The Dreaded Holley Carb Whistle

[Paul S.]

I've got a 67 327/300 powerglide Convertible which is an NOM but correct Holley carb. The former owner already had the carb rebuilt to try to eliminate an intermittant carb whistle, which didn't work. I know from the receipts the rebuild consisted of a standard Holley rebuild kit plus labor, (which I am guessing is not a fix for a whistling carb) and the carb otherwise runs great except when it decides to whistle (which it does at least once every drive and it makes me nuts).

My inclination is to buy a new carb and just put the existing one on the shelf for the future (should I ever decide to source a casting # correct block and go the NCRS judging route). A new carb also means I don't have to send my current carb out and wait/hope assuming a different rebuilder could actually solve the whistle problem.

Is there a current day replacement carb that is a direct bolt-on, same throttle linkage, matches existing fuel line and air cleaner, has an available choke (or comes with it) and all, so I could just unbolt the old and bolt on and set the idle on the new carb and be off? Or am I pretty much stuck with buying another 4160 Holley Model 3810?

Second part of the question, whom would you suggest as a good place to buy a carb?

I see that Chicago Corvette has inventory of reman carbs, but don't know if that's a good choice quality wise. And it's tough figuring out what I should have when I go to sites like Summit or Edlebrock looking for carbs.

I saw an older post in the archives that an edlebrock 1406 has been used but not sure whether that requires changing the fuel line connection. That's the kind of feedback I'm looking for--what works and is still out there in 2010. Thanks.

[John H.]

Re: The Dreaded Holley Carb Whistle

Is there a current day replacement carb that is a direct bolt-on, same throttle linkage, matches existing fuel line and air cleaner, has an available choke (or comes with it) and all, so I could just unbolt the old and bolt on and set the idle on the new carb and be off?

Paul -

The good old Holley 1850 (Jeg's has them) is as close as you'll find as a replacement, but it'll require some changes.

The only way your existing fuel line will bolt up is to use your existing primary float bowl, or buy another one from a 3810, 3814, 3367, or 3605; Holley never used that down-angled fuel inlet design on aftermarket replacements.

You won't be able to use your existing remote choke setup - you'll need the Holley electric choke kit.

[Joe R.]

Re: The Dreaded Holley Carb Whistle

Paul,

I don't have any answers for you on your carb issue. But I would advise avoiding Chicago Corvette at all costs. Do a search on here for Chicago Corvette, I think you'll find there is a consensus on them.

Joe

[Robert R.]

Re: The Dreaded Holley Carb Whistle

Paul,
Its been years since owning my '67 but do remember the exact issue you bring up. I do remember after regasketing the bowls, I also put a thicker gasket between the carb and the intake to finally eliminate my whistle noise.

Also, take heed to Joe's comment on C. C.

Good Luck

[Douglas L.]

Re: The Dreaded Holley Carb Whistle

Paul,

I had the same problem with a Holley. When the carb got hot, it would whistle like crazy. It was the base plate. When the carb is cold the base plate should be flat. Take a straight edge and check the base of yours when it's cold. If is shows a gap in the middle between the base plate and the straight edge, then it is warped and it will only warp more when it heats up. Not 100% for sure, but try a new base plate - it should fix the situation. Stacking gaskets under a Holley is not a good idea. But that's not a good way to deal with a warped base plate. The only other way is to have the base plate resurfaced.

Regarding Chicago Corvette, I have heard the stories. However, I have not had problems. They have new base plates for Holleys.

[Frank E.]

Re: The Dreaded Holley Carb Whistle

There's a company in Alabama that bought the rights to the 4160 model 3367 from Holley (Colt Ind.) and is having them made new. They run about $600 from Corvette America and probably some others. They are a direct bolt on and hookup with manual choke and no fuel line mods required.

I to was having a problem earlier this year with mine and was going to go that route since I've had mine rebuilt many times and was getting tired of it. Fortunately I had float issues and I still have the old Holley. However, the next time it screws up there will be a new one atop the manifold.....

Good luck...

Frank

[Jack P.]

Re: The Dreaded Holley Carb Whistle

I've got a 67 327/300 powerglide Convertible which is an NOM but correct Holley carb. The former owner already had the carb rebuilt to try to eliminate an intermittant carb whistle, which didn't work. I know from the receipts the rebuild consisted of a standard Holley rebuild kit plus labor, (which I am guessing is not a fix for a whistling carb) and the carb otherwise runs great except when it decides to whistle (which it does at least once every drive and it makes me nuts).

