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Rocker ratio
- Thread starter muzzagod
- Start date
Mikeflbmer
Bronze Level Sponsor
Rocker ratios
I have been to the Creative Workshop...what a great place and they have a very nice blue Alpine with some cool mods....They can answer your question as well as what the different ratios will do for your engine...mike schreiner
I have been to the Creative Workshop...what a great place and they have a very nice blue Alpine with some cool mods....They can answer your question as well as what the different ratios will do for your engine...mike schreiner
RootesRacer
Donation Time
Neah, they measure at 1.27 to 1.29. Call it 1.3 if you will.
mototron
Donation Time
Well , I have 1.5 ratio on my rockers
Take your Full Valve lift measured at the spring retainer and divide it by the cam lift at the lifter and you will have your rocker Ratio
On my Race car with stock Rockers come out to be 1.48
Maybe there are different rockers out there
but I have two sets with that ratio
Take your Full Valve lift measured at the spring retainer and divide it by the cam lift at the lifter and you will have your rocker Ratio
On my Race car with stock Rockers come out to be 1.48
Maybe there are different rockers out there
but I have two sets with that ratio
RootesRacer
Donation Time
Coltec (EX Holbay) has the following data for the E128 cam, of which I have one.
Chrysler 1725 E128 35/60 60/30 .465 .330 275/270
Where the .465 is the valve and the .330 is cam lift.
This equates to 1.409/1.
To do (measure) it right you need two indicators so you can record the point where the valve begins to move thus removing the error of the cam ramp clearances as well as the rocker tip lash.
I went back to look into some of my old team.net posts and discovered my memory is a bit faulty (RE 1.27 to 1.29 ratio). From my posts, I found that the net valve lift on the E128 cam was actually about .440 and on several sets of rockers yielded between 1.32 and 1.42 as measured with a dial indicator on the pushrod rim and on the retainer flat. I think Holbay was a bit optimistic about what they thought the rocker ratio was and ended with a lower net lift than designed.
If you have rockers with 1.5 ratio, keep them for sure, but be sure you dont hit the top of the block with your exhaust valves.
Chrysler 1725 E128 35/60 60/30 .465 .330 275/270
Where the .465 is the valve and the .330 is cam lift.
This equates to 1.409/1.
To do (measure) it right you need two indicators so you can record the point where the valve begins to move thus removing the error of the cam ramp clearances as well as the rocker tip lash.
I went back to look into some of my old team.net posts and discovered my memory is a bit faulty (RE 1.27 to 1.29 ratio). From my posts, I found that the net valve lift on the E128 cam was actually about .440 and on several sets of rockers yielded between 1.32 and 1.42 as measured with a dial indicator on the pushrod rim and on the retainer flat. I think Holbay was a bit optimistic about what they thought the rocker ratio was and ended with a lower net lift than designed.
If you have rockers with 1.5 ratio, keep them for sure, but be sure you dont hit the top of the block with your exhaust valves.