I'm stymied. I bought a block with the crank already installed but was unable to turn the crank by hand thinking it had just sat too long and needed some freeing up. I took the caps loose and it was still hard to turn. I measured 40 ft lbs to turn it with the rear cap tightened. The rear journal had the upper thrust bearing installed in it which I thought was the wrong place for it so I've used a caliper to (fake) Mic. it and it is really close to being .010 under. Standard crank is supposed to be 2.2486. It is really close to 2.238 according to the digital caliper. The bearings are .010 under and the thrust bearing is way too wide to fit in the third journal. Any thoughts please.
46FordJohn
302 crankshaft install problem
I'm stymied. I bought a block with the crank already installed but was unable to turn the crank by hand thinking it had just sat too long and needed some freeing up. I took the caps loose and it was still hard to turn. I measured 40 ft lbs to turn it with the rear cap tightened. The rear journal had the upper thrust bearing installed in it which I thought was the wrong place for it so I've used a caliper to (fake) Mic. it and it is really close to being .010 under. Standard crank is supposed to be 2.2486. It is really close to 2.238 according to the digital caliper. The bearings are .010 under and the thrust bearing is way too wide to fit in the third journal. Any thoughts please.
Attachments
Don't confuse "Chebby" with "GM". My GM Oldsmobile motors have the thrust bearing in the No. 3 location. 
Ford SBF blocks have undersize bearings available for cranks with loose side standard dimemsion journals at .001 inch and for reground cranks in .010, .020, .030, .040 inch. The meaning of undersize is that the crank journals are ground or reground to a size smaller than standard production generally this is done to salvage an otherwise good crank that has minor damage done to one or more journals. The bearings are made thicker to chase the now smaller journal while maintaining the specified clearance. This type repair can be on a factory new engine or a field repair to a worn engine. It can be from one of to all of the journals, so all must be inspected for true size against the published standard.
If someone uses an undersize bearing on a standard size journal, it will grab the journal and with the possible exception of the .001 lock the crank from rotation.
If in fact someone assembled this engine with the thrust bearing forced into the number 5 main, the bearing and possibly the crank or even the block have sustained damage.
Undersize bearings are usually stamped on their back sides as std for nominal production size or with the undersize amount .010 as an example. This is not always visable so measurement is necessary to verify what you are looking at is of what dimension. Packaging stating the dimension cannot simply be trusted, mistakes happen for lots of reasons, so checking each and every piece is necessary. Measurement is done by installing the set into the block, pulling the cap bolts to torque then measuring the bearing's bore diameters. At this point it is a good idea to identify what station the bearing is mounted and maintain that position for final assembly. Dimension is taken in the vertical direction for bearings. The main bearing bore is actually not round, but slightly wider where cap meets block. Caps were originally located by position and direction to forward, they should not be exchanged nor reversed. These dimension and position remarks also apply to rods and their caps. These bearing "bores" are not bored round like a cylinder bore; they a shaped with a broaching tool which basically is a finished dimension and shaped file like tool that is rammed through the part to shape and finish the hole.
Measuring the journal diameters and in the case of the thrust also the width across faces will when subtracted from the bearing's as installed dimensions will give the clearance dimension.
Bogie
If someone uses an undersize bearing on a standard size journal, it will grab the journal and with the possible exception of the .001 lock the crank from rotation.
If in fact someone assembled this engine with the thrust bearing forced into the number 5 main, the bearing and possibly the crank or even the block have sustained damage.
Undersize bearings are usually stamped on their back sides as std for nominal production size or with the undersize amount .010 as an example. This is not always visable so measurement is necessary to verify what you are looking at is of what dimension. Packaging stating the dimension cannot simply be trusted, mistakes happen for lots of reasons, so checking each and every piece is necessary. Measurement is done by installing the set into the block, pulling the cap bolts to torque then measuring the bearing's bore diameters. At this point it is a good idea to identify what station the bearing is mounted and maintain that position for final assembly. Dimension is taken in the vertical direction for bearings. The main bearing bore is actually not round, but slightly wider where cap meets block. Caps were originally located by position and direction to forward, they should not be exchanged nor reversed. These dimension and position remarks also apply to rods and their caps. These bearing "bores" are not bored round like a cylinder bore; they a shaped with a broaching tool which basically is a finished dimension and shaped file like tool that is rammed through the part to shape and finish the hole.
Measuring the journal diameters and in the case of the thrust also the width across faces will when subtracted from the bearing's as installed dimensions will give the clearance dimension.
Bogie
Good information!
Did the spec numbers and my measurement values make sense to you?
When I first got the engine the bearings were installed with the thrust on #5. However, it was just the crank in the block and the rest was not assembled. I did turn the crank but it took 40 ft lbs of torque to do that so I knew that was definitely wrong. Now I need to find a thrust bearing that will fit and allow the crank to spin because the bearing doesn't allow the counterweights on the crank to rotate. It is too wide. The one that was installed in the #5 position is too wide to fit on #3 where it ought to be. I'll be seeing the Ford parts place soon. I hope they'll know what I'm talking about.
Thanks again, --John--
Did the spec numbers and my measurement values make sense to you?
When I first got the engine the bearings were installed with the thrust on #5. However, it was just the crank in the block and the rest was not assembled. I did turn the crank but it took 40 ft lbs of torque to do that so I knew that was definitely wrong. Now I need to find a thrust bearing that will fit and allow the crank to spin because the bearing doesn't allow the counterweights on the crank to rotate. It is too wide. The one that was installed in the #5 position is too wide to fit on #3 where it ought to be. I'll be seeing the Ford parts place soon. I hope they'll know what I'm talking about.
Thanks again, --John--
From Bogie:
"If in fact someone assembled this engine with the thrust bearing forced into the number 5 main, the bearing and possibly the crank or even the block have sustained damage."
