Need Some Rebuild Advice

[CedarGrove]

I had a thread going in the 6.2 section regarding a military surplus engine that I picked up from Bragg. I thought I might have gotten a screaming deal on a recently rebuilt 6.2 at $468.00. Turned out to be a GEP block with a cast date of Jan 2008. That part was good. The downside is that it spun the #6 rod bearing and the crank is fubar. Anyway...This rebuild is my little science project for the coming month as money allows. I have the block stripped of everything except for the cam bearings and ready to go to a machine shop for inspection/work.

I have many questions regarding the rebuild but the one I am most curious about at the moment is this one. The oil rail (I think it's called the oil rail?) is stamped at each main with a number. Bearings 1 through 4 are stamped with a 2. Bearing 5 is stamped with a 1. What do these numbers indicate? A photo is attached.

Also it looks like the #3 cam bearing is yellow which I believe indicates that it is .030 undersize? All of the rod and main bearings where standard.

I believe the engine was recently built or rebuilt. I believe there was a snag somewhere in the oil path from the cam or thereabouts to the crank which starved rod bearings 5 through 8. They were all showing signs of getting hot. 1 through 4 rod bearings looked cool as a cucumber. Cam and cam bearings seemed fine as well as main bearings.

So what's with the numbers?

[CedarGrove]

Interesting discovery while doing research this weekend. Only the squirts on 7 and 8 are used on these military engines. The others are disabled by installing the cam bearings 1 through 4 in a particular orientation and a standard oil pump is used. I guess that makes sense as the military has tons of 6.2s and using the standard pump on everything makes it much simpler all around.

If I ever get this thing rebuilt I won't be working it too hard but I do plan to turn all of the squirts back on and use a HO oil pump. I expect this will be the last engine my 84 C10 beater will ever need.

[Robyn]

Hmmmmmmmmmmmm :confused:

The cam bearings have ZERO effect on the piston oil squirters.

The cam bearing bores have a anulus groove machined around the inside.
This allows the oil to flow completely around and allows the cam bearings a "little" latitude and also lets the oil flow to the main bearing feed.

The oil for the squirts is supplied from the main bearing top shell oil groove.

There are oil holes drilled into the main saddle that direct the oil up towards the cylinder. The very upper part of the passage is tapered and has a small orifice tapped into the bore of the passage. (Aluminum pill)

Early squirters were about 8mm daimeter and the later engines had these reduced to 6mm to help stop cracking from the large holes in th web

The cam bearings must be oriented only in one way.

Oil flow in these engines comes from the pump, out to the cooler, back from the cooler and into the block, through the filter then into the main gallery and to the top end (cam/lifters) the oil flows from the lifter oil galleries down through the center bore drilling of the cam bore to the main bearings.

The top main has an oil groove, this supplies oil to the drilled passages in the crank where the oil then flows to the rod beaings.

The top groove in the main has two holes at about 11 and 1 oclock these supply the squirts.

Some 6.2 bearings dont have these holes.

Most all of the new bearing sets are universal and have the squirt holes.

The bottom end is the same on 6.2 and 6.5 engines.

You can use an HO pump on a Non squirt block, but not the other way around
as the huge oil leaks (squirts) require far more oil flow.


Missy

[More Power]

The non-turbo "Fuel Miser" engines produced by AMG only got piston oil spray on 7&8. The TD engines got spray on all 8. This arrangement for the Fuel Miser was to help keep hot oil pressure higher when used in vehicles like delivery vans - that idled a lot.

Jim

[CedarGrove]

10-4. I'm still wrapping my head around this. Thanks for the run down on the oil path. That's another thing I have been very curious about.

Thanks,

Lewis




Hmmmmmmmmmmmm :confused:

The cam bearings have ZERO effect on the piston oil squirters.

The cam bearing bores have a anulus groove machined around the inside.
This allows the oil to flow completely around and allows the cam bearings a "little" latitude and also lets the oil flow to the main bearing feed.

The oil for the squirts is supplied from the main bearing top shell oil groove.

There are oil holes drilled into the main saddle that direct the oil up towards the cylinder. The very upper part of the passage is tapered and has a small orifice tapped into the bore of the passage. (Aluminum pill)

Early squirters were about 8mm daimeter and the later engines had these reduced to 6mm to help stop cracking from the large holes in th web

The cam bearings must be oriented only in one way.

Oil flow in these engines comes from the pump, out to the cooler, back from the cooler and into the block, through the filter then into the main gallery and to the top end (cam/lifters) the oil flows from the lifter oil galleries down through the center bore drilling of the cam bore to the main bearings.

The top main has an oil groove, this supplies oil to the drilled passages in the crank where the oil then flows to the rod beaings.

The top groove in the main has two holes at about 11 and 1 oclock these supply the squirts.

Some 6.2 bearings dont have these holes.

Most all of the new bearing sets are universal and have the squirt holes.

The bottom end is the same on 6.2 and 6.5 engines.

You can use an HO pump on a Non squirt block, but not the other way around
as the huge oil leaks (squirts) require far more oil flow.


Missy

[CedarGrove]

The non-turbo "Fuel Miser" engines produced by AMG only got piston oil spray on 7&8. The TD engines got spray on all 8. This arrangement for the Fuel Miser was to help keep hot oil pressure higher when used in vehicles like delivery vans - that idled a lot.

Jim

This is a N/A engine that I am dealing with. Went back and re-read the resource I was looking at this weekend and it did in fact say that it is the main bearings that feed the squirts. I don't know how I got it in to my head that it was the cam bearings.