RE-Ring In Frame, Advice?

[kenz5380]

I've got a NA 6.2 with 65000 original miles that some nut ball religiously used ether on and has worn out the rings. Compression is about 150 psi across all cylinders. -The diagnosis of worn rings is my own and could be contested but that is my best guess after seeing the ether injection system built into the truck and the results of the compression test.

Anyhow, I'm about to do a re-ring job on the motor and something came to mind. Can I rering the motor in the truck without pulling the heads? Wouldn't it be possible to do the whole job from underneath? I haven't had a 6.2 apart that far so I don't know the details of how it looks in there.

Even if I have to pull the heads, does anyone have any advice for me going into this project?

Thank you all for your advice.

[john8662]

Not possible to pull the pistons w/o pulling the heads.

Pull the engine and see what's going on.

Did you pull compression on all 8?

Does it have a lot of blow-by?

It's possible the engine got hot hot at some point leading to the poor compression, and the starting of ether.

Ether can cause engine failure, but usually in a cylinder or two, not uniformly worn.

Be interesting to see if it has broken rings, etc.

Get the engine hoist out, it's coming out!

[kenz5380]

I think I'm still going to attempt it with the block in the truck. I'd like to not have to pull it out. If I have to pull the heads thats not too big a deal, but I'm trying to keep the project as small as possible.

Yes I did pull the compression on all 8 and they were all in the 100s. Pretty lame from an otherwise extremely clean 1985 vehicle with the original engine and trans and only about 65000 miles.

The closest to combustion I ever got was a little smoke from the tail pipes and from the oil filler tube.

The fact that the engine had an Ether injector wired to a button in the dash made me think that this thing had seen a lot of starts with ether drying out the cylinder walls and wearing out the rings. That was my best guess anyhow. There is no other reason that I've been able to see why it would make such crappy compression numbers.

Any advice on the project as a whole would be appreciated though. I have not had a 6.2 apart before as I said, plenty of other engines just not a 6.2.

[greatwhite]

If I were going that deep into the engine, I would pull the assembly out.

The amount of hassle of doing that kind of work in a gmt400 chassis is just not worth it.

Really, after you get the heads off, the only extra steps we're talking about here is pulling the engine mounts, transmission/torque convertor bolts and a couple hoses/lines/wires.

It can be done in chassis in OTR trucks, but that's a whole different ball of wax.

Not to freak you out, but either in a 6.x can also lead to things like bent rods and cracked pistons. Hopefully, none of that will show up in yours....

[kenz5380]

I'm pretty confident about the motor not having too much internal damage. Not for any real reason, just my gut feeling after listening to it turn over a few times. In my experience bent rods and cracked pistons make some noise when you turn the engine over. I know that is not always the case and I am prepared to go the long route if necessary and do a full rebuild. I'm just hoping it will be as simple as rings.

We'll see what happens. I'll post picks of the internals as they come out when I get into the motor. Maybe there'll be some cool catastrophic damage! Hope not, but it makes for good pics.

[More Power]

If it's an original untouched motor, a new set of gaskets and resealing the tin, top to bottom, would be recommended anyway. The head gaskets used in the 80's 6.2s were not that great, and may partly explain why the compression is low (leaking between cyls).

Unless the rings and pistons were damaged by explosive combustion due to a combination of ether and an operational glow system, I'd not consider ether by itself to cause a problem. I heard once from a longtime 6.2 owner who used ether for every cold start over 200,000 miles without causing any engine damage. He disabled the glow system early on, which is a must when using ether.

Jim

[arveetek]

Definitely pull the motor; you'll actually be saving yourself work in the long run. Plus, it's extremely difficult to perform a decent torque job on the heads when reinstalling with the engine still in the truck.

Casey

[Robyn]

YANK IT OUT

Once out, you can get right into it and have a good look see at the entire sheeee bang.

