View Full Version : Belt tensioners for jackshaft/ supercharger?

07-09-2014, 08:52 PM
My tensioners for the supercharger and jackshaft are shot, and the belts are very loose. I've diagnosed this as the reason why i'm only getting about 9.5 to 10 psi of boost. After spending an exhausting amount of time just trying to find the belts around town, it appears like the stores here don't even have the jackshaft/ supercharger tensioners as an option. Everything that i've seen online also seems to be just the main accessory belt that is compatible with the base V6.

Places like Super Coupe Performance don't even have any on their website. Should I get the heavy duty springs from SCP and install them in the tensioners? How difficult is it to do this?

If anyone knows where to get the tensioners, i'd appreciate a link or a part # through Dayco, Goodyear or Gates, etc.

07-09-2014, 08:59 PM
Where are you located, again?

07-09-2014, 09:02 PM
I'm in Winnipeg, MB, Canada.

07-09-2014, 09:07 PM
As for the HD spring install, the link for that PDF on the MP site seems to be broken...maybe if you search past threads here?

But even if you get springs, it sounds like you might also need tensioner idlers too?

07-09-2014, 09:20 PM
The tensioner idler pulleys are in good shape, so those shouldn't need to be replaced.

07-09-2014, 09:33 PM
Tensioner - AC Delco P/N: AC38299 seems to be one reference...

Example: http://www.autopartswarehouse.com/shop_years/ford-thunderbird-accessory-belt-tensioner-1995.html

07-26-2014, 07:39 PM
There were no real specific supercharger or jackshaft tensioners that i'd found online.....all of them were compatible with the SC, but it's the regular water pump/ AC/ power steering tensioners. The tensioners are non-existent online.

I bought the heavy duty springs from SCP, and let me say I HATE doing this modification! After prying off the front cover and then trying to pre-load the spring......it took me much longer to do than it should have. I don't have a vice to put it in, so I had to improvise with a 1/2" bolt that was 3 1/2" long, a nut, and with a set of washers and a lock washer and two wrenches. If anyone wants tips on how to do it that way, PM me or just ask on here. The trick is to tighten the nut so that it uses the washers to force on the cover, while you're also pre-loading the spring 90 degrees, then when the tab on the cover plate is far enough where it's in the recessed slot area (ie: the area that it will catch on so that it doesn't spring back), you hammer it down so that it doesn't spring back. If the nut/ bolt turns without turning the cover plate, just tighten it up again with the two wrenches (may need to tighten it up a few times) and use one wrench to turn the mechanism so that it's pre-loading the spring.

Les Borda
07-26-2014, 09:24 PM

Call them they're online checkout for Canada is not set up properly, they do ship to Canada talk to Diane or Vern they may split the set up

rockauto.com select Ford,199X(x being whatever year),Thunderbird, 3.8sc motor,belt drive, then belt
Goodyear Gator backs
4080392 supercharger belt $10.89
K070425 jackshaft $13.45
4080897 main drive $17.13

They sell a few other brands too like Dayco, Gates, AC-Delco

Those prices are in Canadian dollars, you can select either US or Canadian dollars, shipping will run you anywhere from 18-25 IF they all come from the same warehouse. They use UPS ground and it's fairly quick, you pay the GST so it comes to us clean.

07-27-2014, 01:40 PM
Thanks for the info, Les.....I was referring to the tensioners, though. The belts I had no trouble finding here, even in town (though it took a few calls to various places).