Rebuild vs. long block

[jag7720]

I'm considering doing a rebuild/build-up. 6.2 Buildup

My current setup is an 85 M1009 with either 50k or 150K miles (who really knows) and a Banks turbo added about 2 years ago.

The reason I am considering this is two fold
1. For the experience and project aspect (I can get my sons involved and make it fun)

2. To have a new engine that is stronger and will last longer. (who know what was done to these truck before we got them and an 85 with 50k miles is still a 27 year old engine.

I'm not into off road performance. My truck is a daily driver and is the occasional weekend back road trip. I do a little towing with a small trailer.

My truck got 21 mpg at 70mph when I drove it home two years ago... I assume it gets a little better with the turbo but I haven't kept track.

I have already upgraded my cooling, rebuilt my tranny and rebuilt quite a bit of the suspension (still stock)


So, my questions are these...

1. Will the 6.2 parts bolt up to a 6.5 long block? i.e. are they completely interchangeable?

2. Having never "rebuilt" an engine would it be cheaper to buy one of the "Improved" long blocks and do a swap of parts? Skipping the rebuild process all together. $4590.00 for the "Improved" 6.5 long block and $3590.00 for a standard 6.5 long block Improved 6.5 Liter Diesel Engines ... or $1500 for something from this place Marshall Engines

3. Or would it be cheaper to find/buy an old 6.5 engine and actually rebuild it?

4. I have read some stuff on the different blocks over the years and some having weaker points and using 6.2 heads on a 6.5 block etc... is there a consensus on this?

5. What is the consensus on the DSG Stud Girdle Kit? Is it worth it? Is it necessary on the "Improved" 6.5 block or the GM 6.5 block or any of the blocks for that matter?

6. Serpentine up-grade vs. non-serpentine belt system?


Any other advise???


Thanks

 

[Tanner]

Marshall Engines are crap...

There. Now that this is out of the way, let's move on.

I'd recommend going over to some of the 6.X diesel-specific sites for the best answers. The 6.2 blocks have more 'meat' around the bores (obviously due to the smaller displacement vs 6.5), and the late blocks were a bit stronger. Some castings are better than others - If it were me and I was planning to keep the truck, I'd drop the coin on an improved 6.5 motor - newer block/head design, etc... you get what you pay for -

When I was working for a major engine remanufacturer, we were having to junk roughly 75-80% of the core blocks that came in - Know this: the cheaper price rebuilds typically reuse the valves & springs. They MAY have odd-sized bores (I've personally seen 'rebuilt' engines with 6 cylinders at one bore size & 2 cylinders at a larger size - not always the case, but not uncommon for cheap 'rebuilders' to only overbore the scored cylinders.

There is a MAJOR difference between a rebuild and a reman engine. Reman engines are brought back to meet or exceed OEM specs. 'Rebuilds' are a crap shoot.

'Tanner'

 

[Warthog]

Try this site. One of many

www.thedieselpageforums.com

www.thedieselpage.

 

[Stonepicker1]

With your setup, if it was me, I would just replace the injectors / glow plugs and maybe the injector pump. Your engine should last you a long time if you don't overdue the RPM's.
I would wait until the engine had problems first before doing a replacement.

But, if you want something different, I would go with a GEP 6.5L.
I have one in my Dually and in my CUCV-II, builds below.

http://www.steelsoldiers.com/cucv/6...florida-rebuild.html?highlight=dually+florida

http://www.steelsoldiers.com/cucv/62434-cucv-ii-south-florida-rebuild.html?highlight=cucv-ii+florida

 

[jag7720]

I forgot to mention that I have replaced the IP... it went bad with in two months of my owning it.... I have not replaced the injectors though.

 

[Stonepicker1]

I forgot to mention that I have replaced the IP... it went bad with in two months of my owning it.... I have not replaced the injectors though.

With that said, I would replace the 6.2L injectors with 6.5L turbo injectors and you should be good to go. Did you check your harmonic balencer?
http://www.steelsoldiers.com/cucv/44202-check-you-balencer.html?highlight=balancer

You could also put some new 6.5 heads on with the ARP stud kit and a 6.5L head gasket. Lots of different thing you could do if you can get a good deal on parts.

With the increase in power you may develop a head gasket leak on that old 6.2.

 

[jag7720]

Funny you should ask that.... I was reading about the balancer last week. I get home from Afghanistan in about 20 days and it will be the first thing I check/replace.

I don't run it hard very much... the occasional hard take off from a light.... so hopefully a head gasket wont be in the works.


What would I ask for as far as 6.5 turbo injectors? How would I know I was getting them for that application and not for an n/a engine?

 

[Stonepicker1]

Take a look at this. I posted some part numbers for the 6.5L turbo injectors.

http://www.steelsoldiers.com/cucv/79972-injector-types.html?highlight=injectors

 

[Tanner]

Why go with turbo injectors when using a stock 6.2 NA IP?

 

[jag7720]

Well, I posted this on thedieselpages.com

Is it possible to build an IP for a 6.2 to the same specs as an IP that is used on 6.5 Marine engine? I have a turbo on my 6.2 and I 'd like to give it more fuel if possible.

Or is IP the same on marine and land vehicles and only the injectors are different?

Anyone know the answer?

 

[Tanner]

AFAIR - 6.5 pumps had larger plungers...

