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Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Tue Aug 04, 2020 4:29 am
by jimfrac
Hey Vibers,
This is my first ever post to the GenVibe forum. I've been lurking for years. A recent mechanical issue and it's solution finally persuaded me to create an account and share what could help somebody else. TL:DR at the bottom.

My 06 has almost 200,000 miles on it. I was discussing it with a friend and saying I don't know what preventative measures I should take, because, well I just keep driving it and it just keeps running. He said, "Serpentine belt?" Ooh I thought. I have never replaced that belt and it seems like the thing that is going to snap on the freeway and strand me somewhere. So I replaced the belt and tensioner and all was good.

Fast forward about 6 months and I hear a rattle. Turns out the tensioner bolt, the one that goes directly into the engine block, had snapped off INSIDE the block. UGH. Maybe I overtorked it, maybe it was just old, maybe it was crss threaded. It was a total PITA to get it back in there. The only way I could see to fix would be to drop the engine, drill it out, and replace. That led me to wonder if I should just put a new engine in. Both options seemed like a big investment for a 14 year old car.

Enter my genius master mechanic neighbor. Eliminate the tensioner! Find a new path for the serpentine belt, measure the size you need, add a bracket to the alternator and cross your fingers. Guess what - it worked great!

It was tricky to measure the length needed, so I bought 6 belts in the range figuring I would return the unused ones. I ended up with a 63 inch belt if you are interested in doing this yourself. It was a strain to get it over the alternator wheel (even in the fully relaxed position) but once it was on I was able to pull the alternator tight and lock it in. I have not been able to stop thanking my neighbor for saving me so much money and headache. I've been driving it on the freeway for 3 weeks with no issues. In fact, it almost seems like it runs better!

Check out the video to see my bracket in action. And I'd be happy to offer any advice if anyone is in a similar situation.

TL:DR - Tensioner bolt snapped inside engine. Rerouted serpentine belt, added a bracket to the alternator, and eliminated the tensioner entirely.
[attachment=0]Screen Shot 2020-08-04 at 8.19.30 AM.jpg

Re: Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Tue Aug 04, 2020 5:17 am
by andrewclaus
I did something like that once to replace the generator in a '56 Chevy with a modern alternator. The alternator had a larger OD and had to be pivoted farther away from the block than the slotted adjustment arm would allow. So I extended the arm with a piece of angle iron I had in the garage.

From what I see, a modified slotted arm like the old alternator brackets may work in this case too.

Re: Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Tue Aug 04, 2020 5:25 am
by tpollauf
Nice work ! :D The only minor drawback would be if/when the new belt starts to stretch as it gets older, there would be no "automatic" tension adjustment taking place. You'll have to manually tighten it as time goes by. This should be minimal and no big deal to do.

Re: Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Tue Aug 04, 2020 10:46 am
by zbyers
Interesting... Nice work around, though drilling out the tensioner bolt isn't as difficult as it may seem.

I was new to making a write up, so formatting and whatnot is...bad, alas, this is how I went about it.

viewtopic.php?t=45824

Re: Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Thu Aug 06, 2020 7:20 am
by jimfrac
tpollauf wrote: Tue Aug 04, 2020 5:25 am Nice work ! :D The only minor drawback would be if/when the new belt starts to stretch as it gets older, there would be no "automatic" tension adjustment taking place. You'll have to manually tighten it as time goes by. This should be minimal and no big deal to do.
Yes, tpollauf, it was your post that inspired me to try the alternator/shorter belt method. If it didn't work, I was headed down the route you wrote up. Thanks.

Re: Belt tensioner? Belt tensioner? I don't need no stinkin' belt tensioner!

Posted: Thu Aug 06, 2020 9:24 am
by tpollauf
jimfrac wrote: Thu Aug 06, 2020 7:20 am Yes, tpollauf, it was your post that inspired me to try the alternator/shorter belt method. If it didn't work, I was headed down the route you wrote up. Thanks.
Glad something good rubbed off me :lol: Now if only the wife would see me that way things would be a lot better :roll: