I have a 41 GMC 1.5 ton fire truck. I recently had a catastrophic engine failure. Luckily I have a backup motor laying around that I took to an engine builder. My current motor has this pulley and Lovejoy connection on the front crank which powers the front mount water pump.
Does anyone know what this pulley is? Is it a normal GMC pulley? Where i could find a spare? The truck does not have a harmonic balancer. Is it required? Or can I get away with not running one so I can continue to use the Lovejoy coupler.
If you want to retain the water pump operational, you should reinstall the coupler, which probably acts as a harmonic balancer and pulley.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Doesn't the broken section of that pulley destroy fan belts? A conventional balancer could be modified to drive a Lovejoy coupler by any machinist with a few brain cells to rub together. It would be a very simple machining procedure to fabricate a bolt-on adapter that uses the puller holes in the balancer to drive a coupling. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
i have been into a lot of GMC engines but I have never seen anything like it. i have butchered fire apparatus to build truck tractors, but they all had a power tower behind the transmission. I think this is something proprietary for the fire apparatus builder. I have seen crank failures with a bad vibration damper. And I have never seen an engine without one. What happened with your catastrophic failure? I would be afraid to run a setup like this because I have seen crank failures caused by a bad vibration damper. Front mounted pumps were common in the 40's and early 1950's. I would see what other fire apparatus manufactures used. The fire trucks that I cut were V-8 and had a power tower. If I was building a truck tractor out of something like this, I would put a vibration damper on it. It will be interesting to discover if this was the accepted coupling back in the day.
I overlooked the broken pulley bit. That's not reusable. What Jerry suggested would be a good approach.
Also, the engines weren't designed to drive much power off the front of the crankshaft. It depends on a simple key that could be sheared by too much power applied to a damper. Or the crankshaft could actually break somewhere just behind the timing gears.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
That pulley is salvageable by a very good welder who is familiar with repairing cast iron. Don't discard it. It can be patched and machined back to its original shape. The GMC crankshaft has the same diameter snout as Chevy engines- - - - -1 1/4" diameter, so you will have a pretty good selection of possible replacements. I have a 228 engine stashed away in my storage area, but I'm pretty sure it has a completely different front balancer/pulley arrangement. Unless you're planning on pumping a lot of water at full throttle, I doubt if there's much danger of crankshaft damage in a restored vehicle.
A lot of the older fire apparatus trucks were called "bumper pumpers"- - - -with the fire pump driven off the front of the crankshaft, so unless something else went wrong, I doubt that moderate loads applied to the crankshaft snout would do any serious damage. I've also seen inboard engine boats with V-drive units that use the crankshaft snout to power the propeller. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
i have been into a lot of GMC engines but I have never seen anything like it. I have seen crank failures with a bad vibration damper. And I have never seen an engine without one. What happened with your catastrophic failure? I would be afraid to run a setup like this because I have seen crank failures caused by a bad vibration damper. I would put a vibration damper on it.
I agree with most of this above. Though there are some engines with out a damper / balancer though, VW aircooled is one everyone knows.
Kicking self for selling off my Taskforce trucks. Still looking for an LCF or conventional big bolt in decent shape.
As of 10-26-2022, A 55.2 Taskforce long bed now the work begins
Yes, which is why I pulled it off and am trying to find a replacement.
Is just a normal GMC 228 pulley? I was afraid it was something unique
Check your private messages- - - - -the little flashing envelope icon at the top right of each forum page. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
