6.5 or 454?

[Buliwyf]

Ah, yeah… I don't know about that one. Did you ever have a 6.2/6.5L apart? They are basically the same engine architecture as a big block Chevy gas. Once you get the heads off a 6.5L you can hardly tell the difference between it or a 7.4L. Neither were designed to be half million mile engines. 250K to 300K on either is doable. 650K, I am skeptical. The later AM General 6.5L engines were definitely better but they certainly do not have a B-life of half million miles. Don't get me wrong, I love 6.5L engines and older diesels as much as the next guy. Heck, I built a 6.5L Suburban for a friend that happens to work for AM General in Livonia, MI. It was turned out nice. He sent a marine spec 6.5L long block, Optimizer 6500 heads and some oddball prototype Bosch injection pump for it instead of the usual Stanadyne pump. It ran like a Duramax when it was done and got 20 MPG going from CO back to Detroit with a direct drive TH400 (no overdrive). The problem is most people can't afford to build something like that especially with access to prototype parts like the Bosch pump.

You're right though, the rest of the world does have reliable fuel effiencent diesel vehicles. Well, we did too in the US up until the last 5 to 9 years or so. With your BMW comment it appears you do not understand the difference between HP and torque.

Dominic is right, we will be seeing new diesel cars entering the US market, and the Chevrolet Cruze is just one of many coming soon. Manufactures are not entering these to the US because they are more durable or reliable. They are introducing them for self serving reasons to help met the stricter CAFE standards looming a head. Some people will be so awed love struck by the MPG they won't realize the higher inception cost, fuel cost, maintenance and the fact you must drive 80,000 miles a year just to break even. I still stand by my claim that new diesels (2007 and later) do not make sense in any vehicle where gas is an option. Open any trucking, commercial vehicle, or SAE periodical where you can see that printed over and over. You may get better MPG but the fuel and maintenance cost more and they cost a LOT more to fix when they break which quickly erases any benefit from having a diesel.

Freightliner now offers gas, International has a gas engine coming and this week Detroit Diesel changed their name to “Detroit” and dropped diesel. The reason…. industry insiders believe they have alternative fuel engine in the pipeline. Like propane and CNG on a spark ignition engine....basically a gasoline engine. Sure seems odd so many truck and commercial manufacturers are dabbling in gas again, no? Yeah, those new diesels are grrrrreat!

DDC has offered Series 50 and 60 NG engines for years.

They are terribly unreliable and need to be parked in a heated garage. For every 1 diesel Series 60 I fix, there are at least 100 NG Series 60/50 engines out there that start poorly. The mixer and throttle are rubbish.

Don't confuse gasoline with NG and LPG. NG and LPG are weak and quite hard to regulate properly. Gasoline engines are a walk in the park in comparison to the complexity of modern NG/LPG engines.

When you get into big engines, as long as you don't mind paying good money for quality, the diesels are still the way to go. The Cummins ISX/QSX/Sig Series are some of the best engines I've ever seen.

But small diesel pickup engines still lack the quality and proper design of the bigger truck engines. But GM and Ford have pretty much perfected the small block gasoline truck engine.

 

[Larry]

6.2 and 6.5 were designed to be diesel from ground up. they are not modified 350. have you seen how wide the cylinder head is in 6.5 vs 350?

I didn’t say the 6.2/6.5 wasn’t exclusively designed to be a diesel. I said the 6.2/6.5L look strikingly similar to a big block gas Chevy engine when they are both sitting next to each other with the cylinder heads off. The lower engine architecture is basically the same. So much so, you can hardly tell which is the gas and which is the diesel. Not sure where you come up with a 350, that is a small block. I never mentioned anything about the little 5.7L 350 Chevrolet gas.

Buliwyf, you realize the LPG and NG engines are running spark ignited gasoline engines that are converted to LPG/NG right? If you are talking about regulation and quality control of the fuel itself, you are 100% correct. There is very little regulation and quality standards for the fuel in place at this time. That is changing as we speak as more manufacturers and fleet seek alternative fuels. Corn based fuels are joke.

 

[BurbanAZ]

so if i did get a 6.5 though (even though ill probably just go with another 454 if i need to) would it bolt up to my 4l80e that i have in there now?