My inclination is to buy a new carb and just put the existing one on the shelf for the future (should I ever decide to source a casting # correct block and go the NCRS judging route). A new carb also means I don't have to send my current carb out and wait/hope assuming a different rebuilder could actually solve the whistle problem.

Is there a current day replacement carb that is a direct bolt-on, same throttle linkage, matches existing fuel line and air cleaner, has an available choke (or comes with it) and all, so I could just unbolt the old and bolt on and set the idle on the new carb and be off? Or am I pretty much stuck with buying another 4160 Holley Model 3810?

Second part of the question, whom would you suggest as a good place to buy a carb?

I see that Chicago Corvette has inventory of reman carbs, but don't know if that's a good choice quality wise. And it's tough figuring out what I should have when I go to sites like Summit or Edlebrock looking for carbs.

I saw an older post in the archives that an edlebrock 1406 has been used but not sure whether that requires changing the fuel line connection. That's the kind of feedback I'm looking for--what works and is still out there in 2010. Thanks.

My L79 Holley did same right after rebuild by a good rebuilder, however, he did make a mistake with the gasket between meter bodies. The rebuild kits come with several that look almost alike and you can mix them up. When I took it back to him, he could not hear noise, been around race cars too long, once I told him, he put a hose to ear and knew right away the problem.

As stated, it is a simple fix, once you identify the gasket.

Jack

[David S.]

Re: The Dreaded Holley Carb Whistle



-Dave

[Timothy B.]

Re: The Dreaded Holley Carb Whistle

I would keep the original, it only takes a few parts and the know how to make it right. In order to overhaul the base plate the throttle blades need to be removed and the primary bores probably need to be re-bushed. The new base plates are not exactly the same as the old parts.

The secondary shafts usually only need new teflon bushings so the bores are OK. Also a good idea to check the main body for flatness and look closely at the primary metering block and secondary metering plate.

Lots of good info in archives about holley problems just like you are experencing..

[Stuart F.]

Re: The Dreaded Holley Carb Whistle

Should I assume by "Whistle" here, we are talking about a vacuum leak? Reason I ask is I am curious as to whether there are any other engine operation issues associated with what appears to be a vacuum leak. Is it too minor to cause any problems? When I first read about a "Whistle', I was thinking about the plastic tube that could be added to the float chamber from a modification kit. Any other base plate/gasket problems I have experienced in the past caused running problems, i.e. high idle, lean condition, etc.

Stu Fox

[Paul L.]

Re: The Dreaded Holley Carb Whistle

Paul,
I can comment on the Edelbrock #1406 conversion as I did that with my (former) 1967 327/300 with Powerglide. Once done the car ran fine but the journey to get there was long (and expensive).

-you will be converting to an electric choke
-the GM air cleaner base does not clear the choke; purchase Edelbrock base.
-the spout on the base to accommodate crankcase ventilation is quite small; modify rubber hose connections
-you need a "banjo" fuel inlet pipe to connect at the back of the carb and clear choke
-the 1406 does not have an internal filter; purchase in-line filter and a number of AN fittings/adaptors ($$)
-you have to bend and flare (AN 37*) new fuel tubing, fuel pump to filter
-owing to possible heat percolation use 3/8" phenolic base spacer; top of 1406 does not clear hood, use 2" instead of 3" filter element
-accelerator and Powerglide kickdown rods will require adjustments

I am sure there is more that I have forgotten but that will give you an idea.

[Gerald C.]

Re: The Dreaded Holley Carb Whistle

Paul,

I too have a 1967 and had carburetor problems. I took mine to Forty's Carburetor Repair in East Longmeadow, Ma. Ask for Skip. He completely rebuilt mine and it cost me $275.00. I bolted it on and it works great.

Jerry Coia

[Paul S.]

Re: The Dreaded Holley Carb Whistle

Should I assume by "Whistle" here, we are talking about a vacuum leak? Reason I ask is I am curious as to whether there are any other engine operation issues associated with what appears to be a vacuum leak. Is it too minor to cause any problems? When I first read about a "Whistle', I was thinking about the plastic tube that could be added to the float chamber from a modification kit. Any other base plate/gasket problems I have experienced in the past caused running problems, i.e. high idle, lean condition, etc.

