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.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.