Factory Pistons
#1
Safety Car
Thread Starter
Factory Pistons
I ordered 1 stock CL-S piston and it came in today. The first thing I noticed is that
it hardly has a dome! The dome is about 1mm taller than the rest of the piston surface. Secondly there is anti-friction coating on the skirt - on the two sides that actually would get close to the cylinder-wall. The other sides are where the wrist-pin goes and that is at least a 1/2" from the edge.
There are two compression rings and an oil-ring. These are cast, but the finish is very nice. There are no sharp edgs on the piston surface (prevents hot-spots). Not sure how much a flat piston would reduce compression by... maybe a 1mm dish would do the trick - anybody know the combustion chamber volume?
FYI Part #: 13101-PGE-A010
Price: $26 and includes the wrist-pin and clip(s)
I am going to gives these to JE to do some measurements and order a set of 9.5:1 compression pistons (or 9.0:1, I have not decided yet).
it hardly has a dome! The dome is about 1mm taller than the rest of the piston surface. Secondly there is anti-friction coating on the skirt - on the two sides that actually would get close to the cylinder-wall. The other sides are where the wrist-pin goes and that is at least a 1/2" from the edge.
There are two compression rings and an oil-ring. These are cast, but the finish is very nice. There are no sharp edgs on the piston surface (prevents hot-spots). Not sure how much a flat piston would reduce compression by... maybe a 1mm dish would do the trick - anybody know the combustion chamber volume?
FYI Part #: 13101-PGE-A010
Price: $26 and includes the wrist-pin and clip(s)
I am going to gives these to JE to do some measurements and order a set of 9.5:1 compression pistons (or 9.0:1, I have not decided yet).
#2
Senior Moderator
nice work Ram.
![Thumbs Up](https://acurazine.com/forums/images/smilies/thumbsup.gif)
#4
Safety Car
Thread Starter
Never mind... 3.26 in^3
The 2003 manual says 3.27 in^3
Bore is 89.0
Stroke is 86.0
Bore-spacing is 98.0 (that means the width of two cylinder walls is 9mm - kinda small!)
The 2003 manual says 3.27 in^3
Bore is 89.0
Stroke is 86.0
Bore-spacing is 98.0 (that means the width of two cylinder walls is 9mm - kinda small!)
#5
Suzuka Master
Well the CL-P doesn't have domed pistons and it has a 9.8:1 compression ratio vs. the type-s' 10.5:1. You'd probably need a 1mm dish to get to a 9:1 compression ratio.
#7
Safety Car
Thread Starter
Originally Posted by mclarenf3387
Well the CL-P doesn't have domed pistons and it has a 9.8:1 compression ratio vs. the type-s' 10.5:1. You'd probably need a 1mm dish to get to a 9:1 compression ratio.
J32A1: 3.71in^3
J32A2: 3.44in^3
Now, they also state that the cylinder head volume is 3.26IN^3 for both heads. This means that the combustion chamber volume difference is solely attributed to the dome-size difference between the two pistons (given that the bore and stroke are identical).
So... there is a 0.37in^3 volume difference introduced by the piston. It appears that the dome is about 1mm tall, say 87mm wide (87mm because it is curved on the edges and I don't want to calculate all that)... and about a tad over 1.4" wide. So, 1.4" x (87mm / 25.4) x (1.5mm / 25.4) ~= 0.3in^3. The dome height is more like 1.5mm instead of 1mm. So, to a first order, I can estimate that a flat dome (given the J32A1 compression-ratio) is 9.8:1. Now, a 1.5mm dish given the same constraints will reduce it 0.7:1 further, yielding 9.1:1. I might just go for a 1mm dish which should put it right around 9.5:1.
I am just trying to prove to myself what Mclaren just stated.
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#11
Registered User
[QUOTE=allmotor_2000]
FYI Part #: 13101-PGE-A010
Price: $26 and includes the wrist-pin and clip(s)
[QUOTE]
where did you find it for that price? www.acuraautomotiveparts.org wants 56.52 minus the rings
FYI Part #: 13101-PGE-A010
Price: $26 and includes the wrist-pin and clip(s)
[QUOTE]
where did you find it for that price? www.acuraautomotiveparts.org wants 56.52 minus the rings
#14
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So since you are giving the factory piston to JE, basically that leaves the door open to them to design different pistons for other internal engine modifications, i.e., 3.5L crank+rods+custom pistons, or higher compression pistons for a standard 3.2L engine, etc?
#15
Senior Moderator
Originally Posted by mrsteve
So since you are giving the factory piston to JE, basically that leaves the door open to them to design different pistons for other internal engine modifications, i.e., 3.5L crank+rods+custom pistons, or higher compression pistons for a standard 3.2L engine, etc?
#17
Safety Car
Thread Starter
Yup, they can make anything I suppose. Does anybody want a 11.0:1 set ?? If I order multiple sets it will be much cheapter - I'd say $750 or less for the set (including rings).
PM me because I am going to talk to them on Saturday.
Also, the part # does have that extra '0' at the end - at least my box says so!
PM me because I am going to talk to them on Saturday.
Also, the part # does have that extra '0' at the end - at least my box says so!
#18
Senior Moderator
what kind of gains would we see from 11.0:1 compression?
