270hp Marine 6.5!!!

[bmp34]

I just saw on Ebay a 270hp/440ft lb torque Marine 6.5td. Could you imagine getting you hands on one of those? All for the cost of $16,500 and its yours. Do some more mods to it such as fuel delivery and boost and you would easily be competing with new cummins with chips which would freakin rock.
-"What you got in there?"
-"Ohh, a 6.5 turbo diesel"
-"Those are P.O.S."
-"Lets hook em up then?"

Gosh that would be freakin awesome.

http://cgi.ebay.com/ebaymotors/6-5-L-Turbo-Diesel-marine-drop-in-engine-V-8_W0QQitemZ130079290076QQihZ003QQcategoryZ33615QQr dZ1QQcmdZViewItem

[DmaxMaverick]

Peninsular Diesel (http://www.peninsulardiesel.com) has been building/selling them up to 400 HP for years. It's amazing what you can accomplish with a cooling system the size of a lake.....or an ocean.

[Robyn]

Well put.

The biggest issue with the 6.5 is keeping the engine cool as well as the incoming air charge.
With an unlimited supply of cool water to cool the block and heads and a good water cooled charge air cooler these little engine can build some phenominal Horse Pressure.
In a pickup/Burb installation about 250 horse is about it and then only with very careful management from the driver.

You get too heavy with the boot and you can turn your prize little diesel rat motor into a cinder real quick.

The ability to reject heat is the deciding factor in this whole equation with these engines.

In a custom truck application where you could drastically increase the radiator size the numbers possibly could grow some.

Another area that I am beginning to question is the crank shaft.
These engines have cast iron cranks, any high horse engine I have ever seen uses forged steel shafts.

I am hearing that this is not an issue but I am going to disagree for now.

Hope this helps

Robyn

[DA BIG ONE]

There are many running 6.5td w/much more HP/TQ on the street than the 250hp/400tq marine motor. W/cooling being the limiter these outputs are for short sprints/even pulls on road while monitoring those egt's, iat's and boost levels.....

[Robyn]

I agree with D B O The issue is that there needs to be a very cautious nut behind the wheel that will monitor those instruments and get their boot out of the fan when things start geting up close to the CRISPY ZONE.

This is why GM limited the 6.5 to such low power levels. The first ones would have barely made it out of the gate before someone cooked them if they had really turned up the HP screw.

Years ago there was a fellow here that had a nice GMC 3/4 ton with a 6.2 in it, he had a local shop install a Banks kit and they turned the HP scew up about twice what the law allows.

That pickup was an animal, the owner would tow stuff with that thing that would make far larger more powerful trucks look weak.

We have a hill close to town thats 6-1/2 % for about 2 miles.

One day the fellow was trying to tow a slightly TOOOOOOOOOOOO large track hoe over the hill and the little engine that could melted.

I got the job of fixing it. The poor little thing had 3 pistons that looked more like pot holes in a section of bad road.

A good used engine later for parts and some serious cash and things were back to the usual grind.

I installed a pyro in the thing and ordered him to keep the temps under control.

Well he didn't and the rest is history, about 6 months later he was trying to tow some used equipment out of California over the Mountains on I 5 and fried it again.

That was the end for that truck under his ownership.

He then went on to melt several Power Strokes and finally eneded up with a Dodge cummins.

I don't think he has melted the Dodge YET, give him time.

The moral of the story, Just because you can does not mean you should!

Responsible power levels, gauges, common sense + a little luck = happy camper.

Robyn

[billschall]

...and get their boot out of the fan when things start geting up close to the CRISPY ZONE.

Would you help me understand exactly what the "Crispy Zone" is? Here's my issue: I got the thing hot - really hot - last summer pulling a trailer load of old roofing material up a long, steep hill. Don't remember the exact temp, but feeble memory recalls about 240-250. The truck acted like it was dying, but made it over the top. I now understand that the PCM was defueling the thing due to extreme temps and believe me, the lesson has been learned over the past two months since the machine shop pronounced both heads DOA. Due to heat they said.

Ok, so now I'm going back together and barring any unforeseen gremlins, should get the thing running this weekend.

Alas, I need a thermostat. I've read the tech article about t-stats and of course there are options: 180, 190, 195, etc. The OEM stat was, I'm assuming, a 195 as that's where the truck always ran ('cept for that one little incident). Kennedy's got 180's for my truck, the local speed shop guy says to put a 195 in. As I've read these pages, RobertShaw Stats seem to be the recommended choice, but no one locally has one, nor can they get 'em. I understand that the stat should be of such design that when it fails, it fails open.

So, what stat @ what temp and when do I worry about nearing this "crispy zone?"

[Hubert]

Its all in how it gets to the crispy zone. Hills, towing, and putting ones foot into it will heat up combustion ie exhaust gas temps quick. It takes longer for coolant to react.

Thermostat setting alone won't keep it from overheating. There is still a debate on which temp is best and depends on set up, ambient temps, and preferences. Popular thoughts: a 195F thermostat will give a bit more performance than a 180F. But in hot climates & city driving a 180F is preffered to reduce underhood temps a bit.

One of the deisgn limits of the 6.5 and its factory build is just how hot the heads and pistons get pouring on the fuel. This is due to indirect injection, compression ratio, non-intercooled boost, boost controll, and marginally sized exhaust and intake. You have to monitor EGT as it will climb and warn you of over heat a long time before coolant shows too hot.

EGT also tells the story of the thermal load on the coolant system. If you can lower EGT with better exhaust, intake, a little more boost than factory, and/or intercooling then the cooling system won't be challenged as much.

