My friend is putting new pistion and rings in his bottom end and somebody told him that he should bore it out .25 instead of honing it? my question is it really neccesary to do this or can u just hone the block and put the new rings and pistions

 

No need to bore, just hone if there is no damage to the cylinder walls....if there is damage than yes you should bore out the cylinders.

 

This is where a machine shop comes in. You need to have the bore checked and mic'd. Measure EVERYTHING. Just ask the guy who I rebuilt the motor for. He spent nearly 3k on a rebuild only to have the engine building just throw in another set of pistons without clearencing everything. Needless to say, once we got the engine it was torn down and you could almost move the piston back and forth. Always check. You can't just assume when replacing pistons. Measure and then measure again just to be safe. You could very well have to go more than .25 over. His went .5 over. Just make sure to check everything, or have the machine shop check it. It will be worth it in the end. GL.

 

i have a similar situation. My R motor just spun a rod and i am getting it rebuilt. Couldn't i just replace the bearings and put new rings on the old pistons? Would i still have to hone the cylinder walls?....i'd appreciate the advice!

 

well my friend is planning on putting p30 pistons and new rod bearings and new rings as well in his b18cs bottom end do u guys think its a good piston to go with or no. personally i think it would be better then ctr's (which he was leaning to origianlly) cause its going to be his daily driver as well.

 

Not to completely thread jack, but when you "spin a rod", what exactly happens?? Just hear this term quite a bit here on H-T. Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RGoose18 &raquo;</TD></TR><TR><TD CLASS="quote">Not to completely thread jack, but when you "spin a rod", what exactly happens?? Just hear this term quite a bit here on H-T. Thanks </TD></TR></TABLE>

It's referring to a rod bearing. When you put in new bearings on the crank end of the rod, the bearings are "clipped" to the rod. There is a small groove on both the rod and the bearing to keep the bearing from spinning. The crank itself spins as the motor turns as does the rod (sorta) and the bearing is between the two surfaces, but stationary in/on the rod. When you spin a rod, that bearing "spins" instead of staying in place. HTH and isn't to confusing. If you need better definition, send me a PM and I'll see if I can dig up some pics for you.

 

always plan to bore and hone when rebuilding. cylinder walls tend to get ovular and need to get back to their circular shape. I don't know where you guysget that you bored .25 and .5 over. that is huge, and you probably ment .025 and .05 over.

 

ok yea my bad i meant .025
should my friend go with the ctr or the p30 to raise the compression, remember now this is going to be his daily driver

 

i say go with the p30 because it's a lighter piston and should bump the compression to about 11.4. I heard that the ctr don't allow a good combustion burn also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realis9 &raquo;</TD></TR><TR><TD CLASS="quote">i say go with the p30 because it's a lighter piston and should bump the compression to about 11.4. I heard that the ctr don't allow a good combustion burn also.</TD></TR></TABLE>

CTR pistons have alot of dome. Creating hot spots on the top that cause detonation. Also the presure is built up on the sides instead of having a more even distribution.

 

have anyone tried the rollerwave pistons from endyne?

and when we are talking of spun bearing, what is the risk for a fubar crank?

 

after my friend installs the pistons and new rings would he have to get the bottom end blue printed and balanced again or will it still be balanced

 

Thx for the reply Dave

 

does anybody know i beleive he doesnt have to get it balance again i just wanna make sure

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BoBo Racing &raquo;</TD></TR><TR><TD CLASS="quote">does anybody know i beleive he doesnt have to get it balance again i just wanna make sure</TD></TR></TABLE>

Honda engines are internally balanced. There should be no need to balance it again for what you are doing. IIRC one company and I think Spoon is that company but they sell "spoon" pistons. What they do is get a batch of pistons and then group them together by weight so that all the pistons in the set of 4 are very close to one anothers weight. But to answer your question, you shouldn't have to balance the motor. Unless you had a problem with the crank and had it resurfaced I really don't see the need. But it is one of those "just to be sure" things to consider.