6.2l rebuild to 6.5l

[mt_bar]

Hi, I am new to the site. Could someone direct me to the forum that discusses rebuilding the 6.2l to a 6.5l? Specifically, I am planning to upgrade to 6.5 pistons, heads, and intake. I would like to stick with the DB2 injector pump. Any ideas on this? Thank you.

[Yukon6.2]

There are some good manuals available from the Diesel Page...
Then just use the search and read

[arveetek]

Hi, I am new to the site. Could someone direct me to the forum that discusses rebuilding the 6.2l to a 6.5l? Specifically, I am planning to upgrade to 6.5 pistons, heads, and intake. I would like to stick with the DB2 injector pump. Any ideas on this? Thank you.

Are you wanting to bore a 6.2L out to 6.5L specs? If so, that is not recommended. I know folks who have done it, but the general consensus is that the 6.5L had more metal cast into the block to allow for the larger bore; attempting to bore a 6.2L to 6.5L diameters may result in ultra-thin cylinder walls.

The best bet is to purchase a 6.5L block/engine and start with that as your build platform.

Casey

[More Power]

The "599" block casting (last three digits of the block casting number) is/was popular, as it was the first casting offered for the newly introduced 6.5L diesel engine for the 1992 model year. This casting first appeared in the 1991 model year as a 6.2L diesel, and that same casting was used till the 1995 or so model year. In 1992 and 1993, truck buyers could get either a naturally aspirated 6.2L diesel or a 6.5L turbodiesel. Both used the same block casting. The only difference was cylinder bore diameter.

Thousands of 6.2L 599 castings have been bored to the 6.5 specs - thousands. And, I recommend it. But like others here have suggested, I'd not bore any other 6.2L block castings to a 6.5.

And, the 599 was also one of the most crack free blocks GM produced.

Jim

[arveetek]

The "599" block casting (last three digits of the block casting number) is/was popular, as it was the first casting offered for the newly introduced 6.5L diesel engine for the 1992 model year. This casting first appeared in the 1991 model year as a 6.2L diesel, and that same casting was used till the 1995 or so model year. In 1992 and 1993, truck buyers could get either a naturally aspirated 6.2L diesel or a 6.5L turbodiesel. Both used the same block casting. The only difference was cylinder bore diameter.

Thousands of 6.2L 599 castings have been bored to the 6.5 specs - thousands. And, I recommend it. But like others here have suggested, I'd not bore any other 6.2L block castings to a 6.5.

And, the 599 was also one of the most crack free blocks GM produced.

I forgot about the 599 block when I made my previous reply above. I agree with everything Jim stated about being able to bore the 599 6.2L block to 6.5L dimensions.

Casey

[mt_bar]

Hi, thanks to all for your comments. I did try to do the homework on this question before committing, but it seemed like the consensus was pretty well evenly split..so here goes. I was more interested in finding out what guys had done with 6.5l injectors in such a "swap." By that I mean I came across comments that the earlier DB2 pumps did not put out enough pressure for the 6.5 injectors. If this is correct, what have people done to overcome the issue?

Also, for what it is worth, this project is being undertaken on my '84 C20 Silverado that I bought in 1987. It has the 6.2 in it, and I have put a ton of miles on it and have really had good luck with it. I guess the truck and I both are heading for the twilight years so the overall intent was to keep the truck and get new life on the engine. Thanks.

[DmaxMaverick]

If the engine is N/A (Natural Aspiration --no turbo), there's no advantage to increasing fuel pressure and/or volume at the injector. The engine can't effectively use the additional fuel. The exhaust will just become more black, with an exponential increase in EGT (Exhaust Gas Temp, which will melt the 6.2 pistons, to put it bluntly). If it starts and runs well otherwise, don't fix what ain't broke. A little timing advance can improve performance, compensating for valve train wear over the time/miles (you can do this w/o special tools or a technician). Greater concern should be keeping the rest of the engine healthy, like the crank dampener, hoses, belts, and leaks.

[More Power]

The safest and usually best advice is to run fuel injection components that were made/calibrated for a particular application. i.e. Use 6.2 injectors with 6.2 pumps and 6.5 injectors with 6.5 pumps. Now... these injectors are calibrated to "pop" pressure using shims. If you had the right test equipment you could recalibrate 6.5 injectors to 6.2 specs.

