6.5 REBUILD

[cubby]

Hello everyone, I am a brand newbie to this site. I have 3 old 6.2's, 84,85,86. these motors all have about 250,000 each and have all plowed snow for 15 years. My problem is my crank broke in half in my 86, and I just found out that these blocks are known for the main bearing bolt holes cracking which mine are, even in my spare 6.2 block. So, they are scrap.
I have a good 1997 6.5 engine. I am missing the intake manifold, and the injection pump. I need to know if there is difference between a 6.2 and 6.5 manifold and what the difference is between a C & J block manifold. Also if a 6.2 injection pump will work on a 6.5 engine. Are the cylinder heads different? Desperate, as the snow will fly soon and truck is in pieces literally.
Thanks,

Cubby

[More Power]

The newer cylinder heads used on the late 6.2's and all 6.5's position the injectors at a more upright angle. This means your mid-80's fuel injector lines should not be used.

As long as you use 6.2 injectors with a 6.2 injection pump, it'll work fine (produce power like a 6.2) on the 6.5. For best results, don't mix 6.2 injectors with a 6.5 pump.

All of your 6.2 manifolds will bolt right onto the 6.5. Just make sure you use a 6.2 V-belt water pump if you're re-using all of your 6.2 accessories.

MP

[cubby]

Thank you so much for your reply ! I thought this was the case I just wanted some confirmation. I'm trying to get by cheap on this one, but after reading so much information today it looks like I will start collecting 82-83 red 6.2s . I love my mid 80's chevys and would love to keep them running till I die and then some.This truck is a 1 ton duallie 4x4,complete rebuild, blasted frame,rustoleum coal tar epoxy, spring hangers/shackles,steering box,radiator,motor,trans,texas cab,drive shafts,brake lines run through 3/8 fuel line,poportining valve moved from frame to just under master cylinder, misc...,ect... in three weeks! I'll let you know when it runs again!

[john8662]

Another note on the injection pump, I have been informed that you need to use the top gear attaching to the injection pump for a 6.2 if your using a 6.2 pump. The top timing gear that attaches directly to the injection pump is different from that of a 6.2. If the engine is a 1997 block than it was equipped with a DS4 electronic pump. I think thats all you need to swap out. The advise about the waterpump is right on, counter-clockwise rotation on the serpentine setup, clockwise on the v-belt.

[cubby]

Thanks again for your knowledge and assistance on this. What is a "J" intake? If I come across one in my parts hunting.

[john8662]

A J series intake manifold is the manifold used on 6.2 engines that were in 3/4 and 1 ton trucks that had less emissions requirements. The J series intake has no EGR (Exaust Gas Recirculation) ports in it and is a better free-flowing intake. The C series (1/2 ton light duty truck engines) have an EGR system on them, that basically makes the engine eat its own exaust for better emissions. The EGR intake is somewhat restrictive as compared to the J series intakes.

When looking for intakes consider several things..

82-83 J Series intakes

-these are dual plane intakes, but have the bolt holes on the back of the intake for mounting secondary fuel filter as equipped in 82-83 trucks. This intake will mount on any 6.2 or 6.5. Just mentioned if you had an 82 or 83 with the two fuel filter setup and had a C series engine you were upgrading and needed the correct bolt holes for the secondary fuel filter. Also, this intake has two ports on it for the CDR (Crankcase Depression Regulator -> like PCV on gasser) system, so if used on a 6.5, the CDR system would need to be that of a 6.2.

84-87 J Series Intakes

-These are also dual plane intakes, only differences is the bolt holes on the back of the intake for mounting fuel filter assemblies. In the trucks, the fuel filter setup is mounted on the firewall, so no worries there. In the G-vans it is mounted on the backside of the intake manifold. This intake will work on all 6.2 and 6.5 engines (bolt up). Also, this intake has two ports on it for the CDR (Crankcase Depression Regulator -> like PCV on gasser) system, so if used on a 6.5, the CDR system would need to be that of a 6.2.

8X-9X J Series Hummer 6.2 Intakes naturally aspirated.

-The 6.2 Hummer intakes are a bolt on solution for any 6.2 or 6.5 engine but differ from the intakes found in pickups, blazers, suburbans, and vans. These intakes are LOW PROFILE, so if used in a truck, there would be clearance issues with the factory round air-cleaner box. A spacer would need to be used with these intakes. The pro of this intake is that is is not a dual plane intake, but a single plane intake, just wide open. Also, this intake has two ports on it for the CDR (Crankcase Depression Regulator -> like PCV on gasser) system, so if used on a 6.5, the CDR system would need to be that of a 6.2.

88-93 J Series Intakes & 94-95 NON TURBO 6.5's

-These intake manifolds are the preferred intake manifolds but differ from all the other intakes talked about thus far. These intakes will bolt to any 6.2 or 6.5 (82+ 6.2's and 6.5's). These intakes also are normal profile in height, so will work with the factory air cleaner. These intakes are single plane intakes, wide open, just like the hummer intakes, so if running naturally aspirated, these will get the best flow. The last difference is the way the CDR system hooks up to the engine. The CDR system used with these intakes is a single port setup that hooks directly to the passenger side valve cover. The valve cover on later model 6.2's and 6.5's on the passenger side is fitted with a grommet for attaching the CDR valve to. So if using this intake on an older 6.2 the CDR system would need to be R&R'ed. Also, a late 6.2 or 6.5 valve cover would also be required just for the passenger side head.

In conclusion, the J Series intakes whichever you use will gain better airflow for a C series 6.2. They can enable the engine to burn fuel cleaner and give it a little more power. The dual plane intakes are more common than the single plane intakes and are just as good. The J series intakes will all flow air better than a C series intake. The later single plane intakes might have better airflow, but involve more adaptation on an earlier engine.

[tom.mcinerney]

1.)Nice brake lines!
2.)Coal-tar epoxy is way to go!