2f crankshaft identification help (1 Viewer)

[leathamtj]

Hello and thank you for looking at my post. I have scoured the site trying to find help to my question On identifying the correct crankshaft for installation on a 2f I am rebuilding. I bought a 2f last year that was a good deal, the engine is a basket case and was obviously a good deal for a good reason. I don’t urgently need the motor, I bought the motor so when I buy a 40 I can just drop it in there. my question is this, I have pictures of the removed crankshaft and the crankshaft I bought. They look different enough that I am worried, the counterweights definitely have notable differences(especially the one between the 3 and 4 pistons). The block is a 61013(79-84 2f) the block build date October 29th 1984(must have been one of the very last 61013 blocks built. Within days of it they were using thrust washers on the crank). Anyways thank you again for looking . Troy

 

[leathamtj]

Here is the backstory of the motor as I know it. I forgot to mention I own a 1987 fj60 with a great motor.

i bought the motor last spring. I am a dummy and when I bought it the only checking I did to make sure it had the right head on it was confirming the ports for the smog pump air rail(at the time I did not know the 61030 head had an air rail also). It had a flat top piston block(61013) and a open chamber 61030 head. I have disassembled the engine now and discovered that the #3 piston connecting rod came off. I was quite surprised but there is very very little damage to bore on the block. It cracked the cam shaft in half and also cracked the #3 exhaust lifter in half, the connecting rod is obviously ugly mangled, the piston very lightly struck the exhaust and intake valves..... I found a mint condition connecting rod nut in the oil pan. Given all of this I believe the motor was rebuilt and someone did not properly tighten or torque the connecting rods on the #3 piston.... all the pistons slid freely out the top(no ridge) and none of the lifters with the exception of the #3 exhaust were a fight. Thanks again, troy

 

[65swb45]

Could you more specifically identify your concern? Does the #3 main bearing surface of the two cranks differ, or is it just the difference in the counterweights that is making you nervous.

 

[leathamtj]

Hello and thank you very much for looking at my post.... my concern is solely a visual look and not knowing as much as you all do. Really... when I bought the crank I was hoping there was a part number on it and I could match it that way. I have been looking through posts and classified listings and I think now..... the crankshaft I bought is from an earlier 2f? I don’t know. And to specifically answer..... yes the difference in the counter weights is my concern

 

[65swb45]

If there is no difference in the actual journals, then you are just looking at the difference in weight that makes the 81 and newer engines rev a little faster (a relative term) and have a little less vibration. Accordingly, using the earlier crank will require a little more balancing, and rev a little slower.

 

[leathamtj]

Thank you very much for the info! So may I ask your opinion then..... I don’t have to have the motor right away. It’s a total side project right now.... would you wait and try to find a later crankshaft or just use this one? since I’m in no rush I can wait and do it right. I should have added too, part of my confusion is that on the cruiserparts website they state that two cranks were made, a pre 1982 and a post 1982.... since I’m 84 I figured this was pertinent information.

 

[cps432]

Thank you very much for the info! So may I ask your opinion then..... I don’t have to have the motor right away. It’s a total side project right now.... would you wait and try to find a later crankshaft or just use this one? since I’m in no rush I can wait and do it right. I should have added too, part of my confusion is that on the cruiserparts website they state that two cranks were made, a pre 1982 and a post 1982.... since I’m 84 I figured this was pertinent information.

Years late to the conversation here, but I am sitting on the exact same set of crankshafts. Similar situation to yours.

My engine is an 87 2F out of a 60 series. The keyway has been broken and repaired several times on the original crank so I bought a replacement from cruiser parts.

As I understand it, there are older crankshafts for the F engine that do not use a split thrust washer but rather have a built in thrust washer on the main bearings. Matching bearings to achieve thrust tolerance is necessary for those engines if I’m not mistaken.

The newer 2F crank uses a separate set of split thrust washers to achieve thrust tolerance. They also balanced the crank at the factory and made it to slip through the oil rather than pound it. Like karate chopping water vs punching it. As mentioned earlier in the post it livens the engine up a bit.

I think this change happened around 85-86.

I’m still deciding on what to do in my situation. Do I want to just have this older crank machined and run with it? Or should I attempt to have the original fixed yet again? Or should I hang out until I find a crank from a late 2F? What did you do ultimately?