Diesel to gas - The 1947 - Present Chevrolet & GMC Truck Message Board Network

KrazyRay · 01-09-2013, 11:37 AM

I have an 83 stepside 4wd that used to have a diesel engine in it. I would like to put a small block 350 back in. Do I need to change the dash and engine bay wiring harnesses to run the gas engine and gauges from a gas engine donor truck?
Thanks,
Ray

Redcap · 01-09-2013, 12:14 PM

Quote:

Originally Posted by KrazyRay

I have an 83 stepside 4wd that used to have a diesel engine in it. I would like to put a small block 350 back in. Do I need to change the dash and engine bay wiring harnesses to run the gas engine and gauges from a gas engine donor truck?
Thanks,
Ray

Is your truck currently 24V?

Why would you need to change the gas gauge?

KrazyRay · 01-09-2013, 12:21 PM

My truck is 12v and the current gauge cluster has diesel on it. I will need to power up the HEI instead of the glow plugs, injectors, etc.

manimal · 01-09-2013, 12:44 PM

Its my understanding that the power wire for the injector pump is what you will use to power the HEI as for the gauges, just use the sensors for the 350,fuel gauge will work also, just dont put diesel in it anymore

. Check out The Diesel Place for more info on the glow plug relay wiring.

**Corts60** · 01-09-2013, 04:14 PM

You should be able to unplug the glow plug harness from the main wiring harness and that'll clean up some of the wiring. Make sure to remove the glow plug controller, otherwise you may still get WAIT and GLOW lights coming on.
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**hatzie** · 01-09-2013, 07:36 PM

All of the 73-91 Squarebody the wiring diagrams are in my sig.

The fuel cutoff wire will power the HEI.

The gauges are the same with the exception of a possible "Diesel Fuel Only" warning. You'll have a couple diesel warning lights in the dash that won't do anything but they aren't hurting anything either.

If you have an automatic... You'll need a gasoline tranny. Sell the diesel tranny with the diesel torque convertor if you have them. Manual? get a flywheel and clutch and bolt that baby on.

Stock 82 & 83 diesel tank senders have a water siphon outlet with a line attached to a valve in the forward rear spring hanger. You'll need to properly deal with that.

manimal · 01-09-2013, 10:57 PM

I thought the trans would only require a change in the Governor and Converter?

**hatzie** · 01-10-2013, 12:19 AM

Quote:

Originally Posted by manimal

I thought the trans would only require a change in the Governor and Converter?

I thought there were tuning differences in the valve body springs etc.

f.monroe · 01-10-2013, 12:28 AM

Quote:

Originally Posted by manimal

I thought the trans would only require a change in the Governor and Converter?

If it has the original trans then it will not bolt up to a small Chevy. The diesels were Oldsmobile based and that pattern is different. GM made some transmissions with the BOP (Buick ,Oldsmobile ,Pontiac). They sell adapters to bolt a small Chevy to one buti think you would better off changing the trans.
Frank
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**Corts60** · 01-10-2013, 12:38 AM

Only the olds diesels have a BOP bellhousing. 1981 was the last year for the olds. 6.2 and 6.5 share the same chevy bellhousing.

f.monroe · 01-10-2013, 12:42 AM

Quote:

Originally Posted by Corts60

Only the olds diesels have a BOP bellhousing. 1981 was the last year for the olds. 6.2 and 6.5 share the same chevy bellhousing.

So Old dogs can learn new tricks. I didn't think they were different .
Thanks,
Frank
Posted via Mobile Device

manimal · 01-10-2013, 01:16 AM

Quote:

Originally Posted by f.monroe

If it has the original trans then it will not bolt up to a small Chevy. The diesels were Oldsmobile based and that pattern is different. GM made some transmissions with the BOP (Buick ,Oldsmobile ,Pontiac). They sell adapters to bolt a small Chevy to one buti think you would better off changing the trans.
Frank
Posted via Mobile Device

Are we talking about the OLDs 350 diesel or the 6.2 Detroit? If it's the detroit, it's the same as any other SBC/BBC. And I thought the OLDs 350 was only issued in 78/79?(I might be wrong on that though)

KrazyRay · 01-10-2013, 01:55 AM

Thanks for all of the input. It looks like I will be able to use the original harness, but I will change the cluster since I have one in stock. BTW its a 4 speed sm465 so no worries on the trans.

