6.2/6.5 Diesel Conversions - The High Points

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06-04-2007, 14:09
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6.2/6.5 Diesel Conversions - The High Points
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6.2/6.5 Diesel Conversions - The High Points

By Jim Bigley

A few key points to remember:
1. The GM 6.2L and 6.5L diesel engines share the very same bellhousing configuration and bolt pattern with all Chevy and GMC V-8 gasoline engines (till the LS series of gas engines).
2. The GM 6.2L and 6.5L diesel engines share the very same motor mount configuration with all Chevy and GMC V-8 gasoline engines (till the LS series of gas engines).
3. The GM 6.2L and 6.5L diesel engines are about 200 or so lbs heavier than a gasoline 350 V-8. The bare longblock weighs just over 700 lbs.
4. The GM 6.2L and 6.5L diesel engines have identical dimensions, and nearly every bolt-on component on either engine will interchange with the other.
5. A conversion from gas to diesel will require a hydraulic brake booster, diesel starter, larger diesel radiator, all engine driven accessory brackets, and fan assemblies. Your A/C compressor and power steering pump might work with the correct diesel brackets.
6. The automatic transmission torque converter should be changed to one rated for diesel operation. The stall rpm of a gas converter will be above the 1700-2000 rpm torque peak of the diesel. We suggest modifying the transmission governor setting to upshift at an rpm below the engine's governed rpm of 3300-3600 (if non-electronic transmission). An overdrive transmission is recommended. Low gearing, no overdrive and higher freeway speeds make the diesel engine hard to live with. Best fuel economy is possible when running the engine at about 1800-2000 rpm at your chosen cruise speed.
For anyone considering a swap, I'd recommend buying a diesel donor vehicle, swap all the parts in both directions, then sell the donor. This will result in the best and least expensive conversion. Buying all the diesel-related components usually puts the cost out of reach for most people. Older diesel trucks and Suburbans with body or other cosmetic problems are usually pretty affordable. TDP

Copyright 2007 by The Diesel Page
02-04-2008, 07:37
mmusmanno

conversion

would a diesel van make an ok donor for an 83 k10 gas to diesel swap, or should it really be a truck or suburban? if the van is cheap enough, I can still buy some of the diesel parts new and still make the project reasonable. thoughts? thanks.
07-10-2008, 12:16
COMP

anything new to add ??
07-25-2008, 15:29
stuntdoublejoe

I have a towing special suburban I am going to swap a diesel into. My question is can I use the stock radiator? I know the diesel needs a better one then gas but the towing special has a better radiator for bigger loads. Would this work for the diesel or would it still not be enough.
07-25-2008, 15:42
COMP

Quote:

Originally Posted by stuntdoublejoe

I have a towing special suburban I am going to swap a diesel into. My question is can I use the stock radiator? I know the diesel needs a better one then gas but the towing special has a better radiator for bigger loads. Would this work for the diesel or would it still not be enough.

if it was mine i'd try it,,,but know where to get a upgrade if it didn't cut it
07-28-2008, 20:58
stuntdoublejoe

What problems would I come across using the turbo 400. I don't go on the highway much so not having an overdrive isn't much of a problem, and I've heard it runs on a vacuum and if thats true how much would a vacuum pump cost? Also how would I go about changing the governor for the diesel
07-28-2008, 22:14
More Power

The van diesel engine and various other components would work for a pickup or Suburban installation. There may be a couple minor items that'll need to be changed, but overall, most accessory items would work fine. For example the oil dipstick, oil fill pipe, throttle & cruise cables are different between the two applications.

The gas big-block equipped Suburbans and trucks received the same larger radiator as the diesel - at least they were the same physical size, so I'd try it. If the Suburban was equipped with a 350 gas, it'll need another radiator.

A non-OD automatic worked just fine back in the days of the 55-mph speed limits - the first 9 years of my GM diesel experience was during the days of 55.... Nowadays, you just can't comfortably run at freeway speeds without an OD. Plus, when I upgraded to an OD automatic, I saw an immediate 6-mpg increase.

GM produced vacuum pumps and a VRV (Vacuum Regulator Valve), that was bolted to the side of the fuel injection pump, to simulate manifold vacuum on a gas engine. The VRV allowed a TH400 (or TH350) to function and shift normally behind a 6.2 diesel.

Jim
07-29-2008, 22:11
stuntdoublejoe

Quote:

Originally Posted by More Power

GM produced vacuum pumps and a VRV (Vacuum Regulator Valve), that was bolted to the side of the fuel injection pump, to simulate manifold vacuum on a gas engine. The VRV allowed a TH400 (or TH350) to function and shift normally behind a 6.2 diesel.

Jim

How much would a vacuum pump and VRV cost me? I can get a 700r4 or a 4L80 for about $500. Would this be a better option because I am on a very tight budget and already have the engine and brake booster.
07-30-2008, 00:43
More Power

The 700R4 can be built to shift without electric/electronic control - that's what I did for my 6.2L diesel. Still, the 700 would require a throttle-valve (TV) cable and bracket. A 4L80-E would require a TCM, harness, engine speed sensor and TPS (figure about $1k beyond the cost of the trans).