Using 6.5 injectors with a 6.2 pump could cause hard starting, especially while hot (the pump might not be able to generate the pop pressure at cranking speed with hot thin fuel). And, a delayed pop could possibly retard injection timing enough to be noticeable. Jim

[Robyn]

Just some thoughts

As mentioned.....The 6.5 injectors are/were not designed to work with the DB2 Injection system.

Now...One exception....1992 and 1993 6.5 used a DB2 pump with a bit more volume of fuel available, DB2 4911

These pumps will work with the standard 6.2 injectors......
Getting the injectors rebuilt and set to specs and all very close to identical POP PRESSURE....Makes a very smooth running engine.
stay away from HI POP injectors.....Good factory spec stuff is all you need.

Depending on the year of your rig and what has been done over the years.....There were/are short injectors and long injectors (Body length)

The high pressure fuel lines are not interchangeable between the two types of injectors. The lines from the later 6.5 with the DS4 pumps will not work...

If a bit more power is what you want....

Snoop around and scare up a BANKS turbo kit.....These can be found in the hallowed halls of such places as EBAY.....

An otherwise healthy 6.2 equipped with a Banks Turbo will make as much power as a factory 6.5...maybe a bit better...

These kits were even offered as an option through GM DEALERS at that time.

The early 6.5 DB2 injection pump (In good shape) will bolt right on and work fine.

The Banks turbo is a non waste gated unit.

A larger exhaust is needed.....4" is nice....3-1/2" will work......

As mentioned.....BLACK SMOKE ROLLING IS HEAT.....Rolling coal is a one way ticket to the little community of "Meltville"

The 6.5 has ceramic coated piston crowns...the 6.2 does not....Just a bit of added protection.

Keep the EGT in the 1000F at the LH exhaust manifold outlet and you are fine.

Boost is not real impressive on the BANKS....But is plenty to wake up the little 6.2

This will give good power and not destroy the engine.......I have seen many 6.2/6.5 sent to "Meltville" while their owners tried in vain to impress the troops.....

Do some snooping around.....There were a few other Add on turbo kits for these engines....But Banks was about the best....

Have fun......Good hunting...

[mt_bar]

Hi More Power. Thanks for the input. I was planning to "upgrade" to 6.5 injectors with a '92 DB2-4911 IP. BTW, really enjoyed "The 6.2 Diesel Engine" book.

[mt_bar]

Hi Robyn, thank you for the reply. I think I have the line on a DB2-4911 as you have suggested, but did the '92 use a lift pump also, or just the mechanical fuel pump?

[More Power]

All of the 1988-98 body style trucks/suvs that were equipped with the 6.2/6.5 had an electric fuel lift pump.

Jim

[mt_bar]

Hi all,

I have been researching the site regarding the need for a vacuum pump on 6.2 / 6.5. I have a 6.2 block that I am using for a rebuild that has the "distributor type" oil pump drive with attached vacuum pump. I have no idea on the condition of the existing vacuum pump but am having the devil of a time finding a replacement. The gears on the cam drive portion look good, but could use some thoughts on what to do if I can't find a replacement vacuum pump. Thanks.

[Yukon6.2]

Hi Again
Do you need vacuum for a specific reason?
By turning the one you have by hand should let you know if it works,or you can test it with a vacuum pump and see if it holds vacuum
There are ones you can run from a serpentine belt system,Ford uses a similar one that is belt driven, one that i had i took the pod off the ford mount and replaced the pod on a gm one with it.
If neither of those options work you can get an electric one,and add a vacuum tank then you will have a constant supply

[arveetek]

Hi Again
Do you need vacuum for a specific reason?

On his 1984 C20, he will need vacuum to operate the HVAC controls. Assuming there is no EGR on this 3/4 ton, and that this is a factory diesel with hydroboost, that will be the only essential need for vacuum.

Casey

[Yukon6.2]

Missed the part about what his vehicle was

[mt_bar]

Hi arveetek and Yukon6.2: That is correct, on this truck vacuum is needed for the factory HVAC, as well as factory cruise control, and last but not least the TH400 transmission. Since I last posted I stumbled across a new vacuum pump pod sold by Accurate Diesel. I will just clean up the "gear drive", mount the new pod and go from there. Hopefully this will get me off dead center.