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Replacement tensioners for the 87/88 L4 engines by Rodney
Started on: 11-05-2015 04:00 AM
Replies: 12 (531 views)
Last post by: Rodney on 11-08-2015 07:19 PM
Rodney
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Report this Post11-05-2015 04:00 AM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Copied from my web page:

http://rodneydickman.com/ca....php?products_id=369


This tensioner has been unavailable for a few years now. So what can an owner of a 87-88 Pontiac Fiero with the 2.5 L4 engine do if their tensioner fails?

Here is the story on a finding a suitable replacement:

Several years ago I was at a Fiero car show talking to Fred Bartemeyer. In our conversation that day Fred happened to mention how he modified a GM FWD belt tensioner to work on the 87/88 L4 Fiero engine by cutting some of the casting off that held the power steering pump. At that time that was the end of our short discussion on this topic but I always remembered that conversation we had that day.

Fast forward to a few months ago (Sept 2015): A person calls and tells me his daughter has an 87 Fiero with the L4 and the tensioner has failed. He asks where he can buy one. I tell him there are no new ones available anywhere. I tell him the story of my conversation with Fred Bartemeyer. He tells me he does not want to try and research that so I send him on to some places that sell used Fiero parts. I would assume he found and bought a good used tensioner and had it installed in his daughters 87 L4 Fiero.

So now I start looking into this. I emailed Fred Batermeyer and I asked him for more details on this. I also ask Fred if he wants to start making these modified FWD tensioners so they are available to Fiero owners.

This is Fred Bartemeyers story:

Rodney,
The thought process started with my recollection of when I worked in the GM dealerships that the iron duke L4 was also used in several front wheel drive cars. I visited my local Pontiac Dealership that I have friends at and did some cross reference research to see what cars came with an R code iron duke. Knowing that the P/S pump on the FWD GM L4's mounted where the alternator does on the Fiero, I felt that my idea was dead in the water. But I still wanted to look at this so I trolled the local u-pull-apart junk yards to see if I could find one of the FWD cars on my target list. The day I looked, there was both an Oldsmobile that was on my list and a 88 Fiero coupe in their inventory. So, I took the tensioner off the FWD Olds engine and attempted to install it on the Fiero. The FWD tensioner I took off the Olds bolted up to the Fiero directly without any clearance issues. I bought that tensioner for a couple bucks and brought it home to see what modifications were needed to possibly make it work in the 87/88 L4 Fiero's. I had several Fiero R code iron dukes out of the car at the time, so I did the mock up on a spare engine. I first cut off one of the aluminum ears that held the power steering pump on this FWD belt tensioner. I then fabricated a steel extension bracket that bolted to this FWD P/S tensioner to go to the Fiero alternator which kept the Fiero alternator in the same location. It worked and there were now two 87 coupes out there that had this modification on it. These used FWD P/S tensioners were plentiful at the time, so it was an economical repair. It seems like it was only a couple years later that the aftermarket picked up on the demand and they started producing the tensioner again for the 87/88 Fiero L4's, so the need for this idea went away; until now.

This was done in the early 2000's, maybe 2003ish when GM dropped the Fiero tensioner P/N out of their books. Before we had the luxury of having online parts cross reference available from like O'Reilleys. The GM dealer was the only place that you could get that kind of information at that time.

I do not recall having any clearance issues with the tensioner bracket and the dog bone mount. If I did a modification in that area, I do not recall doing it. The beauty of it all is that the alternator does not need to move and stays in the same location.

Thanks for the recognition, while I do not find it completely necessary, I am just happy that you are taking the intuition to make a product that is helping Fiero owners keep their car on the road. Kind of reminds me of what the guys who restore pre-war cars go through to complete a car. Some of these guys would have went through the expense of having a new casting made to replicate the original.

Seems to me that it was in the time frame of 2000 to 2004 that the GM OEM went out of stock and it took a while for the aftermarket to catch up. This is when I did this to a couple of 87's to overcome the issue.

