I want to know if you can put new pistons in the original bore without worrying about proper sealing of the rings and worrying about having oval cylinders.

 

you dont have to go bigger unless something is wrong just get it honed and youll be fine if the cyls are in good shape already

 

You have to measure it with a bore micrometer. If it is the correct size and not tapered or ovaled, then you can get it honed and go from there. If you don't have the right micrometer or don't want to buy it (mine cost me $350 and it's not one of the more expensive ones), then you can take the block to a machine shop and they can do it for you for a small fee.

If you don't get it measured, then there is no way to answer that question. If you do get it measured, then the answer will be obvious.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridvteceg &raquo;</TD></TR><TR><TD CLASS="quote">you dont have to go bigger unless something is wrong just get it honed and youll be fine if the cyls are in good shape already</TD></TR></TABLE>

 

thanks so much

 

On the other hand, if you are going through the trouble and expense of buying new pistons, why 'cheap out' by not boring the cylinders?

 

It doesn't have anything to do with cheaping out. If the cylinders are not worn out or deformed, then there is no need to bore them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">It doesn't have anything to do with cheaping out. If the cylinders are not worn out or deformed, then there is no need to bore them.</TD></TR></TABLE>

Is there any advantage of boring out .25mm oversize?

would it make a tadd bit more tourqe?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr1244 &raquo;</TD></TR><TR><TD CLASS="quote">

Is there any advantage of boring out .25mm oversize?

would it make a tadd bit more tourqe?</TD></TR></TABLE>

Let's do the math! I don't know what engine you have, but for discussion's sake let's make it a B18C1.

Bore = 81mm
Stroke = 87.2mm

cylinder area (Pi * r * r) = 5153 sq mm

cylinder volume (area * height) = 449 cc * 4 cylinders = 1.797365 Liters, round it to 1.8L

Now do the math for an 81.25mm bore: 1.808477L

So, about .6% increase in displacement. That should get you about 1 extra HP.

 

B18C5 i have.. 81 =&gt; 81.25 mm bore..(CTR piston)

lol 1 hp gain? that's still pretty good.