Dont use 1.7 rockers with stock heads?
This is a quote off the MAC website:
"To enhance the total package, high quality roller rockers (direct bolt on) with a 1.6 to 1 ratio need to be installed. The use of high quality roller rockers will help equalize cam performance from cylinder to cylinder. Stock rockers are stamped and their ratios are inconsistent, be sure to use only high quality roller rockers. Caution: with stock rate springs and heads, do not use more than 1.6 to 1 rockers. Stock springs are not designed for more valve action." Glad i didnt already buy mine, so i guess im getting 1.6's, but how hard is it to replace the stock springs with newer ones, if i decide to just do the springs? thnx |
I know many many people using 1.7 rockers with stock heads and springs with no problems after years of use.
Later, |
Just because MAC says something on thier web site doesnt make it gospel. 1.7's work great on stock springs, as long as the springs are in serviceable condition.
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My stock springs had about 100k on them when i put my 1.7's on originally. A few months later, I noticed that my valves were floating at about 5300 rpm and higher.
I put on a set of comp cams springs (about $70), which installed very easily, and the problem went right away. Also the car seemed to pull harder on higher RPM's as well. |
thats a rediculous statement. 1.7 rockers are the same as running 1.6 rockers with a higher lift cam. so i guess theyre saying you cant get a cam either. unless of course you buy new heads and springs. you can use 1.7 rockers on stock motors and thats what they are primarily used for
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My engine in my '89 has 1.7 roller rockers on it with 120,000 miles and there's no problems so far after they were installed by the previous owner at 80,000 miles.
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I had the same results as fiveohpatrol, I installed them with about 65k on the odometer and they were great for about a month or two then the valve float set in. It would just fall on its face after 5000. When my crank snapped and I get my new motor I gave them to a friend, Same thing with him. He gave them to another friend and the same thing. Stock springs are notoriously weak.
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I put the 1.7's on a 1990 Lincoln Mark VII (5.0 HO, identical engine) at around 75K, and they were fine. I took them off again at around 100K before I sold the car, and had no problems the whole time. Car ran good and made plenty of power throughout the RPM range.
Maybe the Lincolns get superior valve springs? |
I had 1.7RR installed on my 94gt on stock heads. They gave me a nicer sounding idle and added some power. If you have low miles on your car go for it. If you are extremely cautious go with the 1.6RR.
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I cant see the rockers needing better springs. From what i understand the only time (besides if one goes) that you need to change springs is if you go with a more extreme cam. Because if you have an big bad cam you can start to get floating valves because the spring cant hold the lifter on the cam. But roller rockers alone should not need new springs.
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Re: Dont use 1.7 rockers with stock heads?
Quote:
The heads are the weak point of the 5.0 engine. |
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