#19
Safety Car
Thread Starter
Originally Posted by mattg
what kind of gains would we see from 11.0:1 compression?
I'd venture to say with 11.0:1 or higher pistons along with a balanced and blue-printed botton-end, you could achieve 320whp NA.
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I'll have a stock upper intake manifold available in the coming weeks once the IC is installed. I'll offer it for free, with a deposit that will be returned upon the delivery another stock upper intake. This will provide little to no down time while one is being worked on.
#22
Suzuka Master
Originally Posted by allmotor_2000
Yup, they can make anything I suppose. Does anybody want a 11.0:1 set ?? If I order multiple sets it will be much cheapter - I'd say $750 or less for the set (including rings).
PM me because I am going to talk to them on Saturday.
Also, the part # does have that extra '0' at the end - at least my box says so!
PM me because I am going to talk to them on Saturday.
Also, the part # does have that extra '0' at the end - at least my box says so!
I don't see how it would be cheaper if the pistons are gonna be different (9.5 vs 11).
<----confused
#23
Where is my super sauce?
On the same vein as this thread -- has anyone ever gone to Comptech to see if they're interested in doing any of the internal upgrades on the J32A2? According to their site, they supposedly will do staged engine upgrades for B, K, and J block series Honda engines with forged components, cam upgrades, porting, etc?
http://www.comptechusa.com/machine.html
http://www.comptechusa.com/machine.html
#24
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Originally Posted by mclarenf3387
Why an 11.0:1 set? I thought you were going for a low compression ratio.
I don't see how it would be cheaper if the pistons are gonna be different (9.5 vs 11).
<----confused
I don't see how it would be cheaper if the pistons are gonna be different (9.5 vs 11).
<----confused
Lower compression = more boost can be run safely.
Higher compression = more power for N/A applications.
#25
Suzuka Master
Originally Posted by mrsteve
Lower compression = more boost can be run safely.
Higher compression = more power for N/A applications.
Higher compression = more power for N/A applications.
#26
mister D
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Originally Posted by mclarenf3387
I know that, but I thought he was ordering a low compression set, so why would people buying a 11.0:1 set lower the price since the pistons will be different.
#28
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Originally Posted by mclarenf3387
I know that, but I thought he was ordering a low compression set, so why would people buying a 11.0:1 set lower the price since the pistons will be different.
I'd assume that since the pistons have the same dimensions regardless of the top of the piston (dish, flat top, dome, etc) it would be easier to fab something up if it was all done at the same time.
#29
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Originally Posted by darrinb
what can this do for for us n/a guys
Increased compression = more power. How do you think Honda squeezed 240 hp from a 2 liter 4 cylinder engine in the S2K? 11.5:1 compression ratio
![:O](https://acurazine.com/forums/images/smilies/embarrassment.gif)
#30
Senior Moderator
what is the j32 engine maximum bore capability?
#32
Senior Moderator
Originally Posted by allmotor_2000
dunno maybe 0.25" oversize on stock sleeves
#33
Three Wheelin'
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Originally Posted by allmotor_2000
dunno maybe 0.25" oversize on stock sleeves
here's something for ya. A 3.5 turbo in the making.
block sleeved by AEBS
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00027.jpg?bfJJjuBBr.yWy1XH)
main cap studs
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00028.jpg?bfJJjuBBWngxccD6)
stock 3.5 piston with valves from 3.2. working on cc'n the head.
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00041.jpg?bfJJjuBBuoUoMvwL)
stock forged steel 3.5 rod with new pauter rod
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00036---1.jpg?bfJJjuBBQYmZUDs.)
#35
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Dean has a set of pistons still for sale, and CHEAP!
https://acurazine.com/forums/car-parts-sale-361/custom-pistons-sale-155098/
https://acurazine.com/forums/car-parts-sale-361/custom-pistons-sale-155098/
#37
Suzuka Master
Originally Posted by ThinJim
Dunno if I'd go that much, maybe 0.10 at the most. Just look at the spacing between cylnders.
here's something for ya. A 3.5 turbo in the making.
block sleeved by AEBS
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00027.jpg?bfJJjuBBr.yWy1XH)
main cap studs
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00028.jpg?bfJJjuBBWngxccD6)
stock 3.5 piston with valves from 3.2. working on cc'n the head.
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00041.jpg?bfJJjuBBuoUoMvwL)
stock forged steel 3.5 rod with new pauter rod
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00036---1.jpg?bfJJjuBBQYmZUDs.)
here's something for ya. A 3.5 turbo in the making.
block sleeved by AEBS
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00027.jpg?bfJJjuBBr.yWy1XH)
main cap studs
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00028.jpg?bfJJjuBBWngxccD6)
stock 3.5 piston with valves from 3.2. working on cc'n the head.
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00041.jpg?bfJJjuBBuoUoMvwL)
stock forged steel 3.5 rod with new pauter rod
![](http://us.f2.yahoofs.com/bc/410671e1_13c92/bc/DSC00036---1.jpg?bfJJjuBBQYmZUDs.)
![Frown](https://acurazine.com/forums/images/smilies/frown.gif)
#39
Safety Car
Thread Starter
$550 is a very good price - there is no way even if I order two sets from JE, they will go that deep. I have asked Dean for a picture and if they appear suitable, I'll buy one of his sets.