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Anyone Modify 87-88 V6 Dog Bone For Poly Bushings? by reinhart
Started on: 05-10-2021 05:19 PM
Replies: 24 (386 views)
Last post by: Spadesluck on 06-09-2021 12:24 AM
reinhart
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Report this Post05-10-2021 05:19 PM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
Surprisingly I couldn't find anything in the archives of someone doing this. I was able to get a set of poly bushings out of a 4 cylinder dogbone and was going to install in my 88 V6. I know about the internal ridges and figured I'd just grind them down. I easily cut them out with a circle saw but then realized that the OD of the 87-88 is still larger than the 85-86 V6 or 4 cyl.

So the ID is 1-7/8" for the 87-88 vs 1-3/4" for all the other dog bones. I couldn't find a poly bushing of that OD.

A few thoughts on this:
1) Find a metal sleeve/pipe with OD = 1-7/8 and ID = 1-3/4"
2) Make custom poly bushings using liquid urethane and a mold.

Anyone successfully do this 87-88 V6 stock dogbone poly conversion before? How did you do it?
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Report this Post05-10-2021 05:27 PM Click Here to See the Profile for fishsticksSend a Private Message to fishsticksEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't have an answer to your exact question, but that seems like a ton of work.

Do you have a local steel yard? I'm positive they will have the properly sized tube for those bushings. Just make your own dog bone. It's very likely they will have short lengths in the remnant section that you can get for nearly nothing.
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Report this Post05-10-2021 06:25 PM Click Here to See the Profile for skywurzClick Here to visit skywurz's HomePageSend a Private Message to skywurzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure how it was done but my 88 has a factory dog bone with poly pressed in. I have a v6 TFS one around here somewhere I'm probably going to swap in, instead.
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Patrick
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Report this Post05-10-2021 07:32 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by reinhart:

Anyone Modify 87-88 V6 Dog Bone For Poly Bushings?

Surprisingly I couldn't find anything in the archives of someone doing this.



Let's rebuild an 87 dog-bone with pictures

[This message has been edited by Patrick (edited 05-10-2021).]

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fieroguru
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Report this Post05-10-2021 08:19 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
From this thread:
https://www.fiero.nl/forum/...160323-2-124009.html

 
quote
Originally posted by fieroguru:
I can't link to ebay from this computer, but having just purchased some poly bushings listed for the stock 88 2.5 dogbone - buyer beware.

The inside surface of the stock dogbone is not a uniform circular tube that you can just slide a normal round poly bushing into. The inner surface is tapered and it also has an inner lip. To get mine to fit, I had to put them in the lathe and turn the needed taper into the bushings. Once I did that, I was able to install them.


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reinhart
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Report this Post05-11-2021 06:53 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks Patrick. I noticed he didn't tackle the slightly larger diameter issue.

 
quote
Originally posted by Patrick:

Let's rebuild an 87 dog-bone with pictures





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reinhart
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Report this Post05-11-2021 07:09 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fishsticks:

I don't have an answer to your exact question, but that seems like a ton of work.

Do you have a local steel yard? I'm positive they will have the properly sized tube for those bushings. Just make your own dog bone. It's very likely they will have short lengths in the remnant section that you can get for nearly nothing.


If by a ton of work, you mean 5 minutes then yes. I have about 5 min invested in this project so far. Two cuts to get the bushings out and two hole cuts to get the cylinders even. In fairness, I did spend some time looking around the web for a pipe or liquid urethane but I've been interested in the idea of liquid urethane for a while now anyway.

Just found an exhaust pipe on egay that's 1-7/8 OD and 1-3/4 ID. It's 3-1/2" long so more than enough material to cut 2 x 1.5" sections. Seems like that is the easier route at this point. Probably just coat the metals with epoxy so it doesn't try to move on me and that will hold the sleeves in place.
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Patrick
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Report this Post05-11-2021 05:25 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by reinhart:

I noticed he didn't tackle the slightly larger diameter issue.


