rotational torque of crank on rebuilt engine, in inch/#'s? (2024)

Rebuilt briggs flatty engine... seems tight? too tight to SPIN Freely? honed/new rings/new sump gasket, got click click of rod free play... very little, seems like, but .003-.023" is spec's for crankshaft free play. motor was somewhat worn, nothing unusual . i oiled rings with ATF but still... cant get motor to spin fast enough with pull start to get it to pop off. tried using drill to spin it... cooked drill right away.

so.... rotational torque with inch/pound torque wrench of new engine? thx

A Milwaukee hole hawg will crank the crap out if a 1950's 10 hp flathead if on low speed.

If won't start with the rope, check for the 3 requirements.

Spark
Fuel
Compression.

Of course, need correct cam and ignition timing.

If you take spark plug out and you can roll it over by hand, it should run.

Based on past posts, I would suggest checking for the first 3, then work on the 4th to make it all come together.

It seems so simple?

A SIMPLE PLAN said:

NEW rings shd have compression. got gas, i poured gas into the carb with 500 ml RC gas car fuel bottle with gas in it. i can turn the flywheel over by hand with the plug out... just seems a little "tight"???? which with new rings, gapped right... it was worn cyl so there was good gap even with new rings. if i cld get it to spin faster... seems like it wud pop off. just seems tight???? will look into it again.

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Is this a modified cam? Did you index the spark plug? Stock carb? Did you replace the diaphragm gasket? Jet size?

Quote from you: "It's not a FORMULA1 engine or over the road diesel meant to last a million miles. Just a little engine to play with. It will most likely outlive me with good oil n moderate use" For those of you that may need comic relief: https://4cycle.com/karting/threads/valve-guide-replacement-briggs-flathead.123889/page-2#post-887351

I remember your postings when you asked for advice on valve guides. You just argued with everybody that took time out of their day to try to help. Yet you insisted that using a drill, at high speed was good enough. What did you use to measure critical clearances, a yard stick? Did you waste money on a ring compressor or just pound the piston in with a rock? Did you hone it with 80 grit sand paper stapled to a rotten log? With your attitude the number of things you probably did wrong makes speculation impossible.

I apologize for being a bit rude, but if you ask for advice you really should try to listen. Especially when everybody tells you that you are wrong.

Chipg56 said:

Quote from you: "It's not a FORMULA1 engine or over the road diesel meant to last a million miles. Just a little engine to play with. It will most likely outlive me with good oil n moderate use" For those of you that may need comic relief: https://4cycle.com/karting/threads/valve-guide-replacement-briggs-flathead.123889/page-2#post-887351

I remember your postings when you asked for advice on valve guides. You just argued with everybody that took time out of their day to try to help. Yet you insisted that using a drill, at high speed was good enough. What did you use to measure critical clearances, a yard stick? Did you waste money on a ring compressor or just pound the piston with a rock? With your attitude the number of things you probably did wrong makes speculation impossible.

Click to expand...

If I remember correctly he put a modified cam in this engine. And if using a pull starter on it, he will have to give it all he has to get it to run. I am sure I said something about using an electric starter to start it, but I was trying to get clarification on the cam.

Colt sr said:

If I remember correctly he put a modified cam in this engine. And if using a pull starter on it, he will have to give it all he has to get it to run. I am sure I said something about using an electric starter to start it, but I was trying to get clarification on the cam.

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It is nice of you to still try to help, I see you also tried to help him on the valve guide thread as well.

A SIMPLE PLAN said:

Rebuilt briggs flatty engine... seems tight? too tight to SPIN Freely? honed/new rings/new sump gasket, got click click of rod free play... very little, seems like, but .003-.023" is spec's for crankshaft free play. motor was somewhat worn, nothing unusual . i oiled rings with ATF but still... cant get motor to spin fast enough with pull start to get it to pop off. tried using drill to spin it... cooked drill right away.

so.... rotational torque with inch/pound torque wrench of new engine? thx

Click to expand...

Spark plug out? Where in the cycle are you measuring it? It makes a difference. Spring pressures alone can change the amount of torque required to rotate and pull the engine over. If you have coil bind, a valve tagging the head, or some other issue, the torque required could go from 20 inch pounds to full stop in a hurry.

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