66 327 pilot bushing problems

[Greg L.]

I'm having a bit of a problem getting a new pilot bushing for this crankshaft. At first I thought the parts guys gave me the wrong one so I got another one and it was the same deal, too big so now I'm not sure what to do. The old bushing O/D is about 1.060" and the new one is about 1.100". The parts guy says they are all the same from 64 into the eighties....

Now I've read some place that some "auto" cranks were never machined for pilot bushings but could have been later at a machine shop. That may be my case here...I don't know. OR maybe the crankshaft is from a earlier 327, thus the smaller hole for the bushing...

What do you guys think the problem is and my options are?

[Timothy B.]

Re: 66 327 pilot bushing problems

Greg,

I think the standard size for the pilot bushing is 1.094". A few years ago I had the same problem except mine needed to be (I think) 1.084. The crankshaft in my 63 engine had been changed and it's #'s were 4577.

The best approach is to verify the ID of the crankshaft pilot with a snap gauge and micrometer then take the new bushing to a machine shop and have it turned in a lathe to approx .002 oversize so there is interference fit, the bushing will tap right in without deforming anything.

While the transmission is out, check the drilling depth of the pilot hole by measuring the length of the transmission input shaft and do the math just to be certain the bushing will tap in far enough.

On my 63, the bushing actually sticks out approx 1/8" but the measurments show the pilot is completely inside the bushing and the bushing is installed to the stop where there is a line from a lathe marking in the crankshaft.

[Clem Z.]

Re: 66 327 pilot bushing problems

you are not alone. http://webcache.googleusercontent.co...&ct=clnk&gl=us

[Larry M.]

Re: 66 327 pilot bushing problems

Agree with Tim. The OD can be machined or turned down, but you must avoid any machining to the ID where the transmission input shaft rests. Machining will close the OILITE pores and prevent effective lubrication.

You can use the OD of the old bushing as a reference. As Tim states, you want/need about 0.002-0.003 inch interference fit. Make sure one end has a slight chamfer to aid in installing in the crank.

Although a bit controversial, I would boil the new bushing in 30w oil after machining to ensure that it has a good oil supply in the bronze pores. Then put in a freezer bag and put in the freezer overnight. This will shrink it down some. Then install (quickly).

Larry

[Clem Z.]

Re: 66 327 pilot bushing problems

put it on a tapered mandrel thru the bore and turn the outside diameter in a lathe. this will keep the OD and ID concentric

[Greg L.]

Re: 66 327 pilot bushing problems

Thanks guys. Looks like this was an auto trans type of crankshaft in it's first life so I'll have to have the bushing turned down. All the machine shops are closed being Saturday so it will have to wait until later next week. At least I know what's going on now.

[Jeffrey B.]

Re: 66 327 pilot bushing problems

Greg,
There is an article in The Corvette Restorer, Volume 34, Number 4 Spring 2008 on page 36 about the pilot shaft bushing problem you are having. I tried twice to put new standard pilot shaft bushing in my 66 that were given to me by different guys with extensive corvette repair experience. Neither could understand why the standard bushing did not fit. If you happen to have a car that for whatever reason has a powerglide or turboglide crank a standard bushing will not fit. You may either need a Dorman Powerglide Adapter#DOR 690 034 (0.593 x 1.060 x 0.750), or a Dorman Turboglide Adapter #DOR 690 035 (0.593 x 1.722 x 0.750). These adapters are actually just different size pilot shaft bushings. Hope this helps.
Jeff Bailey

[Greg L.]

Re: 66 327 pilot bushing problems

Thanks Jeff, you nailed it! It all makes sense now and I see that we need the DOR 690 034. The problem now is that I called around and apparantly it's discontinued. I see Jegs has one for $15 though so we'll either order that or just get his new one turned down to 1.060".

[Joe L.]

Re: 66 327 pilot bushing problems

Thanks Jeff, you nailed it! It all makes sense now and I see that we need the DOR 690 034. The problem now is that I called around and apparantly it's discontinued. I see Jegs has one for $15 though so we'll either order that or just get his new one turned down to 1.060".

Greg------


I think it's preferable to get a "factory-manufactured" adapter bushing rather than having one machined to fit. Plus, a machine shop will probably charge you a significant amount to do this sort of thing for you.

I do not show the Dorman 690-034 as being discontinued and it would kind of surprise me if it were. Certainly, these things must not sell as briskly as they once did because crankshafts for original Powerglide applications are not too common anymore. However, I would still think the bushing would be available.

However, if you can't find the Dorman piece, NAPA stores carry an equivalent piece under their number BK-615029.

I checked and Rock Auto has all the Dorman #690-034 bushings you want for about 2 bucks each. You can get them in packages of 1 to 25.

[Greg L.]

Re: 66 327 pilot bushing problems

Thanks Joe, As luck would have it the Canadian NAPA stores don't use US NAPA stores numbers and I've had no luck with the Dorman number up here either. Looks like I'll be getting one turned down for now...

[Greg L.]

Re: 66 327 pilot bushing problems

I just came across this while searching for options and thought it might be useful to some of the members.

[John H.]

Re: 66 327 pilot bushing problems

I just came across this while searching for options and thought it might be useful to some of the members.

Greg -

Which manufacturer's numbers are those?

[Greg L.]

Re: 66 327 pilot bushing problems

Yes I guess that would help wouldn't it.

I'm pretty sure it was Dorman.

[Joe L.]

Re: 66 327 pilot bushing problems

Yes I guess that would help wouldn't it.

I'm pretty sure it was Dorman.

Greg------


Yes, those are Dorman numbers.

[Peter L.]

Re: 66 327 pilot bushing problems

I have the same problem, and found the Dorman part, and am going to press it into the crank shaft pilot hole. I am guessing from the posts that I have a crank from a auto/327 original combo. I had the engine made into a 340 HP, and I am mating it to a Muncie 4 speed gerarbox. Does anyone know if I should expect future problems with life on this bushing? Is the preferred method to machine the crank pilot hole, and install the needle bearing that was supplied with the new clutch kit from Paragon? To do that, I wuold have to have the crank removed, machined and replaced, a very expensive option. Does anyyone have experience with using the bronze bushing with a 4 speed manual transmission?