crank seals and bearings.

[lowkhalbalr]

having the cylinder head and jug sent off for a port and polish. while i have the topend off i figured it would be smart to replace bearings and seals and what not.
how do i get to the crank bearings and seals without spliting the case?

new needle bearings? how do you get to the main bearing? split the case and remove the crank?

would it be a good idea to put new rings on the piston or leave them be?

anyone have the specs on the thickness of a stock bore cylinder wall?(so i can measure the wear)
thanx

 

[sicivicdude]

answers in order:

#1 You can't get the to the main bearings without splitting the cases but you should probably replace the lower seals while you have the engine apart if you think they're suspect...

#2 The small end bearing is replaced with the piston and wrist pin. The big end bearing is pressed onto the crank when it's made. It can be replaced but only by a machine shop

#3 I've always heard never ever install old rings. Not saying I haven't done it, just saying that's what I've been told. If you're sending your top end off for a port and polish why wouldn't you want the maximum performance out of it that a new set of rings would offer?

#4 You don't measure bore size by sleeve thickness. You measure by using an inside caliper and a dial caliper, or an inside bore gauge and micrometer, or one of those fancy bore gauges with the dial built in.

 

[lowkhalbalr]

thanks civic dude. the last question was asked so that i can determine how much wear the sleeve has sustained. jw ive heard the 200 uses sleeves rather quickly thats why i ask.

**anyone have the specs on the thickness of a stock bore cylinder wall?(so i can measure the wear)**

 

[sicivicdude]

You still don't use wall thickness to determine wear. The sleeve outer diameter is not a consistent measurement even for that.

Use a dial caliper to measure the piston diameter from the front to the back 10mm above the bottom of the skirt. The pistons start at stock at 66mm or ~2.598" and move up by .25mm or .010" increments to 68.25mm or ~2.687"

You then measure at several points around the cylinder with one of the above mentioned measurement methods and subtract the cylinder size from the piston size. The difference in any two measurements of the bore shouldn't be more than .02mm or .001" in difference and the difference between the cylinder size and piston bore should be no less than .05mm or .002" and no more than .12mm or .005".

Or, you know, something like that....

 

[lowkhalbalr]

sweet. thanks bro

 

[sicivicdude]

Go to a discount tool supplier: harbor freight or cummins tools and purchase a set of technical measuring devices

Like this:

6 Piece Technical Measuring Set - Specialty Measuring - Hand Tools

and a electronic caliper metric/sae selectable

Like this:

6" Digital Caliper

For $30 you have the capacity to measure your piston diameter and bore size.

 

[lowkhalbalr]

true that thanks man.