01-09-2013, 11:37 AM	#1
KrazyRay Registered User Join Date: Jun 2009 Location: Oroville, CA Posts: 4,827	Diesel to gas I have an 83 stepside 4wd that used to have a diesel engine in it. I would like to put a small block 350 back in. Do I need to change the dash and engine bay wiring harnesses to run the gas engine and gauges from a gas engine donor truck? Thanks, Ray

01-09-2013, 12:21 PM	#3
KrazyRay Registered User Join Date: Jun 2009 Location: Oroville, CA Posts: 4,827	Re: Diesel to gas My truck is 12v and the current gauge cluster has diesel on it. I will need to power up the HEI instead of the glow plugs, injectors, etc.

01-09-2013, 12:44 PM	#4
manimal Registered User Join Date: Oct 2006 Location: Southern Kalifornia Posts: 3,066	Re: Diesel to gas Its my understanding that the power wire for the injector pump is what you will use to power the HEI as for the gauges, just use the sensors for the 350,fuel gauge will work also, just dont put diesel in it anymore. Check out The Diesel Place for more info on the glow plug relay wiring. __________________ ------------------------------------------------------ -Lance 2000 Chevy C2500, 5.7, 4L80e 1999 Suburban K2500, 7.4, 4L80e 1980 Camaro..son's car...PROJECT

01-09-2013, 04:14 PM	#5
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,689	Re: Diesel to gas You should be able to unplug the glow plug harness from the main wiring harness and that'll clean up some of the wiring. Make sure to remove the glow plug controller, otherwise you may still get WAIT and GLOW lights coming on. Posted via Mobile Device __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(winter unit)https://67-72chevytrucks.com/vboard/...25#post8900725

01-09-2013, 07:36 PM	#6
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,930	Re: Diesel to gas All of the 73-91 Squarebody the wiring diagrams are in my sig. The fuel cutoff wire will power the HEI. The gauges are the same with the exception of a possible "Diesel Fuel Only" warning. You'll have a couple diesel warning lights in the dash that won't do anything but they aren't hurting anything either. If you have an automatic... You'll need a gasoline tranny. Sell the diesel tranny with the diesel torque convertor if you have them. Manual? get a flywheel and clutch and bolt that baby on. Stock 82 & 83 diesel tank senders have a water siphon outlet with a line attached to a valve in the forward rear spring hanger. You'll need to properly deal with that. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

01-09-2013, 10:57 PM	#7
manimal Registered User Join Date: Oct 2006 Location: Southern Kalifornia Posts: 3,066	Re: Diesel to gas I thought the trans would only require a change in the Governor and Converter? __________________ ------------------------------------------------------ -Lance 2000 Chevy C2500, 5.7, 4L80e 1999 Suburban K2500, 7.4, 4L80e 1980 Camaro..son's car...PROJECT

01-10-2013, 12:38 AM	#10
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,689	Re: Diesel to gas Only the olds diesels have a BOP bellhousing. 1981 was the last year for the olds. 6.2 and 6.5 share the same chevy bellhousing. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(winter unit)https://67-72chevytrucks.com/vboard/...25#post8900725

01-10-2013, 01:55 AM	#13
KrazyRay Registered User Join Date: Jun 2009 Location: Oroville, CA Posts: 4,827	Re: Diesel to gas Thanks for all of the input. It looks like I will be able to use the original harness, but I will change the cluster since I have one in stock. BTW its a 4 speed sm465 so no worries on the trans.



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