Ok... 1st post in the diesel forum. (Update: Think I've decided which engine to get)

[sixb]

As far as time and money, you might be able to get an Isuzu 4 cheaper, but Cummins 4's pretty much always cost more than the 6ers.

Another thing to consider is that the 6bt and probably the 6bd1t are good for any easy 350k if well taken care of so buying one used with 100k to 200k gives you plenty of miles left before a rebuild but from what I've read the 4bt needs rebuilt sooner. Not sure how much but read on 4bt swaps that they can start having problems at 150k which is not good in my book. Now my 92 6bt had 176k on it and I spent alot of money just in gaskets, head rebuild, ve pump rebuild, injectors, piston lift pump and the freight liner high mount ac setup so I didn't have to cut my frame. The point is I didn't really do a rebuild and it was still damm expensive and probably un necessary.

I know now that I have a problem, which is the need to take things apart to see how they work

 

[jonrpick]

Yup. The turbo 6.5's actually got up to 210HP and 520lb-ft. That is pretty much at the durability limits of a stock 6.5 though. With some bottom end reinforcement you can go higher, say, 250HP or so, which pretty much maxes out any standard DB2 pump. If that power level suits you, then it is a hard combo to beat from the standpoint of cost and swappability... as long as you find a good one. If you want much more than that, you will find as I did that it is cheaper to swap in a Cummins than to get something like a P400. It really all boils down to what you want and what you like.

The torque numbers are all I'm really looking at. Like I said, I don't rev my engine up to 5k RPM, EVER. I've never hit the peak HP spot with my 350, but the torque available under normal driving conditions has been less than stellar.

I am going to try to re-cam my 350 in the meantime to make it driving like normal. That engine has never been "right" from day one, and it was a brand-new crate motor.

Even after than, I know my fuel economy will top out at 16-18hwy, and worse in town, so at the very least, I'll be on the lookout for a 6.2, if not a 6.5TD.

 

[longbedder]

Keep an eye on the surplus auctions out there.

I got my 6.5 (new condition) from govliquidation.com: http://coloradok5.com/forums/showthread.php?t=257794&highlight=optimizer

 

[imbobbbb]

Well even if you plan on doing a swap on a blazer you already own my advice would be to look through the classifieds and pretend you are interested in buying something which has an engine you are considering in the same basic class where possible.If you go drive a 6.2 blazer/suburban/pickup you will know roughly what one will be like in your truck.A 5.9 cummins is going to pull a '93 dodge w200 about the same as your truck.A turbo 6.5 is going to feel about the same in a '95 chevy truck as it will in your blazer.You may not be able to test a 4bt or isuzu in anything comparable but you can get a pretty good idea on the other choices.After all of the negative stuff I had heard over the years I was quite surprised how much I liked the 6.2 when I first drove a suburban with one.I also liked how cheap I was able to buy one for and how cheap parts are compared to a cummins.I drive an '85 m1009 military blazer every day and like it a lot.I was worried I wouldn't like only having only three speeds,[military blazers use turbo 400's] ,but I haven't been thrilled with the 700r s reliability either,and with the 3:08 gears and '31 inch tires it does allright.It moves out ok from a stop and cruises 70-75 without a problem.Powerwise its about on par with the 318 powered dodge ramchargers and pickups I used to drive while getting 20-22 mpg when I keep it around 65 mph.Its plenty fast enough for me.Eventually I'd like to switch it to a overdrive manual transmission so that I can install the dana 60/14 bolt 4.56 geared cucv axles I have laying around and still have some top speed on the highway.....one of these days

 

[jonrpick]

Well even if you plan on doing a swap on a blazer you already own my advice would be to look through the classifieds and pretend you are interested in buying something which has an engine you are considering in the same basic class where possible.If you go drive a 6.2 blazer/suburban/pickup you will know roughly what one will be like in your truck.A 5.9 cummins is going to pull a '93 dodge w200 about the same as your truck.A turbo 6.5 is going to feel about the same in a '95 chevy truck as it will in your blazer.You may not be able to test a 4bt or isuzu in anything comparable but you can get a pretty good idea on the other choices.After all of the negative stuff I had heard over the years I was quite surprised how much I liked the 6.2 when I first drove a suburban with one.I also liked how cheap I was able to buy one for and how cheap parts are compared to a cummins.I drive an '85 m1009 military blazer every day and like it a lot.I was worried I wouldn't like only having only three speeds,[military blazers use turbo 400's] ,but I haven't been thrilled with the 700r s reliability either,and with the 3:08 gears and '31 inch tires it does allright.It moves out ok from a stop and cruises 70-75 without a problem.Powerwise its about on par with the 318 powered dodge ramchargers and pickups I used to drive while getting 20-22 mpg when I keep it around 65 mph.Its plenty fast enough for me.Eventually I'd like to switch it to a overdrive manual transmission so that I can install the dana 60/14 bolt 4.56 geared cucv axles I have laying around and still have some top speed on the highway.....one of these days

Good advice... I didn't think about test driving a used one. I may do that...

