Pilot bushing

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I8NEMO

I8NEMO

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Finally pulled the 4spd to install a clutch thought I had the right bushing but o.d. is too much. Tomorrow I guess I'll pull the flywheel off to get my cheapie calipers in there for a measurement. Motor is a '69 340, I believe crank specs are on my office p.c. somewhere, any ideas out there what o.d. I might need?
Thanks!
20220322_150639.jpg
 
Napa sells two diameters One is for a standard shift crank that has been hoend from the factory. The other is smaller for an automatic motor which was never honed. That said both are tight and should be reamed to size after install. I used to buy them at our local NAPA store Gogle's but he just closed due to getting covid.
 
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The standard one is .940 and the smaller one is .915, I think. Napa-Balkamp discontinued theirs years ago. Someone on Ebay sells them I believe, or take the large one and have it machined down.
 
Thanks you guys, got something to go on now. I guess crank must have came from car with auto. Pulling flywheel today, it's cramped under there between 2 Jack stands and the bell housing stand I made. Maybe I can get these old eyes in there lol. The crank hole did feel knurled in there, not smooth. Just another Rabbit Hole!
 
All the 340 cranks I've seen were all machined for a bushing. Maybe the crank is out of something else? Rather than hone the hole and cut down a stock bushing, I think I'd just get the Magnum BEARING version. It fits into the converter button hole instead. This is assuming that you aren't working with a '67 and earlier 273 crank. In that case, you have no other choice but to make a bushing to fit.
 
cudamark said:
All the 340 cranks I've seen were all machined for a bushing. Maybe the crank is out of something else? Rather than hone the hole and cut down a stock bushing, I think I'd just get the Magnum BEARING version. It fits into the converter button hole instead. This is assuming that you aren't working with a '67 and earlier 273 crank. In that case, you have no other choice but to make a bushing to fit.
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Thanks much, the crank very well could be an unknown. I ordered a .915 bushing and then got engrossed in installing brake lines without any further bushing research. So if the crank hole doesn't feel smooth I definitely should hone it? Im assuming with a smaller wheel cylinder type hone.
 
That's what I did with one of mine. Honed the hole smooth with a brake cylinder 3 stone type hone. Then machined down a stock bushing to fit.
 
lemondana said:
The standard one is .940 and the smaller one is .915, I think. Napa-Balkamp discontinued theirs years ago. Someone on Ebay sells them I believe, or take the large one and have it machined down.
Click to expand...
Decades ago (the 70's) Dorman also made an all-brass one that fit the converter bore. Back then I did not realize what they were for. Hell I thought it was a catalog mistake.
 
Had a minute today to see if the .915 pilot bushing would fit, man I dunno, doesn't even look close. **** my pants thinking what if there's one in there and my oil- less gear box has been spinning some with every motor run. I dunno, got some burn out with all the rabbit holes just not feeling it today. Flywheel is coming off tomorrow so I can get the calipers in there.
 
I8NEMO said:
Had a minute today to see if the .915 pilot bushing would fit, man I dunno, doesn't even look close. **** my pants thinking what if there's one in there and my oil- less gear box has been spinning some with every motor run. I dunno, got some burn out with all the rabbit holes just not feeling it today. Flywheel is coming off tomorrow so I can get the calipers in there.
Click to expand...
the only time the pilot shaft turns in the bushing is when the clutch is depressed at junctions and when changing gears. when you're driving (or when in neutral) the shaft and crank are of course spinning at the same speed so no wear then. so there's only a very small amount of time when wear can occur so i wouldn't worry too much about previous use. :thumbsup:
neil.
 
Just get the Jeep- Dakota style that fits in the converter register. It's a roller style.
 
mygasser said:
the only time the pilot shaft turns in the bushing is when the clutch is depressed at junctions and when changing gears. when you're driving (or when in neutral) the shaft and crank are of course spinning at the same speed so no wear then. so there's only a very small amount of time when wear can occur so i wouldn't worry too much about previous use. :thumbsup:
neil.
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Thanks Neil, breathing a little better now
 
Here's a question: say I choose to not align the BH, and I may not given the car will not be driven much at all before disassembly, is a softer pilot bushing more forgiving than a roller bearing set up? I'd think so.
 
Finally found some digital inside calipers that will reach the crank bore (Rockler in Phoenix), tired of on-line right now. Got the flywheel off, work was busy so that's it for progress today wahoodefreakindoo. Conversely 1G of Sta Lube GS4 85-90 was $10 cheaper than NAPA so went with that on Amazon. I'm officially schizophrenic. Cuda, work, lots of DIY at home= need a vacation
 
Im no machinist, if crank bore is .89 and bushing o.d. is .915 pound it in or hone the bore?
 
lemondana said:
The standard one is .940 and the smaller one is .915, I think. Napa-Balkamp discontinued theirs years ago. Someone on Ebay sells them I believe, or take the large one and have it machined down.
Click to expand...
The desoto bushing.

