6.2/6.5 assembly tips

[Missy Good Wench]

Hello fellow GM diesel lovers and 6.5 freeks

Well I am taking this time during my DaHooooley rebuild to capture some tech tips and get them in pix and make comment.

The pix will follow but are pretty self explanatory and have notes where needed.

One of the biggies is to be sure the rear cam plug is sealed well.
Apply permatex to the plug and drive in with a suitable driver and a hammer. (large socket that just fits inside the lip on the plug)

Be sure the lip is just flush with the back of the block.

Now for anyone who has ever had one leak or worse yet COME OUT
I prefer to do two things.
I drill and tap two 6/32 holes in the plug boss and insert two little button head allen screw with a washer to catch the edge of the plug.

I also do a covering of the joint with JB weld

Having seen what happens when they leak or come out I will always do this.

A large oil leak from the bellhousing leaves a huge sick HOLE in the pit of your gut

This procedure takes little time and make it bullet proof.

The holes only need to be driiled about 1/4 inch into the boss and just close enough to the plug that the washer fully catches the rim of the plug.

Next is the Plasti gauge procedure.

With the upper bearing shells in place, lay the crank carefully into the block and position so the counter weights are as far out of the way as possible.

NOW resist all temptation to turn the crank as there is NO LUBE ON IT.

Next apply a very light smear of oil to the main journals (just enought to make a smudge)

Take a small piece of the Plasti Gauge material and lay on the main journal.

Set the caps on and tap into place. Torque the bolts down to at least 75% of the value.

Remove the caps

Now have a look at the smashed plasti gauge.

We can see using the little paper sleave graphics that the bearing clearance is right about .002" possibly a couple tenths more.

This is not rocket science and works easy and fast.

Be sure to check all the mains

We will do the rods later on as we get that far.

Never assume that all is well, Check all the bearings ALWAYS

Now scrape the plasti gauge off using your fingernail. Wipe the journal clean and take the crank out.

Lubriplate 105 is the real deal for a build and is the choice of campions.
It stays where you put it and does not run out but washes out with the oil when the engine is fired off.

Lube the upper inserts and set the crank back into the block.

Lube and insert the rear main seal into the crank with the seal lip facing the inside of the engine.

Align the back edge of the seal with the inner edge of the little chamfer on the block and cap.

You can lift the crank slightly to do this. Be sure the seal is square and straight all around.

Apply High tack as shown in the pix (Lightly) this will assure an oil tight seal between the cap and the block.

Apply 105 to the inserts in the caps. (Be sure to remove any left over plasti gauge first)


Set the main caps on one at a time and snug the bolts.
Be sure the rear seal is even all around. DO NOT LUBE THE OUTER RIM OF THE SEAL. This will assure a good fit between the ribs of the seal and the block and cap.

Leave the bolts on number 3 (Thrust main) just barely snug

Once all the rest of the mains are snug use a large rubber dead blow hammer or a wood mallet to smack the crank for and aft to seat the thrust main cap and even it up.

Now start the tightening procedure.

I like to do the center main first and do the inside bolts to 50# and the outer to about 35#

Do all the mains and check to be sure at every change in torque that the crank will turn by hand.

Next bring all the bolts up to about 75# inner and 50# outer
Then do the final torque to 110# inner and 100# outer (12MM bolt blocks new blocks use lighter torque on the 10mm outers)

HINT that will SAVIOR A$$

After each main is brought to final torque, mark the cap with a sharpy pen.

Now this may seem stupid !! but believe me, when the phone rings and you come back later, DUHHHHHHHHH where was I ?????????????

The ones with the marks you know are good to go.

This is also to be done as each rod cap is brought to torque.
Mark it on the pad on the bottom.

Here is a shot of the nice finish of the crank.

This is the crank that came from the engine that cracked the block.
I hand pollished it with some 600 grit emery that I ran over a sharp piece of steel to knock the sharp off the paper

Very nice finish with only smudges from handling. Crank may have 75K miles not sure.

You can look at the pix and pretty well see whats what here.

The cam was installed prior to the procedures above and the clearance checked for and aft with the cam plug

(make sure you have about 1/32" of back clearance so you dont chew the cam plug)

Use blue locktite on the cam plate retaining bolts.
Bolt comes out its game over.

More later as the build progresses.

I hope to document the whole build this way so it will provide reference for others.

Main seal setup is slightly different on the older 6.2 engines but late 6.2 is like the 6.5 shown

Just a note here. You can see the inserted center main bolt holes well in the one pix

Just a note to the Mods, Ya might want to stick this one so it will stay easy to find.

MGW :grouphug:

 

[Acesneights1]

Nice job.

 

[Odlaw]

Nice work MGW!
Great write up and pix.

Thanks
Smitty

 

[Missy Good Wench]

Thanks for the kind comments.

Just trying to help and to justify the new DSLR camera I bought myself for christmas a year ago ):h

 

[bk95td]

Great thread. I can never seem to have my canon powershot handy when I should be taking pics. You are absolutly correct to allways check clearances. Assuming things are right can spell disaster. Did you do the finish honing and piston clearanceing before starting assembly? If I remember correctly, there is different clearances for different cyl.

