Rocker Arm Ratio
11-17-2009, 06:47 PM
#12
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
First your right, I did initially post with the intent of doing the project and wanted to know that what I am planning on doing is worth while. Second, I do not appreciate how you automatically treat me with contempt as though I am somehow unintelligent and incapable or rational thought. Third, I am sorry if what I said offended you as that was not my intent.
I have never thought about doing just the exhaust rocker arms, what would that do to improve the operation of the engine that doing both intake and exhaust wouldn't? Could you give me a brief explanation of what changes I could expect in the operation of my engine by doing either just exhaust or both intake and exhaust rocker arms?
Thanks, I do value your input.
I have never thought about doing just the exhaust rocker arms, what would that do to improve the operation of the engine that doing both intake and exhaust wouldn't? Could you give me a brief explanation of what changes I could expect in the operation of my engine by doing either just exhaust or both intake and exhaust rocker arms?
Thanks, I do value your input.
Anyway, whatever head you are using with an sbf the issue has always been on the exhaust side for sbf's for example, lets use a stock e7 head, valves are 1.78/ 1.46 respectively, a vast difference in size and one thing you don't want to do is leave the exhaust side restrictive so that all exhaust gases are not expellled during the cycle , if it remains in the cumbustion chamber when the intake valve is open so it's a/f charge can be drawn in, you will have combustion issues, so what alot of cam manufactorers due is use a split/dual pattern cam with either more lift and or duration on the exhaust side , hence giving the exhaust more time during the cycles to be expelled, however , some cams like the famous letter cams are sigle pattern on both the intake and exhaust lobes, a cam as such could benifit from a split set up such as 1.6/1.7 ratio splits, thus making the engine more efficient
wait what?!?
11-18-2009, 10:58 AM
#15
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
11-18-2009, 11:35 AM
#16
in limbo
Join Date: Jan 2007
Location: Iowa
Posts: 7,300
^^i have a 5.0 magazine from years ago the they did dyno pulls on a single pattern cam. they did the following test.
3 pulls with combinations of 1.6 and 1.7 rockers. of the 3 pulls they took the average and posted the numbers.
1.6/1.6
1.7/1.6 = biggest net loss
1.7/1.7
1.6/1.7 = biggest net gain but it was only a few HP. i think 10hp and 15tq or something.
3 pulls with combinations of 1.6 and 1.7 rockers. of the 3 pulls they took the average and posted the numbers.
1.6/1.6
1.7/1.6 = biggest net loss
1.7/1.7
1.6/1.7 = biggest net gain but it was only a few HP. i think 10hp and 15tq or something.
11-18-2009, 05:40 PM
#17
2nd Gear Member
Thread Starter
Join Date: Jun 2005
Location: Arizona
Posts: 419
I am sold on the exhaust side rocker arms only however I have a few more questions.
Is it ok to have roller rockers on the exhaust and not the intake? I feel as if their would be a imbalance in the engine by doing that, and uneven ware.
On the assumption that doing a roller rocker and non roller mix is bad, where could I get some stamped steel 1.7 rocker arms, I have not been able to find any, and I don't want to spring for roller rockers and have to buy them individually so as to get the ratio mixture I want (individual is way more expensive then a set). I try to feed this money pit as little as I can and still get what I want. Or if there is a way to get 8 1.6 roller rockers and 8 1.7 roller rockers.
Or is it completely stupid to try and increase the ratio without changing over to rollers?
Is it ok to have roller rockers on the exhaust and not the intake? I feel as if their would be a imbalance in the engine by doing that, and uneven ware.
On the assumption that doing a roller rocker and non roller mix is bad, where could I get some stamped steel 1.7 rocker arms, I have not been able to find any, and I don't want to spring for roller rockers and have to buy them individually so as to get the ratio mixture I want (individual is way more expensive then a set). I try to feed this money pit as little as I can and still get what I want. Or if there is a way to get 8 1.6 roller rockers and 8 1.7 roller rockers.
Or is it completely stupid to try and increase the ratio without changing over to rollers?
11-18-2009, 07:42 PM
#18
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
I am sold on the exhaust side rocker arms only however I have a few more questions.
Is it ok to have roller rockers on the exhaust and not the intake? I feel as if their would be a imbalance in the engine by doing that, and uneven ware.
On the assumption that doing a roller rocker and non roller mix is bad, where could I get some stamped steel 1.7 rocker arms, I have not been able to find any, and I don't want to spring for roller rockers and have to buy them individually so as to get the ratio mixture I want (individual is way more expensive then a set). I try to feed this money pit as little as I can and still get what I want. Or if there is a way to get 8 1.6 roller rockers and 8 1.7 roller rockers.
Or is it completely stupid to try and increase the ratio without changing over to rollers?
Is it ok to have roller rockers on the exhaust and not the intake? I feel as if their would be a imbalance in the engine by doing that, and uneven ware.
On the assumption that doing a roller rocker and non roller mix is bad, where could I get some stamped steel 1.7 rocker arms, I have not been able to find any, and I don't want to spring for roller rockers and have to buy them individually so as to get the ratio mixture I want (individual is way more expensive then a set). I try to feed this money pit as little as I can and still get what I want. Or if there is a way to get 8 1.6 roller rockers and 8 1.7 roller rockers.
Or is it completely stupid to try and increase the ratio without changing over to rollers?
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