Failing Timing belt tensioners vs upgraded valve springs.

[donniekak]

also not true, at rest when there is slack between the heads the tensioner is almost fully pushed in, thats the spring tension between the heads and the crank pushing it in. if it stays pushed in like that or is slow to push out for some reason thats how people jump timing.

If you have slack between the heads with the car running, there is to much slack in the belt.
As I stated above, it's normal for the tensioner to compress from belt tension related to spring tension when the engine is not running.

On a side note, I see you also live in Arizona. I'm surprised we haven't met already. I thought I knew almost everyone out here.

[Streamln1]

Not when it's running or rotated but it has pushed in more than it was orginally. That's the point of this thread I believe it's going to fail. It's definitely the tensioner. I have done about 20 timing belts on these cars

Ya in over in Gilbert. Once i get my restoration done i will reach out to the local group. Not a lot of active members here anymore

[familyMAN]

Not much local gathering of 3S owners in AZ unless you count don's house when they need rebuilt

On topic, I had no issues with stock tensioner with high lift 280's, upgraded springs and 8000 rpm. I did the washer trick just in case though.

[aaronatstate]

How far is it from the hole? 10k might be enough to stretch the belt so you can't put it back in.

Just as a note, synchronous belts with fiberglass tensile cords do not stretch more than .001-.003" over the lifetime of the belt. All automotive synchronous belts, from the stock Mitsubishi belt, to the Gates aftermarket belt, to the Gates racing belt all have fiberglass tensile members, and will not stretch. The kevlar portion of the racing belt comes from the kevlar fibers they put into the rubber compound to strengthen the teeth. It makes the teeth stiffer and stronger and less prone to sheering off. Being an engineer at Gates, I don't see any reasons why a Gates Racing Belt would require more tension than the standard belt.

Also, I would almost always advise against using a solid tensioner. It's not because the belt stretches, but as the engine heats and cools, the geometry of the drive system changes, and the forces on the belt change. By not having something to take up this slack and differences in changes, it may adversely affect the belt.

[i3igpete]

silly engineer! what do you know about cars! we only listen to anecdotal evidence here!

[Streamln1]

Just as a note, synchronous belts with fiberglass tensile cords do not stretch more than .001-.003" over the lifetime of the belt. All automotive synchronous belts, from the stock Mitsubishi belt, to the Gates aftermarket belt, to the Gates racing belt all have fiberglass tensile members, and will not stretch. The kevlar portion of the racing belt comes from the kevlar fibers they put into the rubber compound to strengthen the teeth. It makes the teeth stiffer and stronger and less prone to sheering off. Being an engineer at Gates, I don't see any reasons why a Gates Racing Belt would require more tension than the standard belt.

Also, I would almost always advise against using a solid tensioner. It's not because the belt stretches, but as the engine heats and cools, the geometry of the drive system changes, and the forces on the belt change. By not having something to take up this slack and differences in changes, it may adversely affect the belt.

.

That makes sense. Thanks for the input.

[new93TT]

so people are still 50/50 on hydo vs solid tensioner basicly , great as i need to order a 60k service kit

[futurevr4man]

Just as a note, synchronous belts with fiberglass tensile cords do not stretch more than .001-.003" over the lifetime of the belt. All automotive synchronous belts, from the stock Mitsubishi belt, to the Gates aftermarket belt, to the Gates racing belt all have fiberglass tensile members, and will not stretch. The kevlar portion of the racing belt comes from the kevlar fibers they put into the rubber compound to strengthen the teeth. It makes the teeth stiffer and stronger and less prone to sheering off. Being an engineer at Gates, I don't see any reasons why a Gates Racing Belt would require more tension than the standard belt.

Also, I would almost always advise against using a solid tensioner. It's not because the belt stretches, but as the engine heats and cools, the geometry of the drive system changes, and the forces on the belt change. By not having something to take up this slack and differences in changes, it may adversely affect the belt.

so people are still 50/50 on hydo vs solid tensioner basicly , great as i need to order a 60k service kit

I feel as if what Aaron said was pretty definitive. You know, working for the manufacturer of the belt and all...

[lawdogg]

Thanks Aaron for the dose of objectivity. A very helpful thread!