I need to overnight a set of pushrods. I want something stronger than stock. Cam is 236-242, 1.6 rr's, and crane springs. Should I order the stock length?

 

Probably. Best bet is check length with a p-rod length checker and buy accordingly. Pay now or pay more later.

Ryan

 

I understand. I am a dummy. I do not have the tool. I do not have th expertise. The guy doing the work probably doesn't either... I have a points race Sunday. They are currently stock but have been breaking with regularity.

 

Already I'm seeing problems.

 

Stock length pushrods are currently installed.

 

Do you think your problem is push rod strength or geometry? Without the tool I would put in a stock pushrod and then draw on the valve tip with a black marker, re-install the rocker, and rotate the engine through a valve event. Remove the rocker and check the wear pattern on the tip...The marker will wear off where the roller of the rocker arm is riding on the valve tip. You want a centralized wear pattern on the tip...If this is the case then stock length is good.

Anyway, with your mods you should definitely have pushrods which are stronger than stock..Hope this helps..
--Alan

 

You can overnight them on Friday for Saturday and be ready for Sunday's race.

Pull valve cover

Install pushrod-checker set at stock length.

Set valve lash for that valve

Rotate the engine while watching the rocker tip

You want the rocker tip to cover the top edge to the bottom edge of the valve tip as you roctate the engine. You DON'T want the rocker tip to spend more time on one end of the valve tip. Adjust pushrod until you get the rocker as close to staying in the center of the valve tip as possible.

Measure adjustable pushrod with a caliper and order that size.

Also, now is a good time to inspect valve springs with a pressure checker and look for mushroomed valve tips. Your engine is trying to tell you something. Right now it is talking (bent p-rods). It might start yelling at you (valves into pistons).

Just trying to help. Good luck,
Ryan

 

I had a similar situation when building my 383, with the block cut .013 and .039 head gaskets and the heads cut .035 the stock pusdrods had to be almost bottomed out in the lifter to center the rocker when cam was on base circle.
I ended up getting .050 shorter pushrods and I'm spot on now, so if you know how much the block & heads have been cut then add those up and get pushrods that much shorter.
Now of course all this assumes your cam is standard base circle diameter.