Stu Fox

From my limited understanding, I don't think it is a vacuum leak per se, in the classic sense. Prepurchase I had this car checked out by Joe Scafidi and I'm sure I will misquote what he told me (as that conversation is going on two months ago now), but he said something to the effect that he thought it may be worn throttle shaft or the throttle bore has a wear pattern in it and the fact that it is intermittant (occurs or doesn't occur with a cold engine, hot engine, ect...) factored into the "diagnosis". When it whistles it sounds a lot like a teapot--in fact, that's how the former owner described it.

As with everything else, there's no way to know without having it torn down again whether it's contributed to by an incorrect gasket between the carb and its base plate or something else.

I was hoping a new carb would be a quick and (relatively) cheap fix, as I am a bit leery of "throwing good money after bad" having the existing carb rebuilt unless I can find someone in Dallas that I can take the car back to if the "whistle" isn't fixed.

Since the car otherwise runs well with no issues--starts first time, everytime (hot or cold), idles nicely, no hesitation or bogging under light, moderate or full throttle acceleration, and so forth--I will probably pull the carb over winter and send it off for repair or buy a replacement at that time. Too much nice cruising weather this time of year to have a car sitting, waiting on a carb rebuild.

[Gerard F.]

Re: The Dreaded Holley Carb Whistle

From my limited understanding, I don't think it is a vacuum leak per se, in the classic sense. Prepurchase I had this car checked out by Joe Scafidi and I'm sure I will misquote what he told me (as that conversation is going on two months ago now), but he said something to the effect that he thought it may be worn throttle shaft or the throttle bore has a wear pattern in it and the fact that it is intermittant (occurs or doesn't occur with a cold engine, hot engine, ect...) factored into the "diagnosis". When it whistles it sounds a lot like a teapot--in fact, that's how the former owner described it.

As with everything else, there's no way to know without having it torn down again whether it's contributed to by an incorrect gasket between the carb and its base plate or something else.

I was hoping a new carb would be a quick and (relatively) cheap fix, as I am a bit leery of "throwing good money after bad" having the existing carb rebuilt unless I can find someone in Dallas that I can take the car back to if the "whistle" isn't fixed.

Since the car otherwise runs well with no issues--starts first time, everytime (hot or cold), idles nicely, no hesitation or bogging under light, moderate or full throttle acceleration, and so forth--I will probably pull the carb over winter and send it off for repair or buy a replacement at that time. Too much nice cruising weather this time of year to have a car sitting, waiting on a carb rebuild.

Paul,

If you have eliminated a vacuum leak as the cause of the whistle, I think that there is one possibility that should be checked out. That is the secondary throttle plate being too far open.

When it is whistling, try jiggling the secondary throttle shaft to see if it effects the whistle sound. If it does, that might be your answer.

Try adjusting the secondary throttle stop screw on the underside of the base plate to Holley specs. On a 3810, there are actually pinhole idle feeds in the secondary throttle plate bores below the transfer slot, which feed through top of the base plate from the primary side and idle mixture screws on the metering block.

If your secondary throttle plate is too far open, you will find that the idle mixture screws will have no effect on the idle. On a 3810, because of the pinhole below the transfer slot, you really do not need to expose too much of the transfer slot on the secondary side at idle.

You should be able to hear that lean roll at idle as you adjust the idle mixture screws in.

[Dick W.]

Re: The Dreaded Holley Carb Whistle

Paul,

If you have eliminated a vacuum leak as the cause of the whistle, I think that there is one possibility that should be checked out. That is the secondary throttle plate being too far open.

When it is whistling, try jiggling the secondary throttle shaft to see if it effects the whistle sound. If it does, that might be your answer.

Try adjusting the secondary throttle stop screw on the underside of the base plate to Holley specs. On a 3810, there are actually pinhole idle feeds in the secondary throttle plate bores below the transfer slot, which feed through top of the base plate from the primary side and idle mixture screws on the metering block.

If your secondary throttle plate is too far open, you will find that the idle mixture screws will have no effect on the idle. On a 3810, because of the pinhole below the transfer slot, you really do not need to expose too much of the transfer slot on the secondary side at idle.

You should be able to hear that lean roll at idle as you adjust the idle mixture screws in.

I think that Jerry hit the nail on the head. The majority of the whistles are from the secondaries being open too much. You will have to remove the carb to adjust, but once it is off the engine, 30 seconds adjusting, and you are ready to reinstall