I use the needle bearing style that fits in the convertor register on my 4" crank. Last I remember it wasn't drilled to size.
 
Back in 1975 when I got my 68 340 GTS, I pulled the engine, rerung, and new bearings, HV oil pump, Hemi grind cam. I knew enough to put a new pilot bushing in it. Went to the local parts house that knew what they were selling, and got a new bushing. It would not fit, I took it back-they said that's the right one. That was back before everyone knew a machinist. What to do? Put a pair of heavy cotton gloves on, put the bushing on my index finger, and let it spin against the side of the grinder wheel. I checked several times till I got a nice tight fit. I figured the front shaft of the 4 speed was wore enough, so that it wouldn't have to be perfect. That bearing is still in the 340 to this day. So my original 68 340 had the smaller bore from the factory and the parts guy might have not looked down at the footnotes at the bottom of the page. So, I needed the .915 bushing, I was only 18, I didn't know there were
cudamark said:
All the 340 cranks I've seen were all machined for a bushing. Maybe the crank is out of something else? Rather than hone the hole and cut down a stock bushing, I think I'd just get the Magnum BEARING version. It fits into the converter button hole instead. This is assuming that you aren't working with a '67 and earlier 273 crank. In that case, you have no other choice but to make a bushing to fit.
Click to expand...
different bushings
 
Why are putting in a bushing when there is better technology available?The roller bearing that fits in the crank register works 100x better than the pilot bushing. Each and every time.
If you are not going to dial in the bellhousing correctly get used to worn parts in the transmission and eventually a worn thrust bearing. This reminds me of the the timing chain tensioner cancel culture on here
 
I8NEMO said:
Here's a question: say I choose to not align the BH, and I may not given the car will not be driven much at all before disassembly, is a softer pilot bushing more forgiving than a roller bearing set up? I'd think so.
Click to expand...
yes and bear in mind there's probably dozens of cars without a 'correctly' aligned bellhousing for every one that is and they don't all eat tranny's and bearings so i wouldn't worry.
neil.
 
I8NEMO said:
Im no machinist, if crank bore is .89 and bushing o.d. is .915 pound it in or hone the bore?
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I'm not either but I believe .025" is way too much to press fit. I think you need around .002"- .003".
 
SixPaksRule said:
Why are putting in a bushing when there is better technology available?The roller bearing that fits in the crank register works 100x better than the pilot bushing. Each and every time.
If you are not going to dial in the bellhousing correctly get used to worn parts in the transmission and eventually a worn thrust bearing. This reminds me of the the timing chain tensioner cancel culture

yes the bell will get aligned in the future when the motor is out, yes there will be a roller bearing in the future. Earlier in this thread I stated that I simply want to finish fit up and drive a few times before final disassembly for paint so rather than probably pull the motor, and add yet another list of steps backwards, I want to go forward to get past this momentary step. A pilot bearing will be more forgiving than a roller bearing for what I'm doing now. Could this be a bad call and will I have **** shifting for my 2 or 3 drives around the block? Of course. For the record, right next to this car is my 73 Land Cruiser I've owned since High School. I ditched the /6 for a performance 350/Muncie 37 years ago, did all the work myself, efi wiring, engine, bell housing and t- case mounts, tilt column, p/s and didn't know about Bell Housing alignment then either, I just bolted things together. I was like 19 years old then. The truck will sing up any sand dune at 6500 RPMs, has been in the Pacific Ocean up to its headlights as far south in Mexico as Puerto Lobos and the Muncie has been untouched all this time using the same pilot bushing. That being said, seems going roller bearing ( and I will) would be part of pilot bearing cancel culture.
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lemondana said:
Back in 1975 when I got my 68 340 GTS, I pulled the engine, rerung, and new bearings, HV oil pump, Hemi grind cam. I knew enough to put a new pilot bushing in it. Went to the local parts house that knew what they were selling, and got a new bushing. It would not fit, I took it back-they said that's the right one. That was back before everyone knew a machinist. What to do? Put a pair of heavy cotton gloves on, put the bushing on my index finger, and let it spin against the side of the grinder wheel. I checked several times till I got a nice tight fit. I figured the front shaft of the 4 speed was wore enough, so that it wouldn't have to be perfect. That bearing is still in the 340 to this day. So my original 68 340 had the smaller bore from the factory and the parts guy might have not looked down at the footnotes at the bottom of the page. So, I needed the .915 bushing, I was only 18, I didn't know there were

different bushings
Click to expand...
Hell of a story, love it! Reminds me of my 69 440 Road Runner as a Jr. In High School I went through a few clutches. Young and dumb, I muscled out the 4 spd by myself, had no knowledge of clutch disc alignment tools so just eye balling and brute force got it done.
 
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