I just bought a car with a carburated 355 in it. It has World Products SR Torker heads on italong with 1.52 Roller rockers. The guy I bought the car off of also said that the engine has +.100 pushrods in it. My question is... why would this engine need these ? I looked up the info on the World Products webpage and it said that standard OEM pushrods can be used. Is there any other reason that the +.100 pushrods are in there ? And should I change them out for stock length ones ? Thanks,
Stryker

 

The key is that you want proper rocker arm geometry. You want the tip of the rocker to start towards the inside edge (intake side) of the valve stem tip and then work towards the outside edge of the tip as you reach 2/3 (not 1/2 as I used to do it) of your cam's maximum lift. Then the final 1/3 of the lift it will work back towards the inside of the tip again, but not get completely back to where it started.

Usually longer pushrods will be needed if the cam has a smaller base circle than the stock cam. Also, some rocker arms require longer pushrods. Check with the rocker arm manufacturer to see if longer pushrods are required by them- but your heads don't need them.

But with S/R Torquers, stock rockers and a stock base circle-type cam, stock length pushrods are what you want. If anything, they will sometimes be a smidge too long after you get done machining down the heads and block. Going a little too short is usually safer than going a little too long with a higher then stock lift cam.


[This message has been edited by Damon (edited September 06, 2002).]

 

Thanks guys, I'll start checking out all the info on this engine.

Stryker

 

You mean longer?

 

OK here is what I got so far.... I have the world products S/R Torker heads with ARP rocker studs, and the Comp Cams Magnum roller arms #1412-16 ( http://www.compcams.com/information/...gnumRoller.asp )with a 1.52 duration. And as far as I know, the valves are standard length. I am not sure what brand or type of cam is in there other than it is a hydraulic flat tappet cam. Now, I have a couple of questions. 1st, when I looked at where the roller tip sat on top of the valve it looks to me like the middle of the roller tip is about in the middle of the valve or maybe just a hair past the middle to the outside. Do I need standard length pushrods to get the valvetrain geometry back in order ? 2nd, when the rockers are tightened correctly the bottom side of the rocker "ball socket" (not sure if that is the right term, but I dont know what else to call it) actually touches the rocker arm stud and has left slight marks on it. Is it supposed to be like this or is there something that I am missing here ?
Thanks for all the help,

Stryker

[This message has been edited by STRYKER (edited September 07, 2002).]

 

Buy a Moroso pushrod length checker for $12. I think it's Moroso that makes it. It's a simple plastic piece that you slide over the rocker stud and makes contact with the valve tip and the pushrod tip. If it touches the pushrod tip first, the pushrod is too long. If it touches the valve tip first, the pushrod is too short. It's not a perfect or dead-on exact way of checking but it works just great for basically stock setups like yours. I still use this tool all the time to give me a quick sanity check.

Just remember to contact the rocker arm vendor and see if they have any special requirements for pushrod length with those exact rockers (probably not, but it doesn't hurt to check if you've come this far).

It is common with stamped steel rocker arms that use a ball-type fulcrum to leave little wear marks on the sides of the rocker stud as the sides of the slot in the bottom of the rocker arm swipe back and forth past the stud. Heavy wear, however, would be a sign of something wrong. Just "shined up" spots where the 2 parts wear past eachother. If there are ANY signs that the front or back of the slot in the rocker is touching the rocker stud that is BAD. That means it's actually using up all the travel in the slot and binding metal-to-metal against the stud. If you have bad rocker geometry this can happen but it needs to be really pretty far off.



[This message has been edited by Damon (edited September 10, 2002).]

 

Damon... Thanks for the reply. I did find out the problem though. It seems as if the heads were bought a LONG time ago and the raised boss for the rocker studs were never machined down to accept the screw in rocker studs. I had a guy from the local speed shop come over to my house to check it out just to make sure I wasn't going insane. We compared the heads on my car to a head that he brought with him from the speed shop and sure enough, I was right. The heads I have on the car now have about a half inch higher rocker stud boss than the small block chevy head that he had. Sooooo..... its off to the machine shop I go. Thanks goes out to all who have responded.

Stryker