mattharper

what kind of results can i expect from putting type r pistons into a stock b18b?

could i use stock rods/wrist pins?

imported_Lonely Racer

not much the compretion be some thing like 10.3:1 i would use new wrist pins and u can use the stock rods....... what are u building this for? and how many km the motor got on it?

zeeman

iTrader: (1)

most people over look things when thinking about changing the pistons. Like if your compression is 10:1ish you will need to use premium gasoline and get it tuned. You will also have to replace the rod bearings and piston rings b/c you shouldn't reuse rod bearings or piston rings. If you're going to replace the rod bearings i would also recommend using new main bearings and balancing the crank. ARP rod bolts would be a very good idea as well, they're cheap insurance. And if you're going through all this trouble you might as well get a new oil/water pump and some ARP head studs. You will also need a new headgasket. And i would also highly recommend getting 81.5mm pistons and having a machine shop bore it to 81.5mm and hone it. All this, just to replace the pistons? I wouldn't recommend anything less.
Sure you can just get a set of used pistons and new rings/rod bearings and give'er a pass with a drill mounted honeing tool. But its not what i would do. New pistons from honda (in the states) aren't that expensive and there are plenty of people who make respectable power with OE parts.
Generally, they say for every 1 full point of compression increased you will gain 10whp. But combined with some more aggressive cams and the proper valve train and possibly some headwork (port and polish, valve job, work the combustion chamber) will yeild impressive numbers. There are lots of people that build nonvtec b-series with good results.
According to the ZealAutowerks CR calc:
b16 (p30) pistons in LS = 11.6:1
b16 (pr3) pistons in LS = 11.3:1
usdm itr pistons in LS = 11.1:1
jdm itr pistons in LS = 11.6:1
Up from the 9.5:1 CR that the LS is stock you should see at least 20whp or so, but tuning will be essential, same with bolt-ons.
If you are going to do it, do it right the first time.

mattharper

"what are u building this for? and how many km the motor got on it?"

im building this for a dialy driven fun-to-drive 92 dx. there is appx. 130k on the motor(k&N/dc 4-2-1/cat-back)



"If you're going to replace the rod bearings i would also recommend using new main bearings and balancing the crank."

in summary,if i were to do this sort of set up this is the way id dot it(feel free to flame(but good advice is always better), im no pro and not rich by anymeans:

-no major bottom end work... usdm itr slugs(b18b wrist pins needed???), new rings, upgraded rod bolts,rod bearings, drill bit hone-job(cheap/used eagle rods worth it since i already have everything apart?what kind of cost am i looking @ for new main bearings/ crank balance?).
-minor P&P/valve job on head (milling head/thin gasket good or no since comp.rat will be high due to pistons. ??)
-mild cams/springs (crower 3's ok w/LS retainers/valves?)
-arp head studs, new head gasket



i know this is a newb Q buuuuuut............... how much $/gain am i looking at with this set up, doing all labour with the exception of machine work myself?

PS Zeeman, you're exactly who i wanted to respond to this thread

zeeman

iTrader: (1)

i wouldn't use anything bigger than a stage 1 cam on the stock valve springs/retainers.
New main bearings are about $100 and to balance a crank is about the same.
I would at least resurface the head, i don't know how much i would mill it b/c like you said the pistons will raise the CR enough.
You will spend $3000 on this setup easily after all is said and done. And for power, who knows, this isn't an E-dyno, no one can tell you for sure how much you'll make. Build it, dyno it, then let us know how it goes. If you need tuning done, let me know.

imported_eth0r

id use p30 or pr3 pistons instead since there easy to find and cheap...