After discovering some valve issues, I've ordered new lifters, springs and seals. However, the last time I did valve work was on a 1911 Model T with mechanical lifters you had to adjust. I was 12.
It's my understanding this truck has hydraulic lifters that don't need adjusting; you just drop the new ones in and go. Is that correct?
Other than making sure I keep my pushrods and rocker arms in the order they came out, what else should I consider? Is the air pressure method a good way of keeping the valves from dropping into the head? Does the cylinder need to be tdc for this to work?
Are the valve stem seals replaceable without removing the head?
Any and all advice is appreciated. I want to make sure I do this properly.
I just finished re and re my 4.9 and the lifters were hydraulic and they auto adjust.
Mine did not have seals but shield but either way you can replace them with the head on.
My Haynes manual talks about the air pressure method but I haven't actually tried it. It probably works if they suggest it in there.
One thing to consider is to make note if the intake valve springs and exhaust value springs are different heights and which ones have
and which haveand they go back on the same type they came off of.
You can switch out springs and seals (floating umbrella) with the engine still in the truck. It isn't necessary to put the cylinder on tdc to pressurize it. Even if you do the air pressure is likely to push the piston down anyway.
They make a screw down tool that compresses the spring so you can take the keepers out, but its kind of cramped for space. They make a variety of styles of these tools, but not every style will work on these engines.
You can use the hose from a compression tester as an adapter to pressurize the cylinder, but be sure to remove the Schrader valve from the end of it first.
You will want to make sure you have good air pressure, and keep an eye on the hose so nobody disconnects it when you aren't looking. Chances are carbon build up will keep the valve from dropping into the cylinder, but not a good time to find out otherwise.
The valve train is basically non adjustable, just torque down the rockers and you are done. However they make, or used to make, different length pushrods to compensate for wear/irregularities. The process is in the manuals commonly available for these trucks. There are some articles around on the internet about people who have tried to remove lifter noise from the 4.9. Some of the articles are fairly detailed. I gather there is a company that makes custom pushrods for this.
You should make sure you put all the pieces you don't replace back where they came from, but this shouldn't be much of an issue since you can only do one cylinder at a time, and may just as well do one valve at a time, put it back together and move on to the next one. The springs are a different length, and the exhaust valve does indeed have the rotator shown above on it.
What kind of valve issues do you have that requires replacing the springs and seals? I ask because its a fair amount of work and depending on the problem you are having it may not solve it.
I'm considering replacing the springs and seals because the truck sat for 5-6 years without running. I've got it back together after some work, so I'll know if I need to replace seals and springs shortly