hi guys,

Just called the engine shop to see how things are going together. It turns out that rocker arms are about an 1/8" off from where the push rod comes up. I called 440 source and they said it's not uncommon to have to clearance heads. But i'm not sure about taking an 1/8 off, Should i try another set of roller rockers??? the rockers are 1.7 ratio.
Not to sure on how to continue,or should i get them to grind the 1/8" per rod???

Thanks.

Had this same problem with 1.6 rockers on stealth heads. Pushrods that are too short will make problem worse. Solved by clearencing the heads and installing longer pushrods. Hope this helps.

Roger

oh really, he noticed it when he went to check the push rod lenth needed to be ordered.

Any one else have this issue as well?

1.7 is far from stock. You might have to clearance any head for something like that.

Answer me this...

Aren’t the stock rockers 1.5 to one?

And you are at 1.7?

A few companies sell 1.6 but not very many sell 1.7 Wonder why?

hi there,

here are the engine specs,

400 block bored .30 over
440 source 515ci blanced rotating stroker kit
Main studs, Gridle, windage tray, modified deep oil pan,
440 source Stealth Heads
Isky 292H Cam I belive is good for alittle over 500/500 lift,

I recieved these 1.7 rollers as a gift to help my engine build, I was told it would also help to raise the amount of lift.

I was thinking of just buying the whole 1.6 set-up from 440 source and see if that helps.

What do you guys recomend i do?

This is going to be for a race car as well.

Thank you for the help,

Your call but



This is from Hot Rodding

Quote:

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The rocker arm mechanically multiplies the cam's lobe lift. It does this by moving the pushrod closer to the fulcrum pivot point than the valve stem tip is. A simple example would be: if the valve tip centerline is located 0.750-inch away from the rocker fulcrum pivot centerline, then a 1.5:1 ratio rocker would have the pushrod cup located 0.500-inch from the pivot centerline (.750/1.5=.500). When you increase the ratio to 1.6, you obviously can't move the valve or rocker arm stud, you have to move the pushrod cup closer to the pivot centerline. So, now the math (.750/1.6=.470) tells us that the pushrod centerline is roughly 0.030-inch closer to the fulcrum pivot. This arrangement does more than just multiply cam lift. It also multiplies the loads on the pushrod, lifters, and rocker arms, making the proper ratio critical. Too much ratio will open the valves too quickly and can cause valve float at high rpm. It also multiplies the spring pressure seen on the cam lobes, so running too much ratio can wipe out a flat-tappet cam in no time. Thankfully the cam manufacturers have studied these problems and most won't even sell you too much ratio

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If you want to use the 1.7 rockers you will need to grind it.

um, very informative...

So i'd bet at 1.5 ratio there would be no problem since it's at stock.

But when you .1 and up, it brings the center piviot closer causeing the need for clearancing.

interesting about spring pressures. I never even thought about that. um.

I would like power with longevity. so what do you guys think 1.5 or 1.6 ratio????

I guess there are pluses to both but for a mostly street motor I would go with 1.5's and dial in the lift with the cam selection itself. Or maybe go with a roller?

My pushrods were too short when I changed from the iron heads to the Stealth heads. I just had new pushrods custom made to fit for about $115 delivered to my door. A place in Southern California that my mechanic uses. Don't know the name but can get it easily.