Got my 18:1's

[JeepSJ]

Ceramic tops. Microslick on the skirts. Finally can get the block work going!

https://i.imgur.com/rPTjLzb.jpg?1

[Robyn]

Looking very very nice.. :):)

Gonna boost it good and aftercooler it ???

[Aftermath]

Ceramic tops. Microslick on the skirts. Finally can get the block work going!

https://i.imgur.com/rPTjLzb.jpg?1

What other parts are you going to use in the build?

[JeepSJ]

Looking very very nice.. :):)

Gonna boost it good and aftercooler it ???

Not too crazy...probably limit to 15psi. Yes with the cooler.


What other parts are you going to use in the build?

Navistar block, mostly stock other stuff. I'll do some match porting on the intake and exhaust, ARP head and main studs, air/water intercooler setup, etc... Not going for ultimate max power...want good power with reliability.

[Robyn]

15 psi max with a good aftercooling will be sweet.

Big issue with the 6.5 is that it does not have enough head bolts for more boost.

These engine can do real nice in a truck if you don't try to go beyond 350 HP

300 is a lovely sweet spot as well.

Getting rid of the heat is the tough order on these.

Nearly all the combustion heat is up in the heads and its hard to get it to the coolant fast enough.

Have fun on the build.

[Aftermath]

Not too crazy...probably limit to 15psi. Yes with the cooler.



Navistar block, mostly stock other stuff. I'll do some match porting on the intake and exhaust, ARP head and main studs, air/water intercooler setup, etc... Not going for ultimate max power...want good power with reliability.

So what type intercooler and where are you going to mount it?

[john8662]

Are these the latest Kennedy Pistons?

[JeepSJ]

So what type intercooler and where are you going to mount it?

Using a water/air setup. Space is very limited under the hood of my Jeep, as is the area for the cooling stack.


Are these the latest Kennedy Pistons?

I worked with RJ from Schoolcraft on these. Well, he did all the design and production, I just funded it. Kennedy wasn't interested in making any more when I talked to him so I went a different route.

[JeepSJ]

15 psi max with a good aftercooling will be sweet.

Big issue with the 6.5 is that it does not have enough head bolts for more boost.

These engine can do real nice in a truck if you don't try to go beyond 350 HP

300 is a lovely sweet spot as well.

Getting rid of the heat is the tough order on these.

Nearly all the combustion heat is up in the heads and its hard to get it to the coolant fast enough.

Have fun on the build.

Toying with the idea of ceramic coating the chambers, valve faces, and exhaust ports to try to keep heat out of the heads. We'll see where I go.

I'm not so much concerned with 300hp as I am with getting 500ft/lbs of torque.

[More Power]

It's not boost pressure that can weaken head gaskets... It's combustion pressure.

15 or 20 psi boost pressure is small change compared to up to 3000 psi combustion pressures possible. So, it's really the amount of fuel that has more to do with peak combustion pressure. Since the fuel injection pumps were designed around the fueling specs for these engines, it would be hard to deliver enough fuel along with whatever amount of boost to exceed the design limits of the head gaskets/bolts.

Also, I believe injection timing is more important than boost pressure where head gasket longevity is being considered. Next, order of importance could be average power output (i.e. a long distance hauler might have different head gasket longevity than a weekend warrior).

Now we come down to it..... Peninsular told me way back when that they had never seen an 18:1 CR 6.5 with failed head gaskets (w/big marine turbochargers). Further, I was told they went to 18:1 pistons in the first place for the durability improvement over the 21.3:1 CR on-road engines they tested. A marine 6.5 runs at far more power for far longer duration than a pickup truck engine. Jim

[john8662]

Pistons look very good. I had heard RJ was going to work on taking over these, good to see that he has and the product looks great.

Thanks.

[ronniejoe]

For what it's worth...

My Suburban was totaled two and a half years ago along with my travel trailer in a wreck on I-70 in western Illinois. I am finally back up and running with that engine in a 2000 Chevy K3500 Crew Cab DRW Long Bed truck.

I have had two head gasket failures with Fel-Pro gaskets since building my engine the first time in 2005. I have started using Cometic MLS head gaskets to solve the problem.

The Fel-Pro gaskets cannot hold the cylinder pressure that my engine creates with 25+ psi boost and all the fuel the DS4 can deliver.

After freshening the engine with new rings and installing a new forged steel crankshaft from GEP purchased through Kennedy Diesel (picked up at the plant) and a new set of Cometic gaskets, I installed it in my 2000 Chevy late in 2016. In late summer 2017, I started having symptoms that mimicked head gasket failure. I couldn't believe it with the Cometic MLS gaskets, but that sure was what it acted like.

I tore it down in September and found the gaskets were fine. What I found were cracks between the valves on #1, #7 and #8 cylinders. #7 was the culprit causing the symptoms (pressurizing the cooling system and pushing coolant out and eating coolant). These heads were new in 2012 from GEP (Optimizer heads) purchased through Peninsular Diesel and only had 33,000 miles on them. I contacted them and was advised that they would not help because they were closing down the business. What a disappointment.

