I was reading a very detailed post (think it was Jason's & others were pitching in) on pilot bearings. Here is a picture of the back of my 70 455 short block (PLEASE help me with some 70 455 heads that still have some miles in them if near NC) anyhow here is a picture of the back of the crank. It's not here so I have no measurements but "in general" will this work with the 4 speed pilot bearing typically or do I modify the bearing only? Hope I don't have to pull the crankshaft
Ywh but if if there is ANY chance of it being an issue it will be on MY car lol so I am putting it in the win catagory!
I did a 430 4 spd swap in a suncoupe and although the crank was drilled for a bearing it wasn't finished to the standard pilot bearing . I had to have a machine shop turn down a pilot bushing several thousands to get a proper fit. That was much easier than disassembling the engine to mill the crank!
That was my experience this past summer as well. Hole in the crank was 100 thousands too small. Standard pilot bearing is 1.097. IIRC, the hole in my crank was about 1.085. Did the same thing as you. Although the cranks are all drilled, not all of them are finish machined. Makes sense. Why would Buick waste the machining costs if the engine was getting bolted to an automatic? A lot of 350's weren't even drilled for a ball stud
I would have that pilot hole checked first with inside calipers, or micrometers. It looks an awful alot like a crank I had that was semi-finished for a bushing: it had a step about mid-depth that was about 30 thou samller than what is required. Not all bad tho as you can have a bushing custom machined to fit if so.
So using the old input shaft to beat it in, was wrong on the 73 motor Lesabre auto and the 70 Electra auto I thought it had to fit and it seemed to work. Late 80's
I agree. It's been years and then some but had a 455 crank that looked like that step and had to have a pilot bushing machined to fit. It really was no big deal at all.
There is no separate part number for a manual transmission crankshaft. How was the extra machining for the pilot bushing accounted for, performed by and parts stocked?
That's an extremely good question! Don't think they had a different bushing made. Which brings the question back to the crankshaft. How did Buick line workers know what crankshaft goes to manual cars? Paint swabs?
I think your correct Guy, some type of internal id system for cranks that were to go in manual trans cars. I have seen hundreds of BBB cranks over the years, and can count on one hand the ones that were correctly sized for the pilot bushing. Typical size we see is 1.075 to 1.085. Every one was drilled, occasionally I would see one that had a step in it. Every crank we do here now, we modify a simple, inexpensive bronze pilot bushing to match the crank. Customer might have $20 in the bushing and machining, but that's well worth it should they, or a subsequent owner want to run a manual trans. I don't have any idea of the actual workings of the Buick Engine line, but I would imagine that they either ran another op on a specific number of cranks and set them aside for manual trans builds/the parts department, or their was a "job shop" that did the final sizing off line.. I suspect that all the manual trans cars that Buick built in a given year, would be less than 1% of the total built.. probably way less, so they would not spend the money to develop and stock another part number. The interesting question becomes what did the dealer do in warrantee situation, if they had to put a shortblock in s stick car? The answer may be that all cranks, destined for the parts department, had correctly sized pilot bearing holes. I happen to have one of the factory replacement shortblocks in the shop right now, I will measure the pilot bearing hole and report back. JW
Hi, Just a fyi, Oldsmobile engines were selectively drlled for pilot bushings, that is where that myth is true, too many people group Buick, Olds, Pontiac together as there not a Chevy Regards,
I have a story to add here about the 67 GS400 4 speed my mom and dad bought new, warranty issues with a blown up engine, pilot bushing issues,etc. Will have to write later, at work right now.
I'm running into the same issue with my engine. It's a '68 350 that came with an ST300 and I'm planning on putting it in my '65 Skylark, along with a '77 Super T-10 from a Trans Am. My block is already tapped for the Z-bar ball stud, which is a win. I've been told to get a pilot BEARING as opposed to a pilot BUSHING. I see pilot bushings only listed for 1968, but if I look at 1973, there are pilot bearings listed as well with an OD of 1.1, which apparently would need to be turned down a bit to fit the back of my crank. The part number I see is SKF B657. Can anybody tell me if this would work or could be made to work with my stock '68 350 crankshaft? Thanks!
