Which would you rather have?

[NEK5]

Topic in question, engine for a DD. Diesel, or gasser? I thought about putting a diesel in my Blazer because it would give me some pretty good MPG out of it, upwards of 20MPG I would think. Worth it, or would it be better to put a new, strong, 350 in it? What are your guys opinions, if your wheeler is your DDer?

 

[bear76]

Diesels are good for MPG but parts and oil changes cost more, so keep that in mind.

 

[rjfguitar]

Oil changes cost the SAME, as diesel oil is slightly more expensive, but the pan holds a higher amount and you can travel more miles on a single change.

In a blazer, it's kind of a hard call in some ways.

A strong, slightly cammed 350 with all the bolt on goodies like an intake, headers, and EFI is a nice setup. It can also yield half way decent acceptable mileage in a K5 closer to stock.

But.... a 6.2 with say a Banks turbo kit would be much better IMHO.

As far as a newer rig, no question.... I daily drive 22mpg, 800+ft lbs torque worth of diesel every day.

 

[bear76]

How offten do you change your oil? Gas or diesel I change every 5k, more oil on the pan, same interval, means more $ to me.

 

[vortec]

while the torque numbers are respectable, the hp disappoints on the older deisels. not a problem for rock-crawling and stuff, but for street driving, that makes a big difference. i can't tow a mountain with my 350, but it tops out the speedo on the highway with no problem. the new deisels, both naturally aspirated and turbocharged are much more attractive to me than the old ones. torque is even bigger and hp is way up. and turbo lag has been significantly reduced in the ones i've driven. looks like they've finally brought the best of deisel and best of gas together for a very nice final product. but, old gas vs old deisel, give me gas.

 

[trev1981]

Topic in question, engine for a DD. Diesel, or gasser? I thought about putting a diesel in my Blazer because it would give me some pretty good MPG out of it, upwards of 20MPG I would think. Worth it, or would it be better to put a new, strong, 350 in it? What are your guys opinions, if your wheeler is your DDer?

If your going to swap in a diesel go with a 4bt or 6bt cummins. They will run for ever and they are 10x better then a 6.2.

 

[Thunder]

I would go with EFI gas, over an older diesel 6.2-6.5 ect. The older diesels are on their way out. They were designed to run on Diesel with sulpher and other additives. Sulpher is the main lubricating element in diesel fuel. It keeps the seals soft and the injection pump and injectors properly lubed.
The new Ultra low sulpher fuel in older diesel engines, is like removing the lead from Gasoline did to older gas engines. Except it was a lot cheaper to buy a new set of heads for an old gasser, Than it would be to modify an older diesel engines to run ULSD.
Diesel fuel sulpher has gone from 5000 PPM back in the 80s to 50 PPM now.
ULSD fuels were phased in last fall That is all you can get now for OTR driving. Newer Diesel engines are designed to run on ULSD. Older engines are not.
I believe it is only a matter of time before the older diesel engines start having seal, injector pump, and injector problems. ULSD also makes less power than older formulations.
Sure you can get additives for diesel to replace the additives that have been removed. But that just adds expense to a fuel that is already .50 more a gallon than gas.
The days of cheap diesel are long gone. ULSD fuels cost more to make and I dont think it will get cheaper.
IMO it makes more sense to stay with the gas engine.

 

[twoslo4five0]

if i could go to the dealership and order my truck the way i wanted it it would be a chevy with a cummins with a nv4600 (i think thats the one)6 spd....

 

[drop the hammer]

how about most people on this site dont have there k-5s stock so when you have a lifted K-5, deisel vs gas dont matter cause mpg are gonna suck either way (I get about 12mpg hi-way with a 6 inch lift 35's and a 350|700-R4). 6.2 deisels last for ever if properly mantained, 350's if you know what your doing also indestructable, so my preference a properly preped small bolock will bolow a 6.2 deisle away any day. But dont get me wrong in my job I work deisel, so flip a coin

 

[DEMON44]

specifyed oil change interval in the OEM service manual for my '98.5 cummins is 12,000kms on normal duty, and 6,000kms on extreme duty.
but I do 10,000km oil changes. with full synthetic

 

[muddybuddy]

haha your starting to think the way i started thinkin last year. thought about swapping a diesel into my k5, but ended deciding buying a diesel truck would be much easier. ive got a diesel and wouldnt look back

 

