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141 block

ak diesel driver

ak diesel driver

6.5 driver
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My nephew gave me an engine out of an 89 burb, I thought it was a 6.2. Evidently not. Tore it down to a short block today and discovered it was a 141 block with a may 23 96 date code on it. Has at least one bad rod bearing but the block appears to be crack free so far. Thinking about using this block to build a spare engine for my 281k DD
 
Should be a good candidate Les, My 141 in the 95 has 250k miles on it.
 
Have you checked the bore diameter?

The difference between the 6.2 and 6.5 TD is only in the bore and the fact that 6.5 TD's have ceramic coated pistons-there were also some minor compression differences over trhe years.
 
Got the short block disassembled. definetly had some bad rod bearings with the number 3/4 throw being the worst. heated the main webs and sprayed penetrating oil in the outer main holes and couldn't see any evidence of cracks, so I believe I'm good to go. pretty sure it's a 6.5 and a cheapee caliper on the bore showed over 4". cylinders show almost no wear at least no ridge.
 
Does it have piston oil squirters? I encountered a late model 6.5 long block put into a 90 6.2 truck. The block had oil quirters, but they reused the 6.2 low volume pump. The result was a wiped out cam and rod bearings.
 
What's wrong Les, runnin' out of compression? Hearing foot steps? (of your own walking to get a tow) :hihi:
 
racer55 said:
Have you checked the bore diameter?

The difference between the 6.2 and 6.5 TD is only in the bore and the fact that 6.5 TD's have ceramic coated pistons-there were also some minor compression differences over trhe years.
Click to expand...

scottm said:
Does it have piston oil squirters? I encountered a late model 6.5 long block put into a 90 6.2 truck. The block had oil quirters, but they reused the 6.2 low volume pump. The result was a wiped out cam and rod bearings.
Click to expand...

141 blocks were used VERY late 95- VERY early 97, they were 6.5's, and none of them had piston oil squirters. The last 6.2's were 599 blocks, and the first squirter blocks were 506's. 92 on 6.2's were 599 blocks as well as 92-94 6.5's. LATE 94 to EARLY 95 could still be a 599 block OR a 929 block. Then starting very late in 95 GM came out with the 141 casting, and then starting mid way into 97 they went to the 506 block. The 506 is the most confusing because it could be a 97-98 which were the absolute WORST blocks ever for the 6.5, or it could be a decent one all the way up to the best block's for the 6.5's. The date code and internal differences is what set them apart from each other.
 
^^That's a good write up Ferm.. Don't think I've seen the run of gm iron laid out in it's entirety, just bits and pieces.
 
The squirt blocks also came with some early style and late style squirt nozzles.

The early nozzles had a much larger body, and thus a larger hole was drilled into main saddle.
The size was reduced in the later blocks.

The early 506 squirt blocks had the large diameter main bolts in both inner and outer positions as well as the large squirt nozzles.

The later blocks had small nozzles and the outer bolts were reduced to 10mm.

One of the big no no's in any of these blocks is the huge amount of stress risers all through the bottom end.

Before using any block, be sure there are no cracks in the main webs, then remove all the stress risers.

Carefully using a countersink to break all the sharp edges on all the main bolt holes is an absolute must

Chamfer the holes to get about a 1/16 wide break at the hole mouth.

Using a bastard file, break the sharp edges of the main webs to about 1/16 wide on a 45 angle

Use a 1/16" carbide ball in a die grinder and remove the knife edge at the base of the register fit where the main caps sit, especially the center mains.

This stops the tendency for a crack to form here.
Lightly countersink the starter bolt hole mouths as well.

Any sharp edges are an absolute NO NO

If there are any "clips" at the bottom of the cylinders where tooling nicked the lower edge of the cyl bore, these must be smoothed up and rounded so the stress riser is gone.

Think of it as a sharply creased piece of paper, and how easy it tears.

Carefully break the edge of the main bores using a die grinder and a "whip stick" or a sanding drum.
Lightly countersink all the oil holes in the main line.

Just breaking the sharp edge is all that's needed.

The dynamic forces at work in the bottom of these engines is a major player in the incidence of cracking, and "Dehorning" really adds to the longevity, or at least is not going to hurt.

This type of prep is a standard on any high perf race engine.

Will it stop all incidence of bottom end breaking, Maybe, but it's a step in the right direction towards stopping many of the failures.


These procedures take some time, but can be finished in an hour or so prior to the final wash out pending assembly.

Also, clean and run a tap through all the head bolt holes to remove all old sealer and to be sure the threads are clear and in good order. (be sure to use the proper metric tap)

if it has a sharp edge left by machining, fix it.

Nice rounded edges are what we want.

The addition of the squirt holes in the main saddles was a real nasty source of stress risers, and resulted in many blocks cracking through the squirt holes and then on up into the lower portion of the adjacent cylinders, usually hitting the water jacket.

The results were coolant loss and yuuuuuuucky oil.

Take your time and do the prep work, it will pay off.


Missy
 
Did GM ever use pressure activated squirters, or were they all just open? I haven't been inside a 506 to see if they were just open or not. I know the DURAMAX uses spring loaded squirters so they don't squirt at idle. This is why the oil pressure in a DURAMAX stays around 35-45 for so long is that is when the squirters open up and spray oil.
 
The 6.5 just hoses, no matter.

Fixed orifice

This is an area that folks have had issues.

The non squirt blocks use a slightly smaller (lower volume) pump than the squirt blocks
using a non squirt pump on a squirt block will result in almost zero oil pressure at hot idle

Having a missing nozzle will really dump the oil pressure, and when warm the engine will barely have any pressure.

Using a squirt pump on a non squirt block will produced pressure up the whazoooooooooooo

70 psi cold and 60 hot and idle at 40

I have done this and it works fine, just never use anything above 15-40 oil
 
The 506 squirters i have seen are just pressed in inserts with an open orifice.
On the two Chinese blocks i have the bore holes and inserts are smaller than OEM.
 
splain me "heated the main webs and sprayed penetrating oil in the outer main holes".
Is this some kind of quickie ck in loo of magnafluxing?
 
Most cracks are easily seen. The oil will continue to seep out once the surrounding surfaces are solvent cleaned. The above trick has a similar principle.
 
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