I don't know if was due to the particular '87 dogbone used or to the poly bushings chosen, but it appeared he didn't need to.
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Dennis LaGrua
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Report this Post05-11-2021 06:25 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Start with an 85-86 V6 dogbone, cut out the rubber bushing, clean and paint it, insert the Prothane bushings (that are a direct fit) -done.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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reinhart
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Report this Post05-11-2021 08:14 PM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

I don't know if was due to the particular '87 dogbone used or to the poly bushings chosen, but it appeared he didn't need to.


Did you read the thread you linked?
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reinhart
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Report this Post05-11-2021 08:16 PM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post

reinhart

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quote
Originally posted by Dennis LaGrua:

Start with an 85-86 V6 dogbone, cut out the rubber bushing, clean and paint it, insert the Prothane bushings (that are a direct fit) -done.



Haven't seen anyone selling used 85-86 bones for less than the cost of getting a short piece of pipe. Do you have one for <$10 shipped?
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Patrick
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Report this Post05-11-2021 08:33 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by reinhart:

Did you read the thread you linked?


I looked it over quickly (didn't study it) as I'm not the one modifying a dogbone. I supplied the link for your possible benefit. What was it that caught your attention?

[EDIT] Okay, I read the whole thread more thoroughly... and discovered in the 16th and final post of the thread what you're possibly referring to. Reinhart, you probably could've simply mentioned what Electrathon had posted instead of quizzing me.

 
quote
Originally posted by Electrathon;

The issue with using the internal rib bones is that the main hole through the bone is not the same size as the bushings, it is slightly larger. You can see that one of your bushings is tipped in one of the pics. The bushings fit loose in the bone except for the center area that was bored out, allowing for more movement. They will work, but the fit is of poor quality.

[This message has been edited by Patrick (edited 05-11-2021).]

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Dennis LaGrua
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Report this Post05-11-2021 09:24 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by reinhart:


Haven't seen anyone selling used 85-86 bones for less than the cost of getting a short piece of pipe. Do you have one for <$10 shipped?


Dog bones with bad loose bushing rubber should not cost much. If I had one I would sell it for $5 or probably give it away. Without rebuilding its a useless part or core. The parts dealers like Wayne Renninger and Tom Derr should have that part . If you are a welder, want to make one from scrap tubing and don't care about looks or originality, go for it.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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reinhart
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Report this Post05-12-2021 06:21 PM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
Fair enough Dennis. Even so, the shipping on the $5 dog bone would probably get you over $10 total. And I really haven't seen anyone selling cheap or giving one away. But in fairness, I didn't ask around.

Considering how easy the mod is, at least for me, it is a no brainer to at least give it a shot. Total labor invested was about 5 minutes with 30 minutes browsing the web looking for a suitable pipe. To cut the pipe twice and smooth out the edges is probably about another 10 min of work. If it doesn't work, I can always put in a request to get a used bone.

Anyway, I can get the pipe for $2.55 shipped as I found the same part on rockauto and am already putting an order in so the shipping is minimal. It's also available from oreilly for $4.29. I'll report back once I get the pipe and install it.
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reinhart
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Report this Post05-28-2021 06:34 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, I received the pipe and the verdict is. Meh.

It will work in theory. The ID was nearly perfect for the bushings but the OD was just slightly too large compared to the dogbone ID. If I had the proper equipment to grind the dogbone ID down more or the patience to do it by hand it would work. However I don't and I didn't. I tried to force the pipe in and the pipe split the dogbone. If you have a bench grinder it would be rather easy to do this correctly in a couple minutes.

This saga originally started because I got a poly 4 cyl Fiero Store Ultimate dogbone at the junkyard. I elected to make the poly work in my V6 and save the metal dogbone to either sell or save for a future project.

So Plan B:

Well once I broke my V6 dogbone today, I decided to just remake that 4 cyl Fiero Store Ultimnate dog bone to work on a V6.





The dogbone fits perfectly.

By the way Dennis, a few months ago you recommended a battery conditioner. I picked one up on amazon after I read that and it worked amazingly. It made 4 batteries that I thought I'd have to trade in or junk work like new again. Only one battery failed to fix. It was a jump start battery and it won't go over 11.5 volts even after a couple weeks on the conditioner. Thanks for the great idea.

