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-   -   1.8 roller rockers (https://www.offshoreonly.com/forums/general-q/252997-1-8-roller-rockers.html)

soggy bottom 05-06-2011 10:50 AM

1.8 roller rockers
 
Hi why is it that it's not a popular bolt on, it has been around for years, and has proven itself many times over and is an easy swap.

f_inscreenname 05-06-2011 11:02 AM

Most folks that will go that deep will just replace the cam to what they want.

soggy bottom 05-06-2011 11:19 AM

Hi changing rockers isn't that deep 1 hour at best, cam change 8 hours, plus having to degree the cam is not for every one.

Rookie 05-06-2011 03:35 PM

I do not think it is cost effective for the hp you get in return. I just replaced half of my 1.7's with 1.8's cause they are over 11 years old. But I would not have spent the money if they were not so old.

Raylar 05-06-2011 04:13 PM

My suggestion is never try and use a rocker ratio change over 1.7 to do what the camshaft lobe really needs to do. For one, lets take a .300" cam lobe lift size( pretty common size for mild cams) and lets multiply it by 1.7 =.510" net lift at valve. Now lets take the same .300 lobe lift cam and use 1.8 ratio= .540" net lift, a whopping .030" more lift and a few tiny degrees of duration which most engines would not even notice with most heads, intake and exhaust systems. Secondly, you have accelerated the speed of the lift open and closing rates ( jerk and acceleration) and that places more stress and loads on the valves, seats, springs, retainers, etc.
Bottom line, just not a smart thing to do for a ridiculous .030" more lift!
Need more lift and duration in an engine for more real power, change the CAM!!
Try not being so damn simple and cheap about how you make real measurable and useable power!
Old Chinese proverb say "Speed & Power cost money, how fast do you want to Go!"

Best Regards,
Ray @ Raylar

Griff 05-07-2011 02:01 AM


Originally Posted by Raylar (Post 3396715)
My suggestion is never try and use a rocker ratio change over 1.7 to do what the camshaft lobe really needs to do. For one, lets take a .300" cam lobe lift size( pretty common size for mild cams) and lets multiply it by 1.7 =.510" net lift at valve. Now lets take the same .300 lobe lift cam and use 1.8 ratio= .540" net lift, a whopping .030" more lift and a few tiny degrees of duration which most engines would not even notice with most heads, intake and exhaust systems. Secondly, you have accelerated the speed of the lift open and closing rates ( jerk and acceleration) and that places more stress and loads on the valves, seats, springs, retainers, etc.
Bottom line, just not a smart thing to do for a ridiculous .030" more lift!
Need more lift and duration in an engine for more real power, change the CAM!!
Try not being so damn simple and cheap about how you make real measurable and useable power!
Old Chinese proverb say "Speed & Power cost money, how fast do you want to Go!"

Best Regards,
Ray @ Raylar

X2

I want to see you see change and adjust a set of 1.8 roller rockers in an hour max.

soggy bottom 05-07-2011 05:37 AM

Thats why god invented air tools.

1BIGJIM 05-07-2011 11:05 PM

Rayler and Griff are respected people on this formum.

Then you post a wise ass comment. I am good, but there is no way I cam change rockers arm and adjustem then in 1 hour.
I don't even know what part of this project you could use air tools on. I would like to hear this one?

I have done this before looking for more power. You will not gain enough to even notice.

Great free advise, save your money for gas.

soggy bottom 05-08-2011 06:06 AM

1.8 rockers
 
Hey no disrespect to Rayler and Griff, I was a tech for twenty years and then sold snap-on for ten after that, so just very handy with tools, and that hour estimate was not eched in stone but it's not a weekend project either.

rexcramer1 05-08-2011 10:17 AM

Well its definitely a lot quicker than a cam change, probably a two hour job. As Ray stated though, for a very small amount of power you are putting a lot more stress on the valvetrain, which in a BBC is probably the most stressed part of the engine in the first place.

Money wise rockers and a cam are bout the same money. Changing from standard rockers to rollers has a lot more benefit than going from 1.7's to 1.8's

soggy bottom 05-08-2011 11:29 AM

1.8 rockers
 
Thanks to all who replied


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