout on one side to clear the choke or carb Linkage. Plugged the intake holes in addition as I will not use the car as a dayly driver or in cold  climate condition.

 

[telriv]

If the holes have been plugged NO need for the screening.  Remember can't make the manifold too cold as then it will hesitate. 

[XframeFX]

20 hours ago, RivNut said:

If I were you, and I will on my 64 as I reassemble the engine, do as Tom T. suggests and plug the crossover holes at the top of the manifold then run just the “smiley” gasket between the manifold and carburetor.  Because of the way we drive our cars, we don’t need the heat to the carb on those bitterly cold mornings, for which the stainless plate is designed.

Ed, There's a thought I did not consider as I was focused on sealing the entire flange equally and not concerned about heat. Plug the Holes and mount the carb directly on the smiley gasket!

The secondary feature of the heat shield is that it prevents exhaust gas exposure eating away at the carb flange. Not an issue when the holes are plugged.

[XframeFX]

13 hours ago, OldGerman said:

I also used just one of The 3 Mr. gasket 98 steel plates. I need to grind a small cutout on one side to clear the choke or carb Linkage. Plugged the intake holes in addition as I will not use the car as a dayly driver or in cold  climate condition.

Frank, the Mr. Gasket Plates are .07" aluminum not steel or .05" as stated. Being supplied with just 3 gaskets, the product seems to indicate to mount the carb directly on the soft aluminum?

Sorry, I might be a little too much OCD on such a simple task as mounting a carburetor.

 

For your install, I suppose you have 2 smiley gaskets. A regular 4-Hole gasket is all that's required on top of your plate.

I see your brass fitting for the power brake is broken off. Hopefully not the Tee fitting for AC. A 90 degree brass fitting is easy to source for non AC cars.

[telriv]

Too many gaskets will have a tendency to warp the base of the carb.   Just do it like Buick did, IF you don't plug the holes, smily face gasket on mainfold, aluminum spacer under carb. on top of gasket.

OR, IF you plug the holes just the gasket.

 

Tom T.