Fred's 2375 Rebuild Thread Options

[friethmiller]

[A softball question for the Ninja and/or others]

This is the cam card that came with my 2357 engine, which was originally built by Rimco/Fat (long block) a few years ago. Can someone explain why with an intake/exhaust of 448, the lift was only set to 327 degrees? I'm about to rebuild my motor and a lot of focus will be directed at piston "deck clearance" and the valve train geometry that wasn't set correctly. Thanks.

[technicalninja]

You need to be halfway down the skirt, below the pin bore.

Note: this is a guess on my part. The pistons should have come with a card that states where the measurement is supposed to be taken from.

Pistons are NOT round cylinders. They are more like barrels and have a taper to them.

There can be .020"+ of variation top to bottom.

1/2 the skirt below the oil control ring is very common spot.

I think you'll be at 0.002" and are fine. I'd want .002+ maybe .0025

Edit:
I want to see your micrometer!
.001 mm is .000039"
That is 3 HUNDRED THOUSANDS of an inch!

You've SO blown me away!

It's damn hard to work in tenths!

You're 10X tighter!!!!

NFW! At this small a measurement temperature alone will alter things...

Are you REPEATABLE at the third decimal point?

If you are I want to see your tool!!!!!

[friethmiller]

You need to be halfway down the skirt, below the pin bore.

Note: this is a guess on my part. The pistons should have come with a card that states where the measurement is supposed to be taken from.

Pistons are NOT round cylinders. They are more like barrels and have a taper to them.

There can be .020"+ of variation top to bottom.

1/2 the skirt below the oil control ring is very common spot.

I think you'll be at 0.002" and are fine. I'd want .002+ maybe .0025

Edit:
I want to see your micrometer!
.001 mm is .000039"
That is 3 HUNDRED THOUSANDS of an inch!

You've SO blown me away!

It's damn hard to work in tenths!

You're 10X tighter!!!!

NFW! At this small a measurement temperature alone will alter things...

Are you REPEATABLE at the third decimal point?

If you are I want to see your tool!!!!!

It’s the digital tool spitting out to .0001. Any thing more precise is me converting b/w units. I claim no super measuring powers. Repeatable? Somewhat. I take several measurements at each point to make sure it’s repeatable. I think that skirt measurement is good. I moved the micrometer up and down the skirt to find the maximum. I don’t have any piston card but will attempt to find it. I’ll re-measure once I do.

Photo of digital micrometer:



BTW, I split the case and removed the crank. Inserted the cam bearings, added lube, and mounted the camshaft. It moves freely, not tight at all BUT its endplay is large. Probably due to bad geometry, side loading, not sure. I used a .019 feeler gauge at the thrust - cam interface. Obviously it was loosing material here from the abuse. Something else to verify later during assembly with the new cam.

Link to larger/custom cylinder spacers:
https://www.geneberg.com/cat.php?name=Cylin...&cPath=3016