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How much I win with 1.6 againts 1.5 rockers ratio
#489734
10/06/09 01:19 PM
10/06/09 01:19 PM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
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OP
master
Joined: Aug 2007
Posts: 6,095
Valencia, España
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what you read. I dunno how to calculate that.
IN FACT, WHATS THE ROCKER RATIO ? lol... where is that spec located on rocker geometry
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: Mr.Yuck]
#489737
10/06/09 01:37 PM
10/06/09 01:37 PM
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Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem
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master
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
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Quote:
Or you can take your cam say 509/1.5=339.3 and multi by 1.6=542.9
I forgot to show the first step!
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: 68CoronetRT]
#489739
10/06/09 02:13 PM
10/06/09 02:13 PM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
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OP
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Posts: 6,095
Valencia, España
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so, then...
Stock Hp Mopar resto camshaft with .450/.458 will convert in to:
.450/1.5=.300x1.6=.480
.458/1.5=.3053x1.6=.48853
new resto cam will be:
268/284 dur with .480/.48853 lift
and the 474 MP cam
.474/1.5=316x1.6=.5056
new 474 cam will be:
280 dur with .5056 lift
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: 68CoronetRT]
#489740
10/06/09 02:18 PM
10/06/09 02:18 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
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Posts: 25,200
Upper Midwest
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Quote:
Quote:
. . . IN FACT, WHATS THE ROCKER RATIO ? lol... where is that spec located on rocker geometry
A stock 440 rocker has a 1.5 ratio. What that means is the rocker arm opens the valve 1.5 times more than the actual lift of the cam lobe.
In the examples above a cam that has a lobe .334" high will open the valve .334 x 1.5 (rocker ratio) for a total of .501"
That same cam using a 1.6 ratio would open the valve .334 x 1.6 (rocker ratio) for a total of .5344"
NOTE: Caution should be used when changing cams and rocker ratios because without pulling the heads and checking for clearance you may cause the valves to extend so far the piston smashes into them.
No need to pull heads to measue valve to head clearance. Very easy to do with heads in place. 
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: MoparforLife]
#489741
10/06/09 02:21 PM
10/06/09 02:21 PM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
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Valencia, España
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where in rocker is that difference ? I mean physically.
I got a nice deal trying to get adjustable valve train to use with round end pushrods but now I'm unsure if get 1.5 or 1.6 ratio rockers ( 1.7 will be too much ). I'm planing to use 474 cam, but I have a resto cam as a backup.
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: NachoRT74]
#489742
10/06/09 02:32 PM
10/06/09 02:32 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Posts: 16,123
Grand Haven, MI
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your lift calculations are correct. 1.6 ratio rockers have the pushrod tip slightly closer to the pivot. you may have to clearance the pushrod holes for your pushrods because of this.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: patrick]
#489743
10/06/09 02:42 PM
10/06/09 02:42 PM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
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Posts: 6,095
Valencia, España
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More stuff to check !! I think have enough with what I already have... I think I'll keep with stock ratio then. Is enough trying to get this valvetrain to be able to mill down heads without headaches about pushrod lenghts. ( already have rocker shims if I need to correct rocker/valve geometry after the mill down job ) being in USA wouldn't be a problem, but outside USA and being my driver I don't want to comfront more problems trying to get some change and park my car waiting for more parts. even there is LOT OF TEMPTATION on use a resto cam with those new lift values using 1.6 rockers and resto 115 centerline, being a driver car. although, still thinking  will .505 be to much lift on a 400 engine if I get... lets say 10:1 CR ( milling heads OR if KB240 pistons gets zero deck ? ) Does that lift value needs some job on heads at valve guides or wherever at head ?
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: NachoRT74]
#489744
10/06/09 03:08 PM
10/06/09 03:08 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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duration is a bigger influence on drivability and low RPM performance, not lift. lift is an indicator of potential power if head flow can support it.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: MoparforLife]
#489746
10/06/09 03:28 PM
10/06/09 03:28 PM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
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OP
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Posts: 6,095
Valencia, España
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I have around 120 lbs at stock installed height hughes springs... can't recall the PN... I think they are 1016... got them used on Carlisle last year
rest of setup
-Magnum 400 engine standart bore sleeved ( 25K miles on it, so will be just honed )
-KB240 pistons
-850cfm stock TQ carb
-MP 280/474 camshaft ( resto HiPo cam as back up )
-166K TC ( 175K TC to arrive someday as backup )
-basic 2186 eddy intake
-452 heads ported and milled ( dunno how much yet, will be defined when pistons are measured in the holes )
-stock HiPo exhauts manifolds
-exhaust pipes already upgraded to 2.5"
-Summit double timming chain setup
-3.55 SG axle
-27" wheels
-Lunati 75713 retainers
-Stock valves
-Metallic headgasket
-stock pushrods
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: MoparforLife]
#489748
10/06/09 10:32 PM
10/06/09 10:32 PM
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Joined: Aug 2004
Posts: 1,047
Arizona
68CoronetRT
super stock
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super stock
Joined: Aug 2004
Posts: 1,047
Arizona
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Quote:
No need to pull heads to measure valve to head clearance. Very easy to do with heads in place.
Here's my guess:
Cylinder TDC, install weak spring, set depth gauge to top of valve stem and then measure total distance to contact on piston. Subtract known lift?
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: 68CoronetRT]
#489749
10/07/09 12:08 AM
10/07/09 12:08 AM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
Quote:
No need to pull heads to measure valve to head clearance. Very easy to do with heads in place.
Here's my guess:
Cylinder TDC, install weak spring, set depth gauge to top of valve stem and then measure total distance to contact on piston. Subtract known lift?
Starting a few degrees before and ending few degrees after TDC. Valve to piston clearance is not the closest at TDC but usually a few degrees after.
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: NachoRT74]
#489751
10/07/09 02:25 AM
10/07/09 02:25 AM
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Joined: Jan 2003
Posts: 2,111
Bowie, MD
Reggie
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,111
Bowie, MD
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Quote:
so, then...
Stock Hp Mopar resto camshaft with .450/.458 will convert in to:
.450/1.5=.300x1.6=.480
.458/1.5=.3053x1.6=.48853
new resto cam will be:
268/284 dur with .480/.48853 lift
and the 474 MP cam
.474/1.5=316x1.6=.5056
new 474 cam will be:
280 dur with .5056 lift
The quick method for converting 1.5 ratio lift to 1.6 ratio lift is to multiply the 1.5 ratio lift X 1.067.
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: Reggie]
#489752
10/07/09 09:59 AM
10/07/09 09:59 AM
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Joined: Aug 2007
Posts: 6,095
Valencia, España
NachoRT74
OP
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OP
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Joined: Aug 2007
Posts: 6,095
Valencia, España
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well yes I guess, same than changing to 1.7 the multiply factor will be 1.1333
but I wanted better to know where it was exactly the difference.
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How much I win with 1.6 againts 1.5 rockers ratio
[Re: MoparforLife]
#489753
10/07/09 07:19 PM
10/07/09 07:19 PM
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Joined: Apr 2006
Posts: 4,220
West Plains, MO
DrCharles
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Posts: 4,220
West Plains, MO
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Quote:
Starting a few degrees before and ending few degrees after TDC. Valve to piston clearance is not the closest at TDC but usually a few degrees after.
Correct me if I'm wrong here, but isn't the exhaust valve-to-piston closest just before TDC, and the intake closest just after TDC?
-Charles
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