WHAT CAUSED THIS ROCKER ARM TO BE BEAT UP

My engine can sing like the upper octives of CD... I use only genuine FRPP 1.6 rocker arms (blessed by CD, of course) 8)

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Originally Posted by donovan

Cobra Style 1.7 roller rockers are known to prematurely wear the valve guides and create the problem you have photographed.

I would not run 1.7's of any type on a Ford head, ask any decent head guy and he will tell you the same thing.

My GT-40 cast irons heads looked just like that and my GT-40X aluminum heads looked like that till I switched to 1.6 Comp Cam rollers.

DD

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Thanks DD! I had no idea. This was the only one that had any damage. More money to spend!

JJ

don't take my comments and change anything!

Just pull the valve covers and inspect them regularly, and plan on changing the valve guides at the end if each season if you run every event.

I found that is what I needed to do.

I will send you some more info later, I spent three years messing around with the problem.

Quote:

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Originally Posted by donovan

don't take my comments and change anything!

Just pull the valve covers and inspect them regularly, and plan on changing the valve guides at the end if each season if you run every event.

I found that is what I needed to do.

I will send you some more info later, I spent three years messing around with the problem.

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David,

If I change to the 1.6's will that fix the problem?

JJ

Yes that would remove the issue.

Side loading the valves is causing the guides to wear faster than normal. Once they are worn bad enough it will allow the roller tips to walk out eventually the aluminum makes contact with the tips.

I have had this happen twice and both times the guides were worn very bad... the valves were still sealing fine but the top half of the valve guides were badly worn out.

This happened with a Stock Cobra setup and again with aluminum heads with FRPP 1.7s... Once I went to studmount 1.6's I have not see the problem.

DD

Quote:

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Originally Posted by ShadowBolt

If I change to the 1.6's will that fix the problem?

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Unfortunately, 1.6 RR's are not CMC legal. Or so I've been told - 1.6 ratio RR's were never offered on a stock 5.0L engine. The stamped steel rockers are 1.6, but they aren't rollers.

Going to screw in studs and guide plates is really the only way to do RR's, but that's not permitted either.

Quote:

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Originally Posted by Adam Ginsberg

Quote:

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Originally Posted by ShadowBolt

If I change to the 1.6's will that fix the problem?

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Unfortunately, 1.6 RR's are not CMC legal. Or so I've been told - 1.6 ratio RR's were never offered on a stock 5.0L engine. The stamped steel rockers are 1.6, but they aren't rollers.

Going to screw in studs and guide plates is really the only way to do RR's, but that's not permitted either.

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So in CMC the only thing to do is run the 1.7's and tear up the heads?


JJ

or, you can run the stock non-roller 1.6 rockers.

You shouldn't need the rollers to make the numbers.

Quote:

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Originally Posted by donovan

You shouldn't need the rollers to make the numbers.

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According to several FFR's drivers, this is true. They dyno'd before and after installing a set of RR's, and only found ~3-6 HP....not worth the $$ and hassle, IMO.

yup, when I went from 1.7 to 1.6... I saw only a slight change, not even 1 percent..

They are only opening the valve slightly more, you are not going to see significant changes till you open them longer or change the LSA.

DD