I believe this to be the case and I'm going to install another thrust bearing from NAPA this evening. I'll let you know the outcome.
John
"If in fact someone assembled this engine with the thrust bearing forced into the number 5 main, the bearing and possibly the crank or even the block have sustained damage."
I believe this to be the case and I'm going to install another thrust bearing from NAPA this evening. I'll let you know the outcome.
John
I don't know how anyone could even do this, but I've seen some pretty crazy stuff done so, OK, where there's a will there's a way.
If the crank assembly is complete with rods and pistons with rings, I could see 40 ft pounds on a new build needed to overcome first time stiction to get the assembly to rotate. For a bare crank riding on its bearings in torqued caps that much force to get rotation would indicate something seriously wrong. That could be from wrong size bearings for the journal diameter to a badly warped crank or block.
If assembled and very hard to rotate or perhaps not at all you can add things like ungapped or improperly gapped rings, wrong size ring for the bore diameter--- I mean you name it and it's been done by someone.
Bogie
If the crank assembly is complete with rods and pistons with rings, I could see 40 ft pounds on a new build needed to overcome first time stiction to get the assembly to rotate. For a bare crank riding on its bearings in torqued caps that much force to get rotation would indicate something seriously wrong. That could be from wrong size bearings for the journal diameter to a badly warped crank or block.
If assembled and very hard to rotate or perhaps not at all you can add things like ungapped or improperly gapped rings, wrong size ring for the bore diameter--- I mean you name it and it's been done by someone.
Bogie
I'll bet there are any number of ways to goof up a rebuild. I may run into a few more as I reconstruct this engine. I did get the bearings yesterday but I didn't get the crank installed last night. I just ran out of energy. Will try today and keep you informed. I really want to solve this thing!!!!
Bogie,
For Bogie and all the other folks who have tried their best to help me with this issue, it is solved! A trip to NAPA so they could order the part and have it delivered from Louisville and having to buy the whole bearing kit to get the thrust bearing did the trick. It is installed and the crank turns freely by hand when all the caps are torqued to specs. Now its on to the next issue.
The problem was that the thrust bearing which is supposed to go in the #3 journal on a smallblock Ford was originally put in the #5 position and torqued down. It required 40 ft lb of torque to turn the crank.
That deformed it enough so that when I put it where it was supposed to be then the sides of the thrust bearing interfered with the counterweights and wouldn't allow me to even put the crankshaft down into place. I put the new thrust bearing in and I'm a "happy camper."
Fm is short for Federal Mogul and 2603 and 2604 seem to be interchangeable bearings and are .010 under. The NAPA part has F/m 2604 engraved on the back of the bearing. Where the 2603 bearings came from I don't know but they were purchased many years ago when the machining on the block was originally done.
"Ya, know I could be a smart as a butt and say use a Ford part, but at this point you know what your up against."
I did try Ford but they only have parts listings back to 80 so of course they couldn't just look up Ford 302 and see what might fit, they have to have a make and model of the auto you want parts for. That is a major frustration for me. Why aren't there any real experience people in the auto parts departments?
For Bogie and all the other folks who have tried their best to help me with this issue, it is solved! A trip to NAPA so they could order the part and have it delivered from Louisville and having to buy the whole bearing kit to get the thrust bearing did the trick. It is installed and the crank turns freely by hand when all the caps are torqued to specs. Now its on to the next issue.
The problem was that the thrust bearing which is supposed to go in the #3 journal on a smallblock Ford was originally put in the #5 position and torqued down. It required 40 ft lb of torque to turn the crank.
That deformed it enough so that when I put it where it was supposed to be then the sides of the thrust bearing interfered with the counterweights and wouldn't allow me to even put the crankshaft down into place. I put the new thrust bearing in and I'm a "happy camper."
Fm is short for Federal Mogul and 2603 and 2604 seem to be interchangeable bearings and are .010 under. The NAPA part has F/m 2604 engraved on the back of the bearing. Where the 2603 bearings came from I don't know but they were purchased many years ago when the machining on the block was originally done.
"Ya, know I could be a smart as a butt and say use a Ford part, but at this point you know what your up against."
I did try Ford but they only have parts listings back to 80 so of course they couldn't just look up Ford 302 and see what might fit, they have to have a make and model of the auto you want parts for. That is a major frustration for me. Why aren't there any real experience people in the auto parts departments?
X2 with Ericnova74's comments.
You absolutely have to measure every bearing and journal including the width across the thrust surfaces of the bearing and the crank. Hopefully if the crank was turned it was to a common dimension on all journals and to the thrust faces. This doesn't always happen which can push you into buying multiple bearing sets to get the sizes needed or spending the money to have the crank tuned to uniform sizes on all bearing surfaces, or replacing the crank.
The thrust is worry-some from the standpoint that this is difficult to do properly so it sometimes isn't done or is done poorly. So you need to check the dimension and do a visual for surface quality which should be polish smooth without hills and valleys and the surfaces at right angle to the crank centerline, and the facing surfaces parallel to each other.
Bogie
You absolutely have to measure every bearing and journal including the width across the thrust surfaces of the bearing and the crank. Hopefully if the crank was turned it was to a common dimension on all journals and to the thrust faces. This doesn't always happen which can push you into buying multiple bearing sets to get the sizes needed or spending the money to have the crank tuned to uniform sizes on all bearing surfaces, or replacing the crank.
The thrust is worry-some from the standpoint that this is difficult to do properly so it sometimes isn't done or is done poorly. So you need to check the dimension and do a visual for surface quality which should be polish smooth without hills and valleys and the surfaces at right angle to the crank centerline, and the facing surfaces parallel to each other.
Bogie
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