 

[bfdiesel]

If it will bolt to a 454 yes, but I am not sure about the starter hole in the bell housing. I had to use a peanut grinder in mine to get the deeper starter nose to fit, but I have an old 4 speed not a 4l80e. You will also need a different flex plate (the diesels have a different ring gear tooth count), a way to change the shift points, and possibly a different torque converter.

 

[Rot Box]

The diesel has a specific torque converter but the trans will bolt up to the motor fine--worse case you have to do as bfdiesel said and aug out the bellhousing for starter clearance.

If you go mechanical You will need the stand alone (not sure of the proper term) controller for the transmission whether it be aftermarket or off of a 91-93 GM diesel. If you wanted to go the later electronic injection route it would be best to find a donor truck and take the entire harness/computer etc. from a later model (94+) to run both the injector pump and transmission.

 

[Buliwyf]

Buliwyf, you realize the LPG and NG engines are running spark ignited gasoline engines that are converted to LPG/NG right? If you are talking about regulation and quality control of the fuel itself, you are 100% correct. There is very little regulation and quality standards for the fuel in place at this time. That is changing as we speak as more manufacturers and fleet seek alternative fuels. Corn based fuels are joke.

Yeah I'm talking about the fuel regulation systems. Todays NG/LP engines are nothing like the conversions we run in our Jeeps and Truggies.
We have a saying in the industry: "The block, head, and pistons don't do jack." That's easy stuff that never breaks, its the fuel system attached to the engine that makes or breaks it. DDC gas systems are terrible, PSI systems are ok, unless they don't work, as they are allmost non-serviceable.

They have to have a full feedback loop system with o2 sensors and a cat. Usually electric throttles. They have thier own specific computer, mixer/throttle body, and demand regulator. The new systems are absolute unreliable garbage. Just when you think you have it figured out, they scrap the entire fuel system and start selling something even more complex and impossible to repair. Also the NG/LP fuel systems have no standard scan tool software like OBDIII car systems etc. etc. Too often, scan software deosn't even exist, is too expensive to purchase, or deosn't even work well.

So far they work, or they don't, they are not really adjustable. (2009+ models) When the fuel mixture controller goes TU, you're in for a really long day.
Older gasoline engines converted to NG/LP with a simple ZPR regulator system are great. Just an MAS and ZPR to adjust. But those are no longer emmisions legal.

Less that 1% of engine problems are the engine itsself. The fuel system, ignition, and throttle systems are 99% of my nightmare. Gasoline engines are so simple and reliable by comparison.

If you compare a GM 8.1 gasoline to a GM 8.1L NG, the gasoline engine will be 100 times more reliable.


OP, have you thought about 350 and 383 crate engines???

 

[Deleted member 9101]

I hope the Op realizes that in all reality he will never save enough in fuel to pay for any of the mentioned swaps...lol

 

[BurbanAZ]

I hope the Op realizes that in all reality he will never save enough in fuel to pay for any of the mentioned swaps...lol

lol yea i realize that, i just was curious about options. Most likely ill stick with another 454 and make modifications where i can to get slightly better mpg. With the diesels its the type of thing ill keep an eye out for and if i find a really good deal buy it then. I still have a good amount of life in my engine im thinking i have 180,000 on there now so it will still be a little while till i have to worry about replacing it. Honestly im more worried about replacing my 4l80e, those are more expensive than another 454 lol

 

[BurbanAZ]

Yeah I'm talking about the fuel regulation systems. Todays NG/LP engines are nothing like the conversions we run in our Jeeps and Truggies.
We have a saying in the industry: "The block, head, and pistons don't do jack." That's easy stuff that never breaks, its the fuel system attached to the engine that makes or breaks it. DDC gas systems are terrible, PSI systems are ok, unless they don't work, as they are allmost non-serviceable.

They have to have a full feedback loop system with o2 sensors and a cat. Usually electric throttles. They have thier own specific computer, mixer/throttle body, and demand regulator. The new systems are absolute unreliable garbage. Just when you think you have it figured out, they scrap the entire fuel system and start selling something even more complex and impossible to repair. Also the NG/LP fuel systems have no standard scan tool software like OBDIII car systems etc. etc. Too often, scan software deosn't even exist, is too expensive to purchase, or deosn't even work well.