C code pump vs. 6.5 N/A pump - Diesel Place : Chevrolet and GMC Diesel Truck Forums

from jdemaris on the site; usually a good resource of info:

"6.5 needs a bigger pump with a turbo. A 6.5 with no turbo uses the same fuel delivery as a J-code 6.2. 6.5 turbo needs at least .31" plungers, and all 6.2 pumps use .29" plungers.

Two small round plungers do all the injection-pumping in Stanadyne rotary pumps.

All 6.2 injection pumps use the same-size pair of injection-plungers that measure .29" each. That's why all 6.2 pumps have the number "29" on their ID tag somewhere - e.g. "DB2829." 6.5s injection pumps use large injection-plungers that are .31" diameter and have a "31" on the ID tag, e.g. "DB2831."

6.2 C-code and J-code pumps are identical except - those injection plungers travel with a slightly longer stroke on the J-pump determined by the screw adjustment, and also the J-pump uses a different delivery valve.

As the how much fuel can they pump? Standard civilian 6.2 pump can flow around 11-12 gallons per hour unless modified.

A civilian J-code 6.2 pump pumps around 48.5 cubic mms per stroke at 3600 RPM.

A military J-code 6.2 pump pumps around 51 cubic mms per stroke at 3600 RPM.

A civilian 6.5 turbo (early) pumps around 68.6 cubic mms per stroke at 3600 RPM.

A military detuned 6.5 replacement-engine with no turbo, used to replace a 6.2 engine in a HUMVEE gets a turned down DB2831-5209 set to pump 46.5 cubic mms per stroke at 3600 RPM."

 

[jag7720]

"6.5 needs a bigger pump with a turbo. A 6.5 turbo needs at least .31" plungers, and all 6.2 pumps use .29" plungers.

6.5s injection pumps use large injection-plungers that are .31" diameter and have a "31" on the ID tag, e.g. "DB2831."
A civilian 6.5 turbo (early) pumps around 68.6 cubic mms per stroke at 3600 RPM.

Can you build a 6.2 pump with the parts for a 6.5 so you have a .31" plunger and pump around 68.6 mms per stroke?

 

[cedargrove]

I'm considering doing a rebuild/build-up. 6.2 Buildup

My current setup is an 85 M1009 with either 50k or 150K miles (who really knows) and a Banks turbo added about 2 years ago.

The reason I am considering this is two fold
1. For the experience and project aspect (I can get my sons involved and make it fun)

2. To have a new engine that is stronger and will last longer. (who know what was done to these truck before we got them and an 85 with 50k miles is still a 27 year old engine.

I'm not into off road performance. My truck is a daily driver and is the occasional weekend back road trip. I do a little towing with a small trailer.

My truck got 21 mpg at 70mph when I drove it home two years ago... I assume it gets a little better with the turbo but I haven't kept track.

I have already upgraded my cooling, rebuilt my tranny and rebuilt quite a bit of the suspension (still stock)


So, my questions are these...

1. Will the 6.2 parts bolt up to a 6.5 long block? i.e. are they completely interchangeable?

2. Having never "rebuilt" an engine would it be cheaper to buy one of the "Improved" long blocks and do a swap of parts? Skipping the rebuild process all together. $4590.00 for the "Improved" 6.5 long block and $3590.00 for a standard 6.5 long block Improved 6.5 Liter Diesel Engines ... or $1500 for something from this place Marshall Engines

3. Or would it be cheaper to find/buy an old 6.5 engine and actually rebuild it?

4. I have read some stuff on the different blocks over the years and some having weaker points and using 6.2 heads on a 6.5 block etc... is there a consensus on this?

5. What is the consensus on the DSG Stud Girdle Kit? Is it worth it? Is it necessary on the "Improved" 6.5 block or the GM 6.5 block or any of the blocks for that matter?

6. Serpentine up-grade vs. non-serpentine belt system?


Any other advise???


Thanks

In my opinion if you are going to drop some coin on a new engine buy from a reputable dealer of real deal GEP engines. Many folks offer "new upgraded" engines but there are only a few that I would trust to actually deliver a real deal GEP. One is Kennedy Diesel, the other is WW Williams. There might be a couple more out there but check with GEP first to find out who the dealers are. If they are not a genuine GEP dealer, DO NOT *U*K with it. The GEP engines have better metalurgy and a slightly beefier bottom end. In my opinion it's the best of breed block and heads and is the preferred base for doing a rebuild.

I hear where you are coming from and I would like to offer one idea. I am not a MV guy. I'm a GM diesel guy. I have an old tired 84 C10 and wanted an adventure. I know these civi engines fairly well but I have never built one. I bid on a surplus GEP engine on Govliquidation last year and won it. It had some spun rod bearings and I have been rebuilding it as my winter project. It's been great fun and a great learning experience and I would recommend it to anyone looking for a project. Buying from govliquidation does has it's risks but when I am done I will have a nice GEP 6.5 to replace my tired 6.2. I'll have between 2000 and 2500 bucks in it when it is installed. A new GEP long block would probably run close to 6000. I'm thinking of the 2500 bucks as tuition for a good schooling.

There is a GM diesel forum called the truck stop. One of the members did a good write up on a similar project. He built his to some pretty high specs (I'm just doing a regular old N/A rebuild). His screen name is bobbiemartin and the thread is a worthwhile read. It explains the differences between the civi and the humvee engines pretty well.

If this is something your interested in, I'd be glad to help in any way that I can. I'm in the middle of my build right now. Pistons went in last weekend. Timing gears and front of the engine is my task this weekend.

Cheers,

Lewis