Timing Mark and Damper Location on 86 4.3L V6 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

86-C10-V6 · 06-09-2004, 07:29 PM

I had my engine replaced on my 86 C10 way back in 1992 with a GM long block (108K miles). Believe it or not, I have not set the timing on the Engine since it was replaced, it currently has 168K miles. I recently tried to check the timing and found I could not see the timing marks on the new engine, since it is located on the opposite side (passenger side vs drivers' side) of the motor than the original engine.
Question 1) Is the damper splined to the crankshaft in such a way that it can be moved a small amount, say 20 degrees by removing and re-installing.
Question 2) is it possible to relocate the timing mark if I remove and re-install the damper.
I am assuming that the timing indicator is adjustable and I can set it correctly by placing the engine at TDC before I try to make any changes. I am still trying to determine if the timing chain cover will allow me to move the timing indicator from passenger side to drivers' side.
No reponse on engine & drivetrain board, duplicated here.
Thanks for any input.

ChevyTech · 06-09-2004, 10:22 PM

The dampener (Harmonic balancer) is not adjustable. A woodruff key controls it's postion. Groove in the dampener - key slot in the crankshaft.

The outside ring has rubber between it and the inner hub, and can move. When this happens the timing mark is no longer accurate.

Make sure you have your timing light connected to plug wire #1.

The proper proceedure for setting your timing is on the emmission label.

86-C10-V6 · 06-10-2004, 09:23 AM

Thanks for the response.
I knew the balancer was splined somehow but I did not know if there was only one way to install it.
I am not sure why the newer block has the timing mark in a different location, there was only 2 years of production with the carb and the non-serpentine belts.
I was able to see the timing mark by looking straight down behind the water pump, but its difficult to see and I practically have to crawl on top of the engine to see it. The timing appears to be correct at idle, so I don't believe the balancer has slipped or is out of position.
I have a new distributor I would like to install. Since I have a dial back timing light, I may just create a new timing mark on the balancer on the side of the engine I can easily see. I am installing the new distributor with an adjustable vacuum advance, new wires and new plugs.

Thanks again for the response.

06-09-2004, 10:22 PM	#2
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	The dampener (Harmonic balancer) is not adjustable. A woodruff key controls it's postion. Groove in the dampener - key slot in the crankshaft. The outside ring has rubber between it and the inner hub, and can move. When this happens the timing mark is no longer accurate. Make sure you have your timing light connected to plug wire #1. The proper proceedure for setting your timing is on the emmission label. Last edited by ChevyTech; 06-09-2004 at 10:27 PM.

06-10-2004, 09:23 AM	#3
86-C10-V6 Shadetree Mechanic Join Date: Oct 2002 Location: Youngsville, NC Posts: 100	Thanks, this is what I wanted to know Thanks for the response. I knew the balancer was splined somehow but I did not know if there was only one way to install it. I am not sure why the newer block has the timing mark in a different location, there was only 2 years of production with the carb and the non-serpentine belts. I was able to see the timing mark by looking straight down behind the water pump, but its difficult to see and I practically have to crawl on top of the engine to see it. The timing appears to be correct at idle, so I don't believe the balancer has slipped or is out of position. I have a new distributor I would like to install. Since I have a dial back timing light, I may just create a new timing mark on the balancer on the side of the engine I can easily see. I am installing the new distributor with an adjustable vacuum advance, new wires and new plugs. Thanks again for the response. __________________ Dave M. (Hacksaw) 86 C10 Scottsdale LWB, 4.3L, Edelbrock 1904, K&N, 700R4, 3.08 Auburn Performance 89 GMC S-15 Extended Cab 4x4, 4.3L, FI 98 K1500 Xcab, 5.7L, 3.43 Gov-Lok

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06-09-2004, 07:29 PM	#1
86-C10-V6 Shadetree Mechanic Join Date: Oct 2002 Location: Youngsville, NC Posts: 100	Timing Mark and Damper Location on 86 4.3L V6 I had my engine replaced on my 86 C10 way back in 1992 with a GM long block (108K miles). Believe it or not, I have not set the timing on the Engine since it was replaced, it currently has 168K miles. I recently tried to check the timing and found I could not see the timing marks on the new engine, since it is located on the opposite side (passenger side vs drivers' side) of the motor than the original engine. Question 1) Is the damper splined to the crankshaft in such a way that it can be moved a small amount, say 20 degrees by removing and re-installing. Question 2) is it possible to relocate the timing mark if I remove and re-install the damper. I am assuming that the timing indicator is adjustable and I can set it correctly by placing the engine at TDC before I try to make any changes. I am still trying to determine if the timing chain cover will allow me to move the timing indicator from passenger side to drivers' side. No reponse on engine & drivetrain board, duplicated here. Thanks for any input. __________________ Dave M. (Hacksaw) 86 C10 Scottsdale LWB, 4.3L, Edelbrock 1904, K&N, 700R4, 3.08 Auburn Performance 89 GMC S-15 Extended Cab 4x4, 4.3L, FI 98 K1500 Xcab, 5.7L, 3.43 Gov-Lok



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