What issues with engine performance on a 70's car can a bad harmonic balancer cause? Can it cause damage??
Harmonic balancer question
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Not a lot to go on here. What kind of car/engine?
Many balancers are two piece and there is a rubber ring between the two that can rot and dry out over the years and cause the outer ring to move which can make it impossible to set timing and can cause a vibration as well.
Many balancers are two piece and there is a rubber ring between the two that can rot and dry out over the years and cause the outer ring to move which can make it impossible to set timing and can cause a vibration as well.
I had one completely fall apart in my Camry, I mean it completely separated, but its purpose is to keep the crank from beating itself up, and what do you mean by "bad", what kind of design is it? mine was a two piece and when it separated it fell right off.
Originally Posted By: zach1900
I don't see how timing can be affected, it's just basically a pulley isn't it?
The timing marks on many engines are on the pulley. If the rubber dries out and the outer pulley slips then the marks aren't accurate and the timing is off.
I don't see how timing can be affected, it's just basically a pulley isn't it?
The timing marks on many engines are on the pulley. If the rubber dries out and the outer pulley slips then the marks aren't accurate and the timing is off.
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Originally Posted By: zach1900
Thanks, we replaced mine a year ago and didn't consider timing , just removed and replaced it like a pulley, hope I didn't mess up the timing.
They are indexed at the factory, the timing marks on the outer ring are precisely x number of degrees from the woodruff key. You didn't mess it up, although the old one can be messed up using the wrong type of puller.
Some interesting articles.
http://www.agcoauto.com/content/news/p2_articleid/273
http://www.daycoproducts.com/inspecting-and-replacing-harmonic-balancers
Thanks, we replaced mine a year ago and didn't consider timing , just removed and replaced it like a pulley, hope I didn't mess up the timing.
They are indexed at the factory, the timing marks on the outer ring are precisely x number of degrees from the woodruff key. You didn't mess it up, although the old one can be messed up using the wrong type of puller.
Some interesting articles.
http://www.agcoauto.com/content/news/p2_articleid/273
http://www.daycoproducts.com/inspecting-and-replacing-harmonic-balancers
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They are there to stop vibrations. Could cause a crank to break. Usually doesn't but makes the car shake when revved.
Torsional forces, or harmonics, can cause a crankshaft to crack in two. The steel hub and ring bonded with vulcanised rubber cancels these harmonics out. If the rubber bond broke you might see a broken crankshaft in the future, but not likely.
Some engines are externally balanced and require a counterweight on the balancer. swapping the wrong balancer on would shake the car to pieces.
Some engines are externally balanced and require a counterweight on the balancer. swapping the wrong balancer on would shake the car to pieces.
Once you get a few years and a few thousand heat/cold cycles on a standard rubber two piece harmonic damper, it is already "technically" out of spec. Best outcome is you never run an engine at the right RPM long enough to cause damage, which is the vast majority of cases as plenty of 30+ year old engines will attest.
Sometimes the outer ring will "walk" radially and change your relative timing, sometimes it walks forward and either comes off or wedges against the lower pully. Worse is when it walks backward towards the timing cover and eats it. Worst is when your timing chain wrenches apart, or you tear the locating dowel off the front of the cam (Smallblock) and you slam valves. Never have seen one break, but have seen plenty of pictures of disintegrated balancers, and it ain't pretty.
Sometimes the outer ring will "walk" radially and change your relative timing, sometimes it walks forward and either comes off or wedges against the lower pully. Worse is when it walks backward towards the timing cover and eats it. Worst is when your timing chain wrenches apart, or you tear the locating dowel off the front of the cam (Smallblock) and you slam valves. Never have seen one break, but have seen plenty of pictures of disintegrated balancers, and it ain't pretty.
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Originally Posted By: morepwr
Not a lot to go on here. What kind of car/engine?
Many balancers are two piece and there is a rubber ring between the two that can rot and dry out over the years and cause the outer ring to move which can make it impossible to set timing and can cause a vibration as well.
In replacing the timing cover (leaking antifreeze) on my mild build 1971 Buick 350 the rubber in the balancer was found to be bad (fell out). I now know that the erratic timing mark in the past was a sign but did not know then. I addition I always used a digital timing light to set the timing @30. "My Bad" I just hope I didn't cause internal damage.
Not a lot to go on here. What kind of car/engine?
Many balancers are two piece and there is a rubber ring between the two that can rot and dry out over the years and cause the outer ring to move which can make it impossible to set timing and can cause a vibration as well.
In replacing the timing cover (leaking antifreeze) on my mild build 1971 Buick 350 the rubber in the balancer was found to be bad (fell out). I now know that the erratic timing mark in the past was a sign but did not know then. I addition I always used a digital timing light to set the timing @30. "My Bad" I just hope I didn't cause internal damage.
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If you did do damage you would know it. If its running ok i wouldn't sweat it.
Hoping my car will run stronger with stable timing!
One thing that baffles me is that there seems to be no guidance on replacing the crankshaft damper, or "harmonic balancer" as some call it, when it comes to general auto and pickup engines. With heavy duty engines, there is some guidance that the damper needs to be replaced at certain intervals, as the silicone in the damper can harden and the damper can loose effectiveness at absorbing the torsional shock on the crankshaft when a cylinder fires. I extrapolate what I do with my auto and pickup engines regarding the damper from the general idea as it applies to heavy duty engines. For the latter, it is recommended that the damper be replaced at 500,000 miles, which would correspond to the average half life cycle of those engines. So, to that end, I view changing the damp on a auto or pickup engine would be a good idea at 100,000 miles. That is pure self selected. No data I can find that confirms that assumption. So I'll stick with it.
Originally Posted By: 007
What issues with engine performance on a 70's car can a bad harmonic balancer cause? Can it cause damage??
I only had one go bad and the rubber ring started to slide out. The outer ring can then slip giving a false timing indication. Also, a groove can wear in the shaft by a hardened front seal and can start dripping oil.
What issues with engine performance on a 70's car can a bad harmonic balancer cause? Can it cause damage??
I only had one go bad and the rubber ring started to slide out. The outer ring can then slip giving a false timing indication. Also, a groove can wear in the shaft by a hardened front seal and can start dripping oil.
A newer car, a 2001, my harmonic balancer failed and it was causing the serpentine belt to jump a couple of grooves on the pulleys of the accessories driven.
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