 

[Missy Good Wench]

I worked with the shop tech and told him what I wanted.

.004" on 1-6 and .0045" on 7-8

These numbers are right out of the 94 GM shop manual. I could have gone a little looser but decided that the middle of the spec was good.

The Zollner pistons I am using have the black teflon skirt coatings so it will be tight enough to be quiet and loose enough to live.

I hate going too lose right out of the gate and then in a couple years having piston slap.

Many of the 6.2 and 6.5's have select fit bearings. These things could have mains and rods as STD or .0005" under or .001 under or any combination.

Some will have mains at STD and rods with the upper shell only at .001 or .0005
Or any combination you can imagine.

The pistons are marked with a letter code "J" or "K" to denote the size piston used.

The pistons I bought came of a sale on ebay. They were broken lots and I got 6 that were exactly the same size and 3 that were a few thou different.

No biggy especially since we were fitting them to new holes anyway.

But for $199 for 8 pistons I wont complain at all.

Bought the Factory set of GM rings for $35 (all 8 pistons worth) Ebay deal too.

I bought the rings first and then followed up on another sale and the fellow there siad he had the pistons in .50mm OS.. YESSSSSSSSSSSSSSSS as he was showing .75mm
OS

The bearings came from Ebay too. Clevite rods and Mahle mains $50 for all.

Still looking for head gaskets though Need two of the .010" thicker gaskets as we decked the block.

Need lifters too. I did not want to reuse the old ones (full of sloppy oil and glycol)

Mixing the glycol and oil makes such a nasty mess.

later

MGW

Its a crap shoot as to what you will find

 

[Missy Good Wench]

Thinking about picking up a couple cans of the darker Cat Yellow to paint this beast with ):h

OMG I am tired of the Black engines in these things. The yellow at least will allow one to see the nasty black oil leaks

MGW

 

[Matt Bachand]

Thinking about picking up a couple cans of the darker Cat Yellow to paint this beast with ):h

OMG I am tired of the Black engines in these things. The yellow at least will allow one to see the nasty black oil leaks

MGW

Absolutely!!! Don't need to justify it... PAINT HER UP!

 

[DieselSlug]

I too am going with cat yellow from eastwood. AKA: "ratman yellow"

 

[Missy Good Wench]

Ratman painted his the later Light yellow.
I want the darker color of CAT

MGW

 

[nvmtnlion]

Nice work MGW!!

Stuck!

 

[DieselCash]

I can not wait to see her all painted up! Keep up the great postings! :thumbsup:

 

[Missy Good Wench]

Ok now troops, PAY ATTENTION

Here is a pix of a whole butload of different precups.

Scrounged up a set of "rebuilt heads" off an engine that had seen the top end done and then tossed a rod a few months later.

Price was good and my cash is short.

Asked the seller if I could remove the valves one at a time to inspect the seats.
I was looking to see if these heads had indeed been gone through or if this was just a story.

Valves looked great as did the seats.

Heads also had little temperature indicator tabs placed by the builder to indicate if the engine had been HOT (Warranty device)

The first thing that caught my eye was the fact that the precups were not the same in both heads.

This is a very bad idea. Always run a matched set of cups no matter what.

The cups not only have different shaped fire ports but also have differing internal volumes too,

The cups that came with the newly acquired heads were the ones with the single DOT and the ones with the single square.

My heads from the truck had the diamond.

The T ports (2 square dots too) are a set that will likely go back in as I have a complete set.

My original diamonds are too badly cracked (all the way to the fire ring)

The odd duck at the lower end of the pix is a J series 6.2 cup that I tossed into the pic for a comparison.

Quite a spread.

Some look close but are different when examined closely.

MGW

 

[ak diesel driver]

Do you have to resurface the heads when you change precups?

 

[Missy Good Wench]

The issue can't be answered in a Yes or no.

IF the heads are untouched then NO If the heads have been surfaced the yes.

Now this said, the heads should not be surfaced with the cups in place. The cup bores need to be cut (special tool) to reset the depth after the heads are machined.

GM does not recommend surfacing these heads at all.

With the heads all clean and the chamber in the head clean enough to eat off of, the cup should tap in easily and seat nicely.
The spec is that the cup needs to be from flush to .002" above the deck.
Use a block of aluminum that will span the entire cup and then tap with a hammer.
Do not beat on the cup itself as it can be damaged

I have seen stock stuff at .003" and this is fine.

Some of the aftermarket heads, although good once assembled have cups that are of a different material than the GM cups.

Also the aftermarket cups are machined differently too.

The GM cups have a large chamfer on the back side where they seat in the head and also an underground recess in the register area to reduce stress risers.

I have stuffed aftermarket cups into stock heads and the seating depth comes out wrong.

Stock heads can use any of the GM cups but one just needs to be sure that the depth is correct.

MGW

 

[Missy Good Wench]

Head tech
OK
Now that the heads are all steam cleaned and I can get close to them.

Time to pull all the valves, springs, shims and other goodies out and tagem and baggem.

