As I have mentioned in several other threads I have removed the engine from my 26 coupe to install a new low gear drum and align the transmission. I have read the transmission alignment article several times and understand the importance of everything being in alignment. I mounted my dial indicator to a piece of angle iron which I mounted to the back of the engine block to measure the run-out of the mounting surface of the crank shaft flange. The Ford manual and the article say that there should be no more than .001 run-out but, this flange has .005! I checked it three times and got the exact same measurement each time. So, I plan on taking the crankshaft to a machine shop and have them face off enough of the mounting surface to bring the flange back into tolerance. Replacement of the crankshaft is really not an option. I have spoken to Mike Bender a few times about this issue on the phone but, I would really appreciate any further advice to make sure the work is done correctly.
Normally a regrinder will also face off the crank flange. You should also check run out on the tail shaft. I found one that had 0.026 !
Is this what you read? ws
Jack, the transmission shaft and the alignment of the brake drum shaft and the tail shaft will also be addressed.
Trooper, no, that is not the article. I will post it tomorrow.
The crank shaft flange is one area over looked when doing a crank. The thrust surface should be cleaned up as it is usually worn. It needs to be as smooth as the journal on the crank or it will act like file and grind down the thrust face on the cap in short order.
Before you go taking things apart, you should try the shaft and flywheel out--there are numerous combinations of locations, and you may find that the shaft flange and the flywheel surfaces also aren't parallel, but when "dialed in" (changing locations) the total run-out is in spec. The last engine I did, it took 12 tries moving the shaft around and the flywheel around before the assembly was within specs.
True enough David, but .005" flange run out is really excessive. Best to start with something closer to true.
Its not particularly hard to true it up. The more common problem is when the OD of the flange has run out. That happens because the third main does not wear concentric to the flange OD and most grinders center off the third main when grinding. Result is the new centerline of the reground crank is no longer true with the flange center or OD. Most I see have between 2 and 5 thou run out.
You could try to take a stone and dress the flange. This might be an economical alternative to removing the crank and having the flange ground.
The problem is excessive run-out on the mounting surface of the flange.
Maybe it would be best to first have the crankshaft checked to make sure it is not bent. Then if the crankshaft is straight have the flange trued.
Even before that, have it Magnafluxed for cracks,