Head Work Question
Senior Member
Joined: Oct 2011
Posts: 581
Likes: 0
From: CNY
Vehicle: 2000 Hyundai Tiburon
Placeholder. Give me a few minutes to run evereything.
The .1 difference is because of a difference in how I rounded the original answer.
This of course assumes that the head's chamber diameter is equal to the bore diameter, which may not be the case.
bore diameter: 84mm
bore radius: 42mm
total engine displacement: 1975cc
per-chamber engine displacement: 493.75cc
per-chamber head volume: 47cc
shave: .04"
.04"*25.4=1.016mm
bore radius^2*pi = area of bore
(42mm^2)*3.141592=5541.768288mm^2
area of bore * shave = volume lost
5541.768288mm^3 * 1.016mm = 5630.43658061mm^3
5630.43658061m^3 = 5.63043658061cc
per-chamber head volume - volume lost = new per-chamber head volume
47cc - 5.63cc = 41.37cc
per-chamber engine displacement - head volume = per-chamber swept volume
493.75cc - 47cc = 446.75cc
(per-chamber swept volume + per-chamber head volume) / per-chamber head volume = original compression ratio
(446.75cc + 47cc)/47cc = 10.5053191489
(per-chamber swept volume + new per-chamber head volume) / new per-chamber head volume = new compression ratio
(446.75cc + 41.37cc)/41.37cc = 11.7988880832
bore radius: 42mm
total engine displacement: 1975cc
per-chamber engine displacement: 493.75cc
per-chamber head volume: 47cc
shave: .04"
.04"*25.4=1.016mm
bore radius^2*pi = area of bore
(42mm^2)*3.141592=5541.768288mm^2
area of bore * shave = volume lost
5541.768288mm^3 * 1.016mm = 5630.43658061mm^3
5630.43658061m^3 = 5.63043658061cc
per-chamber head volume - volume lost = new per-chamber head volume
47cc - 5.63cc = 41.37cc
per-chamber engine displacement - head volume = per-chamber swept volume
493.75cc - 47cc = 446.75cc
(per-chamber swept volume + per-chamber head volume) / per-chamber head volume = original compression ratio
(446.75cc + 47cc)/47cc = 10.5053191489
(per-chamber swept volume + new per-chamber head volume) / new per-chamber head volume = new compression ratio
(446.75cc + 41.37cc)/41.37cc = 11.7988880832
The .1 difference is because of a difference in how I rounded the original answer.
This of course assumes that the head's chamber diameter is equal to the bore diameter, which may not be the case.
Super Moderator
Joined: Sep 2001
Posts: 10,795
Likes: 5
From: Pflugerville, TX
Vehicle: 2000 Elantra
Interesting. Veeeeery interesting. I have read reports of heads with Singh grooves running just fine on pump gas after shaving 1mm off the bottom of the head. Hm....
Senior Member
Joined: Oct 2011
Posts: 581
Likes: 0
From: CNY
Vehicle: 2000 Hyundai Tiburon
Likely because the actual comp ratio dropped down due to the removed material that makes the grooves?
At least that's the explanation I have.
EDIT: I hate touchscreen keyboards...
At least that's the explanation I have.
EDIT: I hate touchscreen keyboards...