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6.5 Na Max Potential?

I took it down to the short block today. The block is 12555506, date H269 (aug 26, 99?). Heads are 10132567, date D236 and D246. IP is DB2823 - YL4153, injectors are Bosch usa 0430211054. The ip has a sticker from a diesel shop in south phoenix dated 09-2000, so I figure that is probably when the original 6.2 was swapped out. If only they could have waited a couple more years for the GEP blocks!

The firing order - 1 8 7 2 6 5 4 3, looked odd to me compared to the normal chevy gas order - 1 8 4 3 6 5 7 2. Aftermarket cam grinders realized years ago they could swap the 7-4 firing order of gas v-8's for a couple benefits (mostly to eliminate crossfire detonation in cyl 7 from cyl 5's spark). On the 6.5 it looks like gm swapped both 4-7 and 2-3 for whatever reason.

The injector lines are a pita. Has anyone ever made new lines, and routed them straight back from the pump and around the back of the heads?
 
IP lines are a pain but most believe they need to be equal length.

Have you pulled the pan yet? Wondering about main cracks.

Source Unknown
 
I spent the last 2 weeks building a real engine stand, and rebuilding my engine hoist so it's legs will go around the stand base. There was a lot of rust in the no 7 bore, but I cleaned it up with a sanding drum and freed it up with some pb blaster. The bottom end was very clean. The crank and rods are still in it, but I didn't see any cracks around the main caps. It is going to my machine shop for magnafluxing, and hopefully none materialize.

This is a std volume oil pump, plus I think it has the oil jets in the main webs, so it probably had low oil pressure, huh? The third pic shows an oil galley plug with a small hole in it. I assume that is in case of a plugged cooler. The oil filter relief valve built into the block is a nice touch, but how do I get it out?

Another question - I pulled all the lifters, the cam sprocket and cam retainer plate, but it still won't come out. What is holding the cam in?
 

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Yeah, the oil squirters are the reason they made the body extension and longer gears to turn the oil pump into a high volume pump. Unless you are planning on spending most of its life above 4,000 rpm you want a high volume one in there.

Look at the top back section of the block. Oil pump drive is there (think distributor on a gasser) it is driven by the cam gear and drives the oil pump. Remove bolt and retainer then it will lift out. Then the cam will come out. If you ever see an oil pump drive with wires, it does the same thing, but is an engine speed sensor (ess) for engines without a crank sensor.
 
IP lines are a pain but most believe they need to be equal length.

Have you pulled the pan yet? Wondering about main cracks.

Source Unknown

Yes, they have to be equal length otherwise each cylinder will get a different amount of fuel and the timing for each cylinder will be totally out as the IP can't compensate for it.

This is a std volume oil pump, plus I think it has the oil jets in the main webs, so it probably had low oil pressure, huh? The third pic shows an oil galley plug with a small hole in it. I assume that is in case of a plugged cooler. The oil filter relief valve built into the block is a nice touch, but how do I get it out?

Its a bypass of some sort, without that hole, or with the plug, it won't build oil pressure, ask me how I know! The other valve is pressed in so you need to pull it out. I guess remove the guts, and use a screw of some sort or a hammer and screwdriver to cave the sides in.
 
Look at the top back section of the block. Oil pump drive is there (think distributor on a gasser) it is driven by the cam gear and drives the oil pump. Remove bolt and retainer then it will lift out. Then the cam will come out. If you ever see an oil pump drive with wires, it does the same thing, but is an engine speed sensor (ess) for engines without a crank sensor.

The pump drive and pump are out, but it is still stuck. I can hear it hit something after moving forward about .060.
 

I asked about equal length lines on 4BT Swaps a while back. A slight variation in length won't matter, but 12 inches would make a difference. Oil is incompressible, but with any material, a pressure pulse moves through the material at the speed of sound. For diesel fuel, the speed of sound is about 4300 feet per second. At 4300 fps, an extra foot of tube will require .00023 seconds of travel time. At 4,000 rpm the engine is doing 66.7 revs per second. That times 360 equals 24,000 degrees per second. So the 1 foot longer tube pulse would arrive 5.58 degrees late, which would hurt power.
 
The mechanical fuel pump port had a block off plate, but I removed it. I have a couple military shop manuals on cd I bought on flea bay, I will look through them for an answer.
 
I assume you have pulled the lifters out. Maybe one broke or you have a debris issue. I don't recall spinning the cam while taking them out, but, it can't hurt done carefully so you don't nick it on whatever it is hitting.
 
In the first picture the oil pump drive is still there. Guess you took it out after the pic was taken and before trying to remove cam?

Use an inspection mirror and look for spun cam bearing.
 
Yeah, it is cam bearing related. There is nothing holding it in, so there must be a mushroomed edge or something. I am going to weld a couple bolts together to attach my slide hammer to the front of the cam, that should get it.

I took the pistons and crank out last night. I didn't see any cracks, but it has been poorly rebuilt before. I saw a lot of uneven bearing wear, especially on the mains. There were some wear spots down to the brass backing. The reason became apparent after cleaning everything up - some clown has attacked the main cap saddles in the block with a sanding disk, making them uneven. It's kind of hard to see, but notice the rounded right edge and the swirl marks. Probably an air-90 die grinder with a 60 grit disk. Oh well, just another few hundred $ more at the machine shop for a line bore. But it should be done anyway when you go to main studs.. Hopefully there are no other surprises.
 

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My machinist has been in business for 35 years, and has never seen anyone disk sand the block main cap surfaces before.. Just my luck. It will require a line bore AND line hone to fix it, so I almost hope it has cracks! I could not find a main stud kit on the arp website. Do you guys have the part numbers for individual studs? I am going to convert the 10mm outer studs to 12 mm while I am at it.
 
So what you are saying, you need a good block...

X2.

oil squirter block with non squirter oil pump, that they did not know how to put the main caps on properly. Cambering issues which relates back to the oil, and it is not to hard to damage the seats for the cam bearings. If going stock youd be ok there, but high rpm...?

Your wanting to spend how much on trying to get by with this block? The high rpm gonna have to go to a scat crank, different rods and pistons, and new harmonic balancer. That's a good chunk of money to throw inside of the block that is starting out on the non desireable list. Your $ not mine but when that lets go at high rpm you wont have much to rebuild with.

IMO, get an optimizer block.
 
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