Dished Pistons on N/A?
07-12-2012, 10:58 PM
#1
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Thread Starter
Join Date: Apr 2012
Posts: 104
Dished Pistons on N/A?
Well, we finally got our rebuild kit in, and they sent the wrong pistons in. so it got us thinking about whether to send them back and get the flat-tops or to keep the dished ones and see what we can do with them.
here is my question. I dont know if anyone has done this, but here goes:
If we keep the dished pistons, shave the head to raise our CR, and increase the duration of the cam to whatever the dished pistons let us do, would that be better than having a high lift/lower duration with the flat top pistons?
can we get the CR up (if we use the dished pistons) far enough to negate the CR loss of a dished setup by shaving the head, or getting a thinner head gasket?
note: we will be getting the head refinished anyway, so it wont cost us more to shave the head. also, we will port the valves 1mm at this time as well.
here is my question. I dont know if anyone has done this, but here goes:
If we keep the dished pistons, shave the head to raise our CR, and increase the duration of the cam to whatever the dished pistons let us do, would that be better than having a high lift/lower duration with the flat top pistons?
can we get the CR up (if we use the dished pistons) far enough to negate the CR loss of a dished setup by shaving the head, or getting a thinner head gasket?
note: we will be getting the head refinished anyway, so it wont cost us more to shave the head. also, we will port the valves 1mm at this time as well.
07-12-2012, 11:09 PM
#2
If it were that simple, my grandma could design engines. 
Click: Engine Design Utility
Remember... if you shave the head more than ~0.080", you must use shims.
Click: Engine Design Utility
Remember... if you shave the head more than ~0.080", you must use shims.
07-19-2012, 05:21 PM
#6
Registered User
Thread Starter
Join Date: Apr 2012
Posts: 104
alright! the people at RPMMachine.com are great! for just the cost of shipping, they are sending me out itm flat top pistons, .020 over.
for all of you who are looking to rebuild your engine, the parts that they use are from "safety auto parts", and upon examination, they seem to be on the up and up. however, they have their information backwards as far as dished vs. flat top. they are under the assumption that the earlier n/a z cars had flat top pistons, and the 80-83 na's have dished pistons.
if you plan on ordering their rebuild kit, ($301+shipping) be sure you get the right pistons.
does anyone have a good resource on hand for a step-by-step rebuild of the 1982 l28e?
for all of you who are looking to rebuild your engine, the parts that they use are from "safety auto parts", and upon examination, they seem to be on the up and up. however, they have their information backwards as far as dished vs. flat top. they are under the assumption that the earlier n/a z cars had flat top pistons, and the 80-83 na's have dished pistons.
if you plan on ordering their rebuild kit, ($301+shipping) be sure you get the right pistons.
does anyone have a good resource on hand for a step-by-step rebuild of the 1982 l28e?
07-19-2012, 05:41 PM
#7
07-21-2012, 10:41 AM
#9
Mr Z++ Wiki
Join Date: Sep 2009
Location: Victoria, BC
Posts: 2,195
alright! the people at RPMMachine.com are great! for just the cost of shipping, they are sending me out itm flat top pistons, .020 over.
for all of you who are looking to rebuild your engine, the parts that they use are from "safety auto parts", and upon examination, they seem to be on the up and up. however, they have their information backwards as far as dished vs. flat top. they are under the assumption that the earlier n/a z cars had flat top pistons, and the 80-83 na's have dished pistons.
if you plan on ordering their rebuild kit, ($301+shipping) be sure you get the right pistons.
does anyone have a good resource on hand for a step-by-step rebuild of the 1982 l28e?
for all of you who are looking to rebuild your engine, the parts that they use are from "safety auto parts", and upon examination, they seem to be on the up and up. however, they have their information backwards as far as dished vs. flat top. they are under the assumption that the earlier n/a z cars had flat top pistons, and the 80-83 na's have dished pistons.
if you plan on ordering their rebuild kit, ($301+shipping) be sure you get the right pistons.
does anyone have a good resource on hand for a step-by-step rebuild of the 1982 l28e?
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