Hi all !
Anyone know where I can get some information on the crank to cam and the crank to the deck ? my machinist will need them to line bore the mains . any help will be appreciated . thanks, Ken
3.9375" center to center crank to cam.
Thanks for the help guys ! anyone have the measurement from the crank center to the top of the block ?
The centerline of the crank needs to be even with the bottom edge of the block.
Thanks for all of the info ! Is there any other information I should give to my machine shop before I get him to line bore ? he doesn't have access to a T boring bar.
What size of bar and what kind of machine is it.
I don't know what type or name of his machine, but I will ask. he has been doing work for me for the past 30+ years . he has done a few old Buicks and flatheads but no model T's
The 100mm measurement is very important as it sets the lash between the crank and cam gears. It must be indexed off of the camshaft center line front and back.
Paul, Thanks for the info about the crank center being even with the bottom edge of the block. do you have a number for that measurement? don't want to sound nit picken, but I would like to give him any info I can. thanks, Ken
That depends on the diameter of your crankshaft. Standard journals would be about .624 above the block base. But if your crankshaft has been ground that figure changes. Just divide the diameter of the crankshaft by 2 and that would be close.
The important measurement is going to be crankshaft center to camshaft center so that your timing gears fit properly.
Thanks to all that supplied me with the information for my line bore job. very much appreciated. ken
I am not sure how to answer your question. All measurements must start from the center line of the cam shaft. As supplied from Ford a standard T crankshaft main bearing would measure 1.248. The cutter on the boring bar would therefore be set to cut the bearing ID to 1.250. (this would depend on how tight you want the clearance between the crank shaft OD and the bearing ID, I would shoot for .0015 and not .002) The machine shop needs to index off of the centerline of the camshaft and set the boring bar so that it cuts 0.625 above and below the plane established by the bottom of the block while maintaining the 100mm distance between the centers of the crank and cam shafts. If the crank has been ground .010 under sized (or 1.238) then the boring bar needs to cut 1.620 above and below the center line established by the bottom of the block and so on depending on the diameter of the crank main bearing size.
(Message edited by paulmikeska on November 22, 2014)
Several folks type faster than I do!
Thanks Paul! You have been a big help thanks, Ken
It is also very important that the 100mm center to center measurement is maintained front to back of the camshaft center line.
Paul, I printed a measurement work sheet for my machinist and add your last comment to it. thanks again to all that helped.
Print out this whole thread and give it to your machinist. He will understand all of it.
Good idea Paul! thanks
Who is pouring the babbit? The block is cast iron and the caps are cast steel. There are different methods for pouring them and the block bearings need to be peened after pouring or they will lift off of the cast iron. Even a experienced machine shop most likely does not know how to pull this off unless they have been do it for many, many years.
UGG. Late at night and I am tired. Do they know that they need to cut a radius on both ends of the bearings to match the crank mains? Do they know how to cut the thrust surfaces on the rear main bearings and the clearance needed? I would hate for you to invest a lot of money only to have to remove and send your engine to a shop that does this on a daily basis. I use several ISO rated machine shops for my day job that are outstanding but could not rebuild a T engine if I was holding a gun to their heads!
It will not do much good to have a fixed centering gauge if you want the crank to be zeroed in from side to side, and the up and down.
It also does little good to make sure the center line of the crank is zeroed when grinding, and then align bore it in to the block off zero.
There are just 3 things to set in setting a zero align bore job.
1. Side to side setting. That is the boring bar has to be dead center of the main bolt holes, no if's and's or butts, that goes double for Model A's,B's and V-8's, any block with a front and rear seal.
2. Up and down setting for time gear clearance.When the gear clearance has been found, you carry that measurement to the rear main so the crank is level. You don't need any kind of a measurement form the pan rail, or the crankshaft size, that is a useless figure for setting up a boring bar, as you are not using the crank to bore the main holes.
3. End clearance and centering the crank, end to end. There is no place from the block that can be measured to set the rear main except the center main to crankshaft.
The reason a fixed centered distance does not do a consistent zeroing job is the cranks, Blocks, and all the timing gears are way off consistency.
Thanks to all that have given me advice on the main bearing job. with so much that could possibly go wrong I don't want to build a time bomb so I'll put this aside for awhile until I can budget the cost and have it done from someone that has T experience. Ken
Mr. Kohnke - Observation,.......your excellent photography equals your excellent reputation as a machinist!
Aaaaaaaaa shucks Harold, twernt nuthen! But thank you.
I have gotten 3 e-Mails today asking about the Alignment Plugs and pins. I will answer here to save time on two finger typing.
First the plugs. The steel part of the plug is for the Model T with a 1 inch boring bar. "See pictures below" I first use a cold role shaft of the same size for a rough set up, for alignment, and then switch to my actual boring bar with a new crank gear, and a Cam with a New gear. When it is with in about .002 and the block is secured to the Align Bore.
The small part of the plug is a 1/2 inch long, and .500, Minus .001-50 thousandths for the bolt holes. The main part of the plug is 1.260, and could be up to Minus .001-50 depending on what bar is used and wear.
The two brass welds on the plug. The first one is for a Model A, and the second is for a Model B Ford. You have to do one at a time so you can turn them off in the lathe.
The cam Pins I use are from a junked out Hempy-Cooper. Of course, the front pin is bigger then the rear so I pressed a bushing on and cut it the same size an the front to get away from having to always two different Mic settings. I measure from outside bar to outside bar to get both ends the same.
Cold Role steel should be used here of 1.375 O.D., and the same for the rear pin Brass bushing. The pins are 7.140 thousandths long, and the rear is of 1.000 inch Dia.
As you can see, I use a new crank gear, and Cam gear of the same kind to set the clearance as they will all set up differently.