Main cap stud threads stripped

[Scott1ky]

I started reassembly of my engine today, installed camshaft, crankshaft, oil pump and timing cover. I used plastigage to check main bearing clearances, and plan to do the same on rod bearings. Once I measured and cleaned off the plastigage I began to reassemble. All the main clearances were within FO-4 tolerances.

I torqued all the main cap nuts to 95 foot pounds, but had a problem when I got to the last (front) bearing cap/ oil pump housing. On one stud, the threads stripped. Does anyone have any good suggestions for getting the stripped stud out of the block? I'm sure I'll have to pull the front cap /oil pump housing off, but hope I don't have to pull the other two main caps off or re-torqe them. If I could find something that was small enough and strong enough to put in the safety wire hole at the end of the stud, maybe it would turn/loosen and I could replace it. Any ideas?


Also the crank is really tight to turn, is this normal? I put some oil on the rope seals and it seemed a little easier, I just hope it doesn't get too tight to turn once pistons are installed.

Thanks,
Scott

 

[Bob]

Got access to a welder or can you take the block to someone who does?

It would be a simple matter to tack the stripped nut to the stud, then use a wrench to unscrew the stud.

Use some damp cloths to cover things up to keep welding spatter and slag out of internal parts.

I like to install the crankshaft WITHOUT the rope seals to verify clearances and be sure it rotates freely, and only then install the rope seals.

 

[TheOldHokie]

(quoted from post at 01:18:26 06/19/09) Got access to a welder or can you take the block to someone who does?

It would be a simple matter to tack the stripped nut to the stud, then use a wrench to unscrew the stud.

Use some damp cloths to cover things up to keep welding spatter and slag out of internal parts.

I like to install the crankshaft WITHOUT the rope seals to verify clearances and be sure it rotates freely, and only then install the rope seals.

I'd be concerned about ARC welding with the crankshaft and bearings in place. Large current flows arcing across the bearing clearances may be problematic. For example folks have been known to damage the spindle bearings in a lathe welding chucked up shafts. I can't think that at this stage removing the crankshaft is any big deal at which point a pair of vise grips should do the job.

TOH

 

[Scott1ky]

Ok pulling it back wouldn"t be that bad just a hassle. Is 95 foot pounds too much? Maybe I could back the torques off a little.

 

[Scott1ky]

Or maybe I can just pull the front cap off and use vice grips without even removing the crank... might try that first! Thanks.

 

[Dunk]

(quoted from post at 09:15:00 06/19/09) Ok pulling it back wouldn"t be that bad just a hassle. Is 95 foot pounds too much? Maybe I could back the torques off a little.

Tractor_Torque_Specs

http://www.antiquetractors.com/Research/Chris-Klossner/torqspc.htm

 

[DavidO]

What are you using for an assembly lube on the main bearings?

 

[Scott1ky]

I am using gear oil as assembly lube.

 

[Dell (WA)]

Scott.......do you know they sell real assembly lube??? $5 (cheap) Used to use white "Lubri-plate". Designed for brakeshoes. Problem with gear oil, it LEAKS out just setting there. Assy-lube and lubri-plate are a "greese" and takes several minutes for the oilpump to wash the grease outta the bearings. Doesn't hurt yer engine oil.

95ft/lbs is std spec for crankshaft main bearings. And vise-grips are the correct tool for removal and disguarding.

Remember to re-prime yer oilpump gears with chassis greese, lubri-plate, vasoline......Dell

 

[Scott1ky]

I wonder why it shows 80 for 9N and 95 for 8N. It doesn't show 2N at all.

 

[Dunk]

(quoted from post at 15:30:26 06/19/09) I wonder why it shows 80 for 9N and 95 for 8N. It doesn't show 2N at all.

I wondered too, but so far haven't had the time to look it up elsewhere...

 

[Scott1ky]

Not sure if I should back it off to 80ft-lbs or leave it at 95ft-lbs, probably would turn more freely but then I would be worried about it being too loose. It has the studs and nuts rather than bolts. Since it has castle nuts, I've had to over torque on a few just to get the hole in the nut to line up with the hole in the stud. On a few they will be slightly higher than 95ft-lbs.

Maybe it will loosen up but right now it is REALLY tight to turn.

 

[TheOldHokie]

The torque doesn't affect how "tight" the crank is. It determines the amount of clamping force holding the main bearing cap to the block.

TOH

 

[Scott1ky]

So it's probably just the new rope seals? Clearances are all good.

 

[Den N Ms]

Copyied from the Smith site.

Engine
Type . . . . . . . . . . . . . . . . . . . . . . . 4-cylinder "L" head
Maximum Drawbar HP. 2nd Gear. . . . . . . . . . . . . 23.16
Maximun belt horsepower at 2000 R.P.M. . . . . . 27.32
Rated speeds . . . . . . . . . . 1500, 1750, and 2000 RPM.
Idle speed . . . . . . . . . . . . . . . . . . . . . . 400-450 R.P.M.
Cylinder bore. . . . . . . . . . . . . . . . . . . . . . . . . . 3.188 in.
Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.75 in.
Piston displacement . . . . . . . . . . . . . . . . . . . 119.7 cu. in.
Torque . . . . . . . . . . . . . . . . . . . . 92 lbs ft. at 1500 rpm
Compression ratio. . . . . . . . . . . . . . . . . . . . . . . . . 6.50:1
Sleeves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dry type
Piston. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aluminum
Rings. . . . . . . . . . . . . . . . . . . . Compression (2) Oil (1)
Piston pin . . . . . . . . . . . . . . . . . . . . . . . . . . Full floating
Rod bearings . . . . . . . . . . . . . . . Replaceable shell-type
Main bearings . . . . . . . . . . . . . . Replaceable shell-type
Crankshaft . . . Cast steel, static and dynamic balanced
Compression psi at cranking speed . . . . 90 psi minimum
Valve tappet clearance:
Intake . . . . . . . . . . . . . . . . . . . . . . . . .010 - .012 cold
Exhaust . . . . . . . . . . . . . . . . . . . . . . . .014 - .016 cold
Crankshaft journal:
Main bearing diameter . . . . . . . . . . 2.248 - 2.249 in.
Rod bearing diameter. . . . . . . . . . . . . . . . . . 2.094 in.
Torque specs:
Cylinder head:
stud nuts . . . . . . . . . . . . . . . . . . . . . . . . . 50-55 ft lb
bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . 65-70 ft lb
Main cap bolts . . . . . . . . . . . . . . . . . . . . . 75-85 ft lb
Rod cap bolts . . . . . . . . . . . . . . . . . . . . . . 35-40 ft lb

 

[Den N Ms]

Scott1ky ,Did the stud strip, or did the castle nut strip the threads? I have had the old castle nuts not withstand the torque and strip the threads out,(soft nut).I learned to replace them with new grade #9 castle nuts.The studs would still be ok, and usable after chasing the threads with a die.

 

[Scott1ky]

The threads on the stud actually stripped. It is on the one that holds the front main cap/oil pump housing. After looking at the Smith torques, they are less than the 95 ft-lbs. Do you think I over did it by torqing to 95? The book said between 90 and 100 so I figured I'd go in the middle. All others were fine, just the last one I had left to do.

 

[Scott1ky]

I will look at it again when I get a chance and make sure.

 

[Den N Ms]

Scott,Just remove the oil pump,(front main) and get tow 7/16 nf nuts and try to screw them on the stud and lock them together to turn the stud out to replace it.Or just use vice grips to remove it.Or a cam type stud remover.