318 with 3.97 cylinder bore after clean up

[hwy2]

How do you think this will run. 6 cylinders measure .003-005 over. I got new std pistons -6cc chambers. KB hyper pistons. Lets hears what ya’ll think.

 

[toolmanmike]

How do you think this will run. 6 cylinders measure .003-005 over. I got new std pistons -6cc chambers. KB hyper pistons. Lets hears what ya’ll think.

That's pretty sloppy for Hypereutectic pistons. https://www.hughesengines.com/TechArticles/2clearancerequirementsforhypereutecticpistons.php

 

[hwy2]

So .0025 wall clearance =.005 total over?

 

[Professor Fate]

How do you think this will run. 6 cylinders measure .003-005 over. I got new std pistons -6cc chambers. KB hyper pistons. Lets hears what ya’ll think.

Don't think it will run at all; if it does it's going to be noisy as heck and probably beat the pistons to death.
A 318 with a 3.97 bore is already .060 over; and you're going to run standard pistons?
Not sure what you mean by 6 cylinders being .003-.005 over, is that in addition to the .060 overbore?

 

[hwy2]

No only two cylinders Are that much over? The rest are .003 and walls are straight as I can tell

 

[hwy2]

Has anyone known someone who has run a motor like that and how did it do?

 

[Garrett Ellison]

Lets hears what ya’ll think.

I “think” that the thread title doesn’t sound right.

I got new std pistons -6cc chambers.

For a .060 over 318?

 

[hwy2]

I “think” that the thread title doesn’t sound right.

For a .060 over 318?

.007 over so 3.917

 

[RustyRatRod]

.007 over so 3.917

What do the pistons measure?

 

[273]

.007 over so 3.917

So stock 3.91 bores honed .003-.005 over too 3.913-3.915 ? Or a 60 thousand overbore + .003-.005 ?

 

[hwy2]

3.8

What do the pistons measure?

3.700 above compression ring.piston seems to ride on rings. Very little material to touch walls. Just coated part of piston is closest to wall. I believe these pistons expand to fit. Stock piston is 3.850 I believe

 

[Garrett Ellison]

Pistons are usually measured at a 90 degree axis to the pin bore or sometimes the top of the pin bore. There will be directions on UEM Pistons website.

 

[hwy2]

Pistons are usually measured at a 90 degree axis to the pin bore or sometimes the top of the pin bore. There will be directions on UEM Pistons website.

3.910 is what is measured piston according to KB.

 

[hwy2]

So stock 3.91 bores honed .003-.005 over too 3.913-3.915 ? Or a 60 thousand overbore + .003-.005 ?

Yes

 

[Killer6]

 

[hwy2]

I just honed out cylinders starting at 3.910. After cleaning and hone its now at 3.917 in worst cylinder. Piston measures 3.910 where it says to measure it.

 

[SSG_Karg]

 

[toolmanmike]

I just honed out cylinders starting at 3.910. After cleaning and hone its now at 3.917 in worst cylinder. Piston measures 3.910 where it says to measure it.

That's 7 thousandths of an inch. What does the chart say?

 

[273]

Should change the title to 3.917, would be less confusing.

 

[Garrett Ellison]

I’m more concerned how the cylinders are being honed and measured at this point. Is concentricity and taper being checked during all of this operation/ i.e. is a dial bore gauge being used with a fixed hone to do the cylinder work? There some instances where if you don’t have that type of equipment, the work needs to be farmed out.

 

[RustyRatRod]

I respectfully bow out of this one. Good luck!

 

[Scody21]

You might get away with it if you have the pistons coated. Look up Line2line coatings…

 

[PROSTOCKTOM]

If your pistons were an old set of TRW forged pistons you could probably get by with it since those needed about .006" clearance, but I honestly think you're wasting your time
trying to put stock cast pistons in a hole that's .007" over and 0055" to large for proper clearance. If you try it you'll probably have massive blowby and pistons slapping in the bore.

Tom