 

[tRustyK5]

Well even if you plan on doing a swap on a blazer you already own my advice would be to look through the classifieds and pretend you are interested in buying something which has an engine you are considering in the same basic class where possible.If you go drive a 6.2 blazer/suburban/pickup you will know roughly what one will be like in your truck.A 5.9 cummins is going to pull a '93 dodge w200 about the same as your truck.A turbo 6.5 is going to feel about the same in a '95 chevy truck as it will in your blazer.You may not be able to test a 4bt or isuzu in anything comparable but you can get a pretty good idea on the other choices.After all of the negative stuff I had heard over the years I was quite surprised how much I liked the 6.2 when I first drove a suburban with one.I also liked how cheap I was able to buy one for and how cheap parts are compared to a cummins.I drive an '85 m1009 military blazer every day and like it a lot.I was worried I wouldn't like only having only three speeds,[military blazers use turbo 400's] ,but I haven't been thrilled with the 700r s reliability either,and with the 3:08 gears and '31 inch tires it does allright.It moves out ok from a stop and cruises 70-75 without a problem.Powerwise its about on par with the 318 powered dodge ramchargers and pickups I used to drive while getting 20-22 mpg when I keep it around 65 mph.Its plenty fast enough for me.Eventually I'd like to switch it to a overdrive manual transmission so that I can install the dana 60/14 bolt 4.56 geared cucv axles I have laying around and still have some top speed on the highway.....one of these days

Awesome first post, and a paid member right away too! Welcome to CK5, and welcome to our little smoky, rattley corner of CK5.

Rene

 

[jonrpick]

Awesome first post, and a paid member right away too! Welcome to CK5, and welcome to our little smoky, rattley corner of CK5.

Rene

Yeah, I meant to give him the "welcome", as well, but got distracted...

Welcome dude!

 

[imiceman44]

Awesome first post, and a paid member right away too! Welcome to CK5, and welcome to our little smoky, rattley corner of CK5.

Rene

Well I was a paying member before I knew there was a forum, I paid because i was going to BB. didn't end up going since I broke down the day before I was to leave.
But still welcome to our new insightfull paying member.

 

[jonrpick]

I'm bringing this thread back, and renaming it. I've been doing a lot of thinking and some research.

For myself, I've decided that the Cummins and Isuzu swaps are impractical for me, and the 6.x series is the way to go. Now, the big question is, which 6.x option should I choose?

In order of cost (lowest to highest), here's what I'm looking at:

6.2
6.5TD
6500 Optimizer
P400

I've been trying to read up before asking questions. From what I can tell, doing a total rebuild on a 6.2/6.5 can be tough because of the difficulty in finding a totally crack-free block, plus all the costs involved in prepping it (machine work, etc...). Plus, just because you find one that's crack-free, how long could one expect it to stay that way??

That has me thinking about the more expensive, but likely less troublesome Optimizers and P400's. The P400 looks to be a much better option in terms of durability, and looks like it could make more power as a result, especially considering that it's available with a lower, more boost-friendly 18:1 compression ratio. It also seems that it doesn't cost that much more than an Optimizer.

I have much to ponder, but I'm wondering if just saving up for the P400 might not be the best option in the long run. More power potential and more durability.



What say ye?

 

[MaxPF]

I'm bringing this thread back, and renaming it. I've been doing a lot of thinking and some research.

For myself, I've decided that the Cummins and Isuzu swaps are impractical for me, and the 6.x series is the way to go. Now, the big question is, which 6.x option should I choose?

In order of cost (lowest to highest), here's what I'm looking at:

6.2
6.5TD
6500 Optimizer
P400

I've been trying to read up before asking questions. From what I can tell, doing a total rebuild on a 6.2/6.5 can be tough because of the difficulty in finding a totally crack-free block, plus all the costs involved in prepping it (machine work, etc...). Plus, just because you find one that's crack-free, how long could one expect it to stay that way??

That has me thinking about the more expensive, but likely less troublesome Optimizers and P400's. The P400 looks to be a much better option in terms of durability, and looks like it could make more power as a result, especially considering that it's available with a lower, more boost-friendly 18:1 compression ratio. It also seems that it doesn't cost that much more than an Optimizer.

I have much to ponder, but I'm wondering if just saving up for the P400 might not be the best option in the long run. More power potential and more durability.



What say ye?

6.2/6.5's make sense because they are simple AND inexpensive. If you are talking that kind of money, do the Cummins swap. Otherwise, find a good used donor 6.2 or 6.5 for cheap, throw it in, and run it.

