Rocker ratio and hot cam

[turbo91xlt]

ALL roller rockers have the same ratio. The only difference between the the '89-'94 & the '95+ is that the older ones are cast and fit the 11/32" valve stems while the newer ones are stamped steel & fit the 7mm valve stems in the newer dual plug heads. The information from that Route 66 website has been proven false for years now by the "big guys" in the Lima game such as Esslinger & BoPort.

The 1.64 ratio is for the slider followers found in pre '89 heads.

 

[tomw]

Turbo91, I had read somewhere that roller followers could be plopped in place of the earlier slider style.
Is that true? Someone said they had done it and it worked. It seems the boneyards want to sell complete cylinder heads and are not really enthused about selling cam & followers.
If the rollers fit, would they also improve the lift of the older followers given the ratio is different? I'd think the 'contact' spot between roller & lobe would have to move one way to get the ratio to change. Which might make the swap not a good thing.
tom

 

[turbo91xlt]

You could if you really wanted to but I would strongly recommend not to. All the slider cam's are cast while the roller cam's are made from a billet blank (aftermarket roller cams at least, oem ford roller cams use a different method with the lobes pressed onto the shaft). I suspect its for durability issues because other wise everyone would run aftermarket slider cams (under $200) instead of forking out $450+ for roller cams.

 

[tomw]

The roller is a threefer, I think. Ratio upped, less friction vs the sliding follower, and more lift on the cam lobes. What's not to like?
The sliders have more friction, and thus are less durable. I have heard of many inspection reports on rollers, and it seems the cams are the same as when they were ground/assembled with no appreciable wear. The shear spot between the lobe and follower is one of the worst areas to control wear and damage as the parts are in shear. The followers don't even have the possibility of rotating as normal OHV lifters do, which would allow the contact area to move around the lifter bottom as the lifter rotates. Theyz inna bad spot... I also read somewhere that adding a roller cam adds hp & torque, so that's another plus, making it a four-fer? Improved mpg? Sure, why not... a five-fer.
tom

 

[cbr600rx7]

Just to update every one I have been talking to crower and will be sending my stock cam in to them for a re grind. Nothing crazy by any means but I would like to see if they can add 2-4 degrees of cam advancement and see if they can lower the LSA slightly. Just trying to add a little more power below 3000 rpms. They will also spec the stock cam so I will report back with the before and after specs.