It’s a common question in our world: Does this automotive widget work as promised? Roller rockers are among the more popular and often misunderstood widgets, and they promise seemingly magical gains with few downsides.
Do roller rockers really improve performance, save gas and make your teeth whiter? Well, it helps if you know how they work, when they’ll work for …
The use of roller tip rockers with higher than stock ratio will increase lift but also eventually wear out the valve guides (although not as quickly as high lift non-roller rockers would). I don't mean tomorrow, but 30-40K down the road, you may end up with guide issues. It sure works while it works though.
Just don't be 'that guy' that buys valve train components from three different manufacturers because they save $5 doing it, only to find that they ended up with valve spring 'crunch' when the spring is compressed fully with coil touching coil and the rest of the valve train si still trying to compress it more - I've seen that and it isn't pretty.
As noted, increasing rocker arm ratio increases valve lift. Increasing valve lift also reduces valve-to-piston clearance. No, you don't want your valves to touch your pistons - bent valves or punctured pistons can result. This could be a concern if you already have a high lift cam, high compression pistons, a milled head, or a decked block.
In reply to jefeingold :
Correct , you need to do the math and double check everything for clearances. When done right, the gains can be huge....
Let me guess, Dougie - do you cover all that with a nice alloy cover? They certainly are pretty.
Of course the best rockers are none at all.....
wspohn said:Let me guess, Dougie - do you cover all that with a nice alloy cover? They certainly are pretty.
Of course the best rockers are none at all.....
That would be true if your car sat in the garage or only saw the grass of a static car show.....I exercise mine on the track regularly as the upgraded engine was designed for.....
Nice driving Dougie.
Maybe I'll see you out at PIR one of these days. If I can get my car together...
you can waste horsepower with too stiff valve springs
Roller rockers were once suggested by a cam grinder named Racer Brown, who was also an advocate of roller tappets for street motors. This was from an issue of Hot Rod probably in the very early 1960s.
Racer Brown was the originator of the statement, "If a little is good, a lot is better, and WAY too much is... usually... just enough." Interesting guy!
dougie said:In reply to jefeingold :
Correct , you need to do the math and double check everything for clearances. When done right, the gains can be huge....
Thank-You for my new screen saver. Simply meticulous work sir.
Of minor interest. Roller rockers were suggested in the early 1960s by Racer Brown, a can grinder who was an advicate of roller tappet cams for the street. It was an article in Hot Rod Mag. Included in the article was a quote from Racer Brown that I've used a thousand times. "If a little is good, a lot is better and WAY too much is...usually...just enough."
That Racer Brown comment probably came from the use of nitro blends in drag racing. Guys mixed nitro with gas and alcohol in varying ratios right in the pits, and only the bravest went with 95%- right out of the can. Quite a number of those racers also died early of liver & kidney damage blamed on unprotected mixing of nitro, hydrazine and other nasty chemicals.
I found with roller rockers that my oil temps went down with reduced friction, and that the rollers on the tips were only unhardened tool steel that would flat-spot if you floated stellite-tipped valves. Being a poor boy, I refaced a few flat rollers with a drill press and a sharp file. Those were the only effects, and most of the benefit was not having to run an oil cooler in some cases.
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