 

[jonrpick]

6.2/6.5's make sense because they are simple AND inexpensive. If you are talking that kind of money, do the Cummins swap. Otherwise, find a good used donor 6.2 or 6.5 for cheap, throw it in, and run it.

Just curious, why would you choose to do a Cummins swap over a P400? The P400 looks like it'd make very good power and torque, and would bolt in without having to use conversion parts or fab your own...

 

[imiceman44]

Just curious, why would you choose to do a Cummins swap over a P400? The P400 looks like it'd make very good power and torque, and would bolt in without having to use conversion parts or fab your own...

The optimizer obviously is a great engine as a replacement for any GM engine, it's a straight bolt up, it's a new engine with I am assuming a good warranty, but I have never and don't think will ever buy a new car or new engine.
I would buy $300-$400 used 6.2 engines and run them as long as I can, there is always some available to purchase used.
The P400 has one thing the cummins doesn't have that you might want, high RPM range.
But the cummins can have without too much hassle as much as the highest you can get out of the P400 with potential for more power, so if you are looking at insane power cummins is your engine, but I think you would be more happy with the 6.2 or P400.
I would like a 6.2 in my blazer and suburban, but I like a cummins or in my case a perkins in my crew cab, I also love my CAT in my Freightliner.

 

[MaxPF]

Just curious, why would you choose to do a Cummins swap over a P400? The P400 looks like it'd make very good power and torque, and would bolt in without having to use conversion parts or fab your own...

A couple reasons. First off, a good used Cummins (even a whole donor Dodge) can be had for much less than the cost of a P400. Second, the pumps required to get the potential power out of the P400 is very spendy, whereas the Cummins come with pumps that can make the same power or more. Also, the P pumps in particular are far longer lived than the Stanadyne pumps used on 6.x applications. The Cummins can ultimately make more power than the P400, simply because even the best DB4 pump won't go much over 350HP. Finally, the Cummins is direct injected, and DI engines consistently give higher efficiency (MPG) than IDI engines.

Like I said, I'm not knocking the 6.x or the P400. For their design intentions I think they are very good engines. But the primary advantage of the 6.x platform lies in low cost. Once you start talking about P400's, you have gone into a different realm where you are willing to drop some serious coin on a conversion. At that point, I believe it is worth it to do the mods necessary to swap in a Cummins. I wouldn't say you are making a bad decision by getting a P400 - far from it. But I had to make that same decision, and after agonizing over the pros and cons it became apparent that the Cummins would be the better solution. Much of that had to do with potential parts availability and warranty issues with the P400.

 

[KirsL]

For your application I would run a stock 6.2 with either a banks turbo or stock gm turbo setup. You'll get great mileage and the turbo will really help when in the mountains. Best thing is you can run the engine non-turbo until you have the money to put one on. Course you can do it all in one shot too .

 

[jonrpick]

Iceman and Max...

Since this will be a DD, I'm not looking to get ridiculous power levels. I'm more concerned with having good torque. Knowing where the torque is in these engines, I know 350hp is a LOT of torque--way more than my 305 had, or what my 350 has now.

I probably should've thrown this out there: I'm looking for something similar in feel to my girlfriend's Yukon XL (Suburban). Prior to the Yukon, she had a Tahoe with the 4.8L V8 and 3.23 gears. The Yukon has the bigger 5.3L and 3.73 gears. I'm VERY comfortable with its power. It's enough to get out of the way when necessary, but not too much.

Now, I know at this point, many would say, just drop in a used 5.3L and call it good, but the fuel economy isn't awesome. She averages 15-16mpg according to the onboard computer, and I'd say most of her driving is her work commute, which is primary interstate.

I do however feel that the Yukon would be inadequate if I wanted to pull anything other than a very small trailer. Yes, I know my short-wheelbase K5 isn't an ideal towing vehicle, but I'd like to have the option, and more importantly the torque to back it up.

I still think the Cummins would be overkill. Now, you're saying that the upfront cost of a Cummins conversion would be cheaper than the P400? I know the frame can be modified to handle it, but really, what do you think the long-term effects of carrying that much weight would do to the frame? Are there no bolt-in conversion parts to strengthen the frame? Grafting in 1-ton frame parts seems excessive for a DD.

What's the deal on P400 parts availability? I'm assuming that P400 parts are not as readily available over the counter at my local Napa...

Again, my goals are:

1) Better fuel economy than I'll be able to achieve with a gas engine
2) Power--when I need it
3) Durability and Reliability, Durability and Reliability, Durability and Reliability...
4) Oh yeah... Durability and Reliability.

Now I know the Cummins is durable and reliable. I don't think the P400s are old enough for anyone to say for sure, although that is one Hell of a sexy engine...

Edit: Also, keep this in mind... Axle-wise, I'll be upgrading to a 14BSF in the rear, but just a 6-lug version, and I'll be keeping the 10-bolt up front. How well could the 10-bolt cope with the weight of a Cummins bearing down on it?