These heads will be reused as is and with no machine work.
Its important to keep all the parts as they were when they came apart.

In the pictures you can see the parts stack with a zip tie through the set.

This is the exhaust springs and parts.

The rotators always go to the exhaust valves.

Keep the spring shims where they were.

Usually on a stock engine with factory heads there will be one hardened shim under the spring.

This stops the spring from chewing the head casting .

These heads have a mixture of 1 and 2 shims per setup to allow for the seat grinding that was done.

This will keep the assembled height of the spring correct.

Now the valve seats and ports have been all cleaned with a air powered cup brush.

The precup pockets are all cleaned and the sharp corners where the cup seat are all cleaned and free of carbon and crud

Now Notice the Pix of the valve with the carbon.

These engines will form huge envelopes or carbon on the backside of the intake valves over time.

These heads although not run very long had a large amount of carbon.

This is likely due to bad rings and a great amount of blowby. The intake ports were very wet with oil residue.

The story on the engine these heads came from seemed believable BUTTTTT ya just have to take everything for what its worth.

So far the seats and the valves look fine and will go right back to work.

The next step is to get the heads into the shop tomorrow and have them heated in hot water and pressure tested with 50+PSI air to check for any leaks that may not be obvious.

The heads show no cracks that are of issue. I did find a couple very tiny "Checks" on a couple exhaust seats.

Not worth bolting these on without testing.

The cost of the gasket and Bolts is about $60 per head.

Not to mention the work to get things back apart again.

Once the heads come back from the shop (with a clean bill of health) it will be time to install new stem seals on the exhaust guides (teflon press on seal caps) and new Orings.

A little lube on the stems and back in they go.

Button things back up and good to go.


Just a side note here

A 6.2 or 6.5 that has a lot of miles and has sat for a long period can see these large carbon heaps on the intake valves fall off and go into the cylinder.

This is a nasty situation and will lock the engine up tight.

These carbon cones that form on the valve can be very large. The amount of room on top of the piston is very small and if an engine starts and has this stuff fall into the cylinder, it will hammer like hell.

Any used engine that has sat a long time should at the least have the intake removed and the ports and such inspected for this issue.

If the problem exists the heads need to come off and the intake valves removed and cleaned.

This can do serious damage to the engine if allowed to get into the cylinders and hammer things.

A large enough piece can hold a valve open to the point that the piston swats it and then the problem is even more serious.

Piston damage, rod and crank damage. OHHHHHH My


More coming soon

 

[3500GMC]

What kind of valve seals do these 6.5TD's use? Or should I ask, which ones would hold up? I was in awe at the buildup of crusty junk on the intake valve.

Looks like valves from an old BBC with 150k on it.

 

[Missy Good Wench]

The seals are a teflon tyoe hard body valve stem seal that presses over the exhaust seats.
These are very similar to the PC seals used on the BBC

There is also an O ring that fits right under the valve keeper

The intakes have only the rubber ring. Normally the intake port is under pressure so the oil wont be drawn in past the stem through the guide.

This engine was sucking a ton of oil over the CDR as it looks to me. I never saw the rest of the engine.

I did buy the turbo from the guy and it was sloppy with oil.

Once the oil gets into the manifold it spreads out and flows into the intake ports and then around the valves.
The valves are hot and the oil just cakes on over time (short time too)

One valve had a perfect little dunce cap of carbon that was sitting on it. The carbon cap slid off in my fingers. I wanted to get a pix but dropped the little carbon gizmo and it broke.

The carbon loosens with time and moisture (sitting unused)

Best


MGW

 

[3500GMC]

The seals are a teflon type hard body valve stem seal that presses over the exhaust seats.

The seats.. You mean guides don't ya.

Are there any good handbooks for technical specs, clearances, etc?

I did buy the turbo from the guy and it was sloppy with oil.

I have access to a GM-8 that is locked up from a blown engine. Avoid it? Would the commonly available GM-x rebuilds fix one like this 'normally'?

Thanks.

P.S. Any more assembly pics?

 

[Missy Good Wench]

Yes, that was a typo.. Presses over the top of the guide. Too late that day and my fingers were not thinking right.


The best books with the "Right Stuff" are the GM factory manuals

EBAY is the ticket. Give a look, there are usually several sellers with factory books for sale.

I got all mine there.

As far as the Turbo goes, I would rip it apart.

The Bolts that hold the hot side housing on can be a tad Honery but will usually come out.
Get the cartridge out and see what happened.

These are not real tough to work on. One little nut on the compressor side of the shaft holds the shaft, and compressor wheel in the unit. Once the extra baggage is off (Housings) the rest is easy.

The seals are a locking end type ring (looks like a tiny piston ring with a locking end)

If the housing is not torn up and the blades (Hot and cold) are in good shape your set.

If the blades are trashed its ????????? if its cost effective to fix.

Good luck on things.

More pix will follow as the build progresses.

The next step will be to install the Piston and rod assemblies.

I will get some pixs on the ring end locations as well as checking end gap.

As usual I will try and cover all the little nuances that some of us old builders take for granted.

Stay tuned as the "Six Five" turns. (New daytime soap)

MGW