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1.7~1.8 RR's + XP cam?

Roller Rockers with XP cam?

  • Total voters
    3
  • Poll closed .
OrangeL67

OrangeL67

New member
Has anyone done this with some good results?

I'm pretty sure I broke or damaged one of my 4 year old 90# valve springs...

So the plan is to yank the heads, get them agressively ported, install 130# springs, double roller, 1.89 & 1.55 valves, and mill the guides to allow for RR's over the cam.

I swapped to a gen V a couple months ago and I'm really anxious to see what gains can be had from a gen V & ported heads. If I'm not satisfied, I will be putting RR's on top of the cam. I thought about going to a bigger cam, but I don't wanna rev an l26 to 6800rpm.
 


1.8 rollers would be a sidegrade at best... and I wouldnt want to run the 150# springs and upgraded trunion bolts required for #150 springs with that sort of cam profile. You are not going to get any more lift out of a 1.8 roller, although you may get a bit more ramp rate, its not really needed to take advantage of a ported head.

Stock rockers consistantly make more power for a reason. Get an XPZ in there and run stock rockers on it... its proven time and time again that nothing beats a xpz/head combo.
 
darkhorizon said:
1.8 rollers would be a sidegrade at best... and I wouldnt want to run the 150# springs and upgraded trunion bolts required for #150 springs with that sort of cam profile. You are not going to get any more lift out of a 1.8 roller, although you may get a bit more ramp rate, its not really needed to take advantage of a ported head.

Stock rockers consistantly make more power for a reason. Get an XPZ in there and run stock rockers on it... its proven time and time again that nothing beats a xpz/head combo.
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Won't the stock rockers cause more wear to the valve guides with the high lift of the cam. I got an XPZ, but was considering using 1.7 rollers with it.
 
valve guide wear shouldnt be an issue unless youre trying to run the car with no oil.

rollers for the money are just not worth it in the end, regardless of the setup.
 
darkhorizon said:
Get an XPZ in there and run stock rockers on it... its proven time and time again that nothing beats a xpz/head combo.
Click to expand...

^This is what I want to do, but I don't like the rods in the L26. They have a trend of giving in under high boost/ high rpm combo's. I'd hate to yank em up and down at much more than 6k. Won't I have to set the shift points on the moon to take advantage of an xpz?
 
I did 1.8's on the S1X and heard of a few buddies doing it on the XP. It's added lift. I felt that it helped a good amount.

On those valves. Watch out that you don't go outside of the hardened seat area.
 


OrangeL67 said:
^This is what I want to do, but I don't like the rods in the L26. They have a trend of giving in under high boost/ high rpm combo's. I'd hate to yank em up and down at much more than 6k. Won't I have to set the shift points on the moon to take advantage of an xpz?
Click to expand...

No.... Its not a very RPM heavy cam.

You probably wouldnt have any more problems with RPM than you would with anything else.. L26 rods are just wuss so avoid stupid stuff with it.
 
darkhorizon said:
No.... Its not a very RPM heavy cam.You probably wouldnt have any more problems with RPM than you would with anything else.. L26 rods are just wuss so avoid stupid stuff with it.
Click to expand...
(Stupid stuff) Any specifics? I want to shift at 5900-6k on the street (5900 into 3rd). Maybe 6300 1-2on the strip (6000 into 3rd). I was also planning on going with a thin mls headgasket to put my compression at 10.01:1. In theory, the overall internal pressure should be offset by the drop in boost the heads should provide.My understanding is that rr's over a mild cam as opposed to a bigger cam will give a stronger power curve without moving the powerband higher in the rpm's. Anyone that can confirm this?
 
boost has nothing to do with cylinder pressure.

its possible a 1.8 rocker could give some gains in "low end power" but it would be nearly invisible in reality. for 200 rpms you might make 4 more horsepower.

The simple fact that you need 150# springs and drill out your heads for bigger rocker bolts.... should turn you away from that idea.
 
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