removing rocker arms

[robbie]

How is the best way to collapse the lifters to get the rockers off?

[barnstmr]

Re: removing rocker arms

Depress the valve spring (may require a unique tool), then slip out the rocker shaft while it has no pressure on it. It may take 3 hands until you develop the correct technique.

[Pearson]

Re: removing rocker arms

If you turn the prop so that each valve is fully closed, you can usually depress the valve by leaning into it with one hand on the valve. Put a rag between the butt of your hand and the top of the valve. Use the other hand to push the shaft out. It is a easier if you have someone else that can push the shaft out.

[Robert Lees]

Re: removing rocker arms

You don't need to collapse the lifters.

Also, if you need to do this on the front two cylinders, you can first slide the shaft forward to remove the aft rocker, and then slide the shaft aft to get the front rocker off.

This means you don't need to remove the nosebowl for the front cylinders.

If removing the push rods, there is a simple method of preventing pulling the bottom-end cups out (which are a pig to get back in)...blow down the push rod oil holes to break the oil seal at the bottom end, and pull the rods out while biasing the bottom ends of the rod to the left

There is a little stop at the bottom of the push rod tubes (actually at the top of the bottom-end housing) that prevents the cups from pulling out.

If the cup comes out with the push-rod, you will learn all about this !!!!!!

Rob

[robbie]

Re: removing rocker arms

I will be removing the cly. due to ex valve leaking. Comp. is down to 50 lbs.
The cly only has 190 hours on it since it was topped (1999).
Hoping a valve job will do it.

Yes rob, it is a front one #4.

[Robert Lees]

Re: removing rocker arms

Are you sure it's not a spot of crud on the seat?

It is possible to do a small lapping job in situ, but care must obviously be taken with the lapping paste, to make sure it doesn't get where it shouldn't.

Otherwise it's prop off, nosebowl off, baffles off, exhaust & intake off...
etc etc etc

Not an onerous job, but time-consuming.

[Winston L.]

Re: removing rocker arms

If you haven't removed the cylinder you could stake the valve.

Winston

[barnstmr]

Re: removing rocker arms

Staking the valve or sometimes even a good hard run at takeoff power may help loosen and knock off carbon deposits. I have seen many engines improve compression with just run time alone. Did you do your compression check with the engine warmed up first? Compressions should be checked soon after an engine shut-down. This way, the valve and seat will have a slight oil film and will be expanded to operating dimensions.

Lapping without removing the cylinder is very do-able and very well could be the solution. I have heard of using Bon-Ami (kitchen cleaner) - abrasive enough to remove deposits, not so abrasive it would do a lot of damage... just use with caution and clean up after very well. Wouldn't hurt to flush engine afterwards with a oil change and short run time followed by another oil change.

I would "exhaust" (pardon the pun) all options before removing the cylinder. If you do... be sure to re-torque all the through bolts from both sides properly so that the crankcase is properly pre-loaded. If improperly done, a cylinder change can create other problems.

[Goneflyin]

Re: removing rocker arms

As previously mentioned try lapping while the cylinder is on. Try looking through the archives for the "rope in the plug hole" to lap the valve or clean up the stem if leaded up. I've heard this can be done in a hour or two rumor has it.

Bill