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Questioning installing rockers and pushrods process
1996 f250 5.8 - Took the engine out completely and re-did all gaskets and seals. When removing the heads, I took the rocker arms off on one side then removed the pushrods. On the other head, I simply removed the entire head while the push rods fell through the bottom, keeping the rocker heads on. The Hayes manual seems pretty vague on installing the stock pushrods and rockers. It says basically to place the rods, align them up properly with valves and rockers, and toque down the bolt. I feel as though we're missing something here. Here's how I think it should be done, and please correct me.
While working on one cylinder for the head with the removed rocker arms:
1. Rotate crankshaft until the valve I'm working on is protruding from the engine.
2. Install rod, set plate for both rockers, and the rocker and bolt.
3. Torque the rocker arm bolt to 18-25 ft-lbs.
4. Rotate crankshaft until the valve is protruding from the engine.
5. Repeat steps 2 and 4.
While working on the other head with the attached rocker arms:
- After each valve compressed when installing the pushrod and rotate the rocker over the rod and spring.
If that second process is correct, in theory, couldn't I just torque the rocker arms down in the first process, THEN install the whole cylinder head and rotate each arm over the spring and pushrod?
1) Rotate the crankshaft until the valve is protruding from the engine? How would the valve be sticking out of the engine?
2) Now install the pushrod? How is the valve going to move (from step 1) by the rotating camshaft if the pushrod isn’t there?
Are you reinstalling the original pushrods and rocker arms? If so, they need to go back in the same location (cylinder and intake or exhaust valve) where they came from. Pedestal mount rocker arms are not adjustable
I simply removed the entire head while the push rods fell through the bottom, keeping the rocker heads on. While working on the other head with the attached rocker arms:
I would say this is NOT the way to remove or install a head.
You need to remove the rockers and their associated pushrods, number them Intake/Exhaust 1-8, so each rocker and push rod go back into the same place they came out of.
Remove your rockers from your head, then you can reinstall head with the correct torque. If you have pushrods pushing up on your rockers, your not going to get an accurate head torque.
1) Rotate the crankshaft until the valve is protruding from the engine? How would the valve be sticking out of the engine? I'm referring to the hydraulic tappet the push rod sits on. Sorry for the confusion.
All original. I'm trying to figure out when the torque should be applied to the rocker arm bolt. If the tappet is all the way out, pushing on the rod, then it doesn't seem like the bolt will remain at the proper torque once that tappet goes back in. I realize these aren't adjustable like rollers. Just trying to figure out when that torque on the bolt should be applied consider the functionality of the spring and the tappet.
The full proceedure begins with all rockers removed. The crank is rotated to various positions and rockers and pushrods are installed on those valves that will end up in the closed when the rocker is torqued down, then the crank is moved to the next position and some more rockers are installed, repeat until they are all done.
But you're not building a new engine, there is a spec for pushrod preload but since you're simply reinstalling parts that just came off you can literally torque all the rockers to spec without going through any alignment proceedure and it will all be good. Technically the valvetrain is non adjustable, but sometimes shims under the rocker pedestals or in rare cases different length pushrods are required to get everything to spec, but you probably won't find any of that on a stock all original motor.
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