After much research, I purchased a new set of P400 heads from GEP through Leroy Diesel. I picked them up directly at the plant in Franklin, OH. These are the latest and greatest 6.5 heads available. I hope they last. I just got the truck running again yesterday.

If you go back to the article (the second in the series) that I wrote in 2005 for TDP, you will find a good engineering discussion on compression ratio, cylinder pressure and mep/p3.

As I will not build one of these for performance or towing without splayed main caps, I will now not build one without Cometic gaskets either.

[DieselDavy]

Ron,
Glad to hear from you again! I sure hope everyone came out alright from the accident.
Keep up the good work with the 6.5s and keep us in the loop!
dave

[Robyn]

GOOD TO SEE YOU Ron :D

I used a set of Cometics in a 6.5 that was done right with the decks machined and heads were new.

Lasted a year and the gasket on the RH side started leaking.

Not sure what caused it, but it was obvious what had happened.

[JeepSJ]

Hey RJ! Good to see you back.

Hopefully the k-line sleeve treatment to the water ports between the valves will keep my heads from cracking/leaking. Alas, there was some indication that I may have had a leaker also. As soon as I can get a free moment to disassemble them, I can get them to the shop and have them pressure tested.

[sctrailrider]

Just for more info pertaining to heads....

I have cut several gm & gep heads apart and have posted pics on other forums and can post them here if anyone wants...

Also I have cut brand new P400 heads apart also, ( p400 heads are close to 1K each), and I have found they ARE NOT the same casting's, I have the pics to show the mold was changed and their is more material INSIDE the cooling area in certain places and have been redesigned internally, thicker head surface, and many other differences I won't go into... I also can post those pics, they have the same casting numbers & markings except the foundry mark...

I have a set of P400 heads that have the large exhaust valves installed and are highly ported...

The P400 heads are worth the cost, they are not regular 6.5 heads...

[Robyn]

I put a set of P400 heads on my Dahoooooley the last go round when I scared up the Bare GEP BLOCK (lONG STORY THERE)

I gave the truck to my son in law after we got it back together and he runs the crap out of it.

[ronniejoe]

Just for more info pertaining to heads....

I have cut several gm & gep heads apart and have posted pics on other forums and can post them here if anyone wants...

Also I have cut brand new P400 heads apart also, ( p400 heads are close to 1K each), and I have found they ARE NOT the same casting's, I have the pics to show the mold was changed and their is more material INSIDE the cooling area in certain places and have been redesigned internally, thicker head surface, and many other differences I won't go into... I also can post those pics, they have the same casting numbers & markings except the foundry mark...

I have a set of P400 heads that have the large exhaust valves installed and are highly ported...

The P400 heads are worth the cost, they are not regular 6.5 heads...

Why I opted to drop $2100.00 to get a set.

They also have hardened valve seat inserts.

[sctrailrider]

Why I opted to drop $2100.00 to get a set.

They also have hardened valve seat inserts.

Yep, and they have a lot more than that going for them... They really did their home work with the P400, different rods, pistons, pins,valves have a swirl inducing cut on the back side, etc..nothing inside the motor will interchange except maybe the crank & cam, and even the cam isn't the same grind....

[trbankii]

I have cut several gm & gep heads apart and have posted pics on other forums and can post them here if anyone wants...

Raises hand for pictures… :D

[Robyn]

My one question is this ????????????????/


Why did GM not do it right instead of doing a half ass job on the cheap ???

The costs that GM incurred with all the warranties and bad press on the 6.5 surely was far more than the cost of doing it right in the first place.

Even the OPTIMIZER 6500 is a pretty good engine compared to the 6.5 from GM

Too many bean counters getting into the mix maybe :eek:

[ronniejoe]

The 6.2 L Diesel engine was specifically designed from the start to be a Diesel engine by Detroit Diesel Division of GM (at the time) using gasoline engine technology and design approaches in the early 1980s to keep cost low. Their objective was to increase their fleet fuel economy average to meet ridiculous federal CAFE standards. It was designed for an entirely different reason than modern Diesel pickup engines are. Nobody foresaw what was coming.

The 6.5 was a follow-up to the 6.2 to try to keep pace once Dodge offered the 5.9 L Cummins in pick-up trucks in 1990. Remember, the first 5.9 L Cummins offering did not have a charge air cooler. The 1992 and 1993 6.5s actually did pretty well and were very competitive in performance with the early Cummins/Dodges and the Turbo 7.3 IDI from Ford.

With the addition of the turbocharger and once the evolving market began demanding more power from the 6.5, the "gasoline" engine design decisions began to be exposed. Instead of addressing the problems, the bean counters just let it ride. The electronic injection teething problems were justification in their minds to cut their losses and ignore the market -- until it became obvious that they were missing out.

Enter Duramax.

[More Power]

...With the addition of the turbocharger and once the evolving market began demanding more power from the 6.5, the "gasoline" engine design decisions began to be exposed....

But, the 6.2L diesel was designed by Detroit Diesel - not GM, though cost, application and performance goals were GM's. Aside from a few bolts, there are no 6.2L/6.5L diesel engine components that interchange with any existing gasoline engine.

