Converting diesel to gas. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Robert8096 · 03-18-2009, 11:28 AM

I have a chance to pickup a 84 6.2 diesel with a great body and a non running engine. What would be involved it changing it over to a 350 small block?

Thanks
Robert

**old Rusty C10** · 03-18-2009, 06:54 PM

anyone?

kelsfine69 · 03-18-2009, 07:21 PM

I dont know if the trannys match up. Might have to change it as well. Its been awhile since I looked into that.

pokethesmot · 03-18-2009, 07:24 PM

my truck use to be a diesle and is now a gasser...i know one thing for shure u dont need new gauges cuz mine still says diesel

**Captkaos** · 03-18-2009, 08:05 PM

Exhaust and clean fuel tanks/lines.
Tranny bolts up same. Some of the wiring won't be there, but it can be done....

willett · 03-18-2009, 09:04 PM

doesn't te harness have to be changed?

*Stitch* · 03-18-2009, 09:58 PM

the engine harness - yes...others - no...

Storm Chaser · 03-18-2009, 10:21 PM

Yes, the transmission will bolt up- it's the same pattern as a sbc. I'm pretty sure the motor mounts are the same too. So setting the gasser in should be cake.

The wiring- you don't necessarily have to change it unless you are just trying to clean it up. Both engines alternator and starter wires would be the same, as they perform the same functions. Oil pressure gauges read pressure- they don't care what kind of engine is producing the pressure. Same with the temperature gauge.

So that pretty much leaves power to the coil, which if you're using a standard HEI, it needs a 12v key-on source. The diesel harness provides keyed-on 12 volts at the injection pump, so there's your wire.

Blue85 · 03-18-2009, 10:36 PM

You will also have to reuse the diesel's power steering pump so the hydroboost will still work properly.

thirdstreettito · 03-19-2009, 12:29 AM

Why would you change it to gas?

72freak · 03-19-2009, 05:05 AM

A non running GM diesel........go figure! Look into the rear end also.....a lot of them have pretty low gearing. Engine harness YES. The guages will be fine.....Some folks say change the radiator also but we have done this swap a few times and never changed them.

72freak · 03-19-2009, 05:06 AM

Quote:

Originally Posted by thirdstreettito

Why would you change it to gas?

You made my morning!!!!

*Stitch* · 03-19-2009, 07:30 AM

the radiator is actually larger than a gas radiator...well mine is anyways...

Chuck.

pokethesmot · 03-19-2009, 07:37 AM

yeah don't change the radiator my engine stays extra cool cuz the stock diesel radiator

72freak · 03-19-2009, 08:04 AM

Quote:

Originally Posted by pokethesmot

yeah don't change the radiator my engine stays extra cool cuz the stock diesel radiator

It has always been my understanding that you did not mix used coolant or coolant system parts from a diesel with a gas burner, but as mentioned above.....I have done it with no adverse reaction that I could see.

Red_69 · 03-19-2009, 08:28 AM

The only thing not mentioned yet is different valving inside the trans between gas and diesel. It affects when the trans shifts and is specificaly tailored to one or the other as far as I know.

thirdstreettito · 03-19-2009, 09:31 PM

72Freak, what are you talking about? 6.2 diesels are the best GM diesels ever built. Also, what is so funny about my question? I dont see the logic in converting from a 6.2 diesel to a gasser. (No offense Robert8096)

Russell · 03-20-2009, 01:05 AM

I'm a major fan of the 6.2L diesels too! Mine is turbocharged and will take any 454 from the mid 80s on a very good run for it's money, whilst getting 20+ mpg doing it too!

That said, as mentioned above, making the swap is not particularly difficult. The 350 will bolt directly in place of the diesel. Fuel system will need a flush to clear the diesel out, govenor and torque converter on the trans both need to be changed for the gasoline versions. The wiring would be easiest done if you were to get a gasoline engine harness. It bolts right up to the firewall junction block without any modifications.

Robert8096 · 03-20-2009, 07:12 AM

I would keep it a diesel if the engine wasn't shot. I have a good 350/350 combo that I could put in it. I would like to use the transmission that is in it because it has a 4 speed automatic. I like the idea that it has the hydrobost braking system and that most of the accessories work. He says the AC works but that is hard to confirm because it does not run. The only problem with the body is someone took sheetmetal screws and used them to hold on the stick on trim.