[tRustyK5]

how about most people on this site dont have there k-5s stock so when you have a lifted K-5, deisel vs gas dont matter cause mpg are gonna suck either way (I get about 12mpg hi-way with a 6 inch lift 35's and a 350|700-R4). 6.2 deisels last for ever if properly mantained, 350's if you know what your doing also indestructable, so my preference a properly preped small bolock will bolow a 6.2 deisle away any day. But dont get me wrong in my job I work deisel, so flip a coin

I run a 6.2 in my K5 by choice, and just picked up an '83 1/2 ton with 6.2 for DD duty. The K5 runs on 39.5" TSL's, with 7" of lift and will pull down an honest 19+ on the highway and 15 in town. The 1/2 ton tops 25 mpg on the highway. Neither one are any slower than my K5 was with a mild 355 (previous to swapping in the diesel)

The ULSD fuel does have me concerned, but time will tell I guess. For now I keep adding a little additive.

For wheeling I guess it depends on a few things. If you are mud racing I say build a rowdy big block and have fun. For any other kind of wheeling a diesel or FI'd sbc is fine. If you're truck already has FI then a sbc would do OK as long as you factor in getting half the fuel mileage. In my case my K5 had a carb'd 355. As the truck got bigger the mileage got worse and worse as you can imagine, and the carb off road sucked. I was looking at swapping to FI which would have made me happy off road but wouldn't have got my mileage over 9-10 mpg. The 6.2 is mechanically injected and has a metric assload of off idle torque, and will run smoothly at any angle. For me it was a no brainer, and not even a spendy swap.

Rene

 

[Speedo]

I would go with EFI gas, over an older diesel 6.2-6.5 ect. The older diesels are on their way out. They were designed to run on Diesel with sulpher and other additives. Sulpher is the main lubricating element in diesel fuel. It keeps the seals soft and the injection pump and injectors properly lubed.
The new Ultra low sulpher fuel in older diesel engines, is like removing the lead from Gasoline did to older gas engines. Except it was a lot cheaper to buy a new set of heads for an old gasser, Than it would be to modify an older diesel engines to run ULSD.
Diesel fuel sulpher has gone from 5000 PPM back in the 80s to 50 PPM now.
ULSD fuels were phased in last fall That is all you can get now for OTR driving. Newer Diesel engines are designed to run on ULSD. Older engines are not.
I believe it is only a matter of time before the older diesel engines start having seal, injector pump, and injector problems. ULSD also makes less power than older formulations.
Sure you can get additives for diesel to replace the additives that have been removed. But that just adds expense to a fuel that is already .50 more a gallon than gas.
The days of cheap diesel are long gone. ULSD fuels cost more to make and I dont think it will get cheaper.
IMO it makes more sense to stay with the gas engine.

ULSD is 15ppm not 50, 50 is what was in use in California and was known as low sulfur diesel not ULSD. Sulfur isn't the lubricant that lead was in gasoline, the process to remove the sulfur is what takes out the lubricants and also delivers a fuel with a lower cetane rating. There is an SAE minimum rating for lubricity but in most opinions it is too low.

Gus

 

[DEMON44]

ULSD is 15ppm not 50, 50 is what was in use in California and was known as low sulfur diesel not ULSD. Sulfur isn't the lubricant that lead was in gasoline, the process to remove the sulfur is what takes out the lubricants and also delivers a fuel with a lower cetane rating. There is an SAE minimum rating for lubricity but in most opinions it is too low.

Gus

that there is what I know to bo true too

 

[MaxPF]

If your going to swap in a diesel go with a 4bt or 6bt cummins. They will run for ever and they are 10x better then a 6.2.

Both are good motors, but they are both much noiser and have more vibration than a 6.2. The swap will almost certainly be more expensive as well. However, if the drawbacks aren't a problem then yes, they are a good swap option.

In the end it is personal preference as to whether to swap in a diesel or stay with a gas motor. You know the pros and cons of both. I had to do a lot of research before I came to the following conclusions:

The diesel will always get better mileage than any gasser. A 25 year old 6.2 will still give better mileage than the best current gasser technology has to offer. Not even the 5.3's with cylinder deactivation or the 5.3 hybrids can come close, and they are in trucks with much better aerodynamics. Offroad there is absolutely no contest - the 6.2 will run FAR longer than a gasser on the same quantity of fuel. BTW, around here diesel averages only 7 cents per gallon more than unleaded, not the 50 cents someone else stated.