Thanks,
Fred Bartemeyer

There are pictures on my web page.

I do not have any of these steel brackets in stock yet. I made up a couple for R&D and sent one out for someone to install on his 88 coupe. Once he installs it and assures me it fits and works I will start to make a batch of these brackets. Some of the parts will need to be laser cut so this will take a few months. If someone needs one right away let me know. I can hand make a few.

------------------
Rodney Dickman

Fiero Parts And Acc's Web Page:
All new web page!:www.rodneydickman.com
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Phone/Fax (262) 835-9575

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Report this Post11-05-2015 03:59 PM Click Here to See the Profile for vizzionnSend a Private Message to vizzionnEdit/Delete MessageReply w/QuoteDirect Link to This Post
man wish this was available a year and a half ago i paid $106 at rock auto for mine

[This message has been edited by vizzionn (edited 11-05-2015).]

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Report this Post11-05-2015 04:22 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Rodney and Fred.
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Rodney
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Report this Post11-05-2015 04:35 PM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
You are still going to pay over $100. I only supply the bracket. You have to buy the FWD tensioner plus my bracket. But at least something is available.

------------------
Rodney Dickman

Fiero Parts And Acc's Web Page:
All new web page!:www.rodneydickman.com
Rodney Dickman's Fiero accessories
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theogre
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Report this Post11-06-2015 12:13 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Tensioner "arm" shouldn't need much strength...

Alt for this version should have 3 fixed mounting points:
the arm on the tensioner
steel brace on back of alt to the intake manifold. (Some could be are missing this part because of lazy people replacing bad alt..)
Main load is on pivot bolt and bracket at bottom.
CLICK FOR FULL SIZE


Proper torque on pivot bolt makes the very hard to impossible to move w/o both other mounts.
Have two makes sure can't move ever.

Note that Two types on FWD units out now... The one you have and one that tension section is same as Fiero unit. May make a difference which one use to modify.

PM send

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

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Rodney
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Report this Post11-06-2015 06:56 AM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I looked at this for more than a few days pondering how to make the steel bracket. I looked at using two laser cut plates and bending them with an offset. The offset is not equal so both plates would have different offsets. It is very hard to bend a plate and have it be exactly where you want it to be and be parallel. I did not want to make a single plate. IMO it seems too weak. I also pondered and made up a few other different designs. I know my design puts that slot exactly where it should be and perfectly parallel to the ear surface of the alternator. It also equally puts the pressure on the two aluminum ears it is attached to. To make them it has to be bolted to 2 different welding jigs. One to weld the U part together. Then another jig to weld on the slotted arm. My design is HD and precision. So I'll make them like this.

------------------
Rodney Dickman

Fiero Parts And Acc's Web Page:
All new web page!:www.rodneydickman.com
Rodney Dickman's Fiero accessories
7604 Treeview Drive
Caledonia, WI 53108
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Report this Post11-06-2015 07:07 AM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:
Note that Two types on FWD units out now... The one you have and one that tension section is same as Fiero unit. May make a difference which one use to modify.


There are 2 different types of tensioners out there but they are only different in appearance. Dimensionally and functionality they are the same. OEM GM and the Four Seaons are exactly the same. Made by the same company. All the markings in the castings are the same between them. Dorman and Dayco are different in the pivot area. One could assume the GM and Four Seasons would be better units. One would need to take a Dayco or Dorman unit apart to see how they are made. At some point there may not be any more OEM GM or Four Seasons units available so one would only have the Dayco and Dorman (which are the same units) to use. One suggestion for those using the GM OEM or Four Seasons: The pivot area gets rusty over time. Occasionally oil under the head of the bolt. Maybe some oil would get in and lubricate the bolt and steel bushing inside the pivot part. If you take apart an old GM tensioner you will see the rust on the pivot bushing and bolt.

