Hi All Why don't new pilot bushing fit my 455 crank? I have purchase three so far and they don't fit. I guess I need to reduce the diameter of the pilot bushing to make it fit. George
Consider freezing the pilot bearing first. Then consider if you can hone the opening in the crank. Some pilot bearings will be very hard. Another option is to look for a pilot bearing with a smaller O.D. ---------- Post added at 01:27 PM ---------- Previous post was at 12:36 PM ---------- Try using the GM #10125896 bushing shown here: http://www.hotrodders.com/forum/gm-pilot-bushing-roller-bearing-i-d-s-180286.html I would try a slight hone of the existing crank hole as needed. Remember the lube the is needed after install.
This is a common issue. The pilots are being machined to the wrong tolerances. Most people find this out when the pilot has been installed, the internal diameter closes up and prevents the trans snout from going in. You need to have either the crank hole opened up, or the pilot machined down. Either way, it needs to be done at a machine shop, as the pilot and crank need to remain concentric within a few thousands. If you try to fix this by hand, they will be off and introduce wobble. Also, once the pilot is in, check crank snout fit with the trans or a spare trans input shaft before putting it in the car as the hole may close down to an unacceptable diameter.
Very common issue. Autogear now makes a 100% bronze pilot bushing which is a lot better than the Dorman or chinesium ones from the parts stores. I've had the pilot bushing machined in the past, on a lathe, but the crank needs to be close by or mic'd. I just changed a bad pilot bushing last week to a new Autogear piece. What I did, was use a Dremel with the sanding drum: http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=407 And very steadily open up the ID of the pilot bushing. I had a spare input shaft on hand to confirm the tolerances were tight and not egged out. Just be careful not to tighten the set screw on the sanding drum too much or it will open up to .600+ which is too much. I did screw up on the first bushing and had to drive home a new one and start all over. The bronze is soft enough that the 240 grit paper leaves a nice smooth (to the eye) finish.
I had the same issue when going from an auto to 5 speed. I believe not all cranks were drilled for pilot bushings. dick millar racing makes a bushing that actually fits in the torque converter recess of the crank for about 40 bucks. Pete.
Exceprt from http://www.v8buick.com/showthread.p...tic-to-Manual-Transmission-68-72-BUICK-A-Body 32) Remove any oil and grime from the pilot bushing opening in the crank shaft using a little bit of brake cleaner on a rag. Using a micrometer, measure the O.D. of the pilot bushing opening in the back of the crank shaft. Compare that measurement to the measurement recorded earlier of the new pilot bushing O.D. Both measurements should be very close to each other with the pilot bushing being ever so slightly larger (.0005+/-) .Also measure to assure the opening is concentric (centered) on the crank shaft. 33) Using a deep socket that measures slightly smaller than the measured O.D., make one wrap around it with a small piece of 80 grit sandpaper to create a snug fit into the crank opening and twist the socket around to clean up the opening to bare metal. Sometimes this process is needed to enlarge the O.D. very slightly in the crank to accommodate the new bushing. To do so, simply continue to build up layers of 80 grit sandpaper and utilize an air or electric driven until the opening is ready to accept the new pilot bushing. DO NOT oversize the opening. 34) Remove the new pilot bushing from the freezer. If the bushing did not have enough time in the freezer, use the canned compressed air for cleaning computers and blast the bushing until it is frozen white in color. Watch the fingers! 35) Measure the O.D. comparing to previous measurement of the bushing prior freezing and the O.D. of the crank shaft opening. If all measurements agree and it appears the bushing should fit the crank shaft, it is ready to install. If not, take the necessary measures. 36) With the bushing diameter confirmed, proceed to install into the crank shaft opening. Place the bushing squarely into the crankshaft opening. It should just grab the opening. Using a drive impact socket that is the same diameter as the bushing, gently hammer the bushing into position. The bushing should be seated flush to the transmission side face of the crankshaft opening. Avoid installing the bushing too deep and avoid excessive hammering on the crank shaft.
Well I got the old pilot bushing out without a problem. I had to grind the OD of the pilot bushing until it will fit in the crank. I got the bushing in without any problem and test fit the trans into the bushing and all went well. Going to put my engine and trans back into my GS this weekend.
Sounds positive. Out of curiousity, are you using an oil-lite bronze bushing? Did you mic the OD prior "grinding" and after and did you have the capabilty to measure the OD of the crank opening?
It is just a matter of preference for me. I opt for oil-lite, self lubricating, solid bronze, MADE IN USA bushings as I dont like adding any more moving parts down there than what is needed; but they work. I also suggest only experienced mechanics with a solid working knowledge of manual transmission jobs fuss with the roller bearing style.
Scott Yes it was a snug fit, 3 or 4 wacks with the hammer and it went in. I would not use a pilot bushing bearing. I read to many issues with using a bearing. I went to many auto part store and most has the pilot bushing with steel in them, AKA made in china. I finally found a pure bronze oil impregnated pilot bushing, made by National PB-656-HD. The National brand is the only one that is the correct pilot bushing for our cars. There are other brand with the same part number and it was a bearing! George
im trying to install a pilot bearing the hole in the crank has a lip in it about halfway in the hole, it looks like i will have to get a micrometer down there and measure it, then have the back end of the bearing machined to match. the front of the hole is proper dimension. what do you think?
Yes that is what my pilot bushing area looked like in the crank! Mine was a 73 automatic crank. If the crank is out of the car have it machined correctly so they can press fit the pilot bushing. If you dont file fit your pilot bushing then the ID of the pilot bushing will decrease and the nipple of your transmission will not fit, please dont ask me how I know! If your force your transmission into the pilot bushing then you will not be able to shift the transmission, again please dont ask me how I know! George
You have to maintain the centerline of the OD to with a few thousands (or ten-thousands) of the centerline of the ID. This is what concentric means. This can not be done by "grinding" on the outside. The only way it can be done is on a lathe. The pilot being concentric keeps the center of the transmission input shaft aligned with the center of the crankshaft. If they are not concentric, it can lead to vibration, clutch shudder, etc. Hopefully yours will not be out of concentricity much and you will be ok
The dick miller unit is the way to go. i used it and couldn't have been happier with fit and function. grinding on the outside of a bronze bushing to make it fit can only lead to redoing it correctly later on when you find there is a vibration or you wear out your input bearing. it sounds like you have a crank that wasn't drilled for a manual transmission from factory
Just ordered the Dick Miller bushing also. Kelly, let me know how you made out with it. I had to dial the bellhousing cause I kept going thru bushing. I found the factory bellhousing to be out by .011 to .012 thousands off. I ordered my offset dowels. Thanks, Gary
