742B squeal

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Since earlier this summer under normal operating conditions, if the engine stalls there is a high pitched squeal immediately upon restarting. It certainly sounds like a belt squeal. For us old timers who worked on cars in our younger days, it sounds exactly like a power steering squeal. By maintaining high rpms I can sustain the squeal, but if I throttle down, it stops, and does not return when I throttle back up---until it stalls again, and the whole routine repeats itself. The belt is not loose, and this never happens when the engine is started cold. What is the problem? The stalling is a carb problem which I will address some time in the future.

 

[craigb93]

Does it have a belt driven Governor like the 742 Ford engine? If so be sure to check the oil. The governors are made by Hoof and their site covers the check/fill sequence. Best to check it anyway as they are extremely pricey to replace if it runs dry. The governor belt itself does not need much tension to function. -Dick

 

[Tazza]

Does it have a belt driven Governor like the 742 Ford engine? If so be sure to check the oil. The governors are made by Hoof and their site covers the check/fill sequence. Best to check it anyway as they are extremely pricey to replace if it runs dry. The governor belt itself does not need much tension to function. -Dick

Bad water pump or alternator bearing?

 

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Does it have a belt driven Governor like the 742 Ford engine? If so be sure to check the oil. The governors are made by Hoof and their site covers the check/fill sequence. Best to check it anyway as they are extremely pricey to replace if it runs dry. The governor belt itself does not need much tension to function. -Dick

Found the Hoof website, and printed the oil fill instructions to insert into my repair manual. On my governor there is a street el threaded into the bottom hole. This will accomodate a substantially greater volume of oil than the straight plug shown in Hoof's sketch. If this is a factory modification, presumably somebody knew why it is necessary. Does everyone else with this engine/ governor have the same street el? The oil level was way down, so I filled it to the point of overflow, but the engine squeal is still there. Will remove the alternator to check its bearings. It charges just fine.

 

[craigb93]

Found the Hoof website, and printed the oil fill instructions to insert into my repair manual. On my governor there is a street el threaded into the bottom hole. This will accomodate a substantially greater volume of oil than the straight plug shown in Hoof's sketch. If this is a factory modification, presumably somebody knew why it is necessary. Does everyone else with this engine/ governor have the same street el? The oil level was way down, so I filled it to the point of overflow, but the engine squeal is still there. Will remove the alternator to check its bearings. It charges just fine.

With the engine running and the noise going on use a long screwdriver or equivalent up to your ear as a sounding rod as you poke (carefully) the various rotating components. Water pump, alternator front bearing, rear alternator bearing and of course the governor. Easier than taking parts off. Likely you can find the culprit. -Dick

 

[flyerdan]

With the engine running and the noise going on use a long screwdriver or equivalent up to your ear as a sounding rod as you poke (carefully) the various rotating components. Water pump, alternator front bearing, rear alternator bearing and of course the governor. Easier than taking parts off. Likely you can find the culprit. -Dick

The noise being described is more indicative of belt slippage rather than bearing failure, as they don't normally quiet down once they've got a mind to go south. Even a reasonably snug belt will squeal if it is glazed; cold starts will act normal as it is contracted for just enough extra grip, when things warm up a bit it's just loose enough to slip. When you throttle down it allows everything to sync up and the squeal goes away.
If the beveled edge of the belt feels smooth and slick, ideally replace the belt and keep the old one for a spare, or get a stick of belt dressing and touch it up.
For listening to components, Harbor Freight has a stethoscope with a probe for troubleshooting; they are cheap and highly recommended as it's easier and safer that sticking screwdrivers into a rotating group with your head turned so you can't see what's going on.

 

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The noise being described is more indicative of belt slippage rather than bearing failure, as they don't normally quiet down once they've got a mind to go south. Even a reasonably snug belt will squeal if it is glazed; cold starts will act normal as it is contracted for just enough extra grip, when things warm up a bit it's just loose enough to slip. When you throttle down it allows everything to sync up and the squeal goes away.
If the beveled edge of the belt feels smooth and slick, ideally replace the belt and keep the old one for a spare, or get a stick of belt dressing and touch it up.
For listening to components, Harbor Freight has a stethoscope with a probe for troubleshooting; they are cheap and highly recommended as it's easier and safer that sticking screwdrivers into a rotating group with your head turned so you can't see what's going on.

The noise has always sounded like belt slippage, but the belts felt plenty tight. I removed the belts and noted some glaze--no more than 1/4 of the belt depth. With belts off, the alternator, water pump, and governor shafts all felt smooth and tight--nothing to suggest bearing problems. I purchased new belts, installed them to appropriate tightness (IMO) and no more squeal. BTW, I do have a HF stethoscope for the reasons you cite. Thanks for everyone's help.