roller rockers 1.6 or 1.5 or?

so I pull the rocker covers off my bought-at-auction hot rod and find I have 15 roller rockers. And one stock cheby part. So

the rockers are blue alum with "c15" the only marking i can find. what manufacter? what ratio?

a good friend has new set of 1.6 he is willing to donate to the cause. i have no idea what cam piston is in the moter. (sounds stock) is there a way to tell if these will work?

a full rebuild is not in the budget.

thanks for the support

 

you will have to determine your valve to piston clearance.Don't try it without knowing this or you could damage things

 

Chances are they're a 1.5 ratio. Can you get the engine on TDC and remove 1 of the valvesprings? Let the valve fall in the motor, measure it's height, then re-seat the valve and re-measure. There is the amount of travel you can have. Subtract the clearance you need and go from there.

Not the most kosher way to measure but it will get you in the ball park.

 

stick with the 1.5 better safe than sorry more lift more problems

 

Trade him half, put the 1.6's on your exhaust valve...tell him to do the same.

 

Put them on and turn the engine by hand. Measure the distance between the spring coils at max lift. No bind, good to go on the springs. Now while still at max lift, push the valve down to coil bind and feel if it hits the piston. I have never seen a stock setup that couldn't handle going to 1.6. Its the wild stuff you have to worry about.

 

Can you post a photo for brand ID? Mr Gasket used to sell blue ones, and Wolverine as well, IIRC. I have a set of Mr. Gaskets. They date from the seventies, guess I should ebay them as "GASSER!!!!" parts...And run the 1.6's on the intake side NOT the exhaust.

 

There's more to changing to 1.6 from 1.5 than just clearances! If you just bolt them on, and don't check the wear pattern on the top of the valve stem you can get into big trouble! You'll need to put an adjustable pushrod into one hole and then turn the engine over to determine the correct pushrod length to be sure the end of the rocker travels centered on the valve stem. If it's not centered, then you adjust the pushrod until it is, and that's the pushrod length you need to buy.
So if you swap to 1.6 rockers, plan on buying a set of pushrods to correct the valvetrain to those rockers.

 

Blue roller rockers usualy are Pro Comps (China) sometimes they have a name change and will be Summit or Jegs brand.

 

Yup showing my age, forgot about the Pro Comps.

 

You may also need to lengthen the pushrod hole...

 

^ this
its almost a standard thing
some places offer to sell them that way

 

Do NOT do this, verno I am not trying to upset you, so don't go balistic, this way is totally incorrect by all means.

Neither of the valves will be closet to the piston at TDC, it doesn't work that way and any engine builder knows that.

Safe to say without knowing anything of the internals of this engine, the only good advice here is to replace all rockers w/ 1.5 ratio.

Now for $80 Speedway Motors has these awesome little roller tip rockers, not full rollers but roller tip. These are really nice pieces and the price is right on the money. I have used these before in several low end builds. They are called Sportsman Roller Tip Rockers, made out of 4340 H.T. steel. Still check your pushrod length just out of good practice, all the best, TR

 

Be very careful. We have checked a lot of 1.6 rockers at my buddys machine shop. Quite a few different kind. Most of them were a lot closer to 1.7 than 1.6.

 

100% correct.