Keep EGT's below ~1000F preturbo, non-intercooled boost below 12 psi(9-12psi sustained), and a properly operating coolant system should not exceed 210F for most rolling hills. Peg the EGT guage for a few minutes and/or too much boost (especially hot boost) and its entirely a different story.

[dieseldummy]

Truth be known most people with a chip/injectors/intercooler are probably pushing close to 270HP at the crank...

As far as this meltdown talk goes, I guess it all depends on how lucky you feel. EGT's can be held at 1250 for hours on end. ECT can be held at 215-220 fairly consistantly without causing instant meltdown, <210 would be ideal though. It's when EGT's run over 1250 for extended periods and the ECT hits the 240+ range that it hits the fan...

[Tough Guy]

Ronniejoe's suburban is a good example of a 6.5L making power.

Chris

[TJ Moose]

Hey Bill

I know there are all types of solutions to the cooling thing. Best mod is to keep control of what you do with your foot on the long thin stupid pedal. Then read and do all of the TDP maintenance on the radiator so it exchanges heat. I couldn't find a RobertShaw T-state to save my soul - so I finally just went to the local Chev dealer to get a GM one at 195. That combined with a Heath Diesel Duramax composite fan, plus lower temp engaging clutch, plus Heath's coolant mods (off the back of the block as well as the front) really work for me. Coolant stays close to 195 about all the time, and even pulling my Jeep up a hill on the interstate - Its tough to get the gauge past 215. (Again - easy on the foot and not racing the Cummins's up the mountain.) Just telling you what's worked well for me.

[bmp34]

Well since we turned the topic to cooling. I am really lookin at those intercooler upgrades. Are they really worth it? I am goin to get ssdiesel.com's cooling upgrade this spring because i have had points in the winter when i am workin her pretty hard that she will hit 200 for a couple of minutes then drop back down. Which worries me because when i put a/c back in my truck this spring i dont know how ole cheyenne will handle it. Like when i am cruising at 75mph she will hit 190 or so with out a trailer. Is that common?

[a5150nut]

Come spring you might try a real good cleaning of your cooling system. Remove the radiator and squirt everything down with Simple Green, let it soak for a half hour, re-spply SG then wash out with hose and water. You might be suprized how much dirt and bug guts come out. Good time to back flush and put in new anti-freeze too.

[Robyn]

EGT is the killer

The "CRISPY ZONE" is anything above 1000F EGT
A real short (few seconds trip into 1100-1200) wont kill it but 1000 should be kept in mind as a top number for any time on a hard pull.

My big cat never runs over 750F even on a 105F day on a 7% grade pulling hard.

Unchecked and unmonitored the EGT can easily reach a point where the pistons start to melt.

Old boat racer mentality, "Runem till they melt"

The issue is the internal parts such as pistons and valves just cant handle the really high temps.
This was the reason GM decided to use oil spray on the pistons.
The idea was to cool to crown and get the heat into the oil where it could be dumped through the engine oil cooler.

The heads get a terrible blow when the engine is running in the crispy zone.
The heads on these engines are not all that stout anyway and unless you have the HD water pump the heat load can be enormous.

I have seen the valves tuliped into the head from excess heat.
The 94 we have that I rebuilt last summer had most of the exhaust valves sucked up into the head and I attribute this to HEAT.

If the EGT gets up there back off a tad or drop it a gear.

As was mentioned earlier the water temp takes far longer to react than does EGT.

You never want to see water temps in the 220 or above area.

If the truck is going to be used for towing get the water pump upgrade and the fan upgrade. Water movement and air movement is heat movement and this is a good thing.
The radiators on our trucks can dissipate a lot of heat if thay are clean inside and out. ( be sure the area behind the ac condenser is not full of crap)

A lower temp fan clutch is good too as it lets the fan start getting rid of the heat before the engine gets too hot.

If you look at some of the engines that are available you can easi;y find 400 HP 6.5's but they are marine engines where cold water is in abundance and the engine can be kept very cool all the time.
with a freshwater unit the water can be directed right off the draft pitot into the engine and regualted to keep things perfect.

With a salt water boat the system is usually a binary with primary being an antifeeze solution and the secondary system being the saltwater running through a heat exchanger.

Unfortunately we dont have the ability to reject huge amounts of heat in our trucks.

Remember the cylinder heads on a 6.5 take the brunt of the heat and are not real heavy and dont have the best water flow so the stage is set for trouble from the gitgo.
Just drive with an eye on the EGT when you are working it hard and all will be well.

Good luck and dont get caught in the "CRISPY ZONE"

Robyn

[ronniejoe]

In my opinion, 1000F pre-turbo is way conservative and unrealistic for a limit. 1200F is safe for sustained pulling. I personally ran thousands of miles at 1350F...there were many excursions above 1500F in there that hurt the engine after 150,000 miles of use.

Furthermore, if you are running a stock 6.5 and pulling hard, downshifting will make the egt problem worse because boost will fall at higher rpm. You're better off to run in a higher gear lugging the enigne more to keep boost up and egt's down some.

With my current configuration, I rarely see 1200F transient under any circumstances.

[john8662]

RJ's right, 1200 is considered the safe sustained temp, anything beyond that you risk component damange.

For 6.2L Turbo operation the same limit is said to be 1100.

As for downshifting, this is bad in BOTH 6.2TD and 6.5TD as far as pulling.

On my Banks 6.2TD the ECT wanted to rise very quickly pulling heavy when out of OD at 65-70MPH. Driving in OD was the only way to keep ECT down.

EGT's were higher lugged due to non-wastegated turbo with too large of turbine housing.