Hi, i have bought a set of wiseco K576M925 pistons. 92.5 mm

The machine shop cant find the sheet that comes with them giving them the tolerance sizes to bore the block out to.

for a closed deck block if that makes any difference to boring info.

Can anyone help me with this info. needed asap.


Thanks
Jamie

 

You should be able to find out from the Wiseco web site but they
normally run a 0.003" finished/honed Piston to Bore clearance.

Mick

 

 

That will be the ring gaps not the P/B clearance me thinks

 

My bad, you're totally right - see post #38... https://www.scoobynet.com/general-technical-10/722814-has-v6-sti-got-forged-pistons-2.html

What actually does, therefore, piston ring gap refer to (I must admit, I assued it to be the same thing as P/B clearance - hence my post )?

 

Diff is rings fit to bores exactly, pistons don't, hence the clearance.

HTH

DunxC

 

You have size the rings to the individual bores to ensure your running the
correct ring gaps for the brand of piston you are using and what sort of work your engine will be doing (road use/track tool/hill climb/1/4 mile etc etc).
If you trial fit the Top and Second Wiseco Compression rings in the bore,the ring gaps are normally too small - they come out at approx 0.010" and 0.014" respectively on the engines i have done and if left too small,you run the risk of ring butting (sounds painful ) which can cause scuffing to the rings and bores and more importantly damage to the ring lands on your expensive Forged Pistons.


Mick

 

is it different for closed deck block over normal block?

 

Minimum Gap Per Inch of Bore
Top Ring 2nd Ring Oil Ring Rail
Application Bore x Bore x Min. Gap
High-Perf. Street/Strip .................. .0040” ........ .0050” . ... ... .015”
Street-Moderate Turbo/Nitrous ..... .0050” ........ .0055” . ... ... .015”
Late Model Stock .......................... .0050” ........ .0053” . ... ... .015”
Circle Track/Drag Race ................ .0055” ........ .0057” . ... ... .015”
Nitrous Race Only ........................ .0070” ........ .0073” . ... ... .015”
Blown Race Only .......................... .0060” ........ .0063” . ... ... .015”
Note: The chart above is a general end gaps guideline. Each ring should
be fi tted to the particular cylinder in which they are to be installed. The
gap on the second ring should always be