Why am I eating pilot bushings?

brengl1942

Well-Known Member
Joined
May 13, 2015
Location
Hurdle Mills
I'm trying to figure out why my flat fender keeps eating through pilot bushings. When I first got it on the road in 2021, it ate through the first bushing in roughly 50 miles. Last winter I replaced it with a second bushing after replacing the input shaft on the T-90 with a new NOS shaft. The input shaft was the only re-used internal part in the transmission in the initial build, and it had a fair amount of wear which I thought was part of the problem. I also replaced my cave-built homemade bellhousing with a very pricey Quicktime bell, to try and eliminate bellhousing alignment issues (long story, but there is no "adapter" for my engine/trans combo).
Now I have a basically new trans with very little play in the input shaft and a new bellhousing that as far as I could tell was within about .004" tolerance. It was difficult to check though since my gauge is designed for degreeing cams and didn't fit easily inside the bellhousing.
After this year probably putting a couple hundred miles on the jeep, I'm getting some nasty clutch chatter again and a little 'chirping' upon startup. In the photo, the 'rust' looking dust you see around the center hole in the flywheel and on the bolts, that is bronze dust where the bushing has disintegrated.

I've been wondering about the bushing material itself, these had to be custom made since there is no commercially available one for this combo. They were supposed to be "sintered bronze", but I don't think they were oil-lite. @amcjeepman has graciously made me a couple of new ones out of bronze, but I'm hesitant to just put a new one in and bolt it back together expecting a different result, without really knowing the cause of the problem. I don't want to have to pull it apart in another few months again.

Ideas? Maybe I need true Oillite material or something tougher than bronze? Buy a better alignment gauge and re-check the bellhousing alignment for issues? Are there other things that can cause this?
 

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What's the OD and ID of the bushing? I'm not a fan of needle bearings, but will always chose a sealed roller bearing if possible, followed by a bronze/oil lite bushing.

Soliving oddities and weird issues are what I live for!
 
Croatan_Kid said:
What's the OD and ID of the bushing? I'm not a fan of needle bearings, but will always chose a sealed roller bearing if possible, followed by a bronze/oil lite bushing.

Soliving oddities and weird issues are what I live for!
Click to expand...
.827 OD and .627 ID, with a "length" of around .59". I've never found a bearing that matches. The engine originally had a bearing and was mated to a T-5. The old T-90 of course only used a bushing.
 
shelby27604 said:
Sounds to me like your bellhousing is out of alignment (either the center line of the bell and the crank are not lined up or the mounting face of the transmission is not parallel to the rear face of the block).

www.moderndriveline.com

HOW TO: Properly Dial-in Align and Index your Bellhousing

HOW TO: Properly Dial-in Align and Index your Bellhousing
www.moderndriveline.com www.moderndriveline.com
Click to expand...
It's possible the bell is still out and I just couldn't measure it accurately with the setup I have.
Anyone ever used one of these?

the hole is rather small and it's hard to get a dial gauge in there, particularly one designed for camshaft use. There is also the problem of how to modify it if it is off. The EFI Ford 2.3's use a hollow dowel pin and bellhousing bolts go through them into the bellhousing. I am not sure if any sort of alignment dowel exists.
 
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My first thought would be making some threaded pins that barely slip in the bellhousing's bolt holes. Slide it up against the rear of the block and check the gap.

You can also use a coaxial indicator in the crank bore to check alignment. It's definitely going to need some sort of small dial indicator. I do jig bore work, amongst other things, at work and a lot of it requires line bore indicating. That's exactly what this is.
 
Was the engine align bored by chance? As previously stated check concentricity. If it was align bored/honed very heavy it could have thrown off center line
 
The engine has never been rebuilt, it's a factory stock 1993 Ford 2.3. Roughly 120k miles on it.
 
Another challenge with this is that I'm using a McCleod hydraulic throwout bearing that cannot be installed without first bolting the bellhousing to the trans. That means if I were able to make any needed adjustments then I have unbolt the thing again in order to get it installed on the transmission. I cannot install the bellhousing, index it, and then just bolt up the trans. No doubt the process of bolting/unbolting is going to throw off any small adjustments.
 
Ok, got the dial indicator set up again, I found a better way to attach it that works well. Used the method from the Holley/Quicktime video to index it. Based on this I'm ~.009 out in the vertical low direction. Side to side was within .002. I'm going to repeat the exercise a couple more times to be sure because the first time I did this back in the winter I had determined I was only .004 off.
 
I'm not sure what's acceptable in this situation, but is it .009 tir or .009 out of center reading .018". I'm assuming it's showing .009 total. That could make a huge difference. Do your alignment dowels fit tight?
 
justjeepin86 said:
I'm not sure what's acceptable in this situation, but is it .009 tir or .009 out of center reading .018". I'm assuming it's showing .009 total. That could make a huge difference. Do your alignment dowels fit tight?
Click to expand...

So my bottom mark (180 from where I zero'd it) read .018, and you half that to get the amount that it needs to move. The line through where it is zero'd to 180 degrees indicates the direction it needs to move. Most people say the tolerance is .005", so I'm about .004 outside that range. The dowels do seem to fit pretty snug, you can't move the bell by hand once you get it seated on the dowels.

That said, I'm wondering if I just unbolt it and bolt it up again how much of a different measurement I'd get? And, would this degree of alignment issue actually cause the problem I'm having in such a short amount of time? The pilot bushing wear seems extreme for such a small discrepency.
 
Not getting enough fiber in your diet? :D
 
I'd think .009 off center would cause some wear, sure, but do you have a way to sweep it for parallelism? The transmission mount side of the bellhousing vs the flywheel or something. Maybe even check the engine side vs transmission side of the bellhousing to see if they're parallel. It could be a compounding issue of off center AND angularity.
 
I set up the indicator to test the face of the bell for parallel, and it looks to be within .002 all the way around. I think I'm good there, it would be hard to get closer than that and I'm probably within the margin of error just for the measurement process. For grins I tried re-torquing the bellhousing bolts to see if that made a diffference, and I still came up with all the same numbers.
I've been doing some research and found a thread on TurboFord.org (enthusiast site for these same Ford 2.3 engines), and apparently there are no commercially available alignment dowels for that engine. Some folks there came up with various "jury rigged" ways to try and adjust it.
I am reaching out to a couple of machinist contacts to see if I can find someone that can mill a couple for me.
 
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