6.5 cylinders, Info on rebuild

[rjwest]

My Boy in Ak. needs a little help. Has an old engine for his plow truck ( original )94
Said he pulled it for low power and smoke at idle , ( 200k plus miles.)
I told him, did't sound like engine problem, but he has it out and is going to pull the pan,
and take a look to see if bottom is in 1 piece and try to check cylinders.
If good, maybe a valve job while it's out....Any info appriciated...

? How much can be honed out to cover ring marks

Are they sleeved ? Can they be sleeved???

Do you need new pistons, My guess is yes, ( Alum )

Thanks all...

[More Power]

? How much can be honed out to cover ring marks

Are they sleeved ? Can they be sleeved???

Do you need new pistons, My guess is yes, ( Alum )


If this is on the cheap, you could just remove the ridge at the top of each cylinder, use a glaze breaker on the cyl walls, then install new rings after cleaning the pistons. Would be better to bore it to whatever is required to clean up the cylinders and remove any taper, then install new oversize pistons.

GM says .030" is the maximum overbore, but you can buy up to .040 over pistons.

The 6.5 is not a sleeved engine, but a sleeve(s) can be installed by a competent engine builder.

Jim

[rjwest]

More Power...Thanks,!!

[Robyn]

Howdy

Benn through a bunch of these little beasts. The cylinders on the 6.5 generally dont wear much even with high clock time 200K

If the air filter has been maintained and the oil kept reasonably clean you may very well find hardly any ridge at all.
If this is the case and the cylinders look good as do the pistons, use a bottle brush hone and lighty scuff the walls and install new rings.

These are parent material type blocks (no sleaves) do not sleave a 6.5 as it is not the best plan. It can and has been done BUTTTTTTT I would not.

Piston in these can and do run very high miles and are quite usable. I have a 94 that I did an overhaul on at 237K and it was sweet inside. (It lost a head gasket)
Unless there is damage reuse the stuff. These are spendy pistons and if this is a budgit overhaul there is no need.

The important thing is to clean the ring grooves real good prior to installing the new rings. Dont use a wire brush on the sides of the pistons.
The crowns can be cleaned gently.
(Be sure your ring end gap is per spec, some sets need the top or second ones filed to fit)
Look for any cracks in the Recardo Bowl area of the piston crown (little bowl area at the lower edge near the outside of the block)

The bearings are select fit so look at the back side of the shells to be sure what they are.
Generally, unless someone has been in there a set of standards will work.
It not uncommon to find a real mix and match of sizes on the rods and mains due to the select fit.

The numbers on the shells will tell the story (everything is in MM)

Just be sure of your clearances.

A set of fresh head gaskets from FELPRO is in order as are new head bolts

The head bolts are a use once and toss (TTL) torque to yield)
The torque spec and pattern come with the bolts. Also be sure the bolts you get have the orange (or some color) silicone sealer on the threads.

A fresh timing chain is usually all you need as the gears and sprockets wear little.

If the rig has been smoking at idle a fresh set of injectors is in order too.

Check the glow plugs and if a connection across the battery for about 6 seconds will make them glow red from the tip back to at least the center use them over and if not replace them.

Having the injector pump tested while its off is not a bad idea either.

To check the block for cracks in the main webs is a quick and easy job.

With the engine upside down and the main caps off and the crank out, clean the area all around the center main webs where the outer bolt holes are.
This is down both sides of the web.
This needs to be very clean and dry.
Now using a hand held PROPANE torch, warm this area up real good on each web until the web area near the outer holes is very very warm.
Look for small lines of oil oozing from a verticle crack.

Generally these cracks are very fine and hardly visible to the eye unless the issue has progressed a long way and the critter is about to come apart.

A die check kit can also be used if you have it but most of us dont have that stuff.

If any cracks show up, things need to be considered before going ahead with a rebuild.

Have a go at it and let us know.

Good luck

Robyn

[More Power]

You can read more about sleeved 6.5s on this thread. :)
http://www.thedieselpageforums.com/tdpforum/showthread.php?t=27506

Jim