Can you change over from 1.5:1 ratio to 1.6:1 rockers (from V8 ) on a blue head holden six?
And if so are there any issues in doing this?
Rocker ratio
Started by
_Muzzy_
, Feb 06 2015 08:44 PM
14 replies to this topic
#2
rodomo
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Posted 06 February 2015 - 09:52 PM
Yes, providing everything else is pretty much stock.
Start putting in hi-lift cams, machining of head and decking of block and there might be issues.
#3
warrenm
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Posted 06 February 2015 - 11:07 PM
What he said.
#4
_duggan208_
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Posted 06 February 2015 - 11:20 PM
As far as I understand the distance between the pushrod centre and the rocker shaft centre is smaller which increases the ratio and gives more valve lift, however, increased strain on the cam, lifters. I'm also thinking of trying a bigger rocker ratio.
Regards.
#5
_oldjohnno_
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Posted 07 February 2015 - 07:39 AM
Can you change over from 1.5:1 ratio to 1.6:1 rockers (from V8 ) on a blue head holden six?
And if so are there any issues in doing this?
Just remember that the Holden V8 rockers are different dimensionally to those of the six, so you'll have to use SBC rockers to keep the geometry reasonable. These are available in stamped steel or rollers in a variety of ratios.
If you're going to be running really big lifts and big springs, and have to redrill and tap the stud holes anyway, then I like the slightly longer BBC/Ford rockers. You just need to postion the stud a little further away from the guide.
#6
_Macca97_
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Posted 07 February 2015 - 01:54 PM
v6 vn rockers are 1.65 ratio, and ive been told if you run v8 pushrods everything lines up
#7
N/A-PWR
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Posted 07 February 2015 - 07:23 PM
Is this them Danny:-
V6 Left 202 Right
http://pcmhacking.ne...38269dc0a#p2104
v6 vn rockers are 1.65 ratio
#8
_Bomber Watson_
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Posted 07 February 2015 - 07:25 PM
THat v6 rocker looks way out of geometry.
What does the contact patch look like?
Cheers.
#9
N/A-PWR
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Posted 07 February 2015 - 07:36 PM
Probably Retarded,
I thought from the previous post, that the difference in the rocker ratio,
was between the push rod and the rocker mounting stud?
Never the less, it was worth the comparison, and never know, this mod may work 
as stated in the link:-
- guide plates
- bushes
- rocker studs
- hardened pushrods
I could be wrong
Edited by NA-PWR, 07 February 2015 - 07:50 PM.
#10
_Lazarus_
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Posted 07 February 2015 - 07:43 PM
If you click on the link there's more pics and info.
#11
_Bomber Watson_
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Posted 07 February 2015 - 07:57 PM
Thats an interesting little life hack.
Wear mark looks a little bit off but not tooo bad.
#12
_oldjohnno_
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Posted 07 February 2015 - 08:51 PM
I'll bet both my balls that the actual, measured ratio of the VN rocker is quite a bit less than it should be when it's used with the factory 202 stud position. It's about as Mickey Mouse as it gets.
Edited by oldjohnno, 07 February 2015 - 08:52 PM.
#14
Dave6179
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Posted 10 February 2015 - 12:19 PM
I use Summit 1.6 SBC rollers. Also had the long 186 pushrods until I swapped heads, then had to reuse the shorter 202 rods. Funny thing is... the new head is higher comp with less shaved off its face.
#15
_Muzzy_
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Posted 10 February 2015 - 07:37 PM
Had a look at a wrecked V6 commodore engine today
It had pushrod guides, roller rockers no bridges , rather it had studs and beehive valve springs. Is that std on a ecotec VT
It had pushrod guides, roller rockers no bridges , rather it had studs and beehive valve springs. Is that std on a ecotec VT
Edited by Muzzy, 10 February 2015 - 07:39 PM.
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