Crankshaft Issue
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Senior User
Joined: Jan 2005
Posts: 123
Likes: 1
From: Mine Hill NJ
Crankshaft Issue
I've got a 360 FE that I’m stroking out with a 390 crank, pistons, and 428 rods. I got the crank by swapping my old 360 crank with my machinist's shelf stock.
All the resizing and machining is done so here’s my problem.
While assembling the crank, rods, and pistons I found the front bolt on the crank was the incorrect length because when I tried to back it out it damaged the internal threads. There was galling on the bolt and when I chased the internals there was some damage there too.
I dare not run the new correct bolt into the hole as I'm sure it would be screwed up too. Basically I don't trust torking on them to turn the engine by hand.
The thread size is 5/8 x 18.
The wrong bolt was 2 inches the correct bolt is 1 3/4 long. The factory pilot hole in the crank is 2 1/2 inches deep. Where as the threads only go the 1 3/4 inches.
So is my crank shot?
If not what size threads can I re-cut to safely and have strong new threads?
Or
Do I need to just take it back to the machinist?
Thanks
John
All the resizing and machining is done so here’s my problem.
While assembling the crank, rods, and pistons I found the front bolt on the crank was the incorrect length because when I tried to back it out it damaged the internal threads. There was galling on the bolt and when I chased the internals there was some damage there too.
I dare not run the new correct bolt into the hole as I'm sure it would be screwed up too. Basically I don't trust torking on them to turn the engine by hand.
The thread size is 5/8 x 18.
The wrong bolt was 2 inches the correct bolt is 1 3/4 long. The factory pilot hole in the crank is 2 1/2 inches deep. Where as the threads only go the 1 3/4 inches.
So is my crank shot?
If not what size threads can I re-cut to safely and have strong new threads?
Or
Do I need to just take it back to the machinist?
Thanks
John
Last edited by johnnydmetal; Nov 25, 2008 at 06:11 PM. Reason: unwanted Smileys
FE "Freakin Expensive"
Joined: Dec 2003
Posts: 6,461
Likes: 4
From: Smith Mountain Lake, VA
Well it wouldnt have mattered if the wrong bolt was longer....it wouldnt have damaged the threads in the crank..It would have just bottomed out in the hole.. Unless you over Torqued it? seems to me you cross threaded it? I would take it back to my Machinist and with any accesories you have that hang on the end of the crank...Because that hole has to be true to the crank or it will be dangerous and cause major Vibration..
He
'll have to open the hole up to the next size... Rather it be SAE or a Metric size as to not take out to much material..and open up any holes in your Damper and Pulley (Pulleys) depending.. JMO..
~Russ
He
'll have to open the hole up to the next size... Rather it be SAE or a Metric size as to not take out to much material..and open up any holes in your Damper and Pulley (Pulleys) depending.. JMO..
~Russ
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
While assembling the crank, rods, and pistons I found the front bolt on the crank was the incorrect length because when I tried to back it out it damaged the internal threads. There was galling on the bolt and when I chased the internals there was some damage there too.
I dare not run the new correct bolt into the hole as I'm sure it would be screwed up too. Basically I don't trust torking on them to turn the engine by hand.
The thread size is 5/8 x 18. The wrong (
) bolt was 2 inches the correct bolt is 1 3/4 long. ( ) The factory pilot hole in the crank is 2 1/2 inches deep. Where as the threads only go the 1 3/4 inches.
Thanks
John
I dare not run the new correct bolt into the hole as I'm sure it would be screwed up too. Basically I don't trust torking on them to turn the engine by hand.
The thread size is 5/8 x 18. The wrong (
) bolt was 2 inches the correct bolt is 1 3/4 long. ( ) The factory pilot hole in the crank is 2 1/2 inches deep. Where as the threads only go the 1 3/4 inches.Thanks
John
National Fine Thread / 5/8" -18 x 2" / Thread length: 1 1/2"
Fits: 1968/76 F100/350 360/390 / 1965/71 Passenger Cars w/390/410/427/428's.
------------------------------------------------------------------------------
355721S .. Bolt, Damper to Crankshaft
National Fine Thread / 5/8" -18 x 1 1/2" / Thread length: 1"
Fits: 1965/67 F100/350 352 / 1965/67 352 Galaxie/LTD
Better make sure you have the correct crankshaft.
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