Differences between 1.5 and 1.6 rocker arms.......

Posted By: SKR8PN

Differences between 1.5 and 1.6 rocker arms....... - 12/29/08 11:27 PM

My question is, do they move the pushrod adjuster or the roller tip,or BOTH to get the change in ratio difference??? I have Harland Sharp 1.5's and am considering going to 1.6's, but need to finish checking clearances first,and am clueless as to where the change will effect stuff the most......like valve roller to stem and pushrod clearance's in the head.

Posted By: AndyF

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/29/08 11:29 PM

Pushrod moves closer to the shaft as the ratio goes up. So check the bottom side of the pushrod for clearance.

Posted By: Wv68charger

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/29/08 11:34 PM

i'm in the same boat as you just bought HS 1.5s this past season have 25 runs on them now probably going to switch to T&D 1.6s for the new motor.

Posted By: Cab_Burge

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/29/08 11:54 PM

Check your current set for the accuracy, my 1.5 are actually 1.54 to 1.56, same on the new set of 1.6, (actually checked at the retainers 1.64 to 1.66) that I bought three years ago

I use a ail indicator and set the lash at zereo, measure the actaul lift at the retainers and do the math, lobe lift times the ratio for theoritical lift versus actual lift at the retainers

Posted By: blownzoom440

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 12:14 AM

i checked the actual lift on the HS and it is spot on![1.5]

Posted By: Cab_Burge

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 12:28 AM

Quote:

i checked the actual lift on the HS and it is spot on![1.5]

Maybe my complaining did some good

How old are yours?

Posted By: Anonymous

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 12:30 AM

Quote:

Check your current set for the accuracy, my 1.5 are actually 1.54 to 1.56, same on the new set of 1.6, (actually checked at the retainers 1.64 to 1.66) that I bought three years ago I use a ail indicator and set the lash at zereo, measure the actaul lift at the retainers and do the math, lobe lift times the ratio for theoritical lift versus actual lift at the retainers

just somethng to keep in mind, some of the better manufacturers take into account valvetrain deflection under operating condidtions. that's one part of the reason a 1.5 might be 1.54 and a 1.6 is 1.64, give or take a small amount.

Posted By: SKR8PN

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 12:31 AM

I did the same as Metal Storm,but I cheated a weee bit by using another rocker shaft and cutting it down so you are only dealing with two rockers on a very short shaft.

Next question: What is the formula for determining the difference between a 1.5 and a 1.6 rocker arm NOT at full lobe lift? Lets say I want to calculate the difference in lift at 15 degrees ATDC? Do I measure ACTUAL lobe lift(on the lifter) at 15 degrees ATDC then X 1.6 and compare it to what I have actually measured with a 1.5 rocker arm at the retainer?????

Posted By: moparniac

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 12:43 AM

what type of harlands are you looking for standards or offsets....

Posted By: blownzoom440

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 01:17 AM

Quote:

Quote:

i checked the actual lift on the HS and it is spot on![1.5]

Maybe my complaining did some good How old are yours?

thay are about 3yrs old.my other set went to the dont ask me how i know post about checking TQ specs on the hold downs.

Posted By: Sport440

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 01:35 AM

Quote:

I did the same as Metal Storm,but I cheated a weee bit by using another rocker shaft and cutting it down so you are only dealing with two rockers on a very short shaft.

Next question: What is the formula for determining the difference between a 1.5 and a 1.6 rocker arm NOT at full lobe lift? Lets say I want to calculate the difference in lift at 15 degrees ATDC? Do I measure ACTUAL lobe lift(on the lifter) at 15 degrees ATDC then X 1.6 and compare it to what I have actually measured with a 1.5 rocker arm at the retainer?????

I just use the actual lobe lift and X again with the new ratio.
At the lower lobe lifts like at 15* BTDC or ATDC the extra .1 RR adds very little lift as compared to the higher lifts. mike

Posted By: SKR8PN

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 01:01 PM

Quote:

what type of harlands are you looking for standards or offsets....

1.6 standards. They are going on a set of Stage VI MW heads.

Posted By: BradH

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 01:36 PM

Quote:

Quote:

what type of harlands are you looking for standards or offsets....

1.6 standards. They are going on a set of Stage VI MW heads.

MW Stage 6s require a .485" offset intake; std offset intakes won't work.

Posted By: ProSport

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 01:50 PM

I'm trying to make a decision on this also. I have a 500" low deck with 440-1 heads and Indy 1.6 rockers.
I want to step up to Harland Sharp rockers but I'm debating on switching to 1.5's since the new cam is 706/661 lift with 1.5's. I'm worried 1.6's will give me too much lift for a street strip motor.

Posted By: Cab_Burge

Re: Differences between 1.5 and 1.6 rocker arms....... - 12/30/08 05:28 PM

My 518 with Eddy RPM heads loves the H.S. 1.6 rocker(actual 1.64 ratio) with a .420 lobe. The actual net lift at the retainers is around .710 to .730, love the differences bewtween rockers ratios on the same set

As far as to much lift on a BB Mopar type head I don't think that you can get therte from here

More lift is better if you want more power

as long as you have a stable lobe and valve train that will handle it