Upgrade and some other questions...

[turbos10]

Hey All,

I just a bought an '87 C3500 with a 6.5 Turbo in it. I am not familiar with these engines, so I have some questions. The engine is from a '94, but has a manual pump conversion. I am not sure what to expect from the engine, so I am not sure how it is running. It seems a little weak to me, but it runs very good over all other than being hard to start.

That brings me to the first question; if all glow plugs are good, is there something else to look for. I know pump timing can affect it and I have also read about a cold start advance solenoid of some sort. I did find a sensor of some sort on the passenger side head with the wires burned off. I thought that might be to this solenoid, but I did not know if the manual pump has this.

Second is with the vacuum pump plumbing. The pump is "t"ed in to the wastegate and the injector pump. From the injector pump it goes to the transmission(TH400). I have a couple of turbo gas projects so I understand the concept of the wastegate and this plumbing makes no sense to me. It seems the wastegate never sees manifold pressure and could not possibly function properly. What am I missing?

I am planning on bumping the fuel on the pump a tad and I am wondering if there is a conventional wastegate available that I can use for boost control. I would like to use a standard setup with manifold pressure and an adjustment in the cab to "fool" the wastegate. This would also allow me to tune for hauling loaded to keep EGT down.

Last, is with pump timing. How can I check current timing and what is the best direction to go for performance increase?

Thanks for helping a newbie to the 6.5.

[turbos10]

Nobody?....I see someone is reading.

This poor starting is kindof a pain. After sitting for 3-4 hours it still does not bust off without some cranking. Anyone have an idea on the cold start advance?

Any help is appreciated.

Chris

[sixnickel]

First, That thing in the rear of the right head is the cold advance- high idle switch.Replace it with one for a 87 6.2 . You want 12 volts in from the ignition. Below 125 deg Fahrenheit you will have 12V coming out going to the spade terminal on the side of the IP and the high idle solenoid. At 125df the switch opens and shuts off the cold advance and high idle. This should help starting.
Second, A vacuum controlled waste gate needs a ECM, a sensor, and a solenoid valve to function I don'''t think you have that set up. I would get a spring type boost controller like a Turbo Master boost controller. And pull that "T" of the vacuum line at the IP. A waste gate on a gas engine is on the boost side. A waste gate on a diesel is on the exhaust side, boost is controlled by bypassing exhaust pressure.
Third, to advance the timing move the top of the pump to the left(drivers) fender a 1/32" = about 2 deg don't go to much.
Hope this helps Good Luck

[turbos10]

Thanks for the help. That does make sense on the cold start sensor. I have to assume that the sensor is in the water jacket, so I guess I need to be quick;). I am assuming this is a constant 12V source? I have not put a meter on it, but judging from the condition I would no be surprised if it is not salvageable or has been cut loose from the source. I will proably have to run a new wire.

I figured that the wastegate was not setup properly based on what I know about them. I have a wastegate I may just use to fit to the turbo and use the old MAP sensor hole for driving the wastegate. I kindof forgot I had that wastegate from an old project, but it should work with some "engineering". The gasoline setups actually use the wastegate on the turbine side and a blow off valve on the compressor side to bypass pressure when the throttle closes suddenly.

Thanks for the timing direction. I am going to try to get all this stuff done this weekend. I hope it will perk up the truck.

Much appreciated....


Chris

[njdevi11]

That temperature switch gets wired into Ignition, Not constant. It'll Eventually wear your battery down.

Just fyi in case you don't already know:

Constant (on even when the ignition is off)
Ignition (on when the key is turned, and cranking)
Accessory (on when the key is turned off when cranking)
Ignition 2 (on when the engine is running) (i don't think the 6.2 or 6.5 have this signal)

[turbos10]

Got it. Thanks!

Now I just have to find a switch. No one in town has the temperature switch available and Chevrolet did not have it in stock. Go figure....

Chris


That temperature switch gets wired into Ignition, Not constant. It'll Eventually wear your battery down.

Just fyi in case you don't already know:

Constant (on even when the ignition is off)
Ignition (on when the key is turned, and cranking)
Accessory (on when the key is turned off when cranking)
Ignition 2 (on when the engine is running) (i don't think the 6.2 or 6.5 have this signal)