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H/C pistons
Posted: Thu Sep 17, 2020 9:22 pm
by blgitn
What c/r do they come in; Can you get 6:1?
R/Roger.
Re: H/C pistons
Posted: Thu Sep 17, 2020 9:57 pm
by DanTreace
Only one size dome style High Compression piston, they don't come in anything but o.d. sizes for cylinder requirement.
To increase compression ratio, shave the stock iron head. Can't advise how much to shave or what the gain in compression would be.
Re: H/C pistons
Posted: Thu Sep 17, 2020 10:13 pm
by Chad_Marcheese
If I recall right, it is approximately 5- 5.5 to 1.
As a person that builds modern performance engines, and have been delving into T engines specs heavily for a couple of my own builds, I can absolutely tell you any number given is just a wild guess until components are measure via liquid and a burette.
Every engine differs, and you can find anywhere from 1/2 to 1 point of compression variance on average when actually measured on all the components (modern day stuff manufactured in the last 25 years is actually very close engine to engine though). All heads, blocks, cranks, and rods are not created equal, they all contribute to the final compression ratio.
Re: H/C pistons
Posted: Fri Sep 18, 2020 12:43 am
by ModelTWoods
Jeff Cordes of Houston, told me that a virgin high head can safely be milled .150. If you do that and run any of the commercially available high compression pistons, either Egge or Snyders, you may not get as much compression as from a Z head, but it'll be cheaper and you'll get as much compression as possible from an iron high head.
Re: H/C pistons
Posted: Fri Sep 18, 2020 7:37 am
by Henry K. Lee
There is so much meat so to say on the top of those, you can easily machine the tops to make you own custom ratio with even a a low head.
Just saying. You can not run them out of the box with a low head.
Hank
Re: H/C pistons
Posted: Fri Sep 18, 2020 5:06 pm
by Kerry
Hank, I've never had a problem fitting out of the box HC domed pistons to a low head. May be some difference in Canadian ones to the USA ones?