Pushrods

[nuteguy]

I'm rebuilding my 440 right now and went with an Edelbrock top end kit. The builder who did my machine work recommended 80 wall pushrods so I called Edelbrock and asked for a length. I was told 9.125" so I ordered some from Jegs (http://www.jegs.com/i/Manley/660/25928-8/10002/-1). Now that I have finally gotten to put them in, they are too short. I tried my stock ones and they seemed to fit well with the stock rocker arms that I am using. I am going to return the pushrods that are too short. However, I measure the stock pushrods to be 9.25". On Jegs, COMP Cams has pushrods that are 9.300" which they say are the stock length (http://www.jegs.com/i/COMP-Cams/249/7923-16/10002/-1?parentProductId=).

What should I do? Also, are the tips on the COMP Cams pushrods above correct?

Thanks.

 

[lewtot184]

stock ball/ball pushrods are 9.31". i've found that the edelbrock heads need a custom length push rod.

 

[Cranky]

Any time you make changes to the top end from head gaskets to heads, you need to measure to make sure what's exactly needed....

 

[khryslerkid]

I ran into the measurement discrepancy not that long ago. Some measure the ball and cup pushrod from the outside of the cup, some measure from the inside of the cup. I ordered what I needed, they were advertised as overall length and when I received them they were too long. The measurement was the inside measurement. So always ask...

 

[Cranky]

I ran into the measurement discrepancy not that long ago. Some measure the ball and cup pushrod from the outside of the cup, some measure from the inside of the cup. I ordered what I needed, they were advertised as overall length and when I received them they were too long. The measurement was the inside measurement. So always ask...

Some of the phone techs have no idea how they are measured but for the most part, these guys know how to measure..... http://www.pushrods.net/

 

[nuteguy]

stock ball/ball pushrods are 9.31". i've found that the edelbrock heads need a custom length push rod.

Would you know what that custom length is?

Also, Edelbrock advertises the heads as bolt on, out of the box. I know assuming is the worst and that may be said only for advertising purposes, but that would mean you should be able to use stock pushrods with those heads.

 

[Xp29h]

I've done a couple of different custom length pushrods for two separate applications. I had to mock up with expandable pushrod to correct length, measure then used these guys both times. They came in perfect.

http://www.4secondsflat.com/smith_brothers_custom_pushrods.htm

They have good directions for measuring. Good luck hope it helps..

 

[lewtot184]

Some of the phone techs have no idea how they are measured but for the most part, these guys know how to measure..... http://www.pushrods.net/

this! smith bros. can walk you thru the hole process,

- - - Updated - - -

Would you know what that custom length is?

Also, Edelbrock advertises the heads as bolt on, out of the box. I know assuming is the worst and that may be said only for advertising purposes, but that would mean you should be able to use stock pushrods with those heads.

i'm using a solid lifter cam with the edelbrock rpm's. to get proper geometry i had to order push rods .170" longer than the standard off the shelf push rods for a solid cam. i don't consider edelbrocks a true bolt on. geometry and push rod length must be checked.

 

[Yatzee]

Don't mess around guessing the right lengths because the thickness of your head gaskets can adversely affect the operation of your valve train in respect to travel. You need to purchase a rod length checker for the type of rods your engine uses and measure the length with the heads torqued on. This is the best place to purchase custom length rods:

http://trendperform.com/

They will walk you through the type, wall thickness and oiling method. They will want the effective length you require which is from the tip of the ball to the bottom of the cup. You can only get the proper length by using a rod length checker, anything else is just a guess at best.

 

[lewtot184]

rocker geometry!

 

[nuteguy]

I'm using Edelbrock's hydraulic cam and lifters. Figured I'd add that information.

 

[lewtot184]

type of rocker arms is relevant.

 

[nuteguy]

type of rocker arms is relevant.

Stock

 

[moper]

It is critical on any build that the last thing that gets ordered is the pushrods, and they are ordered only after measuring for correct length. This is more critical if you're using a modern camshaft grind, and non-adjustable rockers. My advice would be to assemble everything, buy a pushrod length checker (Summit/Comp sells them) and then measure to ensure proper lifter preload. Then call Manton or Smith Brothers and order exactly what you need.

Edit - the reasoin it's critical is the block and heads were probably machined (or replaced entirely), the gasket thickness varies by design and manufacturer, the valve job, and camshaft manufacturer will all affect the effective length of the pushrod.
Rocker geometry has nothing to do with pushrods on a shaft-type rocker system like factory Mopars use.

 

[lewtot184]

geometry needs to be corrected first before push rods can be measured. mine was off a bunch.

 

[Rocketman]

I did the 2087 top end kit but I went with Comp cam, rockers, and pushrods and the pushrods were custom made, I can't remember how long they were and unsure if I have the receipt.

 

[nuteguy]

I just called and spoke with Edelbrock. Apparently I need to run adjustable rockers with a stock ratio. This is the first I'm hearing of this so needless to say I'm slightly annoyed that that was not advertised a bit more.

 

[lewtot184]

I just called and spoke with Edelbrock. Apparently I need to run adjustable rockers with a stock ratio. This is the first I'm hearing of this so needless to say I'm slightly annoyed that that was not advertised a bit more.

you can run stamped steel rockers if you want. i keep beating on this so i'll ask straight up, do you know how to set the geometry? if you don't set the geometry the rockers will eat up the valve guides; mine were awful.

 

[nuteguy]

you can run stamped steel rockers if you want. i keep beating on this so i'll ask straight up, do you know how to set the geometry? if you don't set the geometry the rockers will eat up the valve guides; mine were awful.

I don't know how to properly set geometry but am more than willing to learn/teach myself. Why can I run stock rockers if Edelbrock says to run adjustables? Why does Edelbrock say to run adjustables?

I'm not questioning you or your logic, just trying to get a concrete understanding.

 

[dvw]

geometry needs to be corrected first before push rods can be measured. mine was off a bunch.

Would you like to elaborate on how it was corrected? As others may or may not know, lift at the valve dictates the optimum shaft height. If its incorrect, the shafts are in the wrong location. Push rods do not alter geometry on a shaft rocker system. So ideal geometry depends on valve lift for each application. I believe this is out of reach for the average street enthusiast.
Doug