------------------
Rodney Dickman

Fiero Parts And Acc's Web Page:
All new web page!:www.rodneydickman.com
Rodney Dickman's Fiero accessories
7604 Treeview Drive
Caledonia, WI 53108
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Rodney
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Report this Post11-06-2015 09:25 AM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Looking at this again I can see how I could make a single laser cut plate with a two offset bends and it would bolt to the back of the aluminum arms. My concern over time is a possible failure of the aluminum arm(s) from vibration. The 2.5's produce a lot of vibration. My double plate design makes for a very sturdy design.

------------------
Rodney Dickman

Fiero Parts And Acc's Web Page:
All new web page!:www.rodneydickman.com
Rodney Dickman's Fiero accessories
7604 Treeview Drive
Caledonia, WI 53108
Phone/Fax (262) 835-9575

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Report this Post11-07-2015 07:40 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Rodney:
Looking at this again I can see how I could make a single laser cut plate with a two offset bends and it would bolt to the back of the aluminum arms. My concern over time is a possible failure of the aluminum arm(s) from vibration. The 2.5's produce a lot of vibration. My double plate design makes for a very sturdy design.
Yes your product looks nice and strong but many will find another way because of Price. This is Why I put several examples in PM not Here.

"The 2.5's produce a lot of vibration" is partly true and partly myth... For your argument OE arm is "weak" too yet very rarely to never breaks, even w/ missing steel brace.

Again... Alt Pivot bolt and the bracket takes most of alt's weight torque and vibration loads because is allot stronger and limits movement to 1 plane.

Don't confuse this w/ V6 alt bracket breaking the adjusting slot.
GM made that weak but other things are factors here, including many DIY and "Mechanics" over torque the short bolt.

 
quote
There are 2 different types of tensioners out there but they are only different in appearance. <snip>

Picture from RA and others don't agree with that statement.

Even when Everything else is the same...
  • Fiero spring arm points to and mostly cover bottom mount bolt w/ pulley.
  • Dorman/Dayco is close to Fiero. Might be able to accept OE belt size w/o problems. Too tight and the spring will bind causing problems. Many Dayco units have stops to set range of travel.
  • "GM" types spring arm is ~90° above Fiero setup. The arm covers the top mount bolt w/ pulley. If they clear WP pulley at rest then could have problems getting a belt on. The scale on body moved too. see http://www.summitracing.com/parts/cel-49211 has "GM" design view from top showing pointer and scale. (the part was flipped 180°.)

    FWD Dorman/Dayco might work but "GM" unit can/will fail. Once you cut them and can't return them then have $50+ paper weight.

    The "GM" units were made by Dyneer corp and sold thru ACDelco, Gates and others. (Titan International, Inc. bought Dyneer in 1993.)
    Most Dyneer units have same "scale" marks on top as shown in my cave, Serpent Belt.

    Dyneer and most/all Dayco units... You can't rotate the arm out of range and won't run long w/ a belt hitting either end of travel.
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    Rodney
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    Report this Post11-08-2015 01:16 PM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
    So I spent some time experimenting with this today as I realized (because theorge pointed it out) they clock at different angles. I was going on what Fred Bartemeyer told me. Good news and more good news:

    I experimented with a OEM NOS GM tensioner and an aftermarket tensioner (Dorman or Dayco). The Dayco and the Dorman tensioner are exactly the same unit.

    What I found: The GM unit has a much smaller rotational window. The limiting tabs are internal.

    So I tried playing with the aftermarket tensioner: The rotational limiting tabs are external and very easy to get at. Experimenting some I found if you cut this small limit tab off the Dorman or Dayco unit they easily rotate into the range of motion needed to match the original GM Fiero tensioner. The limiting tab for the backwards rotation does not get modified.

    Next I took my torque wrench to looked at the amount of tension both provide. When I moved the used OEM GM Fiero tensioner to the end of it's rotational limit (about straight down) it showed about 16 foot pounds. When I rotated the aftermarket tensioner to about the same location it read from 18-20 foot pounds. So they are about the same considering the OEM GM tensioner I have is used and I'm rotating the aftermarket tensioner farther than it's max rotational limit. The aftermarket tensioner easily rotates that far and even farther.