With a hairdryer the 6.2 will make the same HP as my TBI 350 (210HP), and considerably more torque. It isn't a modern DMax, Cummins, or PowerSmoke, but it is still pretty damn respectable for a 25 year old IDI diesel. Even without a turbo the J code motor I got was rated for 165HP, which is similar to many early 80's 350's IIRC.

The older diesels, especially the 6.2/6.5 and even the older IH 6.9/7.3's used in Fords and the older Cummins BT's, are pretty cheap to build and repair, even compared to similar generation gassers. They are definitely cheaper than most modern gassers and MUCH cheaper than modern electronic DI diesels. When I added up the cost to build a 383 vs. a 6.2, the 6.2 ended up being less expensive. Granted, I could have built a plain-jane stock 350 for less, but the idea was to improve either power or mileage.

I was concerned about the ULSD and such, but good additives solve this problem while only adding a few cents per gallon. Since the additives typically improve mileage die to improved cetane ratings, the added cost is typically recouped in added mileage. The pumps live and everyone is happy. If a person wants to be able to run crappy fuel without worries they can always use a military IP, which has harder internal parts designed to resist wear due to poor fuel lubrication.

Diesel oil costs the same as gasser oil, but the 6.2 holds a bit more. Oil change intervals are similar, so the diesel will cost a few dollars more at oil change time. Fuel filters are a yearly change item. Keep in mind gassers need fuel filter changes as well, although they typically cost less than a diesel filter. Air filter change intervals are similar. Overall, the diesel will cost a bit more in maintenance, but the fuel cost savings will more than offset it.


Anyway, for me the advantages of the 6.2 outweighed the disadvantages. I had the advantage of prior experience with the 6.2 though - I drove HMMWV's and CUCV's in the Army in the late 80's. The HMMWV was a turd, mainly due to it's weight. However, the M1009 CUCV's (diesel Blazers) ran fairly well and were pretty much trouble free, even though they were driven like rentals by a bunch of young GI's. Besides that, I like the way the 6.2/6.5 sounds

 

[BKinzey]

...If a person wants to be able to run crappy fuel without worries they can always use a military IP, which has harder internal parts designed to resist wear due to poor fuel lubrication....

Never heard of a "military IP." The IP used in the CUCVs is the same as the Civy model.

 

[bear76]

I've also heard that the mil. IP's were diferent. I remember reading about being able to use jet fuel, and other not common fuels in mil. trucks. due to hardend internals.

 

[MaxPF]

I've also heard that the mil. IP's were diferent. I remember reading about being able to use jet fuel, and other not common fuels in mil. trucks. due to hardend internals.

That is my understanding as well. I have heard from many sources that the military pumps have internals that are hardened to a greater degree than civvy pumps. Is it hard fact? I dunno, but I do know that the.mil often has different specs for their stuff, and I do seem to remember being told in the military that a HMMWV could be run on JP5 if no diesel was available. OTOH, maybe the pumps are the came as the civvy item and they figured trashing a pump is acceptable in a military emergency...

 

[stumblefoot]

My K5 came with the 6.2L diesel, after a 4"lift and 35s I changed the 3:08s for 4:10s and put detriot lockers front and rear, I still get about 15-18 mpg, as far as the ULSD it sucks, but I'm able to get commercial B-20 Bio Diesel that takes care of the lubricity issues. Plus I would rather give 20% of my $$ to an American farmer than give 100% to a ****** that wants to kill me. I run B85 ethonol in my 67 F100 with no problems too.

 

[BlazerBud]

Gas if it's old. Turbo Diesel if it's new. I have a rebuilt 350 in the old blazer and a 2004 powerstroke F-250 daily driver.
People who drove the old 6.2 like it was a gas engine destroyed them. Diesels are machines, they need to be cared for as does ay engine. Start it up and let it warm up, all the way up, don't just get in and go. This is worse on diesel than gas engines, but should be practiced on both. Modern turbo diesels eliminate some of the sluggish feel of a cold diesel engine, people mistake this for a free liscense to just get in a hammer it when it's still cold cuz feels like it's ready just like a gas engine. Worse, a turbo needs time to cool down, especially when working hard. Remember, run it 10 minutes before driving on a cold start up, and let it cool 5 minutes before killing it after a hard tow are some hot doggin. Do this and they will last forever.