Get the heads off, drop the pan, then yank out the rod and piston assemblies.
Be sure to stamp the rods with numbers on the split line on the outside
Match the numbers with the cylinder numbers.

The rods are not numbered from the factory 1-3-5-7 on the LH side and 2-4-6-8 on the RH side

The ricardo bowl always goes to the low side of the cylinder (little dish in the piston top)

Once the assemblies are out, pull the crank out, then the cam.

Store all this stuff and then check the block out.

DO replace the soft plugs as they will be nearly rotted through most likely.
Check the cylinder decks around all the cylinders an make sure that there is not any errosion where the fire ring has eaten into the deck.

Anything that you can feel will require the deck to be cut up to a max of .010"

If the decks are good, then look at the cylinders.

Check the cylinders for ridge.

If the bores are good, then run a Bottle Brush hone through them to freshen the surface.

No need to get crazy.

If there is a ridge, run a ridge reamer up through it before honing.

Once this stuff is done, power wash the block well to get rid of all the crud.

Install the new soft plugs, then install new bearings, main seal and so on.

Remember, the head bolts are a one time use.
Get a set of Felpro bolts and new head gaskets.
Follow the torque instructions.
First time through the pattern to 20 Lb then back through to 55 LB then back through the pattern one last time going 1/4 turn more.

Use the red or orange High temp silicone on the pan rails and where the pan touches the timing cover.
The rear main area has a rubber strap there.
Use a gasket between the timing cover and the block.
Use the silicon goop on the Valve covers

The push rods go one way only ( With the orange colored end UP)
This can be hard to see in a high miler, so mark them when you pull them out.

Replace the rocker guide buttons if the engine has stamped steel rockers.
These are a plastic gizmo that hass a barbed end that goes into the rocker shaft.

These get brittle and can break allowing the rocker to fall off the valve and in some cases can cause the spring keepers to come out and the valve to drop :eek: yup, game over

Replace the timing chain only, rarely are the sprockets worn much.

Use a ring groove cleaner tool to clear all the carbon out of the grooves
Be sure the wrist pins are not loose in the pistons or the rods.
Any that are really sloppy will need fixing. (these normally are ok)

This is the way missy says to do it :eek:

Dont argue with Missy :D

Keep us in the loop and have fun

[Vin82k3500]

I agree with the others do yourself a favor and yank it
1 its not worth the back breaking work of trying to do it in the vehical
2 opening up an engine is like a box of chocolates as forest gump would say you never know what your gonna get
3 if your tearing it apart to do rings you should seriously take a good look at the bottom end rear main seal ect,

I love these engines though I am still a little green on them myself I do know if you are considering doing a ring job and you know it has had ether pull the heads and pull the engine first
I have seen precup damage from ether and have actually seen the precups make dents in the block that are not repairable
also the blocks have issues with cracks and harmonic balancer should be inspected and replaced as necessary
my own story I had an na 6.2 it ran great for years then 1 day it blew the rear main seal I replaced it in the truck by dropping the pan I have been a wrench for 24 years and well lets say after the rear mains seal failed and i replaced it it was not long before I pulled it last month i bit the bullet know what i was possibly in for and replaced it with a P400 long block from Penninsular diesel not saying what to do but comparing what I could have shelled out not knowing the condition of the block the piece of mind was well worth the 6 grand I spent for the long block and it runs awesome;) I still have my old 6.2 and if the block is good I will rebuild but man the manifolds alone come off so much easier with the engine on a stand and from what I understand serious detail needs to be attended to on the piston to head clearance my 2 cents for whats its worth.

[Robyn]

If the engine has seen ether use, the likelyhood of precup damage is high.

A good set of Clearwater aftermarket heads would be a good choice too.

The heads from the 6.5 will bolt right on.

If the precups have cracks that start at the fire hole and progress anywhere near the fire ring of the gasket, dont reuse the heads.

Most likely too is that the heads are going to be cracked badly.
Any cracks on the fire deck is a game over scenario.

Missy