ignition timing 1980 gmc - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**1972BackInBlackC10** · 09-02-2012, 12:13 AM

hey im trying to get the timing set on my 1980 gmc but there isnt any markings on the balancer, the balaner is clean it isnt greasy and there is no arm/needle on the timing chain cover

anyone have any info or tips? is there a way i can set my timing without using a timing light?

86c20 · 09-02-2012, 08:11 AM

you can use a vaccum gauge and try for 18-20. also there may be a grove on the balancer that is the mark for it and then you need the arm and your good have 3 of them like that not the best i think but works

**Corts60** · 09-02-2012, 10:14 AM

I'm pretty sure 1980 is one those weird years where they put the timing tab behind the water pump. Hop up on your bumper and look straight down between the water pump and the block. there should be a weird barrel looking thing attached tithe timing cover. After that go over your balancer again, the line is probably just filled with grime, but it should be there.
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ProStreet83C10 · 09-02-2012, 02:20 PM

i agree with cort, mine is also behind the water pump

**1972BackInBlackC10** · 09-02-2012, 02:55 PM

really? lol that sucks, so im assuming if its there you have to stand and point yur timing light there?

Pampas56 · 09-02-2012, 07:23 PM

I think that the timing mark was moved to behind the water pump on engines equipped with the A.I.R. system pump. The late 70's Targetmaster that I just bought had the timing mark low on the driver's side of the motor, which would be completely hidden by the power steering pump.

IIRC the P/S pump used to sit low on the passenger side and the driver's side was open. When the air pump was added the P/S pump was moved to the other side so the timing mark needed to be relocated. Not a big deal to swap timing covers and vibration dampeners.

I would be curious if anyone knows what the tube to the right of the timing marks is for. Maybe some weird motor application that required 9 degrees ATDC?

**Corts60** · 09-02-2012, 11:46 PM

Quote:

Originally Posted by 1972BackInBlackC10

really? lol that sucks, so im assuming if its there you have to stand and point yur timing light there?

Winner, winner.

**1972BackInBlackC10** · 09-03-2012, 12:16 AM

Quote:

Originally Posted by Corts60

Winner, winner.

chicken dinner? lol now i just need to figure out what degree the timing needs to be set at

09-02-2012, 12:13 AM	#1
1972BackInBlackC10 Senior Member Join Date: Jan 2012 Location: Estevan, Saskatchewan Posts: 1,025	ignition timing 1980 gmc hey im trying to get the timing set on my 1980 gmc but there isnt any markings on the balancer, the balaner is clean it isnt greasy and there is no arm/needle on the timing chain cover anyone have any info or tips? is there a way i can set my timing without using a timing light?

09-02-2012, 08:11 AM	#2
86c20 Registered User Join Date: Mar 2012 Location: edgartown mass Posts: 852	Re: ignition timing 1980 gmc you can use a vaccum gauge and try for 18-20. also there may be a grove on the balancer that is the mark for it and then you need the arm and your good have 3 of them like that not the best i think but works __________________ 1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph 1985 k30 "the ice cream truck from hell" no rust az truck 197-8??? c30 "ramp truck" 454 1978 monte carlo 350 350th with 2.73 gears. no rust. sc car

09-02-2012, 10:14 AM	#3
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: ignition timing 1980 gmc I'm pretty sure 1980 is one those weird years where they put the timing tab behind the water pump. Hop up on your bumper and look straight down between the water pump and the block. there should be a weird barrel looking thing attached tithe timing cover. After that go over your balancer again, the line is probably just filled with grime, but it should be there. 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/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

09-02-2012, 02:20 PM	#4
ProStreet83C10 Drag Racer Join Date: Nov 2006 Location: Mason City, Iowa Posts: 1,276	Re: ignition timing 1980 gmc i agree with cort, mine is also behind the water pump __________________ Zach Hall 1983 Chevy C10 R/T: .194 60': 2.322 330: 6.379 1/8: 9.803 MPH: 71.37 1000: 12.781 1/4: 15.314 MPH: 88.79

09-02-2012, 02:55 PM	#5
1972BackInBlackC10 Senior Member Join Date: Jan 2012 Location: Estevan, Saskatchewan Posts: 1,025	Re: ignition timing 1980 gmc really? lol that sucks, so im assuming if its there you have to stand and point yur timing light there?

09-02-2012, 07:23 PM	#6
Pampas56 Registered User Join Date: Jul 2012 Location: Concrete, wa Posts: 75	Re: ignition timing 1980 gmc I think that the timing mark was moved to behind the water pump on engines equipped with the A.I.R. system pump. The late 70's Targetmaster that I just bought had the timing mark low on the driver's side of the motor, which would be completely hidden by the power steering pump. IIRC the P/S pump used to sit low on the passenger side and the driver's side was open. When the air pump was added the P/S pump was moved to the other side so the timing mark needed to be relocated. Not a big deal to swap timing covers and vibration dampeners. I would be curious if anyone knows what the tube to the right of the timing marks is for. Maybe some weird motor application that required 9 degrees ATDC?



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