1.7 Rockers w/stock LOPO everything else?

[91gmblack]

Hi,

I'm going to replace the original VC gaskets this spring, and have the following question (i did a search, but I'm still not sure):

"Can I use the Crane 1.7 roller rockers (that a lot of members seem happy with) on my stock 1991 LOPO 302 and not have to change anything else? "

The engine has 200,000 miles, runs great, no oil burn.
I'm asking now before i order them online.

I'm thinking of doing this to extend the life of the engine.
Any thoughts? Opinions?

Thanks Much,
91gmblack

[mrltd]

Yeah, you can. But it won't help anything, except to make you wallet thinner. It will not extend the life of the motor at all.

[Blaze86Vic]

If anything it'll make it start burning oil. Old engines don't take well to modding, because the old parts are all throughly worn together.

[phayzer5]

Scorpion rockers are a better value than the cranes. Same part less $$. If you ever went crazy on your motor the pedestal mount rockers would limit your aftermarket head choices

[Lincolnmania]

i agree

[import convert]

so what are the different types of rockers and what do they do besides make the valvetrain work a little smoother? ive always wondered what the different ratios meant (1.5, 1.6 1.7) and if they extended the lift distance or anything like that? ive heard some kids say they arnet worth useing but i was never sure if htey were right or not?

[gadget73]

the stock ratio is 1.6:1. basically for every x amount of lift at the cam lobe, the valve moves 1.6 times that. Changing the ratio changes the effective lift of a cam. Cam specs are normally given as the lift at the valve with a given rocker ratio, usually whatever ratio is stock, or it will specify.

example cam specs, this is a stock HO cam
intake lobe lift: 0.278 inch
valve lift with 1.6 rocker: 0.444 (this is the figure everyone knows)
valve lift with 1.7 rocker: 0.471

the roller rockers also have roller bearings and a roller tip where it contacts the valves. The stock rocker is stamped steel, and has a half-circle pivot, just metal on metal which makes for a lot of friction. Same with the contact point at the valve tip, metal on metal. Roller rockers are aluminum, they have a wheel on the end to contact the valve tip, and actual bearings on the shaft. Basically it reduces the friction in the valvetrain a little. Its probably not enough to actually feel in any case.

Honestly on a high mileage stock engine, its probably not going to give you much. With 200k miles, I'd also be leery just because any cruft thats built up on the valve stem outside where it normally moves through the seal will suddenly be moving into the seal with more valve lift. This might damage your oil seals and make it start burning oil. If its running well, change the gaskets and leave it alone.

[1987cp]

I installed an HO cam in my bone-stock '87 motor after rebuilding the shortblock but not the heads, and really annoying ticking noises resulted. This sounds like a really convenient time to upgrade to a better factory head ....

[cld783]

1.6 rollers wouldnt hurt anything, im not even sure a set of 1.7s would either if your motors in good shape.

if you insist, just to be safe get a good set of 1.6 ratio for cheap with some new rods and you cant go wrong. either way like others said you wont gain much.