Hi All:

So far, I have 6 different D series pistons to work with. I have almost every piston from 1.6 liter engines. I think I'm missing one from the 96+ Civic HX, but nobody has that car.

Here are the contenders so far:







I've measured the P29 and PM7 pistons in several ways and as far as I can tell, they are exactly the same. I wonder why Honda made 2 different part numbers and castings for the same piston? Hmmm...

Sonny

 

maybe usdm and jdm thing??? i dunno has to be a reason...materials?

 

i havent been reading past posts

just wondering what are you tryin to accomplish with this piston project?

best Honda d-series combo?

heres something i found very interesting the Honda GNX? (the natural gas car)
has 12.5:1 pistons in it ....it think these would make a great contender in this
project of yours

 

id be more than happy to host all those pics for you and specs for each one

d16a.com is my site and im looking for more tech articles/specs etc

lemme know if you wanna do that...

 

The main motivation behind this project is to determine what compression ratio is yielded using different combinations of D series pistons and D series heads. There is such a large variance in the way that Honda designed the pistons that just about any compression ratio is doable.

For example, the PG6B (86-87 Integra) and the P28 (92-95 Civic) both have the same compression height (1.181"). They will be flush with the top of hte block when installed. However, the Integra piston has a small dome, but the Civic piston has a HUGE dish. The difference between the 2 pistons afa compression ratio is very large.

Here are some pics comparing the P29 (88-89 Integra) to the PM7 (88-91 JDM ZC). This Integra piston was slightly modded on top, but I've seen a very clear picture of the top of this piston and can say that it is identical in shape to the PM7.





Sonny

 

Ok guys, last pic for now.



Sonny

 

Great posts! I love to see someone actually doing some reasearch about their car. I wrote an article a while back about all the different spring companys and, all the varying spring rates...(a lot of phone time) I think i got 3 responses..heh. Keep up the good work!!

-Jake

 

are you going to do a B Series piston project next?

 

If someone wants to donate a B series engine and some pistons, I'd be more than happy to!

A B series compression calculator has already been done by several people. C-SPEED has a really good one, here:

http://www.c-speedracing.com/howto/c.../compcalc.html

Sonny

 

Thanks Sonny, fabulous work that you have done!

If you can please post your results on the Honda D Series engine building page:

http://pub34.ezboard.com/fhondadseriesfrm6

Our members would really appreciate it.

Thanks,

Chas Wolf
Administrator, Honda D Series
http://pub34.ezboard.com/bhondadseries