02
Aug
Ive got the 1984 300DT up on ramps and am about to adjust the alternator belt tension. If you can twist the belt around past the halfway point meaning the ribs are actually facing upwards it is too loose.
Im thinking the belts should be adjusted so they can only be depressed approximately 12 inch.
How tight should an alternator belt be. There ARE tension specifications for new and used belts and they can be measured with the correct tool. Looks like a plank with a couple of feet you press on the belt and read the tension off a gauge. And your finer shops should have em to.
On the typical lycoming alternator setup 14 would be about right. Tight enough not to slip under load and not so tight as to cause undue stress on the belt or bearings. If its too loose youll note glazing of the belt surfaces in relatively short order.
Most auto parts stores sell a belt tensioner that will provide a more exact reference. Answer 1 of 2. Assuming you are speaking of a V-Belt.
Just tight enough it doesnt slip on engine startup when alternator loaads are highest. There is an actual spec for it as detailed in the factory service manuals. Involves using a scale pulling in the center of the span of the belt between w.
Properly tensioned new belts should have 7-9mm of play reused belts should have 9-11mm. Sorry if it sounds complicated just writing what the tech manual shows in pictures. Ive got the 1984 300DT up on ramps and am about to adjust the alternator belt tension.
When I press down in the middle of the belts I can push approximately one inch. Im thinking the belts should be adjusted so they can only be depressed approximately 12 inch. How tight or loose should alternator belt be.
Pull the alternator away from the engine until the belt is tight. You want to be able to press down on the belt at a mid point between two pulleys and only be able to move it downward about 18 to 14 inch. Pull the alternator away from the engine until the belt is tight.
You want to be able to press down on the belt at a mid point between two pulleys and only be able to move it downward about 18 to 14 inch. When you have the alternator in the right position have an assistant tighten the top bolt and nut to lock the alternator in. Consequently can you over tighten an alternator belt.
A belt should never be over-tightened. An over-tightened belt can burn out any bearing that the belt rotates on including alternator power steering pump AC compressor idler pulleys etc. How tight should the alternator belt be.
How tight should the alternator belt be. All Time Today Last Week Last Month. All Discussions only Photos only Videos only Links only Polls only Events only.
How tight does an alternator belt need to be. The required measure of tension in the serpentine belt is that it should not deflect more than ½ inch when twisted either way from the middle. If twisted more the belt is loose and if twisted less the belt is too tight.
Either of the positions does not work for the vehicle. What happens when alternator belt breaks while driving. The belts should have flex in them and not too tight.
I just changed mine on the Tacoma and my Tundra and they were within spec on the flex of the belt. If they are too tight it will cause bearing issues among other things. You should be able to twist belt 90 degrees not the entire belt just pick an area with good clearance from the tensioner and pulley and twist.
Yikes mine are too tight then. I like that method. Back in the Game.
It should be tight but you should be able to twist it with some resistance involved. You want a maximum of 8mm deflection on the main drive belt. Any more than that and you need to re-adjust the system.
During the measurement of the belt slack it the belt does not go down ½ inch you will have to release tension off the tensioner bolt. A tighter belt can even be a result of the belt being smaller than what is required around the alternator. Below is some information about getting a new belt installed.
I have a 3GMD raw water with a constantly loose alternator belt. I just cant seem to get it to stay tight by tightening the two places I know of - the shaft that it rotates on and the bolt that holds it in position. I use a long bar to get the body sufficiently tight but not too tight slight deflection when pressing on belt.
Expect the belt to loosen some with running. A new belt will probably need to be tightened again after several hours of running. If the belt is too loose it will continue to squeal and cause overheating.
If its too tight it could damage bearings in the alternator and or water pump. The alternator will allow to be moved forth and back. To loosen the tension or remove the belt alternator would cock in the position to ease the tension.
Because the amount of tension is tightened the alternator can be pried against the pulleys. On the drive belt the alternator will be tightened down to increase vehicles tension. Twisting the belt was a method I read about in several posts found through googling I wasnt sure how to measure the deflection.
Ive now put a ruler along the belt and pressed down at the points indicated A and B in the diagram and the deflection on A is 8-9mm and about 11-12mm on B so looks like I should tighten the AC belt a bit more. If you can twist the belt around past the halfway point meaning the ribs are actually facing upwards it is too loose. 2If you cant twist the belt at all it is too tight.
If you can twist the belt around the the halfway point ribs pointed outwards and not past there the belt is. There are specs and tools to measure the tension but the rule of thumb for adjustable belts is that they should be tight enough so that you can twist them 90 degrees.