just picked up a block and looks like there are some verticle scratches/marks around some of the cylinders. A few of them i can catch with my nail but most of the others can not even be felt. They look very very shallow but i'm wordering if a hone would take such marks out or if they can be felt will they definitely have to be bored?
I was going to use this block for a build and already have STD size pistons...if i bored over could i just get oversize rings? or would oversized pistons be needed/reccomended?

Thanks,

Vince

 

if you get oversized piston rings and use std pistons after boring, then you'll have hella piston slap and sound like a loud diesel engine. also not sure about how safe that would be. you shoudl try honing it to see if it'll make the scrathes go away, but chances are you'll have to overbore just a tad. honing is only meant to scuff up the walls of the cylinder and make a hatching pattern on the walls so the pistons/rings seat properly.

 

Yeah, you will have to run oversize pistons after boring. If they are large enough to catch a finger nail in then it will probably require overboring. Do you have any pics?


A machine shop could take a look at it to determine if they could be taken out with boring, and how much is necessary.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v-attack &raquo;</TD></TR><TR><TD CLASS="quote">Do you have any pics?
</TD></TR></TABLE>

Just took some Any help is appreciated because this is my first build



Thanks guys,

Vince

 

not related to the subject but I noticed the layer at the top of the cylinder wall always has build up there. Is this normal?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tazmoe &raquo;</TD></TR><TR><TD CLASS="quote">not related to the subject but I noticed the layer at the top of the cylinder wall always has build up there. Is this normal? </TD></TR></TABLE>

Yes, that is normal with higher mileage engines. It is carbon buildup from where the rings do not contact the cylinder wall.

Vince, even if you run stock "std." bore pistons you will still have to have the cylinders honed to match each cylinder accordingly.

Are the scratches the vertical ones or the ones on the left of the pic?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v-attack &raquo;</TD></TR><TR><TD CLASS="quote">
Vince, even if you run stock "std." bore pistons you will still have to have the cylinders honed to match each cylinder accordingly.

Are the scratches the vertical ones or the ones on the left of the pic? </TD></TR></TABLE>

The one's i'm talking about are the verticle ones...maybe the ones you see are light trickery? Please point out what other ones your talking about so i can make sure.

Yeah i know i'd have to get it honed, but if i need a bore i'll have to sell my STD pistons and look for overbore P29's.

Somebody told me that they could just be, "machining scratches?" When i got the engine i didn't see the verticle scratches and didn't notice them untill i turned the crank a few times. I may have done it that way if there was some dirt or something i pushed up the wall.

Vince

 

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

The one's i'm talking about are the verticle ones...maybe the ones you see are light trickery? Please point out what other ones your talking about so i can make sure.

Yeah i know i'd have to get it honed, but if i need a bore i'll have to sell my STD pistons and look for overbore P29's.

Somebody told me that they could just be, "machining scratches?" When i got the engine i didn't see the verticle scratches and didn't notice them untill i turned the crank a few times. I may have done it that way if there was some dirt or something i pushed up the wall.

Vince</TD></TR></TABLE>

I would take it to a machine shop, they will be able to tell you the severity of the scratches. Personally they dont look that bad. Most likely the machine shop will hone it and see what results they have
Yeah I see the vertical ones, there were some off to the left, that must be light.

 

cool thanks man, i'll keep my fingers crossed

Vince

 

dont just hone it! you are going to run a piston-wall clearance that is well outta spec. JUST DONT DO IT!
sell or trade your pistons back in for oversized pistons with rings, and try to get low tension rings while youre at it...longer engine life with them. have the machinist bore it, then have him plateau hone it to 0.0005, this way you really wont even need rings. that entire package shouldnt cost over $70. *stock piston-wall clearance is 0.0015-0.0017.

the only time you use standard bore pistons is when you get an engine fresh from the factory or you re-sleeve the block.

do it right the first time so you wont have to do it the second time. just some words of advice.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RABHonda &raquo;</TD></TR><TR><TD CLASS="quote">this way you really wont even need rings.</TD></TR></TABLE>

what?

 

what he means is the tolerances will be so close that the pistons will expand to fill the cylinder almost completely, which eliminates the need for rings, but nevertheless, GET THAT BLOCK TO A MACHINE SHOP, either re-sleeve and keep the std bore pistons or hog it out. vertical scratches aren't the best things.

 

well...IMO, i'd get oversized (.5 mil) and get the block bored to spec by a quality machinist. Bore job quality is so important; BUT, if you were just throwing this together for fun and the bores are not ovalled, you could lightly sand with a very fine grit SP the scratches that catch ya nail, just enough to kill the sharp edges so you wont flatten a ring..

