custom push rods for E7 Heads?
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custom push rods for E7 Heads?
I'm working on a 302 (flat tappet) I pulled from an '85 F150 and put in my '71 F100.
I got a rebuilt set of E7 heads for less than the cost of new springs for the old D8OE heads, so thought that would be a good idea. At the same time, upgrading to a Comp Cams 252H Camshaft, lifters, and timing set. Lifter preload has got me confused...
Comp references .020 to .040" preload on the lifters. I'm finding closer to .070". I'm wondering if this is due to using heads from a roller cam motor???
Is there a stock pushrod that will work here? Or should I shim it? Or some combination?? Thanks for advice.
I got a rebuilt set of E7 heads for less than the cost of new springs for the old D8OE heads, so thought that would be a good idea. At the same time, upgrading to a Comp Cams 252H Camshaft, lifters, and timing set. Lifter preload has got me confused...
Comp references .020 to .040" preload on the lifters. I'm finding closer to .070". I'm wondering if this is due to using heads from a roller cam motor???
Is there a stock pushrod that will work here? Or should I shim it? Or some combination?? Thanks for advice.
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Joined: Jun 2006
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From: Ottawa, Ontario
All 302/5.0 flat tappet motors use the same 6.905" pushrods and E7 heads have non adjustable pedistal mount rocker arms so lifter peload is ignored and this is a simple torque down procedure.
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From: USCGC Never Home
Lifter preload shouldn't be completely ignored in this case. If the heads, and deck have been machined down he could possibly be better off getting shorter push rods. Running double the lifter pre load that is recommended by the lifter mfg cant be good. Maybe consider finding push rods that are .035" shorter
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What I've done so far is install Ford Racing shims under the rocker arm. .060" shims all the ways accross got all of the lifters within spec, very close to .020" or just over. That does make me think that the heads may have been milled some. Hard to say...
I did some more research on the subject and found that it is common among drag racers to run LOTS of preload. The thought is that a certain volume of oil may have a certain percentage of air in it. By reducing the oil volume, you are reducing the air volume to a minimum to ensure you maintain max lift.
On the other end of things, running very low preload will minimize lifter pump up in case of weak valve springs. I don't know anything about my heads for sure. Supposed to have been rebuilt, but you know how that goes!
So like I said, I shimmed them and spum the engine over by hand to check the valve geometry. It looked right to me. I intend to pop the valve cover off after a while and see what I can see.
By the way, the Comp 252 Cam is an awesome cam. It sounds good, no lope or anything but is a lot of fun with low and mid range. Highly recommended!
I did some more research on the subject and found that it is common among drag racers to run LOTS of preload. The thought is that a certain volume of oil may have a certain percentage of air in it. By reducing the oil volume, you are reducing the air volume to a minimum to ensure you maintain max lift.
On the other end of things, running very low preload will minimize lifter pump up in case of weak valve springs. I don't know anything about my heads for sure. Supposed to have been rebuilt, but you know how that goes!
So like I said, I shimmed them and spum the engine over by hand to check the valve geometry. It looked right to me. I intend to pop the valve cover off after a while and see what I can see.
By the way, the Comp 252 Cam is an awesome cam. It sounds good, no lope or anything but is a lot of fun with low and mid range. Highly recommended!
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