Main bearing question

[raystractors]

I started to build a spare block that I had bought a few years ago, and when I was cleaning the main bearing retainers I used compressed air to blow through the oil holes to make sure there was nothing to ruin my work. My question is, does the oil flow into the rear bearing from the block, or does it travel through the crankshaft from the front? The reason that I ask is while blowing out the oil holes in the rear bearing there was no flow of air through to anywhere, and looking into the hole it appears to be solid flat bottomed with no opening for oil to flow. The other two have an exit to the cam bearing at least. Just want to be sure before I button everything up. One more question; has anyone tried to rethread a crankshaft? I have one that has the threads striped. I think that it could be threaded but the size of the hole in the pulley would limit the size. Thanks for any information.

[John *.?-!.* cub owner]

According to the Blue Ribbon lubrication manual for cubs each main gets it's oil supply directly from the oil gallery above it, not from another main. Go here and click on the GSS-1013 Engine lubrication manual to see the diagram.
http://www.farmallcub.com/[ Sorry, direct links to manual section is not allowed. ]/index.p ... ls&order=0

[Rick Spivey]

My shop messed up the threads in a crankshaft, and ended up drilling out, threading, then putting an insert in (homemade). In other words, they put in a threaded rod, then drilled and threaded it back to original. Hope that makes sense, it is an older machine shop way of repairing a threaded hole back to standard size.

[raystractors]

Thanks John, and Rick
John, that was what I was looking for. Is it possible that this block was not machined correctly, and may be the reason that the block was not used again. I bought this block from a small machine shop along with some other parts.
Rick that is what I was thinking of doing. A helicoil would be short for the threads of the crankshaft, and I am not sure that it would be enough to pull the pulley back on the shaft.
Thanks for your replies.

[John *.?-!.* cub owner]

I have never had any reason to look into that part of the lube system, so cannot give much advice there, nor do I have a block handy to look at. Use the hole at the front of the inside of the oil filter to blow air in with a rubber tipped nozzle or similar and see if you get air out the hole at the top of the bearing. It may not be much air, because with the crank out there is a lot of places for air to leak out. You do have the top half of the bearing out don't you? If not the hole may not be lined up properly.

Regarding the threads in the end of the crankshaft, you can stack Helicoils, simply thread the hole full length and screw one in then screw second one till it stops against the first one then break the tang off and retrieve either using air or a small pick up magnet. The threads on them will line up due to the fact they are screwed in following the threads that were cut in the installation. As to the threads being strong enough to pull a pulley on, Helicoil claims a repaired thread is stronger than the original, though I have never tired to test that.

[Jim Becker]

For installing the pulley, if you heat the pulley in a toaster oven, make sure it is completely heat soaked at about 250 degrees, it should go on fairly easily. Be sure to work quickly after you start to install it.

[raystractors]

Thanks for the info. It will be this weekend before I will be able to take another shot at this engine block, but using an air gun with a rubber tip is how I found that there was no flow to the rear bearing. I had the block upside down and with a flashlight looking into the hole there is no open passage from the bearing. The hole is about 3/4" deep and has a flat bottom, not like a drill bit would leave. I may be able to take a pic of it, but that is a very small opening.

[Clark Thompson]

as far as the main bearings, the main bearings get oil directly from the oil pump. then throught the main journels the oil is fed to the rod bearings. as to installing the crank pulley. I always clean the crank surface with emery cloth as well as the pulley bore. Heat the pulley to around 300 t0 400 degs. I use a torch. lube the crank and pulley bore. The pulley should start onto the crank about 1/4 inch by hand. Then I us a wooden block with a small sledge to coax it the reast of the way. and done forget to grease the seal surface.

[raystractors]

The good, and the bad. I tried to take some pics of the main bearing oil passage, but I couldn't get the light and the phone to a position where you could see the bottom of the passage. After I had scratched my head for a while I decided to try to open up the passage, so I first used a steel rod that was just smaller than the diameter of the passage, no luck. Then I picked up a drill index and started using a bit that was smaller than the rod, and turning it by hand I started to make some progress. I then went to a smaller size bit and the good news is that I have an open passage to the oil gallery. The bad news is that I have what ever was in the passage now in the oil gallery. I guess that a trip to a shop to get it cleaned out will be next. The best part of this problem is that I found it before I had the engine back together. I think that it would have had a short life if there was no oil flow to the rear bearing and rod. Thanks for all your help!!

[bob in CT]

Good job! That would have been a disaster.

[raystractors]

I got the engine cleaned out so now I feel better about the rebuild. A few other problem have popped up along the way, but making some progress. The crankshaft threads were striped out about 1/2" down inside the shaft, so my fix was to drill down to the good threads and tap. I now have 9 full threads that start about 1/2" below the front edge. Any thoughts about this, will this be enough to pull the crank pulley on? I would use a threaded rod to pull the pulley on. Another thing that happened was I lost 2 of the wrist pin retainers, so I called the local parts supply, and lucky me they had only 2. I got home and started to put the pistons together, first one went good, second one went flying across the shop into some shelves where we store everything from Christmas lights to cans of paint. Live and learn I guess. I did find it after half and hour or so. Another question is why they didn't use a snap ring for the retainer, that would be so much easier? Again THANKS for all your help.

[bob in CT]

I got the engine cleaned out so now I feel better about the rebuild. A few other problem have popped up along the way, but making some progress. The crankshaft threads were striped out about 1/2" down inside the shaft, so my fix was to drill down to the good threads and tap. I now have 9 full threads that start about 1/2" below the front edge. Any thoughts about this, will this be enough to pull the crank pulley on? I would use a threaded rod to pull the pulley on. Another thing that happened was I lost 2 of the wrist pin retainers, so I called the local parts supply, and lucky me they had only 2. I got home and started to put the pistons together, first one went good, second one went flying across the shop into some shelves where we store everything from Christmas lights to cans of paint. Live and learn I guess. I did find it after half and hour or so. Another question is why they didn't use a snap ring for the retainer, that would be so much easier? Again THANKS for all your help.

I just found a retaining clip for an internally-retained u-joint that was AWOL for a month.

[challenger]

With regard to the wrist pin retaining clip, I read something awhile back on this forum about the proper positioning of the retainer clip that made sense to me. The open end of the clip should be either facing up or down when installed in the piston. As I understand it, the reciprocating movement of the piston and the inertia working on the clip can slightly flex the clip together if the open end is positioned on the horizontal.

[pickerandsinger]

I rebuilt one of mine and found it had a helo-coil in the end of the crank, which reduced it to 7/16th with no issues…….I also have a toaster oven as Jim suggested….Dave