72freak · 03-20-2009, 09:39 AM

Quote:

Originally Posted by thirdstreettito

72Freak, what are you talking about? 6.2 diesels are the best GM diesels ever built. Also, what is so funny about my question? I dont see the logic in converting from a 6.2 diesel to a gasser. (No offense Robert8096)

mmM

My years of experience with and opinion of(you know what they say about opinions) on the Duramax predecessors are well documented on this forum. Search key word "boat anchor". This thread will turn into yet another GM, Cummins, Powerstroke diesel thread and we reallly dont need any more of them cluttering up the forum.Agree to disagree?
I am a firm supporter of transplanting gas motors when the GM diesels start to give you problems....again.....OPINION based on past experiences only.

thirdstreettito · 03-20-2009, 02:14 PM

Quote:

Originally Posted by 72freak

mmM

My years of experience with and opinion of(you know what they say about opinions) on the Duramax predecessors are well documented on this forum. Search key word "boat anchor". This thread will turn into yet another GM, Cummins, Powerstroke diesel thread and we reallly dont need any more of them cluttering up the forum.Agree to disagree?
I am a firm supporter of transplanting gas motors when the GM diesels start to give you problems....again.....OPINION based on past experiences only.

You are thinking of the 5.7's totally different, they ARE boat anchors, the 6.2's ARE NOT. That being said, 6.2's are very easy to fix. I am not disputing what diesel is better. Just saying that 6.2's are good engines.

Robert8096 · 03-20-2009, 03:55 PM

Thanks for all the info. Please don't turn this into who's diesel engine is better or gas VS diesel.

Thanks
Robert

72freak · 03-20-2009, 06:15 PM

Quote:

Originally Posted by thirdstreettito

You are thinking of the 5.7's totally different, they ARE boat anchors, the 6.2's ARE NOT. .

My experiences I have based "MY OPINION" on have been with 6.2's AND 6.5's. I have owned and worked on my share of them over the past 25years. I finally sold my last one about 3 years ago. Again....there are a lot of people who have had GREAT luck with them and thats great...keep them burning up the streets!!! We all like different stuff and and have had good and bad experiences with the same stuff.....heck ..I ride a vintage British motorcycle so you know I dont mind constantly turning wrenches to keep something running.

Bottom line...if you want to convert to gas...follow the advice given above and convert to gas......If you want to stick with the original GM diesel do it. Do your research, take your time and enjoy it. Learn all you can about whatever you decide to do! Diesel mods, tweeking injector pumps, or a nice punched out 5.7 gas. Its all turning wrenches and having fun.

booger69 · 04-04-2009, 05:49 AM

i am doing this same swap the only thing im not sure is to go to a brake booster instead of the hydroboost set up would i have to change the stearing box or can i still use the stock one
thanks

03-18-2009, 11:28 AM	#1
Robert8096 Registered User Join Date: Nov 2007 Location: Goose Creek SC Posts: 161	Converting diesel to gas. I have a chance to pickup a 84 6.2 diesel with a great body and a non running engine. What would be involved it changing it over to a 350 small block? Thanks Robert

03-18-2009, 06:54 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,276	Re: Converting diesel to gas. anyone? __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

03-18-2009, 07:21 PM	#3
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: Converting diesel to gas. I dont know if the trannys match up. Might have to change it as well. Its been awhile since I looked into that. __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

03-18-2009, 07:24 PM	#4
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: Converting diesel to gas. my truck use to be a diesle and is now a gasser...i know one thing for shure u dont need new gauges cuz mine still says diesel __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-18-2009, 08:05 PM	#5
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: Converting diesel to gas. Exhaust and clean fuel tanks/lines. Tranny bolts up same. Some of the wiring won't be there, but it can be done.... __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

03-18-2009, 09:04 PM	#6
willett Another Day, Another Dollar Join Date: Nov 2008 Location: North Vancouver, BC Posts: 1,316	Re: Converting diesel to gas. doesn't te harness have to be changed? __________________ -78 K20 Cheyenne 454 long box, 4" lift, 35" MT's, '84 cab, '80 box "its hip to be square"

03-18-2009, 09:58 PM	#7
Stitch Account Suspended Join Date: Jul 2008 Location: Where I come from, it's cornbread and chicken... Posts: 3,122	Re: Converting diesel to gas. the engine harness - yes...others - no...

03-18-2009, 10:21 PM	#8
Storm Chaser Registered User Join Date: Oct 2006 Location: In the Indiana Corn Posts: 449	Re: Converting diesel to gas. Yes, the transmission will bolt up- it's the same pattern as a sbc. I'm pretty sure the motor mounts are the same too. So setting the gasser in should be cake. The wiring- you don't necessarily have to change it unless you are just trying to clean it up. Both engines alternator and starter wires would be the same, as they perform the same functions. Oil pressure gauges read pressure- they don't care what kind of engine is producing the pressure. Same with the temperature gauge. So that pretty much leaves power to the coil, which if you're using a standard HEI, it needs a 12v key-on source. The diesel harness provides keyed-on 12 volts at the injection pump, so there's your wire. __________________ 1988 R2500 Crew Cab Immediate plans- get it running! Future plans- Rear disc swap & Hydroboost Dually conversion with shackle flip-n-switch 4x4 conversion with 52" springs Maybe some new body panels Who needs a car when they make crew cab trucks?

