[C5] Pilot bushing?

[Rich Z]

So I'm getting together all the parts I may need when I change out my clutch (presuming the squealing noise will resume sooner or later) and of course I figured I would need a new pilot bearing or bushing. Still undecided about which one would be best. From scouring the web, it appears that opinions are solidly 50/50 on the answer to this question. So I figured I would get both so I can decide later when I'm getting ready to pound one or the other into the crank.

So I placed an order for both a bearing and a bushing from Summit Racing, along with some other stuff. When I got the box (overnight, no less) I was confused to see that I had five (5) bushings in there. Did I click the "add to cart" button too many times? I checked my invoice, and yep, I had only ordered one. So I contacted Summit and asked them how they wanted me to ship the extras back to them. They told me because of the low value of the items, to just go ahead and keep them all. So if anyone needs and extra pilot bushing...... Summit Racing is tops on my lift of people to buy from. They have only made two errors in all the ordered I placed with them, and both were errors in my favor. Each time they just told me to keep the extras.

Anyway, I checked the bushings with a magnet and sure enough the magnet firmly sticks to the bushings. It's not even like it is just a LITTLE bit or iron content. So these really aren't bronze or brass as I had hoped for. When I was reading up about the bushing/bearing choice, people who suggested the bushing highly recommended getting brass or bronze ones and NOT ones made with iron. The term Oilite was used quite often. So I went on a search for a genuine Oilite bushing and found one at a company called Novak Conversions (http://www.novak-adapt.com/catalog/p...hings/gm2-gm1/). The website says:

Novak pilot bushings are made from quality Oilite bronze alloy....

So OK, I went and ordered two of them, just in case I damaged one trying to install it. I had hoped I would get REAL bronze bushings this time.

So anyway, the bushing(s) arrived today, and there were three (3) notable issues with what I got. Two of which can be seen in the below pic:



First off, what they sent me looks nothing at all like a stock pilot bushing (pictured on the right in the photo). Secondly, I only received one, instead of the two I ordered. Unless this oversized one counts for two, I guess. The third problem is that the bronze bushing is DEFINITELY magnetic, so it's apparently no better than what I already have. And lord knows I really don't need another pilot bushing that is not what I want.

Am I missing something? Is that bushing they sent some kind of "new and improved" model of pilot bushing? I think some of the later model GM cranks take a larger diameter bearing, so is this sort of a "one piece fits all" part?

[Cor66Vette]

Man, that looks nothing like what you want to replace.

And what's up with it not being as advertised (brass)?

These vendors must think their customers don't know how to test if metal is magnetized.

Sad and pathetic.

[Rich Z]

The more I look at the pic of the bushing they sent me the more doubtful I am that it could possible work in my car. The beveled edge is supposed to be OUT away from the front of the engine so that the input shaft of the torque tube will more easily slip into it. So there is just no way that thing will work. Even if it were designed to fit in both a small and large pilot bushing application, the center part is sticking out WAY too far to be used. If I thought I had damaged form the Pfadt carbon fiber driveshaft being just 7mm too long, imaging what that bushing would do.

Anyway, I found a writeup and a pic of the two sized bearings I mentioned earlier.

http://ls1tech.com/forums/manual-tra...-vs-small.html

[Rich Z]

Well, I have gotten a reply from Novak concerning that pilot bushing, and it appears that what they are selling is some sort of bushing for mating a Gen III engine with some type of older transmission. Not clear on that quite yet. I found it with a Google search for an Oilite pilot bushing for Gen III engines. I read over their site again and I'm still reading it as being compatible with GM Gen III engines AND some other applications.

But the guy did give me an interesting explanation of why the bushing is magnetic:

Secondly, the composition of the bushing is a good discussion. Starting in the late-eighties, Dorman, a major OEM supplier, had determined that they could achieve better wear characteristics by the addition of steel to the oiled bronze alloy the industry had been using. This created a longer wearing bushing without sacrificing the tip of the transmission shaft. This is due to the fact that the steel is much softer (say, 15 Rockwell C) than the transmission input pilot tip (55+ Rockwell C). So, strength was increased as well as wearability, without sacrificing the lubricity of the existing porous bronze alloy. We had a great conversation with a Dorman engineer and subsequent other enthusiasts about this not long ago. We’ve more comfortably followed suit with the industry since learning this. As a deeply experienced engineer in this industry, I would choose this bushing over a rolling bearing and the classic oiled bronze alloy version. I'll add at this point that most of people's wear problems come from misaligned bellhousings (a condition most don't check nor correct for) than from bushing composition.