[BogiesAnnex1]

I have new speedpro pistons and scat 5700 bushed rods. Some of the wrist pins slide in pretty easy and the wrist pin spins in the piston and rod. a few other pins spin freely in the piston but it doesnt spin in the rod. I use assembly lube on anything the rotates/spins/moves I was able to push them in by hand, but they dont spin in the rod like its a pressed fit. Is this normal? Will it loosen up after first start up and it warms up? or is something wrong here?

Another question. After I installed new main bearings torqued them down to spec (I didnt forget to seat the thrust bearing) It seemed like the crank was frozen.It took some effort to break it free, but once it is moving, it spins very freely. But after it sits for a minute it freezes up again. I feel this is normal but im unsure.

The rod to pin if tight but slides together is fine. The primary motion is in the piston pin bores. The floating fit in the rod is a back up for a list of just incases when it comes to articulation while allowing simple assessembly and dissassenbly that does not risk damage to the pin, rod or piston pin bores.

You second problem is called stiction, again not a concern once the engine is fired and run awhile that will go away.

Bogie

 

[BogiesAnnex1]

I wouldn't have sandpapered the inside of rod bushings, this is an area where a little too tight isn't as bad as too loose. Plus you need to be more than matiulous in cleaning sanding residue any left imbedded in the bushing will continue to sand the part.

Frankly I haven't found Plastigauge to be all that off as many others report. It's just part of my routine to get several checks on bearing clearances so I use it along with mics to get a handle on these critical clearances. Since your numbers are almost exactly .001 tight I'd first look to the bearings to see if they are a plus .001 set before I go and grind or polish on the crankshaft. Bearing packages can usually be had in standard or .001 over and .001 under for a proper fit without regrinding the crank. There are also oversizes for .010, .020. .030 or more undersized jounals so don't get these things confused. .001 over are often sold from parts stores for worn cranks.

It sounds like you need to put some money into at least an inexpensive set of micrometes from Harbor Freight. That way you can take some measures without guessing.

A set of telescopes Telescoping Gauge Set 6 Pc

A set of outside thimbles from 1 to 3 inch in 1 inch increments is a minimum 3 Piece Micrometer Set

A dial indicator magnetic base Multipositional Magnetic Base with Fine Adjustment

A dial indicator 1" Travel Machinist's Dial Indicator

Or you can go to Granger and or MSC and shop around for similar items. These imports won't hold up in a production shop but they are plenty sufficient for the occasional engine builder. They read with marks to the .001 you can estimate the .0011 to .0019 range.

Bogie