Rebuilt flathead tight - too tight?

fortyonerag

fortyonerag

Well-known member
I'm in the final throes of rebuilding a 59A flathead. I'll be the first to say I'm an electrical guy, so I have been relying on manuals etc and advice from friends on this journey.

Nothing special - 8BA internals (pistons rods and valves) bored .060 over. New Mellings oil pump. The crank was linished with matching bearings fitted. Stock cam with new bearings.

With assembly nearly finished I wanted to fire it up before putting it in the car just to give me some assurance I did it right. The motor is stiff and hard to turn over. I'm told it will free up with running.

With plugs in the starter (Powermaster 9507) just barely turns it over, although I might have bad jumper leads

With plugs out it takes about 45 ftlbs of torque to move the crank.

Is this normal for a rebuild?
 
I just went down to the shop to test the one I am putting together. I'm not an expert, but have assembled about 8 or 9 of thse over the years and the current one feels just right to me. The cam gear was next to it so I placed it on with two bolts. Has no flywheel or heads on it, but valve train in.. Turns at 30 ft/lbs. So your's seems tight but maybe not beyond reason. I'm sure others will chime in, but that's what mine is.
 
Fortyone, are you using only jumper leads from a battery to crank the engine? If so, hook up the actual battery cables and it'll crank far better. 45 ft/lbs is tight but not extreme as some rope type seals really add to the stiffness of a newly assembled engine.
 
The type and number of rings also plays into this. A 4-ring piston with cast iron oil rings will have a lot more drag than a 3-ring piston with metric rings and modern oil-rings.

It is hard to compare unless you've ran the exact set of parts on two engines that are exactly the same (including the clearances and types of main seals).

Seals: If you are using the "traditional" rope seals on the front and rear mains, then hopefully you soaked them in oil for a couple days - this lubricates them. With that said, they put a lot more drag on the crankshaft during assembly than a modern "doughnut" seal on the front and a graphtite seal on the rear. . . .

Also, if you're testing without the riming cover on, then you're only using 1/2 of the front oil seal (if you're running traditional rope type seals).
 
I just tried my C59A also with a 0.060” over, stk crank, fully assembled with plugs in place. Engine still hasn’t been run, so essentially same as yours. I got 35 ft-lbs.
 
I checked my notes on a recent 3 5/16 + .040 engine with a 4.250 stroke crankshaft, Ross pistons, metric rings - was 20 lbs of torque to rotate the lower end (without the pan or timing cover on).
 
When I install those rope seals, I use aluminum stock about the same diameter as the crank journals and pound them in with a rubber mallet before trimming. You can get the stock at McMaster. Those seals are like two brakes and can really seize it if not seated properly.

JB
 
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