6.2 Lifter Installation Question

[yolo]

I'm trying to replace the hydraulic roller lifters in my 84' C20. Can this be done without removing the head? I removed the retainers and used a magnet to get 4 of the lifters out, but getting the new ones in seems near impossible. The pushrod holes aren't large enough to simpily drop the lifters is, they have to come in on an angle. Is there a special tool for doing this? Thanks for any input.

[Robyn]

You can drop them in through the center area of the heads and then fish them over to the end lifter bores.

Coaxing them into the bores can be done with a brass rod down the push rod holes in the head.

Once the lifter is in the bore, squirrel them around so the flats will align with the guide bars and then install the clamp plates.

Now, this said, with an 84, unless the heads have been off recently, I would seize the opportunity and yank the heads and replace the gaskets.

Get a pair of gaskets and two sets of bolts.
The bolts are one use only.

The push rods only go one way, with the copper colored end to the rockers.

If your engine has stamped rockers with the plastic guide buttons, replace the buttons too.

This will take advantage of the work of having all the lines, covers and such off the engine, plus at this time the gaskets are likely used up.

Good luck

Missy

[john8662]

I use two telescoping magnets. One in the center of the plunger and one on the edge to tilt.

You need a way to pressure up the oil system before you torque down the rocker arms and put pressure on the pushrods and plungers in the rockers.

I have a theory that dry starting these lifters damages them on first run. I've had a terrible track record with these lifters installed in sets and having a few bad ones.

I noticed that AM General's production 6.5 lifters off the assembly line come pre-primed pre-pumped up! I got to thinking about that, why would they be pre-primed? Maybe to inspect them and to protect them from not having a hydraulic pressure in them when under pressure of the valve train before oil pressure can pressure them up and provide the necessary oil cushion.

So, for replacements in my humble opinion you have two options.

Shelved lifters from SBI, Sealed Power, Melling, Etc. and pre-prime them by running the oil pump in the engine w/o any pushrods installed until they all have pressure. For this you'd need to make an oil pump priming tool out of an old vaccum pump stalk. You can't just turn the oil pump shaft with the vaccum pump removed and build pressure for the lifter valley. After you've got the lifters filled with oil by pressure, then assemble the top end.

Or, buy some AMG Lifters, call Peninsular Diesel up and get a set from them at a very good price!

I've two two sets of the AMG lifters with great success after such a long track record of failures.

I will also get brave enough to try some boxed lifters again and prime them first and see what results I get.

You can do this job with the heads on, it's hard but doable...