Re: questions on roller rockers

From: Bob Tom (tigers@bserv.com)
Date: Sat Oct 23 1999 - 11:25:06 EDT


At 04:53 AM 10/23/99 -0500, you wrote:
>Now that my dak is pulling harder and higher in the upper rpm band (I'm
>shifting at 5200 - 5500) I'm starting to worry about the valvetrain. I'm
>thinking I should upgrade to some good roller rockers, maybe stiffer springs
>and some hardened push rods. But I don't really know where to start. When
>you do roller rockers do you change anything else (springs or rods)? I want
>to make things as safe and reliable as possible for higher revs. So what
>should I do?

Me again.

Mike, you could just do roller rockers by themselves but would need pushrods
if you use rockers different from the stock 1.6. I'm using the MP 1.6
aluminum
roller rockers. A set of strengthened and properly-sized pushrods comes
with them.

Some feel that a set of aftermarket 1.7 rockers would give more power than the
combination of aftermarket 1.6 rockers and MP cam. If you decide to go the
1.7
route, some modification will have to done to the stock valve covers. The
other
alternative is to get the MP Magnum valve covers because they are a bit
higher.
Naturally, you would have to get a properly-sized, strenghened pushrods for
the
1.7 (they may or may not come with the rockers).

To strengthen your valvetrain components, you would definitely need to replace
the stock valve strings. I use the MP valve springs which require a set of
special retainers. The springs allow me to go to 6000 rpm without
experiencing
valve float.

I'm using the MP cam with the MP springs/retainers/rockers/lifters. With
the MP cam
comes a beautiful set of lifters (as a matter of fact, got 10 with them?).

I selected these parts because Ontario has just implemented their clean air
testing
program. What I found was that these valve train components gives the
stability
and durability that I needed (did not show up with great et improvement
numbers).
The MP cam really showed itself at mid/upper rpm with a bit of loss of low end
torque. The F&B TB brought back more of the low end torque than I had loss
and
increased torque/hp throughout the rpm range. My missing part was to change
the effective gear ratio. I was running 28" drag radials (e.g.r. of 3.50).
When I switched to 26" drag radials (e.g.r. of 3.80), I broke into my goal
of the 14.9s. A gear swap would have been better in my view but I couldn't
justify the cost and I really liked how the Dak runs on the street with the
28".

I couldn't find the invoice for the parts so I could't include the part
numbers.
If you would like them, I'll see if I can find them and send them to you.

Hope this helps.

Bob. Southern Ontario, Canada.
'97 FR CC Sport, 5.2L, 3.55 SG, auto.
Racing weight: 4,350lb ET: 14.934 Trap speed: 90.78 mph



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