6.2 Rebuild Advice

[upsidedown_04]

Hello..

Just looking for input.. I have an 86 Suburban K20 N/A 6.2 J.. She has about 130K and runs pretty good. It leaks oil like an old Harley though. Well I figured it would be good to replace the rear main and oil pan gaskets. Hmmm Might as well replace the front seal.. Hmm might as well.. Well you see where this is going. Now Im up to a re-ring kit. And as the progression goes Im thinking should I replace the pistons? Well thats my question Im throwing out there. I dont know what they look like now as Ive yet to open her up.. but I just bought a reman IP and looking on Ebay theres a re ring kit for about $350. My budget for now is kinda tight so the re ring is attractive. Whats everyones thoughts on this?

[redbird2]

run a compression test if clyinder are well balanced and not bunning oil just fix the leaks and run it save some money

[upsidedown_04]

Oh cool.. ok.. Good idea..

[Robyn]

Hello


Well after having been through several of these little beasties, there really is no short cuts at 130K

If you are going to keep the rig I would yank the engine out and give it a good dutch scrub all over.

The head gaskets are going to be aproaching a point where they could fail.

Lift the heads off and clean well
replace the rocker arm guide buttons (plastic insert in the center of the rocker)

Remove the pan and check the bottom end over. (have a look at the bearings)
If they are worn roll in a new set of shells on both rods and mains.
The sizes are stamped on the inside of the shell.

Easy now to replace the rear main and the front cover seal.
While the front cover is off toss in a new timing chain as the old one will be worn a lot.

Soft plugs are easy to get to now so why not. (they are a bitch in the truck)
Check the oil screen and wash the pump and screen out if need be.

Wash and reinstall the pan

If you do decide to go a little further be sure to mark the rods as you pull them off (stamp the Part line of each one on the pan rail side.

Drivers side 1357 Pass 2468 stamp each rod and each cap right at the split as the factory does not do it.

Also the pushrods have to be installed back with the same side up as it is now. One end is hardened and one is not.

Most pushrods have a copper colored ball on one end. Place this at the top next to the rocker.

The rering set you spoke of??? come with gaskets too or just rings??

Use Felpro head gaskets. Also you must use new head bolts these are Torque to yield bolts) Use once and toss.

Check the heads for cracks between the valves (almost all used heads will have some cracking) also check the precups too. If they have small cracks that start at the port mouth this is OK if the crack crosses the head gasket fire ring its not good and needs to be replaced.

If there was no signs of coolant leaking into the engine things are probably good to go.

If the compression is good now.

330 and up on all cylinders without any real wild cards you should be fine to leave the pistons in and just freshen things a tad.

If the engine has a lot of blowby, (Smoke at the oil filler when idling in large quantity) I would do rings.

Maybe a new water pump, T stat too.

Replace the injectors with some fresh ones or get yours done.
Fresh glow pugs

Add a couple rattle cans of fresh black paint and poof all pretty again and ready to go.

Wash the engine bay out while your there and also flush out the radiator good with loads of fresh water.
Remove the radiator and be sure there isn't a bunch of leaves or crap between the AC condenser and the radiator that will stop air flow.

Given a little attention now your little diesel rat can give you a whole lot more trouble free miles with good performance and milage.

I just did the 6.5 TD in our 94 Burb and it had 240K on it and it got Rings, bearings, seals, gaskets, oil pump, lifters, timing chain and a set of injectors glow plugs and a set of heads.

Good for another 240K me thinks

My feeling is this, the engine may not need all of these things to continue to run ok, but given the attention now the usable service life can be extended greatly and some inevitable failures avoided (head gaskets).

I would much rather work on a rig on my time table and in good weather rather than have to stomp around putting out a fire when I really need the truck and dont have the time to work on it.


Glad to help
Let us know

Robyn

[upsidedown_04]

Thanks Robyn!

Im going to get a compression tester and get that recorded before a tear down. I like your advice as my goal is to have a clean (no more leaks!) reliable truck. I want to get a banks kit eventually so having fresh rods and mains and headgaskets will be good. And did I mention I wanted to fix the oil leaks? Sounds like the timming chain is a must. Cant swing the fancy timing gear set up so new chain will have to do. Good tip on the Felpro Headgaskets. I will make sure of that. I think a new oil pump should be included no mater how little else I do.

This thing runs pretty well right now. I bumped up the IP shortly after I bought it late last year so it has a little more pep. The only issue Ive had recently is its starting to idle rough especially when the AC is on. It smothes right out as soon as i accelerate. I purchased a rebuilt IP on ebay(in fact I have a posting on the general 6.2 forum.. should have been in the tech one) Oh is the Harmonic Balancer an issue on the 86?

thanks for all the input!

[Robyn]

Generally on the 6.2/6.5 the timing sprockets are fine its just the chain that stretches. Do a new chain only unless the sprockets really look nasty.

The rough idle can certainly be the injectors or the pump.

If the engine does not have much blowby you may be fine with just some bearings and gaskets, seals and such.

Compression is the biggy tell tale.
Low compression means its going someplace, either by the rings or through a leaky valve.

Let us know what you find and we will go from there.

Robyn

[moondoggie]

Good Day!

"...is the Harmonic Balancer an issue on the 86?" The harmonic balancer is an issue on any 6.2 or 6.5. If the rubber doesn't look perfect, replace the balancer. There is a suspicion that when the balancer fails, it can take out the crank. I know the balancer can be had for $70 or $80, so it's pretty simple math.

Blessings!