new to 6.2, putting it into customized '57

[Flat57]

I have been doing lots of studying on this board for the past few days. Talk about a wealth of info! [img]smile.gif[/img]

My 14 year old daughter and I recently purchased a '57 flatbed pickup to restore/customize. I also just purchased a 1985 suburban with 6.2L and 700R4. It has about 130K miles I think. We are planning to remove the suburban body and put on the 57 cab and build a new flat bed for it. Probably will put on a turbo, and stack(s). It's hard starting so I bought some new glow plugs to put into it. I have some questions maybe some of you can help with.

1) How do I measure compression? Can I measure compression through the glow plug holes with an adapter?

2) How much electronics are there on these suburbans? I guess it has a computer, but what does the computer control?

3) Has anyone else tried putting on stacks?

This is my second diesel, I also own a 2000 Ford F-350. I am really looking forward to this project, and to doing it together with my daughter.

Thanks for help.

John.

[john8662]

Actually this will be a straight forward project to install a 6.2L.

Some glow plugs could help to spruce up the starting, you will probably be better off testing them first to make sure. The simplest way to test them is to use a test light, get power directly from the battery, then use the tip of the tester on the tab on the glow plug. If it lights, its usable, not burned up and is probably contributing towards starting the engine.

The 6.2 in an 85 suburban will be completly mechanical, no computer.

To measure compression you'll need a compression adaptor for a diesel for the glow plug hole, A healthy engine will have 350 psi, below that can also still be good, but not close to peak.

Stacks, you'll be better off just making a nice single 3.5" mandrel exhaust system off the turbo kit that you choose to run on the 6.2. You can probably consider using 6.5L TD turbo hardware, if you have the room under the cab (and I suspect you will).

[G. Gearloose]

I thought the CA emissions trucks had some hokey computer.

Put on a J intake, remove the exhaust flappers and don't look back..cool project.

[Flat57]

No computer? How do they control the lockup of the torque converter?

How do I turn off the diesel to the cylinders during compression testing?

[G. Gearloose]

Remove the orange wire atop the pump to disable fuel when cranking.

700R4 Lockup is enabled via a 10% throttle switch, (closed >= 10%) interrupted via a special brake switch then opens when you hit the brake. Then there is a mechanical cable connection to the throttle called a TV cable to adjust line pressures.

4wd mode disables lockup in 2nd and third, in 2wd lockup in 2,3 & 4 via three-wire input to 4wd trannies, two wire for 2wd trannies.

You don't need no steenking computer.

[ 02-15-2005, 08:33 AM: Message edited by: G. Gearloose ]

[DmaxMaverick]

The '85 CA models do have a computer. It monitors engine/tranny parameters and emmissions. The EGR is controlled by throttle position and tempurature.

They are right about the TCC, But it is also controlled internally by the tranny's speed governor on the hydraulic circuit. They work well if the electrics are bypassed, including the brake circuit, and you install a manual switch to control it. When engaged, it will lock with 10% throttle input and stay locked until you disengage it or you slow to the minimum lock up speed, which will be between 30 and 35. The speed is controlled by the tranny governor. Mine has worked this way for over 500K without a rebuild on a 700r4. I attribute the long tranny life to more lockup time, which translates to less heat.

I have a good wiring diagram scanned for the '85. If you don't have one, get one. You will need it at some time during your project. If you would like me to send it to you, drop me a line to dmaxmaverick@yahoo.com

Your project sounds like a lot of fun. Welcome aboard!

[Flat57]

Thanks for the info. I am rather familiar with the 700R4, I rebuilt one to put into my 1973 corvette. However, in my vette I am using a computer from a 1990 van (1227747), and it controls the TCC.

So, if the throttle switch engages the TCC at greater than 10%, is there another throttle switch to disengage it at WOT? Or does it shift down without disengaging the TCC? Or is this also controlled by pressure (due to the TV cable)?

On my Vette, I don't have the right code in my computer yet (still has manual tranny code), and the torque converter never locks up, but it is a later model tranny (1988 I think), so maybe it doesn't have the hydraulic lockup. There's also no connection to the brake on my vette. The computer engages/disengages it at certain speeds and MAP values (obviously can't do MAP on a diesel).

