1952 GMC 228 with a Carter YF instead of the original Zenith carb. Run it down the road at 40 MPH. Let off the gas a little, just enough to slow down a few MPH. Ken and I can both hear a high pitched whistle. Not loud, but definitely there. Let off the gas completely and the whistle gets a little louder and higher pitched. Get back on the gas slightly (just enough to maintain speed) and the noise stops. What I've done: Removed the vacuum line that supplies the wipers and plugged the hole at the manifold. Made no difference. Removed the vacuum line that supplies the power brakes and plugged the hole at the manifold. Made no difference. Tried spraying ether (starting fluid) around carb, carb to intake manifold interface and intake to head interface. Made no difference in engine speed, but I can't hear the whistle when the truck is idling anyway. I happened to road test with the air cleaner removed and I can no longer hear the whistle. There is more carb noise with the air cleaner removed and maybe that additional noise is covering up the whistle. Or maybe not??? Any suggestions?
Whistle stop Bill, Maybe the whistle noise is related to air through the breather, or between the air cleaner and the carb? Don't you have an early air cleaner with a dry element? Put Ken,s oil bath on your truck and see if it whistles going down the road? Seems the engine would idle a bit rough if the whistle is a vacuum leak. Good luck with this. when I hear whistles, it is usually feedback from my hearing aids. Jim
Yes, my air cleaner is the dry (not oil bath) model. I've replaced the original element (dip it in oil every 1000 miles, more often in harsh conditions) with a modern paper element. Chevy air filter on a GMC? Probably wouldn't even start.
What tune does it whistle? Since it's a 228, my guess would be "Whistle While We Work". Just whistle along with it. Maybe it is coming from the wind flowing over the hole in Ken's head?
I thought of that, but it happens when the truck is in Texas and Ken is in Tennessee. Maybe it is the hole in my head??
Vacume leak ? Bill. I`ll gues the wistle sound comes from the not original element you have put in your air cleaner. Maybe the airstream goes to fast through inside the cleaner house as allmost no resistance picks out the dust ? If RPM drop is the question you would feel that at once! Get your vacume lines installed back a gain as i dont think it helps to prop them ! Martinius.
Martinus: The hoses went back on as soon as I confirmed they made no difference. I'll pull the filter element and see if it makes a difference.
Zig, I thought about that so I plugged both of my ears! The whistling went away for me, but Bill said he could still hear it!
Have used a vacuum cleaner hose rigged (southern engineered) to the carb with tape, ties, and/or clamps so the air inlet could be routed well away from the carb body. This isolates the suction noise the carb makes plus eliminates the air cleaner. If whistle is still present it then pretty much has to be a gasket, shaft, or internal carb noise. If you can get the end of the hose out to the grill area a little Texas dust and a few June Bugs will surely make an old 228 run better.
Vacuum leak ? Evan and Bill You might be into something that the gasket is leaking or maybe the cleaner house socket clamp is`nt tight anaugh. A simple vacuum pressure test would uncover any leakage right ? Martinius.
D-Nile is just not a river in Egypt! Bill and I know the cause! #5 cylinder is the culprit! I'd bet Zig's life on it! I've got an extra oil bath cleaner I'll bring over next week to try, but I don't think that will help.
D- river Nile is running through Aswan Egypt Hey guys I went to egypt a month ago to work on a friends boat a bit but mostly fore plessure and whas looking fore old USA cars or trucks to photograph but did `nt found any over there, just old Taxi peugot cars and old MB busses .But here are some shots i want to share from the nile river. Some good old music from group the Clash , the cashbah! http://www.youtube.com/watch?v=bJ9r8LMU9bQ
Pix & Whistle As there's no pigs in the pix..... . Anyway , I'm betting it's the dry air filter . I like those photos Martinus ! .
Bill, Is the whistle by chance coming from the vacuum wiper hose? The 60 jeep of mine has a whistle caused by an leak in the hose and bad wiper motor. Martinus, Good photos, thanks for sharing. Charles
Does it with wiper hose disconnected. But I just realized I didn't try it with the vacuum advance disconnected and plugged.