If on a tight budget, and if you wanted to use a TH400, you could post an ad in the classified ad section for a VRV/vac pump. Buying used would be less expensive than new.

Jim
07-30-2008, 06:00
convert2diesel

Jim:

What method did you use for locking up the 700? When I was building the Buick, the only thing that was available would only give me lock up in fourth. As I tow with the car, it is important that I have lock up in third. Currently use a switch on the dash that does work but would love to find a way to do it without having to remember to work the switch.

Bill
08-28-2008, 21:44
stuntdoublejoe

Quote:

Originally Posted by More Power

The 700R4 can be built to shift without electric/electronic control - that's what I did for my 6.2L diesel. Still, the 700 would require a throttle-valve (TV) cable and bracket. A 4L80-E would require a TCM, harness, engine speed sensor and TPS (figure about $1k beyond the cost of the trans).

If on a tight budget, and if you wanted to use a TH400, you could post an ad in the classified ad section for a VRV/vac pump. Buying used would be less expensive than new.

Jim

I now have the VRV/Vac Pump, so now my question is how do I change up the governor and shift points?
01-22-2009, 00:13
kyle41005

what about a 5 speed i noticed diesels clutches are all different numbers from gas motors, even when they dont have the dual mass flywheel, is there anyway to reuse a gas clutch/flywheel? are the crankshaft patterns the same where your flywheel/flexplate bolts on?
03-05-2010, 13:33
More Power

Quote:

Originally Posted by kyle41005

what about a 5 speed i noticed diesels clutches are all different numbers from gas motors, even when they dont have the dual mass flywheel, is there anyway to reuse a gas clutch/flywheel? are the crankshaft patterns the same where your flywheel/flexplate bolts on?

The diesel flywheels, clutches and pressure plates are specific to the diesels. Gas versions won't work.

Jim
10-16-2011, 11:33
duallyman30

swapped 454 for 6.2

i cant seem to get it started now that its in my one ton
10-17-2011, 12:33
duallyman30

finally got it runnin but its kinda rigged.i still need to find the power steering brackets.
10-17-2011, 12:35
duallyman30

Quote:

Originally Posted by More Power

The diesel flywheels, clutches and pressure plates are specific to the diesels. Gas versions won't work.

Jim

the clutchpak off 454 is the same as 6.2.the flywheel is different but the clutchpak is the same part number.at least thy are on a 4 spd
11-13-2011, 19:25
MMcGee

C ya

are one and two peice rear mains the same as far as the flywheel

mark
11-14-2011, 12:14
More Power

Quote:

Originally Posted by duallyman30

the clutchpak off 454 is the same as 6.2.the flywheel is different but the clutchpak is the same part number.at least thy are on a 4 spd

The clutch disc used with the dual-mass diesel flywheel does not have any internal springs or dampers. The clutch disc used with the newer single-mass diesel flywheel incorporates a series of springs/dampers.

So.... you have to be sure what flywheel you have before ordering/installing a replacement clutch disc.

Quote:

are one and two peice rear mains the same as far as the flywheel

mark

The same flywheel/flexplate can be used on either rear main seal engine.

Jim
10-25-2012, 15:48
DieselPickUp

I have a 1990 Chevy K2500 with a 6.5 V8 Turbo Diesel in it. I was woundering what kind of motor(s) I could swap out and also what else I would have to swap for the gas motor. And could I keep the turbo for the gas.
10-25-2012, 19:44
Yukon6.2

Hi
Any GM truck engine will fit,250 6cly,283-400 small block,or 454 big block.
You will have to go to a carb and distributor.Unless you want to swap in the wiring harness from a gas truck of the same vintage.If you have an auto trans you will have to change the tourge converter.And no you can't keep the turbo from the diesel and use it on the gas.
You would be further ahead to replace the diesel engine.You say it's a 90?
If so someone has already replaced the engine,it would have come with a 6.2 mechanical injected,and no turbo.
Whats wrong with the engine? Lots of help here if you want to fix it.
Thomas
11-24-2012, 15:19
chvycmnslvr68

Quote:

Originally Posted by stuntdoublejoe

I now have the VRV/Vac Pump, so now my question is how do I change up the governor and shift points?

Hello there ... New on here ... Which trans are you going with .. If you use the TH350 you can get a variable modulator valve that you just make slight adjustments to until you get it shifting where you want it ... I am not sure with the TH400 .. but the 700R4 is the easiest of all.. you simply pull the pan ( you would want to install a new filter kit anyway ) and while you have it dwn you pull out the electric lockup actuator and put a 5/16 rubber ball bearing on it and place it back in .. this makes the 700 work completely automatic .... you then just have to have the shift valve control cable hooked up and set propely .. ( although there are different valves available for gas and diesels ) this cable not only controls the shift range but also controls the pressure applied to the clutch packs so it is vital that it is hooked up on a 700R4 ... I made this mistake once with my '66 chevelle and burned up my tranny ...
02-01-2013, 23:57
Balambo

Do you know of any low mile 4x4 donors. Prefur a 6.5

Thanks!
04-02-2014, 13:47
AdrenalineJunkie

Quote:

Originally Posted by More Power

[LIST=1][*]The GM 6.2L and 6.5L diesel engines share the very same bellhousing configuration and bolt pattern with all Chevy and GMC V-8 gasoline engines.[*]The GM 6.2L and 6.5L diesel engines share the very same motor mount configuration with all Chevy and GMC V-8 gasoline engines.

