Engine: Stromberg WW - Odd problem

[Phatfenders]

I have 2 Stromberg WW's (I'll call them backdrafts) on a 259, both are rebuilt and the throttle shafts don't appear to have excessive wear. Also the engine starts and runs very well with these carbs and there are no vacuum leaks, vacuum is just over 18 in. So my problem is that there is a very noticeable, piercing whistle at idle, I believe its air passing by the throttle plates. Has anyone else experienced this and is there a cure.

[rusty nut garage]

I had this problem on a Stromberg a few years ago on a customers car. I thought I kept good notes but can't find them at the present. If memory serves me I think that the base plate gasket was the wrong one. Once I corrected this whistle went away. Remove carb, and inspect baseplate gasket against manifold. Make sure its the correct one or if you still have your old one compare against it.

I have 2 Stromberg WW's (I'll call them backdrafts) on a 259, both are rebuilt and the throttle shafts don't appear to have excessive wear. Also the engine starts and runs very well with these carbs and there are no vacuum leaks, vacuum is just over 18 in. So my problem is that there is a very noticeable, piercing whistle at idle, I believe its air passing by the throttle plates. Has anyone else experienced this and is there a cure.

[SN-60]

I had this problem on a Stromberg a few years ago on a customers car. I thought I kept good notes but can't find them at the present. If memory serves me I think that the base plate gasket was the wrong one. Once I corrected this whistle went away. Remove carb, and inspect baseplate gasket against manifold. Make sure its the correct one or if you still have your old one compare against it.

The only difference I've come up against with those WW carb base gaskets is that one style has a hole for manifold vacuum to enter carb for proper automatic choke operation.......while the other style is solid. (made for vehicles, trucks?, with manual chokes.)

[Phatfenders]

Thanks for the thoughts on the base gasket. I have had several variations of gaskets and even spacers, some I made, trying to get this setup engineered and I never noticed any difference in the whistle but I was concerned about other things at that point. I currently have new factory stock base gaskets (no spacers) for the stock style downdraft WW's, I'm amusing the gaskets would be the same.

[StudeRich]

The gasket with only one big kidney shaped hole: 1540006 is for the '57-'64 WW 6- Carbs. I believe the one with 2 holes was used on the Old '51-'52 Bendix Aero Type Stromberg downdraft top carb.

UPDATE: No correctly setup WW's whistle, when the correct internal and exterior Gaskets are used, no need to plug anything.

[Dick Steinkamp]

I had 2 WW's on the Kart Hauler...



I pulled out the choke butterflys on mine and made sure I plugged all the holes the chokes used...including the inlet to the choke housing for the heat tube from the manifold. They did not whistle.

You might check to see if there is a small unplugged orifice no longer being used that is causing the whistle.

[Dan Timberlake]

listening with a length of small diameter plastic or rubber tubing with one end held near an ear can help identify whistle location.

like 1/2 of this.

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSONeo6SP7l8-GNesWYT8ahsSCx0yMwoxs2sXGt6t7DVehaDN82HQ

[Dan Timberlake]

Hi Dick,

Do those carbs have the small holes to atmosphere in the throttle bodies opposite the mixture screws?

regards,

Dan T

[bosshoss61]

My thoughts---if the whistle was coming from an internal gasket, wouldn't the noise just reverberate up and out the filter. So the stethoscope method (which I have used) might not help. Noise is usually made from air at very high velocity through a venture, such as a restricted filter. Was something changed, like the filter size? I the media different?

[Dick Steinkamp]

Hi Dick,

Do those carbs have the small holes to atmosphere in the throttle bodies opposite the mixture screws?

regards,

Dan T

Dan if you mean IN the throttle body by the throttle plates, yes...but I think all carbs have those. If you mean outside the throttle body on the opposite side of the mixture screws, I don't remember for sure, but I don't think so.

[Tom Bredehoft]

I found that some of the WW carbs have holes (underneath the side draft intake) that need to be closed by the propper gasket between the carb and the manifold. They are for atmospheric air to some part that doesn't have vacuum to it.

[Phatfenders]

The gasket with only one big kidney shaped hole: 1540006 is for the '57-'64 WW 6- Carbs. I believe the one with 2 holes was used on the Old '51-'52 Bendix Aero Type Stromberg downdraft top carb.

UPDATE: No correctly setup WW's whistle, when the correct internal and exterior Gaskets are used, no need to plug anything.

The gaskets I am using are kidney shaped with a small slot on each end, so based on your info these are the right base gaskets. Thanks Rich

[Phatfenders]

These are my carbs, I know the consensus is a mismatched base gasket but I just don't think that's my problem. I am thinking that the whistle may be coming from air passing by the throttle plates because it goes away just off idle. Has anyone ever tried to file a slight bevel on the leading edges of the throttle plates ?

[SN-60]

That's a nice looking dual carb setup!

[Dick Steinkamp]

That's a nice looking dual carb setup!

I agree. I love those air cleaners with the 90 degree turn. Very sanitary installation. Even the chokes are hooked up to the manifold stove.

What car do you have that Stude engine in?