What Engine Did I Get??

[Matt Bachand]

Wow thanks for all the info guys. So should I install a secondary temp guage for the engine since the stock one is so inacurate? I might as well try and save the 506 i have in my truck right now. And the hotrod is not doing that great. Its in Red Deer getting the tranny rebuilt. I told them i want it to handle what ever the hell im gonna throw at it. And not to go for a long time! So they put in a shift kit alto clutches and a heavy duty torque. Hopfully im good for a while.

Scanners can be had for cheap for these trucks, you can double check it with scan tool.

Don't really need a 2nd one, just know its not dead nuts accurate. When its going HOT, so is your engine! But 210 hashmark, may be 217, as Is mine, verified with my scanner software Car-Code (cheap).

FWIW Only.

Of course a nice aftermarket one would be the best way!! But not needed in my opinion unless you towing heavy and often. And then still questionable... EGT/BOOST/FUEL PRESSURE/TRANNY I'd do first before aftermarket coolant temp.

 

[buddy]

The PCM is getting its reading from within the head, and the gauge is from the crossover. So there is one source of difference, What may be best is to put one on the rear of the passenger side, or just move the one from the crossover to there.

That might be something a vendor could offer. A replacement coolant blockoff plate with a bung for the temperature sensor, a plug for the x-over and an extension cable hookup.

Unless there is another hole that can be used, but nothing else is as easily accessed as the coolant blockoff plate back there.

 

[guybb3]

Unless there is another hole that can be used, but nothing else is as easily accessed as the coolant blockoff plate back there.

Nice suggestion. I think that's where I'll put the sensor for my electric fan!

 

[DZZ71]

Same here! I have the EGT and BOOST guage and also have a spare hole left in the tripple piller so the tranny guage is gonna fill that one. but i for sure wanna get the coolant temp guage for the electric fans. I wonder where im gonna mount that one.....

 

[redshift96]

2002+ 506 Block improvements

Quote:
Originally Posted by Brooklyn Tow
But, the AMG Optimizer and P400 are 506 blocks....Correct?

Yes, but they are also built in a differnt decade with better metalurgy and machining

It's not just that. There's some serious redesign as well. I believe that the main webs are thicker, cooling passages revised, alloy revisions, etc etc. Not to mention the addition of a forged steel crank! So a 506 block from Navistar is pretty much a different animal than the pre-2002 506 it superceded.

I believe that they retained the oil squirt design, but I'm not positive.

 

[bk95td]

The PCM is getting its reading from within the head, and the gauge is from the crossover. So there is one source of difference, What may be best is to put one on the rear of the passenger side, or just move the one from the crossover to there.

That might be something a vendor could offer. A replacement coolant blockoff plate with a bung for the temperature sensor, a plug for the x-over and an extension cable hookup.

Unless there is another hole that can be used, but nothing else is as easily accessed as the coolant blockoff plate back there.

The sensors are just the opposite. Temp gauge SENDING UNIT[for the gauge] is in the driver's side head front, Engine coolant temp SENSOR[for the ecm] is in the coolant crossover.
The optimiser 6500 is a minor redesign from the GM block. Something like 40 lbs. of casting was added to strengthen the weak points. Chrome was added to the grey iron in the heads to reduce or eliminate the cracking. Molyedoluim was added to the grey iron in the block for more strength.
THe P400 was a major redesign of the lower end to strengthen the crank and main journals. A custom oil pan would need to be fabbed for a P400 to fit in a truck frame.

 

[bobbiemartin]

It's not just that. There's some serious redesign as well. I believe that the main webs are thicker, cooling passages revised, alloy revisions, etc etc. Not to mention the addition of a forged steel crank! So a 506 block from Navistar is pretty much a different animal than the pre-2002 506 it superceded.

I believe that they retained the oil squirt design, but I'm not positive.

GEP Optimizer 506 blocks are oil squirters. The Optimizer does not have a forged crank. I may have read the very latest ones do, not sure on that.

 

[bobbiemartin]

The PCM is getting its reading from within the head, and the gauge is from the crossover. So there is one source of difference, What may be best is to put one on the rear of the passenger side, or just move the one from the crossover to there.

I think its the other way around, at least on my 95 it was. The crossover is where temp sending unit for the PCM and the LH head for the temp gauge.

If you need a place for an extra sending unit, you can use the temp sender on the pass side head, but its very hard to reach on turbo engines. Early 90's 6.5's (I think 6.2s as well) used that spot for the cold start on the DB2 pumps. Later trucks moved to the crossover. Its much easier to reach. (trust me I know all about reaching that spot)

I would think the crossover or the front of the head on the drivers side is about the best place for a temperature gauge, as the water should be the hottest going back into the radiator. It would not be hard to weld in an extra fitting to the crossover for an additional water temperature sending unit if that is what you wanted.

I think the problem is the factory gauge is not super accurate, not the placement of the sending unit. A friend had a Cyberdyne Digital gauge on his car (not a 6.5) and you could see very small changes in the temp, depending on if you stopped, in traffic, as the electric fan came on, etc.

On a related note, I always wondered why GM just didn't use a signal from the PCM to the temperature gauge and the tach - The information is there, why not use it? That is how the speedometer works. Or combine it into one sending unit, like the OPS. Oh well, I sure there was a good reason.

 

[buddy]

Yep, I just typed that up backwards. PCM from crossover and and gauge from head.

If there is a flow imbalance that causes cylinder 8 next to the turbo to be the most common gasket popper or worse I suspect that temps would be worst at that point.