in frame rebuilt c123, very hard to turn over...normal?

PretendFarmer

Well-known Member
Just got my c123 put back together. New rings on 3 honed cylinders. Replaced the piston, rings and sleeve on number 1. Its very difficult to turn over...why?
 
You don't say whether you installed new rod/main bearings. If you did, are they the correct size? Did you overtorque the rods that you had out? Just a couple of things to check. An easy way to check is to turn the engine over by hand after torquing the rod you just torqued before moving on to the next one.
 
well, a brand new rebuild will need to "wear in" a bit. You have also increased (probably) the compression with the new rings and valve job. new rebuilds are always "tight".

Now, you could have a bearing cleance issue. Did you install the pistons in the correct orientation? Are the main caps installed with the correct orientation? Did you use assembly lube or oil when you assembled?

There could be a number of things "wrong" or it could just be "new, tight".

I don't know your level of experience or background, so please don't be offended by my questions.
 
The pistons and rods are installed in the correct orientation. I am going to drop the pan, and take another look. The numbers on the rods, indication which cylinder they belong in, are facing the distributor side of the engine.
I reused the rod bearings. No new bearings.
 
Do you have good oil on the pistons you dont want them to be dry as some smoke after starting wont hurt a thing. Sounds like you did OK
 
Take the plugs out and turn it over by
hand to see what you've got. If it is not
binding you might have the timing
advanced a little to far.
 
you may have batt. problems, or cable problems.
just pull it and go from there.
if you used the same brgs then that eliminates tight brgs.
i believe its electrical, not mechanical.
 
ooh i see its got clutch problems too, so it could be anything from flywheel back to diff.
next step, get clutch loose or removed.
 
For sure if the trans is turning and it is less than 50 degrees where the tractor is located, it will be way hard to crank with the trans lube being stirred!. Pull it is OK if you don't try to start it till the clutch is loose. Block down the clutch then (ignition off) rock the tractor hard in road gear. If no joy, with the clutch blocked down) lock the brakes or block the wheels if the brakes won't hold, and use 12 volts on the starter to break free the clutch. Jim
 
You need a hand crank, very useful for setting the valve clearance. get it so it turns over smoothly with the crank and then tow it to start it. you will burn up the starter trying to start it.
 
I would pull the sparkplugs and pour some engine oil on top of the pistons. Then bump the engine over. If you're using a 6 volt battery you should have 00 battery cables no longer than necessary. Hal
 
Did you check ring end gap to make sure it is in spec?? If you did not you could well have rings with no gap and if so then yep you will not spin it over and could even break a ring trying to do so
 
pretend, C and SC were none to have bad grounds
Move the ground cable to someting cast under battery box. I have done this on all of mine with good heavy cables it should spin fine if it is not your engine build. oldiron29
 
What Dave Allgire said! You may want to pull pan and recheck all your rods and mains : loosen each 1 at a time and rotate the engine BY HAND after each 1.Pull your plugs and rotate by hand also. I saw a guy spin a rod bearing that jumped out of it's seat and pull started it ruining the crank! Mark
 
he said he used the same old brgs. just as long as they are not missmatched from original locations, and in good shape it will be fine.
 

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