 

[jonrpick]

For your application I would run a stock 6.2 with either a banks turbo or stock gm turbo setup. You'll get great mileage and the turbo will really help when in the mountains. Best thing is you can run the engine non-turbo until you have the money to put one on. Course you can do it all in one shot too .

I am looking to do it all in one shot. Ideally, I'd get a 2nd frame to build the drivetrain on, and just drop the body on that.

 

[MaxPF]

Iceman and Max...

Since this will be a DD, I'm not looking to get ridiculous power levels. I'm more concerned with having good torque. Knowing where the torque is in these engines, I know 350hp is a LOT of torque--way more than my 305 had, or what my 350 has now.

I probably should've thrown this out there: I'm looking for something similar in feel to my girlfriend's Yukon XL (Suburban). Prior to the Yukon, she had a Tahoe with the 4.8L V8 and 3.23 gears. The Yukon has the bigger 5.3L and 3.73 gears. I'm VERY comfortable with its power. It's enough to get out of the way when necessary, but not too much.

Now, I know at this point, many would say, just drop in a used 5.3L and call it good, but the fuel economy isn't awesome. She averages 15-16mpg according to the onboard computer, and I'd say most of her driving is her work commute, which is primary interstate.

I do however feel that the Yukon would be inadequate if I wanted to pull anything other than a very small trailer. Yes, I know my short-wheelbase K5 isn't an ideal towing vehicle, but I'd like to have the option, and more importantly the torque to back it up.

I still think the Cummins would be overkill. Now, you're saying that the upfront cost of a Cummins conversion would be cheaper than the P400? I know the frame can be modified to handle it, but really, what do you think the long-term effects of carrying that much weight would do to the frame? Are there no bolt-in conversion parts to strengthen the frame? Grafting in 1-ton frame parts seems excessive for a DD.

What's the deal on P400 parts availability? I'm assuming that P400 parts are not as readily available over the counter at my local Napa...

Again, my goals are:

1) Better fuel economy than I'll be able to achieve with a gas engine
2) Power--when I need it
3) Durability and Reliability, Durability and Reliability, Durability and Reliability...
4) Oh yeah... Durability and Reliability.

Now I know the Cummins is durable and reliable. I don't think the P400s are old enough for anyone to say for sure, although that is one Hell of a sexy engine...

Edit: Also, keep this in mind... Axle-wise, I'll be upgrading to a 14BSF in the rear, but just a 6-lug version, and I'll be keeping the 10-bolt up front. How well could the 10-bolt cope with the weight of a Cummins bearing down on it?

So, let me see if I understand correctly. You want excellent fuel economy, plenty of power (but not a ridiculous amount), you don't want to have to overly mod your chassis (i.e. no 1 ton frame swap or boxing) and you want durability and reliability x 10. Do I have this right?

OK, you still have 2 options. Sadly, a used GM 6.2/6.5 isn't one of them. I like the engine, but they are known for long term durability issues. If you're looking for an engine to take you cross country with 350k on the odometer and not worry about dropping a main web or crank, the old GM 6.x's are off the table IMO. Because you don't want to mod your frame at all, that also takes the heavy 6's out of the picture. What you are left with is the P400 or maybe the Optimizer 6500, which are really unknowns in the long term durability department, or the 4BT which supposedly get about the best fuel economy you can ever hope for from a diesel swap. The downsides to the 4BT (in my opinion) is cost (more than a 6? Are you kidding? Less than a spanky new P400 tho...), and the fact that they are a bit... harsh. Your truck will sound like a Case 580 back hoe and they are known to shake a bit. The guys at 4bt swaps seem to favor the fluid motor mounts to dampen the shake, but it will always still sound like a tractor Then again, my 6BT sounds like a tractor, so who am I kidding That was one thing I loved about the 6.2 - it sounded good! I'm particularly talking about the exhaust note - it sounded like a good big block, which is A Good Thing in my book I don't know if I will ever grow to like the sound of the Cummins, so the swap had better not suck otherwise

 

[kennyw]

Reliability per dollar (reliable miles per dollar) will be far better with a dirt cheap used 6.2L than anything else. I have picked up a free motor, tossed in new gaskets while inspecting for cracks, then ran it for 150K miles before failure (original miles unknown when I received the motor). In the end block cracks and/or snapped crank was the killer. My current 6.2L powered K20 has 265K miles on the original motor and I paid $1000 for the whole truck two years ago.

However, if you want it to last 300K miles from the day you drop it in... only a new motor is going to do. Rebuilding the 6.2/6.5L motors generally do nothing for block cracks and turning the crank is only going to make it more likely to snap.

The most your looking at paying for a used 6.2L is $300, and that would have to be a low mile CUCV donor at this time. But always plan on pulling the oil pan and inspecting the bottom end for cracks before buying any used motor.