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6.5 to vm638

All I would need is the cpu from the donor right? I doubt there is much tuning for the stock computer but I figure if a new db2 costs over 1000 then a pump built for a 638 might be ok. I was already thinking of a 4bt or 6bt for one of my future projects so it's all gonna have custom parts.
 
tanman_2006 said:
All I would need is the cpu from the donor right? I doubt there is much tuning for the stock computer but I figure if a new db2 costs over 1000 then a pump built for a 638 might be ok. I was already thinking of a 4bt or 6bt for one of my future projects so it's all gonna have custom parts.
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If you get a donor vehicle, then yes, you'd have what you need to run it. Most of the behring trucks have an allison... would be a sweet conversion!
 
Cumminsfever said:
I suspect it to actually be an aisin. Everyone calls it an allison tho. If it is indeed an allison, it would be at least the 1000 series.
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I doubt it would have came with a 1000 series as the engines output didn't warrant it, most likely a AT545 or an AT545 AISIN copy. JEEP put VM engines in the downsized CHEROKEE in international markets, and they were hated because of head cracking and reliability issues. I looked into doing one in my old COMANCHE a few years back, and just couldn't bring myself to going through with it.
 
I could see a jeep having a cooling flow issue. I'm thinking of sticking it in a 78 k2500 service truck for sale across the road and going ahead and scrapping my 82
 
Does anyone know how to make the in-dash tach work without having the alternator there to generate the signal?
What do I need to feed that wire to make it work?
 
Would have to make sure crank pulley to alt pulley is same ratio as GM 6.X series are... A buddy of mine went through the same thing with his 12v Cummins in his Chevy, tach worked fine from the alt, just that the rpm's were off due to different crank pulley diameter.
 
Cumminsfever said:
Does anyone know how to make the in-dash tach work without having the alternator there to generate the signal?
What do I need to feed that wire to make it work?
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Dakota digital makes a tach adapter that may work to recalibrate and correct the tach signal to reuse the stock tach.
 
I would like to make the factory tach work. On the gas engines, we just feed it 4 pulses per ngine revolution. But the 6.5 tach runs off the alternator... I doubt 4 pulses per engine revolution would do anything for the 6.5 computer...
 
Autometer makes an alt pickup tach that straps the pickup to the outside of the alternator. The tach is adjustable to compensate for pulley diameters as well.

Works great on my K-5. extremely accurate.
 
iamdave0887 said:
Autometer makes an alt pickup tach that straps the pickup to the outside of the alternator. The tach is adjustable to compensate for pulley diameters as well.

Works great on my K-5. extremely accurate.
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This definitely sounds workable!

Does anyone know what signal the alternator puts out on that tach wire? Ac? Dc? Pulse width? Square wave? Or mebbe I should just throw a labscope on it and find out exactly what it is?
 
Getting the pump benched. Time for variable timing. This was my first pump build. Could never get timing rite, so I just blocked it. Now, with what I've learned, i have more available timing, and can dial it in wherever i want it!
6.5 marine injectors set to 3800psi.

This will be a totally different animal than I had before.
 
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