Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

buick v6 increase compression ratio?

VRV6BT1

New Member
Joined
Mar 21, 2008
Messages
343
Reaction score
0
Points
0
Location
telarah
Members Ride
S1 VR V6 BT1
G'day,
Just wondering if I put a slimmer or thinner head gasket on the old girl.
Question1.
Will it increase the compression ratio?

Question2.
If so roughly by how much?

Question3.
Is there a recommended brand and/or supplier.


Cheers and thanks for reading.
 

Reaper

Tells it like it is.
Joined
Aug 15, 2004
Messages
6,439
Reaction score
6,646
Points
113
Location
SE Suburbs, Melbourne
Members Ride
RG Z71 Colorado, 120 Prado , VDJ200 Landcruiser
G'day,
Just wondering if I put a slimmer or thinner head gasket on the old girl.
Question1.
Will it increase the compression ratio?
Yes

Question2.
If so roughly by how much?
Depends how thin it is compared to the old one. In reality it will probably be 2/10 of fa. Shave the heads or put in higher compression pistons if you want higher compression.

Reaper
 

VRV6BT1

New Member
Joined
Mar 21, 2008
Messages
343
Reaction score
0
Points
0
Location
telarah
Members Ride
S1 VR V6 BT1
Thanks reaper.

I have thought about higher compression pistons, but as I will be doing the work myself its really not an option as im not confident enough to replace them.

So... roughly how much would it cost to shave the heads? And also I have been told that VN series 1 heads (V6) have larger valves, so as I want to purchase a second set of heads to work on will they bolt straight up without any stuffin around.

And im also considering replacing the semi roller rockers with yt's and maybe different valve springs.

Unfortunately I am on a very limited budget and want to do everything myself and on the cheap(but not nasty), maybe I can get some secondhand roller rockers.
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,521
Reaction score
3,638
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
all the buicks use the same size valves. the VR models had a higher CR because they used different pistons. if you look through the ACL catalogue you will see the higher CR pistons there. you would need to get a machine shop to fit the new pistons to your rods (you need a press). you would also need to deglaze the bores (or bore the block oversize depending on the amount of wear). shaving the heads will gain some CR butyou are limited to how much you can take off as well. it really depends on how much extra CR your after. certainly fit some new valve springs ifyou intend to rev it. no doubt your 300,00-km springs are getting a little soft and saggin a little by now.
 

hakhawk

smooth moderator
Staff member
Joined
Jan 18, 2005
Messages
6,333
Reaction score
114
Points
63
Age
35
Members Ride
BMW E21 320i, E36 "318IS" coupe
And also I have been told that VN series 1 heads (V6) have larger valves, so as I want to purchase a second set of heads to work on will they bolt straight up without any stuffin around.
the rocker studs on the vn s1 heads were bigger diameter,but the valves stayed the same from vn-vr. you also need to drill holes in the head for pcv to make the vn heads work on a vr. only worth the effort if you pick up some vn s1 rockers for cheap and want to do some headwork at the same time.
 

VRV6BT1

New Member
Joined
Mar 21, 2008
Messages
343
Reaction score
0
Points
0
Location
telarah
Members Ride
S1 VR V6 BT1
Ok cool, thanks for the input.
The car only has 182000 that's the onlt reason im considering working with this motor and not getting a junker that would be an unknown quotient.

I have had a quote on getting the heads shaved 10 thou for forty bux.

Would it be an option to leave the standard valves, install new push rods, lifters, yt rollers and a cam with the head shave?
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,521
Reaction score
3,638
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
for 10 thou you don't need to worry about the lenght of the push rods. you have hydraulic lifters that will allow for that easy. 10thou isn't all that much, not going to have much effect on the CR. i certainly wouldn't bother with that if it's the only thing you intend to do.

what is it your intending to do? is it just a quick freshen up or a full rebuilt? other then the CR, are you going to do any other peformance enhancing mods?
 

Adamvr93

New Member
Joined
Sep 16, 2008
Messages
119
Reaction score
1
Points
0
Location
Moorebank
Members Ride
VR S Pack - 5 speed
i was thinking about shaving the heads for higher compression too rather than spending alot of money on pistons... what would be the most you could shave off without having the change other things.. like shorter push rods or somthing.. and would it even give a noticable increase in power?.. also with yt rockers and new valve springs what would be the maximum fairly safe rpm to set the rev limiter to
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,521
Reaction score
3,638
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
i was thinking about shaving the heads for higher compression too rather than spending alot of money on pistons... what would be the most you could shave off without having the change other things.. like shorter push rods or somthing.. and would it even give a noticable increase in power?.. also with yt rockers and new valve springs what would be the maximum fairly safe rpm to set the rev limiter to
with the roller rockers the valve train would be able to withstand more revs, however your cam and springs are really the limiting factor. there realy isn't any need to rev the engine much higher then the point where you make peak power. also depends on the springs and where they will not control the valves properly (bounce & lofting). new springs should fix that issue.
 
Top