The Ford/International 7.3L diesel though, was originally derived from a gasoline engine - very robust gasoline engine.

[Robyn]

Gotta love the bean counters.

Whats sad is that GM engineers should have known that the stresses placed on the engine structure would cause issues.

Detroit had made good diesel engines for years and should have known better.

The 6.2 did a good job in getting the MPG'S up.

An 86 K2500 4X4 with stock tires and 4.10 gears could easily get 25 plus mpg on the Hwy...

The electronic injection was nothing but salt in an otherwise open wound...

Way too little proving before it was unleashed on the public, plus the technicians were totally in the dark as to what the real issue was and how to fix it.


As far as the block cracks and other points of self destruction goes...they should have looked at the data and been able to see what was going to happen.

A deep skirt block (made of good iron) like the cross bolted Ford 427 side oiler's (Add a forged crank) and they would have had something...

Cheeeezy iron and no bottom end beef and of course it was doomed..

[ronniejoe]

But, the 6.2L diesel was designed by Detroit Diesel - not GM, though cost, application and performance goals were GM's. Aside from a few bolts, there are no 6.2L/6.5L diesel engine components that interchange with any existing gasoline engine.

The Ford/International 7.3L diesel though, was originally derived from a gasoline engine - very robust gasoline engine.

First, Detroit Diesel was a division of GM at the time. In fact, it was part of Detroit Diesel Allison Division (DDAD as it was referred to then). This division structure did not change until after I started working for General Motors in 1983. I worked at DDAD Plant 8 in Indianapolis then, where gas turbine aircraft engines were designed and produced. So, I worked for Detroit Diesel Allison Division of General Motors. My paychecks said "General Motors" on them, just like the guys who designed the 6.2 in the 1980 time frame.

Nobody said anything (at least I didn't) about using any interchangeable components from gasoline engines. What I said was, and what is fact is, that the design approach, methodology, technology and practices were borrowed from GM Powertrain's gasoline engine design manual to keep cost low. Their early advertising even said as much. Hence, the shallow skirt crankcase design, the lack of piston oil spray cooling (before 1997), the cast nodular iron crankshaft design, the crossed axis helical oil pump drive off of the cam, etc.

Detroit Diesel was GM. That is a fact.

On edit: It is also a fact that in the early 1990s, when I worked at Plant 5 in Indianapolis, Detroit Diesel 6V92 engine blocks were machined in Plant 5 alongside of the gas turbine engines. The 6V92s were even assembled and tested there for a while. It is also a fact that in late 1992, I was almost run over and killed by a wayward fork truck driver moving a stack of two 6V92 blocks at once so that he couldn't see in front of him. If I hadn't glanced to my right to wave at a coworker in a break area, I would not have caught sight of him coming up behind me and would have been crushed. I actually jumped over a guard rail into the break area to avoid being run over. The fork truck driver then saw me and slammed on the brakes nearly toppling the engines off the front.

Again, Detroit Diesel was GM when the 6.2 L was designed. Therefore, it was a GM engine through and through. It is a false distinction to say that Detroit Diesel designed the engine, not GM.

Back at that time, all of the gears for Electromotive Division (you know, the folks who made locomotives for GM?) were made at Plant 5. Also, many gears for Allison Transmissions were made there. The roots blower drive gears for the 6V92s were made there as well.

[Robyn]

I heard one clown once mention that you can tell the 6.2/6.5 were warmed over gas engine because you can see where the distributor went in. :rolleyes:

Some folks just gotta make you laugh EH ??? ;)

[JeepSJ]

...and even the cam isn't the same grind....

Say what?

Any improvement over the standard 6.5 cam? Or should I say would there be enough performance difference to dig one up?

[Robyn]

I am curious as to what they changed on the cam specs.

A naturally aspirated engine has a sweet spot that is far different than one with a huffer..

The cams used on the 6.5 I am told are the same as the 6.2

Not sure about this.

The low boost that the 6.5 runs likely can't really benefit much though.

After getting into the Mercedes thing I am seeing that they use variable cam timing on both the intake and exhaust cams.

Their 4.7 liter V8 twin turbo thats used in their GLS (About the size of Tahoe)
delivers NEARLY 500 hp at about 5500 and 516 ft lb of torque thats full on at 1800 Rpm and the torque stays there up into the 5k area.

Variable valve timing and a pair of huffers giitener done.

[ronniejoe]

The cams used on the 6.5 I am told are the same as the 6.2

Not sure about this.

Exact same part number...

[ronniejoe]

I've worked on the Mercedes 3.0 L turbo Diesel and 3.5 L M272 gas engine as used in the Sprinter vans.

You can have them...

[sctrailrider]

Say what?

Any improvement over the standard 6.5 cam? Or should I say would there be enough performance difference to dig one up?

Unique Diesel ran the cam on a "cam doctor" so we would know what was what compared to stock.

They are different, how much of a difference it will make I don't know yet, that one would be a lot of work to find out on a engine dyno..

I'm not going to post the specs as it was our R&R and cost me to get the info for my build on this P400..