[DmaxMaverick]

The TV cable will force an unlock at WOT, and under low RPM/high throttle. It is comprehensive, depending on speed, gear selection, actual gear and throttle position (TV cable position). The TCC solenoid allows/disallows hydraulic pressure to engage the clutch, and the clutch actuator has a dump valve controlled by the tranny speed governor and valve body to prevent lockup under specific conditions, like the minimum speed. There are switches on the valve body that complete to ground. Both + and - are switched to control the solenoid by various inputs/conditions. There is also a forced engagement lead at pin "E" on the diagnostic test connector, which is a tan/blk wire.

I don't remember if the TCC unlocks during shifts in OEM configuration, but it stays locked with it bypassed like I have. The shifts are very firm, but it aparently has had no adverse effect on longevity in my case. I did the change over 15 years ago.


On edit:
The "no-lock" on the 'Vette may be due to not having the brake switch in the circuit. It is part of the batt. + circuit to the TCC. If the circuit is open, it will "see" the brake being applied all the time, and not lock up. I don't like the TCC to unlock (EPA thing) with brake application, compression braking is lost. This practice has been changed for the Allison, which pleases me that the TC stays locked on compression, even when braking, until the minimum speed is attained.

[ 02-15-2005, 12:37 PM: Message edited by: DmaxMaverick ]

[Nelsoncat]

How do you tell a J intake? I have 3 6.2's to choose from. The one I intend to use has 380psi comp in all 8. It appears to be a Mr Goodwrench replacement. The intake has an EGR in the center. Another 6.2 that I have has no EGR in the center. Is this a J or can the EGR be removed and still be used?
Thanks
Craig

[DmaxMaverick]

C=EGR

J=No EGR


You can use the C intake with the EGR disabled. The J is better (marginally) because it doesn't have all that stuff in there to cause additional restriction.

If you use a C intake an intend to disable the EGR, remove the valve (toss it) and plug the hole with a freeze plug, or make a blank plate that will replace the EGR valve. Not doing this can lead to undesirable effects later.

[Flat57]

Yup, you're right on the brake switch. I just looked at the diagram for the 90 van and that is how it is wired, so that is how I wired it. It has been a few months since I did that part of the project so I had forgotten.

My recollection of when I had a 2004R was that when I engaged the coverter lockup, it didn't matter what speed I was going, it was locked up. You could stall the engine by keeping the voltage to the pin on the connector of the tranny while coming to a stop using the brakes. Is the 700R4 different than that?

[DmaxMaverick]

Yes, it is different. It will open the hydraulic circuit internally to unlock and a given speed, even if you have voltage at the solenoid. I tried to get mine to lock up like the 200, but couldn't do it without re-porting the valve body to accomodate it. I gave up on the idea.

[Flat57]

Got it. Thanks for the info. Now I know how to fix my vette as well as the project mentioned above.

John.

[Ratau]

DmaxMaverick

Do you get auto lock up in 2nd and 3rd ?

With the 10% throttle switch connected does the lock up disengage if you go downhill and you take your foot off the throttle?

Danie

[DmaxMaverick]

Originally posted by Ratau:
DmaxMaverick

Do you get auto lock up in 2nd and 3rd ?

With the 10% throttle switch connected does the lock up disengage if you go downhill and you take your foot off the throttle?

Danie

It locks up in 2nd (30+ MPH with go pedal input) and stays locked. It will not unlock until the speed drops below 30 MPH. I bypassed the brake pedal switch, so it will also stay locked with the brakes on. Originally, I installed a toggle switch to allow me to include/exclude the brake switch as desired, but I never liked it unlocking with the brake, so I omitted the brake toggle switch.

There is no "throttle switch". The tranny gets throttle input from the TV cable, which interacts with the hydraulic circuit of the tranny. Be careful with this. If you try to adjust the TCC parameters with the TV cable, you will throw off all the other shifting characteristics, including shift speeds and line pressures. This could result in too much slippage, and fry your tranny.

I got your email, and sent you the diagrams.