So far they work, or they don't, they are not really adjustable. (2009+ models) When the fuel mixture controller goes TU, you're in for a really long day.
Older gasoline engines converted to NG/LP with a simple ZPR regulator system are great. Just an MAS and ZPR to adjust. But those are no longer emmisions legal.

Less that 1% of engine problems are the engine itsself. The fuel system, ignition, and throttle systems are 99% of my nightmare. Gasoline engines are so simple and reliable by comparison.

If you compare a GM 8.1 gasoline to a GM 8.1L NG, the gasoline engine will be 100 times more reliable.


OP, have you thought about 350 and 383 crate engines???

i havent really put much thought into getting another small block but its a good option. The main reason is because my last suburban had a 350 tbi in it and it was fine but as for power and towing no where near my 454. My current 92 suburban with the 454 pulls better up hill pulling a stock trailer than my 350 did with just its own weight.

 

[Deleted member 9101]

lol yea i realize that, i just was curious about options. Most likely ill stick with another 454 and make modifications where i can to get slightly better mpg. With the diesels its the type of thing ill keep an eye out for and if i find a really good deal buy it then. I still have a good amount of life in my engine im thinking i have 180,000 on there now so it will still be a little while till i have to worry about replacing it. Honestly im more worried about replacing my 4l80e, those are more expensive than another 454 lol

Hey, options are always a good thing to keep an eye out for...lol. I feel ya on the tranny, I know for a fact that it will roll over and die long before that beast of a motor....lol.

 

[86cj]

lol yea i realize that, i just was curious about options. Most likely ill stick with another 454 and make modifications where i can to get slightly better mpg. With the diesels its the type of thing ill keep an eye out for and if i find a really good deal buy it then. I still have a good amount of life in my engine im thinking i have 180,000 on there now so it will still be a little while till i have to worry about replacing it. Honestly im more worried about replacing my 4l80e, those are more expensive than another 454 lol

The L29 Vortec 454 in my Dually does a nice job and would make a decent upgrade when the time comes. http://www.pirate4x4.com/forum/showthread.php?t=953550
It does sound like just as much hassle as a 8.1 swap, it could be a bit cheaper though.


With a tune and better valve springs/little more cam, the L-29 will really wake up, the heads are much better than your L-19 TBI 454. Mine is stock except for an X pipe and dual exhaust, it's an eager puller and gives 10-12 MPG with 4:56 gears.

 

[BurbanAZ]

The L29 Vortec 454 in my Dually does a nice job and would make a decent upgrade when the time comes. http://www.pirate4x4.com/forum/showthread.php?t=953550
It does sound like just as much hassle as a 8.1 swap, it could be a bit cheaper though.


With a tune and better valve springs/little more cam, the L-29 will really wake up, the heads are much better than your L-19 TBI 454. Mine is stock except for an X pipe and dual exhaust, it's an eager puller and gives 10-12 MPG with 4:56 gears.

yea i dont know about going to vortec because one of my favorite things about the tbi is how simple it is to work on anywhere, i think id lose that a little going with the vortec plus i could get 10-12 out of my tbi with a little work probably

 

[86cj]

It looks like the L 29 heads are a bolt on for your Gen V block, I don't know about your intake but that would be ideal, a TBI w/ Vortec heads. http://sdparts.com/details/gm-factory-replacement-parts/10141280

 

[Rot Box]

I remember back in the late 90's a couple of my friends had the Vortec heads and the GM performance/adapter intake on their TBI 350's. Seemed to really wake them up. I never thought about doing the same on a big block TBI... should be worth looking into anyway.

 

[Larry]

Yeah, L29 Vortec heads are a great upgrade on an L19 TBI 7.4L. I added a set of those to a 454 crate engine a few years ago before doing the L18 8.1L swap. The Vortec heads seem to flow well but I was using a Marine MPFI intake and MEFI-4 ECM and could never get the calibrations worked out to where I was happy when lugging the engine at low RPM’s. Gave up and tossed the 8.1L in.

Differences between the L19 TBI heads, L29 Vortec and L18 8.1L. I can’t find a picture of the combustion chamber side though. That is where the big differences are. L29 flows well while 8.1L flows better however 8.1L heads are not compatible with older engines.

454 HO with L29 Vortec heads and L29 Marine MPFI intake.

8.1L

This truck has pretty much had every engine at one time or another except a 6.2/6.5L diesel.