Hey Carl this sounds like an upgrade

part 

But it may only fit the newer cranks

 

perhaps you could machine a small size crank hole bigger?

-- Edited by SGS Welding on Friday 23rd of November 2018 09:59:28 PM

-- Edited by SGS Welding on Friday 23rd of November 2018 11:00:55 PM

SGS Welding wrote:

---

Hey Carl this sounds like an upgrade

part 

But it may only fit the newer cranks

 

perhaps you could machine a small size crank hole bigger?

-- Edited by SGS Welding on Friday 23rd of November 2018 09:59:28 PM

-- Edited by SGS Welding on Friday 23rd of November 2018 11:00:55 PM

---

There are two very strong opinions, two different camps on this pilot bearing vs. pilot bushing discussion. You can take my input for what it's worth but I will never use a bearing. I've seen a few times where the bearing has failed and it absolutely shreds the input shaft on the transmission.

I have seen a pilot bushing wear out the odd time but with no other damage, just replace the bushing and proceed. Because it's way softer than the input shaft, no damage is done when it fails. To me, it's a no brainer. However, some guys say you are living in the dinosaur age if you use a bushing. I'm fine with being a dinosaur if it saves me time, money and effort repairing damaged transmissions!

And with that said, I'm sure someone here will say "never again will I use a bushing"!

Carl that bushing is going to rob

power and you know it!!

Go with the needle bearings!

With your quick shifts you will pick

up 2 tenths!!

(just kidding your argument makes great

sense to me)

ALL OF IT!!!!

 The roller bearings do cause grief and I have had many here myself with the snub of the input shaft worn out. I have also replaced many of the bearing type with the bushing type because of this and when the customer did not want the shaft fixed/replaced and all times it was 100%. In looking at this, anyone that knows how to drive a manual transmission will realize to take their foot off the clutch went at a stoplight or when they are stopped talking to someone.  This is when the damage occurs because the bearings fail. Also the race of the bearings are manufactured of a harder material than the input shaft. The shaft is soft in comparison.

 I have had to teach many people this over the years to remove their foot of the clutch pedal when stopped as they don't realize the damage it causes or may cause. I don't believe the bearings are bad to use but I do appreciate the bushing more because it is more forgiving.

I have never heard of anyone soaking the bushing because they are always oil impregnated right from new. Not sure how the brass would absorb more lube.. 

This 5-speed transmission is out of a 1998 1/2 ton Chevy with a 4.3 L engine.

 

 

-- Edited by 67Poncho on Monday 26th of November 2018 11:48:39 AM

Greaser wrote:

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67Poncho wrote:

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I have never heard of anyone soaking the bushing because they are always oil impregnated right from new. Not sure how the brass would absorb more lube.. 

 

---

 

I wondered if Oilite Bronze could be another option?

 

-- Edited by Greaser on Monday 26th of November 2018 01:00:49 PM

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Guess you self answered! (lol)

 

Napa #B656 $4.80

 

https://www.crankshaftcoalition.com/wiki/Pilot_bearing_and_bushings

 

Pilot bearing and bushings

 

-- Edited by 67Poncho on Monday 26th of November 2018 01:15:58 PM

67Poncho wrote:

---

Greaser wrote:

---

67Poncho wrote:

---

 

I have never heard of anyone soaking the bushing because they are always oil impregnated right from new. Not sure how the brass would absorb more lube.. 

 

---

 

I wondered if Oilite Bronze could be another option?

 

-- Edited by Greaser on Monday 26th of November 2018 01:00:49 PM

---

 

Guess you self answered! (lol)

 

Napa #B656 $4.80

 

https://www.crankshaftcoalition.com/wiki/Pilot_bearing_and_bushings

 

Pilot bearing and bushings

 

[edit] Types of pilot bushings/bearings

[edit] Bushings

Sintered oilite-type bushing. GM p/n 3752487 or Doorman p/n 690-014 are similar to this

"Good" pilot bushings that GM and the good NAPA bushing is an oilite made of sintered bronze. If a magnet is attracted to it, this indicated an iron content- which isn't recommended in many cases.

A "good" pilot bushing is an oilite. Oil is put into the sintered bronze material under a vacuum- an impossibility w/non sintered material- being as how a solid bronze part has no real porosity of any kind.

An oilite bushing contains all the oil that the material can "soak up" already. The amount of pressure that's used when it is sintered will determine how much porosity- and how much oil it can absorb. Different applications will have different properties.

Adding additional lube other than a slight amount as an installation aid isn't recommended and will serve only to attract/collect debris coming from the clutch and clutch plate, dirt, etc. An oil-bearing material like oilite has all the lube it needs already incorporated into the material itself, anything additional is not needed.

-- Edited by 67Poncho on Monday 26th of November 2018 01:15:58 PM

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I was very happy to find that NAPA had the bronze bushings. I ordered 2 of them. Picked them up today at NAPA and I only had to take one look at it to know it wasn't good.... I brought it home and it failed the magnet test miserably, so back to the drawing board. I must be able to find a bronze one somewhere but so far it's eluded me.

And I don't want to put this bushing in. I tested the really shot bushing I pulled out and sure enough, it's full of metal too. I wish I could find an old GM bushing. Might have to suck it up and pay ebay prices to get one...

That would be great, thanks.

I just spent about an hour online and I did manage to find one seller who specifically states "Heavy Duty Clutch Pilot Bushings Are Manufactured Of 100% Bronze" but I either have to run to the US or pay a crazy shipping amount to get it here. Regardless, whoever has one and however I get it, I'm going to pay what it takes. I am NOT putting in a magnetic bushing. Seeing the one I pulled out of this crank convinces me that it's bronze or nothing.

I am not sure why they call the bronze bushing the heavy duty one. I do know that using any other than a bronze one is looking for trouble. The correct bushing measures about .593" ID. The one I removed from my crankshaft was .798" ID, give or take. I say give or take because it's so hammered out it's not perfectly round but it's way over what it should be.

I admit to not knowing until recently that the bushings seemed to have slowly gone away from bronze to steel/bronze blend. I assumed that any pilot bushings with the bronze appearance were good, but that is certainly not true. The 2 I picked up at NAPA look to be bronze but the magnet grabs them real hard.

I see no reason why you can't get a shop to make you a bushing assuming you have the correct material to start with.

For what it's worth for the info, just measured my TH400 originally equipped 67 327, and it has a crank bore diameter of 1.093.

I had mentioned before about soaking the bushing in oil overnight. Well what I used to do and I think works better is: squish the bushing hard with your finger and thumb with oil in it. You will see the bushing sweat oil through the outside. Now install it. Im not sure if these were iron mixed bushings or not. Just did it and no comebacks. In the picture Im using a bearing style just as a mock up as I dont have a bushing one.