After I bailed out of our hard scrabble truck farm, I became a heavy equipment mechanic. I “had ’em fooled” for 42 years before I retired.
During those 42 years, I saw a lot of stuff and had lots of unnecessary adventures, mostly caused by me. This brings to mind an incident that I witnessed not long before I retired.
It had been a dry September, beautiful weather with low humidity. This is important because I believe it had something to do with what I experienced.
A customer had brought a New Holland backhoe to the shop with the complaint of a noise at the front of the engine. I mention New Holland because some of you readers may have New Holland equipment with the same engine. But this could pertain to any engine
I did a visual check of the engine; nothing was visibly awry. Starting the engine, I immediately heard a clicking/snapping noise. Looking at the front of the engine I was baffled by what saw: a blue electrical arc, almost like a welding arc, jumping from the outside of the fan belt/damper pully to the bolt that holds the damper to the crankshaft. I didn’t stick my hand down there!
At first, I thought maybe the damper pully was wearing out. They are two pieces with the inner and outer sections bonded together with rubber (I think). Maybe slipping caused a buildup of static electricity which in turn caused the spark. But I’d never seen a damper pully worn out. I did see one that had come off of a V12 Cummins. It made a mess!
Note: If I was rebuilding an engine (which I have no intent to ever do again) with a zillion hours on it, I’d replace the damper pully!
Really looking at it, I noticed the fan belt, although tight, was adjusted to the maximum. Checking further, I figured out that the customer had installed the wrong belt. Replacing the belt with a factory belt corrected the problem.
I have to wonder if this would have been noticed if there had been damp weather, the moisture giving the static electricity somewhere go with out the buildup? Maybe I did learn something in school after all!
Anyhow, if this spark would occur in say a combine or other field equipment with dry chaff or other flammable material building up, it could start a fire, probably ruining someone’s day.
Since no one is able to predict the weather, make sure your equipment has the right tight belt.
It’s a lot cheaper than me diagnosing the problem and replacing the belt!
Gordon Meeder
Midland, Pennsylvania
