I am just full of questions tonight. graemlins/clonk.gif I need to measure for non stock length pushrods. Is there any prefered method or measuring tool for this? The Manley pushrod length checker looks the simplist...anybody ever tried one? I assume I will need a non stock length because of the small base circle cam and block being milled .020.

I can't speak for the Manley checker, but I used Comp Cams 7901 (http://www.compcams.com/catalog/277.html) and instead of adjusting the length by the adjuster nuts that come with the rod, I just stacked flat washers inbetween and tightened down the two rod pieces. It works out nicely, this way you can tighten down the rod and not worry about the stop nut spinning.

If I remember right the 7901 has a min. length of 7.5".
If that 'small base circle cam' is a roller or you have made other mods you may need the shorter 7905 model, it meassures from just over 6" to about 7.5" if memory serves.
I use two of both so I can check one cylinder at a time - saves set-up time.

check out that comp link above, and scroll down to the hi tech checking pushrod. i have # 7703-1, and it works incredibly sweet. each rotation equates to .050, so you dont have to mess with measuring the overall length, since its already known, + number of turns, its very simple. i have used it several times, and its been dead on every time. before you buy a checking p-rod, throw a stock one in there and see how close it is. this will tell you which way to go with the checker. you may be surprised to find the stock one very close. you lose some length with decking, and gain some with small base circles. and then the valvetrain setup (such as longer valves) change things further. just check it with a stocker, then go from there. hope that helps, good luck

travis

Check the following link for info on checking your push rod length.

http://www.holley.com/HiOctn/TechServ/TechInfo/IECVTTech1.html

http://store.summitracing.com/partdetail.asp?part=TFS%2D9001

http://www.powerhouseproducts.com/store/merchant.mv?Screen=PROD&Store_Code=PH&Product_Code=POW101215

http://www.powerhouseproducts.com/store/merchant.mv?Screen=PROD&Store_Code=PH&Product_Code=POW101220

You can use the Manley tool($15) and buy an adjustable pushrod( $12.00 - $17.00 ) for a total $30 bucks vs $65 for the Lunati kit. You can get one of the adjustable pushrods for from Summit or Powerhouse Products(CompCams) or I am sure your local speed shop can get them. You can get by without the Manley tool and just use a standard 7.800 pushrod and see what the pattern reads, too long or too short then do the procedure with the adjustable push rod and adjust according. Keep trying until you get the correct pattern then measure the adjustable pushrod or if you use the Powerhouse(CompCams) pushrod count the turns out from the base and multiple by .050 and add to the base size of the adjustable pushrod and order the correct size pushrods.

Jeff

Travis,
I made my own using a 3/8" sbc pushrod. Cut a small section from it, tapped the inside for a stud and threaded the halfs to it. I also ground some flats on each end for help is adjusting, but it's not really necessary.

Dave

The Manley is really easy. USe a stock length pushrod, get the cam on its base circle for that lobe ( as if you were setting lash), put the tool on and see if there is a gap off the pushrod ( pushrod too short )or off the valve tip ( pushrod too long ), measure it and you know the correct length to order up. Fool proof.

Fool proof, I might have just gotten that backwards.

WOW, I'm really missing something here......it's me for sure....but, I can see how the Manley tool works, but with an adjustable pushrod and a rocker installed, at what point do I check the length? What do I run the lash adjustment down to? It seems to me that you can run the rocker adjustment nut down and close any gap. I am missing something...what is it? Thanks for the help!!

Wow :eek: this thread is 3 years old!

Chuck, there are two (or more) ways to check for correct pushrod length.

The easiest way to get "in the ball park" is using the Manley or Tavia fixture. The lifter needs to be on the cam base circle and you put the pushrod in and install the fixture instead of the rocker arm. Then you use a feeler gauge to determine how much too short or too long the pushrod is. If its is more than about .050" then get different pushrods.

The other way is to use an adjustable pushrod and install it like a normal pushod at the length you believe is correct. Color in the top of the valve tip with a marker or layout dye and install the rocker arm like you would with the engine running. Rotate the engine over by hand at least two full revolutions and remove the rocker arm. There will be a "witness" mark in the ink on the valve tip. The mark should be narrow and centered on the valve tip. Adjust the pushrod length and restest until you have the best results.

Thanks Eric....I think I have it now...just set it up per standard with an approximate length estimated, then rotate 2 times to check pattern, then adjust longer or shorter, with correct lash, from that point to get the rocker arm to travel evenly over the same valve tip area. Not too far one way vs the other.