Upgrade 84-86 2.5s w/ newer 87 belt system, possible? (Page 1/1)
82-T/A [At Work] JUN 10, 04:29 PM
Hey guys, looking for all the parts that I'm going to need for my daughter's Fiero once I have it pulled, and it occurred to me that I was never too pleased with the old belt system on my 84 Fiero. It was ALWAYS squealing... like, constantly. I know the 87 Fieros had the newer belt system which also included a belt-tensioner. Is there any reason why I shouldn't expect that I can simply upgrade the 84-86 (specifically my daughter's 85) with the new belt system?

I'm guessing I'll need the following:

- belt tensioner
- new water pump w/ 87 pulleys
- new alternator w/ newer pulley
- belts

Anything else I'm missing? Is there anything that's going to prevent me from doing this?


Thank you!
sleek fiero JUN 10, 04:38 PM
By the sound of it you want a brand new car when your finished. Haha.Did Rodney D. not have all those bits? If it was v6 i could help as I've got spares of most original parts.
82-T/A [At Work] JUN 10, 08:55 PM

quote
Originally posted by sleek fiero:

By the sound of it you want a brand new car when your finished. Haha.Did Rodney D. not have all those bits? If it was v6 i could help as I've got spares of most original parts.




Haha, yeah... pretty much. We're not just fixing things, every single mechanical component will be gone through. Everything will be "like new."

I have Rodney's kit for my V6 too... I installed it years ago, but totally different concept for the 84-86. If I'm not mistaken (I need to look), I think it uses a V-belt for both...
Patrick JUN 10, 09:05 PM

quote
Originally posted by 82-T/A [At Work]:

Is there any reason why I shouldn't expect that I can simply upgrade the 84-86 (specifically my daughter's 85) with the new belt system?



"Simply"? No.

Finding a way to effectively deal with loose V-belts on the '84-'86 duke has been a topic of discussion many times here over the years. I don't recall a viable solution ever being offered.
FieroJimmy JUN 10, 09:05 PM
Well, the '87+ 2.5 belt tensioners aren't available anywhere that I'm aware of at this time, so that will make it harder.

The AC compressor was also on the same belt on the '87+, so you would need to replace that as well, if equipped.

I don't have any late 2.5s around to look at, but the brackets likely have a different offset for the components as the early models ran 2 belts and the later ones only ran 1.

It is certainly possible to convert to a single auto-tension belt. Unless you can find a complete take-off set of accessories and brackets it will probably require a lot of custom fab work.
82-T/A [At Work] JUN 10, 09:46 PM

quote
Originally posted by Patrick:

Finding a way to effectively deal with loose V-belts on the '84-'86 duke has been a topic of discussion many times here over the years. I don't recall a viable solution ever being offered.




quote
Originally posted by FieroJimmy:
Unless you can find a complete take-off set of accessories and brackets it will probably require a lot of custom fab work.




Thanks guys, I guess that's kind of what I'm asking. Are the engine blocks the same at least from 86-87 so that, should I find an 87+ motor, I can basically swap everything over using the newer parts? If that's a yes, then that's probably the direction I'm going to try to go...
Patrick JUN 10, 09:54 PM

quote
Originally posted by 82-T/A [At Work]:

Are the engine blocks the same at least from 86-87 so that, should I find an 87+ motor, I can basically swap everything over using the newer parts?



I believe there's more to it than that... otherwise I suspect it would've been an option mentioned here numerous times over the decades. The Ogre probably knows a reason or two why it wouldn't work.

[This message has been edited by Patrick (edited 06-10-2023).]

shemdogg JUN 10, 10:49 PM
Only found 1 thread

https://www.fiero.nl/forum/Forum2/HTML/139512.html

Kinda sounds like it was better to swap in a whole newer 4 banger

shem
GabeBjerk JUN 11, 09:01 AM
You only can get the tensioner from Rodney Dickman. He modifies ones from a different car. they are $180
82-T/A [At Work] JUN 11, 01:11 PM
Thanks guys... it seems that the engine casting itself has actually changed to be able to support the serpentine belt system. I did find an engine for sale that I was just going to buy so I could take all the stuff off of it, but from the link that Shemdog posted (which I apparently responded to many years ago), Ogre states the block is actually different in this case, and aside from all the bolt on stuff, lacks the necessary holes to install the tensioner. So... I guess that's that. It can definitely be done (appears to be a single bolt), and we can modify the bracket to support it... but the juice is definitely not worth the squeeze as they say...