    I dissembled the NOS OEM GM tensioner (not hard to do) and ground the limit tab out so it could rotate more (kinda hard to do) and put it back together. When rotated to that same maximum position (about straight down) it was very hard to rotate as I got to almost straight down like maybe it has a flat band spring and you are reaching the limit and it starts binding up. So the GM FWD tensioner should not be used at all. Only the aftermarket Dorman or Dayco.

    The aftermarket Dayco/Dorman tensioner unit looks to be a very nice quality unit. It has a plastic washer for a wear surface. I did not take it apart.

    So I've changed my web page to show these things.

    I'm still torn on using a single offset bent steel plate instead of my 2 plate welded design. The single plate idea just seems weak to me. I had thought of this originally and dismissed is as possibly being too weak in the long term.
    ------------------
    Rodney Dickman

    Fiero Parts And Acc's Web Page:
    All new web page!:www.rodneydickman.com
    Rodney Dickman's Fiero accessories
    7604 Treeview Drive
    Caledonia, WI 53108
    Phone/Fax (262) 835-9575

    [This message has been edited by Rodney (edited 11-08-2015).]

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    Rodney
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    Report this Post11-08-2015 03:53 PM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
     
    quote
    Originally posted by theogre:

    FWD Dorman/Dayco might work but "GM" unit can/will fail. .


    The pictures of these are misleading in a sense. The Dorman/Dayco units are per-retracted and have a steel pin keeping the pulley at about 80% of it's clockwise rotation to aid in installing the belt. With that pin removed the pulley rotates back to about the same location as the OEM GM units.

    ------------------
    Rodney Dickman

    Fiero Parts And Acc's Web Page:
    All new web page!:www.rodneydickman.com
    Rodney Dickman's Fiero accessories
    7604 Treeview Drive
    Caledonia, WI 53108
    Phone/Fax (262) 835-9575

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    Report this Post11-08-2015 06:27 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
    I know the pin is remove after install for some units...
    Just the Fact moves that far makes a huge diff.

    Dayco unit will be close to binding... Depend on actual belt used and tolerance stack up of whole system.
    Same issue using different belts on OE tensioner covered in my cave.

    Means If you have to force belt on to the idler then you will have problems.
    Change brands or try using next size.
    Size label on a belt is not always exact size... Look at maker's catalog.
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    Rodney
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    Report this Post11-08-2015 07:19 PM Click Here to See the Profile for RodneyClick Here to visit Rodney's HomePageClick Here to Email RodneySend a Private Message to RodneyEdit/Delete MessageReply w/QuoteDirect Link to This Post
    I rotated the Dayco/Dorman unit well past where the OEM Fiero tensioner rotates to hit the limit stop and there is no sign of binding. The GM tensioner did bind up and get hard to rotate that far. So you can not use the GM OEM tensioner. Only the Dayco/Dorman.

    Working with my local Fiero friend Steve today we found another snag. The found the at rest position and no belt installed made the pulley hit the water pump pulley when you tried to install this tensioner on the block. So I designed a part to make the at rest position of the pulley the same as the OEM Fiero tensioner (about 4:00 to 5:00). Will be easy to drill a hole and bolt this part in. My kit will need this additional part now but it will remain a kit and not me buying a bunch of tensioners, modifying them and selling them modified and complete. I do prefer to sell the kit. The customer does the modifications. I may also offer them complete. We'll see.

    I'm going to get a few more of these tensioners and set one up for Steve. It should just bolt right in now I hope. I very sure it will. Those with 87/88 L4's can relax knowing there will be a replacement tensioner available again.


    ------------------
    Rodney Dickman

    Fiero Parts And Acc's Web Page:
    All new web page!:www.rodneydickman.com
    Rodney Dickman's Fiero accessories
    7604 Treeview Drive
    Caledonia, WI 53108
    Phone/Fax (262) 835-9575

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