Piston size!

[Enthusiast]

Scenario : Heard from another guy that previous owner of my car bored the block to 82mm.......but my car now only using b16a2 piston.....which is 81mm......

Question :

1)will this cause a lost of compression?
2)will it makan alot of engine oil?
3)what pistons can i fit into a 82mm bore?!?!

 

[hattech-v]

maybe aftermarket piston...
compression lost normally bcoz of piston ring not in good condition anymore...

 

[Enthusiast]

so issit safe to run 81mm pistons?? or should i opt for type r 81.5 pistons?

 

[akuma]

wait a minute..dun get u....ur block has been bored to 82mm or bored to fit 82mm pistons?
n how r u running 81mm pistons?won it b too loose n u shud b loosing quite alot of compression...
n good,since u brought up d topic abt piston size..can i confirm w u guys dat der is actually a 0.5mm oversized Type R pistons,ie 81.5mm?i've seen d 81.25mm,but never d 81.5mm n sum ppl tell me ders no such thg as a 81.5mm oversized Type R pistons...
any1 can clarify?
thx

 

[shiroitenshi]

wait a minute..dun get u....ur block has been bored to 82mm or bored to fit 82mm pistons?
n how r u running 81mm pistons?won it b too loose n u shud b loosing quite alot of compression...
n good,since u brought up d topic abt piston size..can i confirm w u guys dat der is actually a 0.5mm oversized Type R pistons,ie 81.5mm?i've seen d 81.25mm,but never d 81.5mm n sum ppl tell me ders no such thg as a 81.5mm oversized Type R pistons...
any1 can clarify?
thx

Strange story eh akuma.. running 82mm bore with 81pistons. Actually can run, although I'd be thinking the pistons skirts would show some scratches on them being run so loose with the stock compression and oil rings

Anyway.. I oso confused with that measurement of 81.25/81.5 ... but from what little I know, the bore is used to calculate capacity, not the piston size.. Since actual compression is aided by the ring seal, so it's possible to run pistons either tightly (with tight tolerances) or loosely (with looser tolerances)

Some pistons need less than .5mm clearance, like .25mm or so, while some are actually running .5 piston wall clearance (forged units). This actually affect capacity (though not by much)..

So I think maybe it's the same piston size, but in a looser bore? .25mm is kind of a bit tiny difference, no?

 

[Enthusiast]

hmmm yeah weird....ill go find out more about the bore size.......i've also found it VERY VERY weird when my engine is a b18c.....but my geran sez b18c 1834 cc..........i was like......@_@?>??>??>????????

 

[J101]

1834 would be B18B :p

akuma, its .25

hmmm yeah weird....ill go find out more about the bore size.......i've also found it VERY VERY weird when my engine is a b18c.....but my geran sez b18c 1834 cc..........i was like......@_@?>??>??>????????

 

[akuma]

B18C SHUD b 1797cc,right?
n yeah...1834cc is B18B

J101,
sure?coz jacky told a fellow CRX owner he got 81.5mm Type R pistons..m gona query d fella tmr

 

[avantasia]

B18C SHUD b 1797cc,right?
n yeah...1834cc is B18B

J101,
sure?coz jacky told a fellow CRX owner he got 81.5mm Type R pistons..m gona query d fella tmr

from wat i know, oversize pistion for Tip R is 81.25, mine B18C 1797cc :shades_smile:

 

[J101]

akuma,
sometimes its easier to say 81.5 than 81.25....also business strategy ha ha ..unless its a CP and JE aftermarket piston.

B18C SHUD b 1797cc,right?
n yeah...1834cc is B18B

J101,
sure?coz jacky told a fellow CRX owner he got 81.5mm Type R pistons..m gona query d fella tmr

 

[akuma]

J101,
no...d story does like dis..fren bought a lemon B18CR..was fitted w 81.25mm pistons oredy..but d bored was even,hence d engine actually looses compression...so he advise 2 rebore n fit in 81.5mm pistons....

 

[hattech-v]

oem tep r oversize is .25mm

 

[Enthusiast]

no kidding man....block says b18c xxxxxxx....geran also says b18cxxxxxxx...but cc there put 1,834.......wtF? any explanations for this?

 

[hattech-v]

i got one of my fren going to jpj for engine endorsement..
suprisingly one of the officer told my fren that b16b is not 1.6 but 1.5 instead...
so now he registered his b16b with 1.5 in the reg card...
ur case shud be similar... except its higher than it suppose to be.. haha

 

[akuma]

hattech-v,
care 2 get ur fren 2 ask dat officer whr he got his Master in CC Calculations?i oso wana learn lar!hahhaha

 

[Enthusiast]

LOL WTF! so issit conclusion is its still possible to run 81mm b16a pistons in a block boared to fit 82mm pistons rite? just that engine oil will leak into combustion chamber rite?

 

[budin99]

I bring this thread up again..

got few question regarding piston size and compresson.

1. Anyone know the price of 81.25mm piston + ring for b16a?
2. I lost compression, should I oversized the piston or try to change piston ring first?

 

[akuma]

budin99,
if i remember correctly,d CTR 81.25mm pistons cost ard RM550 not inclusive of d rings..try calling Lin Hup Seng in Jalan Ipoh 2 enquire.....
03-62576975
they r d main ppl 2 look for whn it comes 2 Honda parts...but of coz u can look 4 Mie Avantech oso...ehehehhehehhehe

 

[evoX2]

act how much compression difference does ctr .00 & .25?

 

[budin99]

budin99,
if i remember correctly,d CTR 81.25mm pistons cost ard RM550 not inclusive of d rings..try calling Lin Hup Seng in Jalan Ipoh 2 enquire.....
03-62576975
they r d main ppl 2 look for whn it comes 2 Honda parts...but of coz u can look 4 Mie Avantech oso...ehehehhehehhehe

TQVM Akuma...

Long taim no see u in this forum

Gonna cal dat number soon. need to confirm 1st the root cause.