Rebuilt engine hard to turn over, but then loosens up?

[unioncreek]

I had time this morning to plastigage the #1 connecting rod. I did it 4 times on the cap, rod and on each side, all four measured 0.0015". I also did #2 twice and it measured 0.002". I also did three measurement with the Starrett snap gauge and got 1.497, 1.498 and 1.497.

I believe the crankshaft journal diameter is 1.498 from the factory. Do you think it's possible that there is a twist in the cap making it tight enough not to rotate. Yet still gave consistent measurements with the plastigage?

I'm going to order one new connecting rod.

Bob

 

[Hammermechanicman]

If you have some prussian blue or dykem blue coat the entire inside of the rod and install and torque the cap on and twist the rod just a couple degrees and then carefully remove it and you should be able to see any tight spots where it rubbed.

 

[unioncreek]

I have both. I'll try that tomorrow.

Bob

 

[Hammermechanicman]

I have both. I'll try that tomorrow.

Bob

You must be a machinist.

 

[unioncreek]

A hobbyist. I have an old Atlas lathe and small mini mill.

Bob

 

[Hammermechanicman]

I have a 4" Atlas lathe. Haven't done much with it in the last few years. Last thing i turned was a set of wedding bands from a bar if titanium. The guy got it as a cutoff from where he worked. Stuff was an absolute pain in the butt to turn.

 

[shadetree#1]

I DO THIS TO MOST 4 CYCLE small ENGINES BEFORE I TAKE THEM APART. (doing so gives me a heads up of how much I will need to bring them to minimum specs on the crank end play) I've even seen some of the Briggs at the upper end of the crank specs (still within Briggs specs) and they would have a knock due to too much end play.
Test/check this when re-assembling the engine. I rig a dial indicator at the end of the crankshaft, usually the pto end and gently pry the crank back and forth to get an accurate reading. I then take the crank end play specs to minimum.
When you first get the engine back together check the crankshaft end play.
If you detect a tight spot with the crank/engine setting vertical in running position) try raising up on the vertical crank and see if it makes any difference.

 

[unioncreek]

I have a 4" Atlas lathe. Haven't done much with it in the last few years. Last thing i turned was a set of wedding bands from a bar if titanium. The guy got it as a cutoff from where he worked. Stuff was an absolute pain in the butt to turn.

I started with a HF 8 x 14,. Did quite a bit with it, just wasn't long enough. Bought the 10" Atlas for $300, it has a 48" bed. Right now I'm building a wood pellet mill (we heat with wood pellets) I don't get much time to work on it with everything else going on. I retire from work 18 months ago, had to go back to work, due to the economy.. I work for a farmer April thru Nov.

Bob

 

[unioncreek]

Test/check this when re-assembling the engine. I rig a dial indicator at the end of the crankshaft, usually the pto end and gently pry the crank back and forth to get an accurate reading. I then take the crank end play specs to minimum.
When you first get the engine back together check the crankshaft end play.
If you detect a tight spot with the crank/engine setting vertical in running position) try raising up on the vertical crank and see if it makes any difference.

I will do that when I get to that stage. My connecting rod should be here in about a week.

Bob

 

[unioncreek]

I DO THIS TO MOST 4 CYCLE small ENGINES BEFORE I TAKE THEM APART. (doing so gives me a heads up of how much I will need to bring them to minimum specs on the crank end play) I've even seen some of the Briggs at the upper end of the crank specs (still within Briggs specs) and they would have a knock due to too much end play.
Test/check this when re-assembling the engine. I rig a dial indicator at the end of the crankshaft, usually the pto end and gently pry the crank back and forth to get an accurate reading. I then take the crank end play specs to minimum.
When you first get the engine back together check the crankshaft end play.
If you detect a tight spot with the crank/engine setting vertical in running position) try raising up on the vertical crank and see if it makes any difference.

The repair manual doesn't give a procedure to adjust the crankshaft end play. How do you adjust it?

Bob