[This message has been edited by reinhart (edited 05-28-2021).]

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Spadesluck
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Report this Post06-02-2021 10:30 PM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
I took my stock dog bone and ground out the rib on the inside. Then used a urethane bushing all the way through. Not difficult, got the idea from this forum.
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reinhart
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Report this Post06-06-2021 04:20 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spadesluck:

I took my stock dog bone and ground out the rib on the inside. Then used a urethane bushing all the way through. Not difficult, got the idea from this forum.


If you don't mind it flopping around good for you.
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Report this Post06-06-2021 08:58 PM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by reinhart:


If you don't mind it flopping around good for you.


Its nice you assume mine is flopping around... Come on man, why would I build something like that or why would anyone do that? I can assure you it works as intended with nothing loose.
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Report this Post06-06-2021 09:05 PM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
and BTW here is the thread....

Modify 87 Dog Bone
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Patrick
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Report this Post06-07-2021 03:46 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spadesluck:

and BTW Here is the thread....


I linked to that in the 4th post of this thread.
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Report this Post06-08-2021 01:13 AM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

I linked to that in the 4th post of this thread.


I am just trying to hammer home the fact that it does work. 😆😉
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reinhart
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Report this Post06-08-2021 06:10 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
double post

[This message has been edited by reinhart (edited 06-08-2021).]

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reinhart
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Report this Post06-08-2021 06:27 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spadesluck:


Its nice you assume mine is flopping around... Come on man, why would I build something like that or why would anyone do that? I can assure you it works as intended with nothing loose.


LOL you're the same person that linked to a thread where it is quite obvious the end result is a bushing that is visibly loose and sloppy in just a picture, let alone once installed. If you are using that as an example of a successful operation then yes it does make me question whether you did yours correctly.
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reinhart
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Report this Post06-08-2021 06:29 AM Click Here to See the Profile for reinhartClick Here to Email reinhartSend a Private Message to reinhartEdit/Delete MessageReply w/QuoteDirect Link to This Post

reinhart

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quote
Originally posted by Spadesluck:


I am just trying to hammer home the fact that it does work. 😆😉


If your idea of "works" is a bushing that if you're meticulously lucky, contacts the center third of the width of the dogbone then it "works" as in the bushing goes in. Now if you do a simple measurement before making a single cut in the inner ribbed bone, I can easily prove to you that there is no way the standard dog bone sized 1-3/4" urethane bushings are contacting 2/3rds of the diameter of the bone hole. The outer width at the edges gets as wide as 1-7/8". I was able to hammer in a 1-7/8" sleeve nearly all the way in before the aluminum cracked when it got to the center 1/3rd where I failed to hone it enough. I didn't hone any of the outer 2/3rds and it slipped in fine umntil that center 1/3rd. Reread my posts if you came in late.

Now the 1/3rd contact area is assuming you perfectly cut the center section at the perfect 1.72 inches the urethane bushings are. This would get you that 1/3rd contact area. Now measure an uncut bone and you'll see the outer third on either side on both ends is significantly larger than 1.72 or 1.75 inches. It's 1-7/8". Thus it is physically impossible for the bushing to solidly mount inside the entire width of the bone.

Realistically, the likelihood of even getting that perfect cut for a 1/3rd contact is slim. Check the thread you linked to and you can see just his slight deviation in the boring left at least one of the two bushings flopping around. I had the same experience when I cut mine. Even if you got the outer parts of the center 1/3rd cut correctly, if you deviated in the middle of the center a little more, then it wouldn't wobble but would have no support in the middle of the center 1/3rd either. But again even a perfect cut is only supported by 1/3rd of the bone. It would be the equivalent of cutting the bone into 1/3rd of its original width and reinstalling it. That the loss of support you're achieving under the best case lucky stars scenario.

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Report this Post06-09-2021 12:24 AM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
Reinhart, you are right. I will gracefully bow out.
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