 

haha hey Built (laughing because i was just replying to your post in the D-series.org engine building forum, tuning, queens, etc.)...well this isn't just something i'm throwing together, it's for my all motor D build. This is my first one so i didn't know what to do but i'm going to just bore it out as much as i can. Right now it looks like some OEM replacement P29's at .40 over and maybe some total seal rings? The only place i could find .50 over pistons is oem which are almost double the price of OEM replacement elseware.

I'm wondering if going OEM replacement such as NIPPON would matter for pistons...and also what rings i should look into getting? (Acura P29's only have .25 and .50 over rings/pistons).

Vince

 

hmm...

well, i always use .5 over P29's from http://www.acuraautomtiveparts.net and get .5 over y8 rings from my local dealer...

I don't have personal experience w/ other OE replacements out there, you mean like borg-warner and ****? Man...I just love Honda quality, it's werth the extra money to me IMO, but, let us know what you find out there from elsewhere. If you get some strange overbore size and you need an aftermarket ring set, total seal are nice, but not necessay; hastings, federal mogul all make quality oe replacement rings for the right price. I love Honda rings tho...

 

how much does it run you total for P29's, wrist pins, rings? Look's like $300+ for everything

Someone on D-series is getting a group buy for nippon P29's. $100 for pistons, pins, and rings. What i wanted to do was use those pistons and go for some better rings, or even OEM but acura only has the .25, .50 sizes. I'll look into the ring manufacturers you listed.

Thanks,

Vince

 

are the p29's domed? if so, they arent the most efficient piston design out there. the pm3's would be the ideal choice because of their flat top, with minor valve reliefs.

i can get the pm3's for $130, OEM.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RABHonda &raquo;</TD></TR><TR><TD CLASS="quote">are the p29's domed? if so, they arent the most efficient piston design out there. the pm3's would be the ideal choice because of their flat top, with minor valve reliefs.

i can get the pm3's for $130, OEM.
</TD></TR></TABLE>

this has been discussed over and over...talk to bisi about this-

BTW, can you get p29 for 130? pg6b as well?

 

Builthatch-


it was me on d-series that can get nippon p29's for 100 shipped, any bore size they have. I am waiting for mine to come in to judge the quality of them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic-4-ges &raquo;</TD></TR><TR><TD CLASS="quote">Builthatch-


it was me on d-series that can get nippon p29's for 100 shipped, any bore size they have. I am waiting for mine to come in to judge the quality of them.

</TD></TR></TABLE>

Sounds good, let me know asap on them. If not then i guess i'm going to acura

Vince

 

1mm over on the poor stock cyl walls seems a bit much especially with the cylinder pressure from the high compression and such...

 

I understand, I also believe the guy may have just quote me wrong. IM happy as long as its an overbore. if they go to 76mm, ill try it, let my engine be a guinea pig. Im pretty sure they are only 75.5's that i am getting

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic-4-ges &raquo;</TD></TR><TR><TD CLASS="quote">I understand, I also believe the guy may have just quote me wrong. IM happy as long as its an overbore. if they go to 76mm, ill try it, let my engine be a guinea pig. Im pretty sure they are only 75.5's that i am getting</TD></TR></TABLE>

In you're PM on D-series you said .20 and .40 over. Can you get .25 and .50 as well??? That would be great because honda rings could be used! to builthatch.

Vince

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by builthatch &raquo;</TD></TR><TR><TD CLASS="quote">1mm over on the poor stock cyl walls seems a bit much especially with the cylinder pressure from the high compression and such...</TD></TR></TABLE>
thin cylinder walls should raise more of a temperature problem than compression. all of the compression/combustion should happen between the piston and cylinder head. this applies to FI engines as well. the lip of the negative dome (dish) should come out of the cylinder, to get the best seal.

im sure i can get p29's for $130 including all hardware, ie: rings, pins. ill find out tomorrow.

but i would suggest the pm3 pistons with a single layer head gasket, making sure the pistons come out of the bore by .5mm. but it all depends on the head being used.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RABHonda &raquo;</TD></TR><TR><TD CLASS="quote">
the lip of the negative dome (dish) should come out of the cylinder, to get the best seal. </TD></TR></TABLE>

With the p29, the piston sits about 1mm in the bore from the deck...

Regardless of piston design, i tend to look at the inherent possiblity that the more you take from the bore by boring, that leaves the cylinder wall more susceptible to damage (ie cracking) from detonation (which = super high cyl. pressures not always when the piston is where it should be), and also makes that open deck setup that much weaker than it already is...we all know the object is to have no pinging, but sometimes it happens with high-compression builds, and it jsut seems silly to me to take that extra .5 mm away...the negligible torque gains will not be worth the risk...

Honda seems to agree that .5 over is the limit on stock cylinders.

RABhonda, def let me know about the P29 availability