Git er done

Was just talking about how I miss my 6.5 suburban. It was a great everyday driver, and did all that I asked when towing. I had a big block before that got an average 0f 10 and the 6.5 burb returned 17-18 most the time. Hwy would be more. Still keeping my eyes open for another one. These new diesels are very expensive, and complicated.

You're right Turtle. I didn't word that very well. More air does lower exhaust temperatures and help the cooling system out but I can't claim this 300 HP 6.5 could survive on the stock cooling system. However my daughter's bf has pulled a 14,000 lb stock trailer through the mountains with it and had no issues whatsoever. There is a shop close by my home that rebuilds the 6.5 heads I could send you his contact info if you like.
The total cost of this project was over $16k but he bought a complete engine with new fuel system and turbo. Then we replaced the entire cooling system, clutch, flywheel and starter, brakes, ball joints, tires, exhaust system, alternator and the power steering pump. Now the gauge cluster is acting up .... It acts as though it is a bad ground because multiple gauges quit working. (No speedometer or odometer, no fuel level, oil pressure reads lower than actual, engine temperature and TAC are accurate).

By putting more air through the engine, not only can you inject more fuel/get more power but higher air volume also provides for much lower exhaust gas temperatures and therefore less demand on the cooling system.

Doesn't quite work that way. The energy has to go somewhere. Either out the exhaust or into the cooling system. More power, (energy)(BTU's) means more demand on the cooling system. You put 300 HP of fuel through a 6.5 you better jack up the cooling system to handle another 100 to 125 worth of heat. That why the late model twin stats and Dmax fan mods are popular on hopped up 6.5's. It does a better job of getting rid of 100 more HP worth of heat.

BTW can you buy a bare block and do you know how much complete heads run?

blt2ski wrote:
Nice thing about a 6.5, decent fuel mileage. Cheap to work on. Problems are known, most are very easily fixed. Power, yeah a bit on the under stated side compared to todays motors. STILL, a 200/400 motor is nothing to sneeze at, and they will overall pull upwards of 8-10K without issues at reasonably decent speeds etc. Keeping them cool is the main issue.

I went from the pre97 cooling mods, to the post 97 with dual t-stats, high gpm pump that is about double the water flow, and a 7 instead of a 5 blade fan with a different fan clutch, made a lot of difference for me, IE I could use the AC vs not and still have lower engine temps.

Marty

The big thing about the Peninsular over the stock 6.5 is the lower compression pistons and large turbo. By putting more air through the engine, not only can you inject more fuel/get more power but higher air volume also provides for much lower exhaust gas temperatures and therefore less demand on the cooling system. We installed the 7 blade fan and high flow water pump as well. The Peninsular diesel uses a steel crank and the new 6.5 blocks are much stronger than the old blocks as well as having heads which provide better cooling and are much less prone to cracking. The truck is fairly quiet and I believe it must be putting out over 300 HP by the way it pulls.

The cheapest fix for your load leveling problem is a pair of 4" x 6" wooden blocks. An acquaintance used to put a set between the axles and the frame on his half ton truck when hauling cement blocks.........

Bill

Nice thing about a 6.5, decent fuel mileage. Cheap to work on. Problems are known, most are very easily fixed. Power, yeah a bit on the under stated side compared to todays motors. STILL, a 200/400 motor is nothing to sneeze at, and they will overall pull upwards of 8-10K without issues at reasonably decent speeds etc. Keeping them cool is the main issue.

I went from the pre97 cooling mods, to the post 97 with dual t-stats, high gpm pump that is about double the water flow, and a 7 instead of a 5 blade fan with a different fan clutch, made a lot of difference for me, IE I could use the AC vs not and still have lower engine temps.

Marty

Thanks!

Still running a 6.5 in the C20 I gave my Daughter.

Cummins12V98 wrote:

blt2ski wrote:
Do as I did to my 96. Put an upper 6 leaf instead of the 5 pack, with all the leafs being 1/16" thicker. Gave me an 8500 lb pack instead of STD 6400 rated spring pack.

I've also heard good things about the penninsular diesel for 12+ years now. If I still had the 96 and that motor went out, I would get one from them.

Marty

What is the difference? I just know from 3 crate 6.5's being replaced they have thin cylinder walls.

From about 99-2000 on or so, The 6.5 has been poured from the same plant as the Navistar V8 diesels, with a higher nickel? count in the block. Which has made it stronger. Reality is, the stock or penninsular diesel from this time on is better this way.

But even before this time, the Penninsular diesel had a slightly lower compression, ie instead of around 21-1, lowered to 18 or 19-1 as the Navistar V8's had, as does the cummins and most other turbo diesels. THis allows them to handle the higher pressures from the turbo, and generally speaking, allows this motor to last longer.

The majority of diesels with 22-1 compression were in reality, never designed to be turbo's, including the idi6.9/7.3 navistar v8's. ALtho many did turbo them.

Marty

blt2ski wrote:
Do as I did to my 96. Put an upper 6 leaf instead of the 5 pack, with all the leafs being 1/16" thicker. Gave me an 8500 lb pack instead of STD 6400 rated spring pack.

I've also heard good things about the penninsular diesel for 12+ years now. If I still had the 96 and that motor went out, I would get one from them.

Marty

What is the difference? I just know from 3 crate 6.5's being replaced they have thin cylinder walls.

Do as I did to my 96. Put an upper 6 leaf instead of the 5 pack, with all the leafs being 1/16" thicker. Gave me an 8500 lb pack instead of STD 6400 rated spring pack.

I've also heard good things about the penninsular diesel for 12+ years now. If I still had the 96 and that motor went out, I would get one from them.

Marty