160 miles on a fresh rebuild with a large sideport, 6mm up.



16.2" @ 820rpms

6 degs advance

new stock mazda 3 piece seals, rest were used all clearanced within spec.

Used housings.





How does that sound?

Here's my 2 yen on vacuum and compression numbers on a rebuild or used motor. To many variables to make a good judgment on the condition of the motor. I.E. port size, how much pre mix, cranking rpm, housing condition, timing, and many other things. As long as the motor starts easy and runs good when tuned properly the motor is good. Getting a base vacuum reading and compression numbers after a few heat cycles are only for reference later if something seems wrong.



A "large" side port motor idle solid at 820 rpms, sounds like it's running good.

chuck.

16.2 @ 820 RPMS on a large Sideport is pretty good,

Just wanted to add that this is an s4 engine.



GregW

my stock s4 mana motor would pull about 12-13", the ported s5 motor in the cym car pulls 18+"

My stock S5 N/A at 750RPM with various exterior engine modifications pulls 20Hg.



Reading these numbers, I'm wondering if my gauge is off? :O