Correct me if I'm wrong, but 6.2s/6.5s don't share the very same bellhousing configuration as all GM/GMC v-8 gas engines. According to wiki's list of GM bellhousing bolt patterns anyhow http://en.wikipedia.org/wiki/List_of...using_patterns.

EX- The GM 5.3L LS4 V8 uses the GM metric bellhousing pattern.

I'm a newbie on here and am by no means an expert. Hope this is helpful.
04-02-2014, 14:45
DmaxMaverick

Quote:

Originally Posted by AdrenalineJunkie

Correct me if I'm wrong, but 6.2s/6.5s don't share the very same bellhousing configuration as all GM/GMC v-8 gas engines. According to wiki's list of GM bellhousing bolt patterns anyhow http://en.wikipedia.org/wiki/List_of...using_patterns.

EX- The GM 5.3L LS4 V8 uses the GM metric bellhousing pattern.

I'm a newbie on here and am by no means an expert. Hope this is helpful.

Referring to the 6.2/6.5 GM Diesel engines, they are the same as the gas V8 engines of the same light truck tooling series (GMT-xxx). Also note this does not include the BOP patterns. The (current) LS4 was not offered in a light truck, and was not in production at any time the 6.2/6.5 Diesel engines were an OEM option. It's a muscle car engine.
04-03-2014, 11:13
More Power

The transmission bolt pattern statement was 100% accurate at the time it was written about 15 years ago. If Chevy/GMC changed its bolt pattern for some newer engines, that would be good to know, and I appreciate your input.

For a little historical perspective: GM established the Chevy transmission bolt pattern we're talking about here with the introduction of the 1955 model year 265 C.I. smallblock gas V-8 used in its cars and light trucks. That bolt pattern was carried forward into GM's 1960-90s era 396/427/454 C.I. and 8.1L bigblock gas engines. That bolt pattern was carried forward into (as Greg mentioned) into all Chevy/GMC full size gas and diesel powered light trucks through the entirety of the 6.2L/6.5L production. And finally, that is the same bolt pattern currently in use by the Duramax 6600.

Jim
06-09-2014, 05:49
alabama mike

Quote:

Originally Posted by AdrenalineJunkie

Correct me if I'm wrong, but 6.2s/6.5s don't share the very same bellhousing configuration as all GM/GMC v-8 gas engines. According to wiki's list of GM bellhousing bolt patterns anyhow http://en.wikipedia.org/wiki/List_of...using_patterns.

EX- The GM 5.3L LS4 V8 uses the GM metric bellhousing pattern.

I'm a newbie on here and am by no means an expert. Hope this is helpful.

If you read the article closer you will see that the LS4 was adapted to put in a front wheel drive vehicle, Most front wheel drive GM's use the metric pattern. All the other v8's still retain the original Chevy bolt pattern.
06-14-2015, 00:08
Gradient

Quote:

Originally Posted by DmaxMaverick

Referring to the 6.2/6.5 GM Diesel engines, they are the same as the gas V8 engines of the same light truck tooling series (GMT-xxx). Also note this does not include the BOP patterns. The (current) LS4 was not offered in a light truck, and was not in production at any time the 6.2/6.5 Diesel engines were an OEM option. It's a muscle car engine.

The 5.3L is not a factory muscle car engine, it's the half ton PU and Tahoe platform engine. However, it is swapped into muscle cars because it can handle a lot of boost on the stock bottom end (iron block version). Same goes for LQ9 6.0L engine.
06-14-2015, 08:04
DmaxMaverick

Quote:

Originally Posted by Gradient

The 5.3L is not a factory muscle car engine, it's the half ton PU and Tahoe platform engine. However, it is swapped into muscle cars because it can handle a lot of boost on the stock bottom end (iron block version). Same goes for LQ9 6.0L engine.

Not all 5.3L GM gassers are equal. The LS4 was never a light truck engine, and shouldn't be confused with other historical "LS" series engines. They were OEM in late model "muscle cars" brands, such as Monte Carlo and Grand Prix (in transverse configuration), among others. The LM4 is the aluminum block light truck engine, the LM7 is cast iron. There are numerous "5.3L" engine option configurations from 1999 to present model years. There is no correlation between any of them, and late model 6.0/6.2L gasser engines. Different animals, with very different applications and control systems. The 6.0L LQ4/9 light truck engines are unique unto themselves, not to be confused with the "LS" (and other) series 6.0L's.
05-11-2023, 11:07
More Power

The following link contain a number of member vehicles that, some at least, are focused on 6.2L/6.5L diesel conversions. Some are from the early years of The Diesel Page, while others are somewhat newer. All are interesting. Have a look.
https://www.thedieselpage.com/readers/readers.htm