03-18-2009, 10:36 PM	#9
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,171	Re: Converting diesel to gas. You will also have to reuse the diesel's power steering pump so the hydroboost will still work properly. __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

03-19-2009, 12:29 AM	#10
thirdstreettito Resident of Here Join Date: May 2008 Location: Wesley Chapel, FL, USA Posts: 7,716	Re: Converting diesel to gas. Why would you change it to gas? __________________ ~Bradley~ 2004 Black GTO LS2/T56 too much to list Miss having a truck

03-19-2009, 05:05 AM	#11
72freak Rottenwood Garage Member Join Date: May 2005 Location: Marietta, Georgia Posts: 4,321	Re: Converting diesel to gas. A non running GM diesel........go figure! Look into the rear end also.....a lot of them have pretty low gearing. Engine harness YES. The guages will be fine.....Some folks say change the radiator also but we have done this swap a few times and never changed them. __________________ 2004 Chevrolet Suburban C1500 2001 Chevrolet 2500HD Crew 6.0 1999 Harley Davidson Electra Glide 1972 Chevrolet C-20 Custom Camper "Dump Truck" 1972 Chevrolet C-20 Suburban "Big Green" 1969 Chevrolet C-50 Wedge Hauler "Leonidis" 1966 C-10 2x4 short fleet 327 4 speed "Race Truck" 1952 Plymouth Cranbrook "Rican" (my grandfathers) 1931 Ford Model A Coupe "Black Beauty" 1930 Ford Model A truck "Club Cab" 4x4 Rottenwood Garage and Speed Shop.....where everything must be racy! *It's not just a hobby..It's a LIFESTYLE!!!* Thanks for nothing Barrett-Jackson You cant fix stupid or teach accountability! Time wasters, looky Lous and tire kickers are everywhere!

03-19-2009, 07:30 AM	#13
Stitch Account Suspended Join Date: Jul 2008 Location: Where I come from, it's cornbread and chicken... Posts: 3,122	Re: Converting diesel to gas. the radiator is actually larger than a gas radiator...well mine is anyways... Chuck.

03-19-2009, 07:37 AM	#14
pokethesmot profeshinaly unimployed Join Date: Dec 2008 Location: hazlehurst, GA Posts: 1,232	Re: Converting diesel to gas. yeah don't change the radiator my engine stays extra cool cuz the stock diesel radiator __________________ my ride click here my myspace "having mud flaps is like asking for a smaller trophy"

03-19-2009, 08:28 AM	#16
Red_69 Registered User Join Date: Apr 2008 Location: IL Posts: 160	Re: Converting diesel to gas. The only thing not mentioned yet is different valving inside the trans between gas and diesel. It affects when the trans shifts and is specificaly tailored to one or the other as far as I know. __________________ 1986 Chevy 3/4 Ton 4X4

03-19-2009, 09:31 PM	#17
thirdstreettito Resident of Here Join Date: May 2008 Location: Wesley Chapel, FL, USA Posts: 7,716	Re: Converting diesel to gas. 72Freak, what are you talking about? 6.2 diesels are the best GM diesels ever built. Also, what is so funny about my question? I dont see the logic in converting from a 6.2 diesel to a gasser. (No offense Robert8096) __________________ ~Bradley~ 2004 Black GTO LS2/T56 too much to list Miss having a truck



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03-20-2009, 01:05 AM	#18
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: Converting diesel to gas. I'm a major fan of the 6.2L diesels too! Mine is turbocharged and will take any 454 from the mid 80s on a very good run for it's money, whilst getting 20+ mpg doing it too! That said, as mentioned above, making the swap is not particularly difficult. The 350 will bolt directly in place of the diesel. Fuel system will need a flush to clear the diesel out, govenor and torque converter on the trans both need to be changed for the gasoline versions. The wiring would be easiest done if you were to get a gasoline engine harness. It bolts right up to the firewall junction block without any modifications. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

03-20-2009, 07:12 AM	#19
Robert8096 Registered User Join Date: Nov 2007 Location: Goose Creek SC Posts: 161	Re: Converting diesel to gas. I would keep it a diesel if the engine wasn't shot. I have a good 350/350 combo that I could put in it. I would like to use the transmission that is in it because it has a 4 speed automatic. I like the idea that it has the hydrobost braking system and that most of the accessories work. He says the AC works but that is hard to confirm because it does not run. The only problem with the body is someone took sheetmetal screws and used them to hold on the stick on trim.

03-20-2009, 03:55 PM	#22
Robert8096 Registered User Join Date: Nov 2007 Location: Goose Creek SC Posts: 161	Re: Converting diesel to gas. Thanks for all the info. Please don't turn this into who's diesel engine is better or gas VS diesel. Thanks Robert

04-04-2009, 05:49 AM	#24
booger69 Registered User Join Date: Mar 2009 Location: pueblo CO Posts: 86	Re: Converting diesel to gas. i am doing this same swap the only thing im not sure is to go to a brake booster instead of the hydroboost set up would i have to change the stearing box or can i still use the stock one thanks

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