my brothers 6.5 just took a dump. He needs his truck for work, and hasn’t had any luck finding them decently priced. Does anyone have a good one laying around? Will travel for right price.
CK5
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Anyone have a good mechanical 6.5 laying around?
- Thread starter jekquistk5
- Start date
All truck versions of the 6.2 and 6.5 are pretty much the same. If he finds a good engine but it has the ds4 pump he can use just has to change a couple things. The timing cover housing is different as the mechanical engines don't have an optical sensor. SO you can just use the cover off his old engine. And of course the injection pump is different.
Otherwise it's swap all external parts over to the "new" engine and run it.
Otherwise it's swap all external parts over to the "new" engine and run it.
The differences are minor. If his mechanical (DB2) IP is in fine shape I would simply swap it as @KirsL said. If not, I would grab the whole harness from the DS4 donor (with the ECM and PMD). A newer engine will also come with a newer turbine (like the GM8). The interchangeability of all the parts gives you a lot of options.
Same. The turbine may be different, but they are swappable if you want to upgrade. Though the computer-controlled waste-gate won't work if you stick with the mechanical fuel system.
Some intakes have EGR and MAF "features" that you won't be needing on your older truck. But they all swap if you want to keep your original manifold.
I haven't personally run a GM8, but the internet seems to prefer the later turbines to the older ones.
http://www.thetruckstop.us/forum/threads/gm-4-turbo-vs-gm-8-install-performance.19378/
Paging @GWeakland620, @AgDieseler, @longbedder, @Russell, @KirsL, etc.
Vombrown
Mountain Man
Gm8 is better. Also if you find a 6.5 electronic I would put that in there straight away. They make stand alone computer for them that is pretty cheap and it will go in really easily. So I guess it depends on what you find. I will add that now is also a good time to rebuild the injector pump on whatever is going back in.
The GM turbos (-3 thru -8) all use the same cores (turbines and bearings). The differences are in the housing sizes and wastegate configurations, so the flow maps are a bit different amongst them. Saying that one is better than another isn't really relevant in the context of getting a work truck back to work, whereas finding the one that's available and affordable is.
It's pretty common to make or buy a mechanical wastegate controller for the later turbos which were vacuum actuated. I made mine with a hardware store spring and a bracket I welded up. Deleting the vacuum pump is a big reliability upgrade - its ONLY job on a 6.5 is wastegate control, and the pumps are very prone to failure.
It's pretty common to make or buy a mechanical wastegate controller for the later turbos which were vacuum actuated. I made mine with a hardware store spring and a bracket I welded up. Deleting the vacuum pump is a big reliability upgrade - its ONLY job on a 6.5 is wastegate control, and the pumps are very prone to failure.
I got a couple leads on some 6.5's. Let me do some checking.
Everything is an easy swap with the 6.x engines.
Just make sure you get a truck version as the turbod vans and hmmvs used different heads.
As for turbos, yes the gm8 is better the the gm4 but not by a huge difference. A hx35, hx40 or an A-team turbo are far superior to any of the gm turbos. Just depends on how the truck is used. The gm turbos have crazy high drive pressure, like 2.5 to 1, which causes extreme heat to be retained in the engine. Any of the ones I listed are closer to 1 to 1 drive pressure. So the engine will actually cool better while making more usable power.
I second having the pump and injectors checked out since the engine is down.
Just make sure you get a truck version as the turbod vans and hmmvs used different heads.
As for turbos, yes the gm8 is better the the gm4 but not by a huge difference. A hx35, hx40 or an A-team turbo are far superior to any of the gm turbos. Just depends on how the truck is used. The gm turbos have crazy high drive pressure, like 2.5 to 1, which causes extreme heat to be retained in the engine. Any of the ones I listed are closer to 1 to 1 drive pressure. So the engine will actually cool better while making more usable power.
I second having the pump and injectors checked out since the engine is down.
Vombrown
Mountain Man
I wish you guys weren't so far away, I would give you a good long block.
I have no idea. Both popped up within a couple of days.Where were those leads a couple months ago?
Well we have two leads on a mechanical dirrect swap, and 4 with ecm control. Its his truck, i'm just helping and towing said truck he buys back for the swap.
