Leo's book recommends a chrome moly .075" wall thick pushrod for street use. Where can these be sourced thru because I'm not seeing them in places like Jegs and Summit.
I'm running a Clay Smith cam with a 560 lift in my 292 and I just broke a stock one. I'm hesitant to go back together with a stock pushrod and I'm wondering what caused it to break in the first place.
Every cam manufacturer sells them, as well as Smith, Trend and Manton.
The important thing is the biggest diameter that fits, wall thickness is an afterthought. If they don't make .075" (not familiar to me) get the next thicker size, the weight penalty is too small to bother with.
I like using Smith Brothers Pushrods. You may consider upgrading to 3/8 pushrods that are .080 wall. With the 292 PR length of 11.6" give or take, they are like spagetti when only 5/16 diameter. You will have to open up the holes in the head and get guide plates.
X2 - do it, one less thing to worry about.
Yeah I hear ya as much head work as we did on this head...we didn't open it up for 3/8" pushrods.
Guess I'll see what I can accomplish in the 5/16" family. This cam is just a little 280 degree hydraulic with recommeded springs and I figured stock pushrods would be fine....guess not.
Its really uncommon to break a pushrod with such a small cam, I would look for other issues, like coil binding of the valve springs, or retainer to guide clearance. Never assume the machine shop was spot on.
I'm going to pull the other pushrods tonight and see how they look.
When I put this together I checked to insure the rockers (stamped long slots) weren't maxing out on their slot and that the springs weren't binding. With only a .560 lift the retainers don't come close to the guides but I will double check all of this.
I've got some Trends on the way that are .105" wall. The stocker that broke is .060" wall.
Tom
Will stock pushrods work for your medium lift cam and bigger valves with after market rockers ratio 1.75
What kind of head work will be done?
I have toms medium lift cam larger valves 1.94 1.6 lump purts hydraulic lifters after market 1.75 ratio rockers screw in studs
Are you using guide plates? Just as a personal preference, regardless of engine type, I never use the stock pushrods in any engines I build for myself or other people. I always use hardened.
No guide plates and those can be obtained from any place stated above?
Josh,
I have used stock pushrods with that cam. Had one bend. I suggest getting new pushrods from Smithbros. Same diameter but with a heavier wall thickness. Also suggest waiting to get them till the engine is bolted together. Then you can measure the correct length needed. Use the old ones as a reference length.
Well i got oem ones from napa and they were all proper length i guess you would say do you have a part number from smithbros? And hows the valve cover coming did you get my order for my harmonic balancer?
PM sent about your order.
You will have to contact Smith bros about part numbers.