Timing Marks and Timing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

edszuk · 03-30-2010, 09:57 PM

After fighting the carb rebuild I finally got the truck to idle and run a bit better. I hooked up a timing light to set the timing but could not find any timing marks on the crank pulley. I brought No. 1 to TDC and checked the pulley again, but nothing. Am I missing something.

Ed

**DPowers** · 03-30-2010, 10:10 PM

No groove line on the pulley?
Do you have a timing tab on the timing gear cover?

JRBECK64 · 03-30-2010, 10:25 PM

The groove is actually on the Harmonic Balancer and the marks should be on a tab that is on the timing gear cover. If you have a lot of paint build up or grease on the Harmonic Balancer you might not be able to see the grove on the Balancer.

edszuk · 03-30-2010, 10:36 PM

Quote:

Originally Posted by JRBECK64

The groove is actually on the Harmonic Balancer and the marks should be on a tab that is on the timing gear cover. If you have a lot of paint build up or grease on the Harmonic Balancer you might not be able to see the grove on the Balancer.

I'll look again tomorrow. I do have the timing tab on the timing cover. Anybody have pics of what it looks like.

**DPowers** · 03-30-2010, 10:59 PM

283

Sick5 · 03-30-2010, 11:08 PM

ive hand an engine with the tab on the side
but ran with the mark on 12oclock
ive seen some engine have tab on 12oclock
right behind the water pump

austex66 · 03-30-2010, 11:16 PM

PHP Code:


			
ive hand an engine with the tab on the side 

but ran with the mark on 12oclock

ive seen some engine have tab on 12oclock

right behind the water pump

Thats the problem I have....

Sick5 · 03-30-2010, 11:21 PM

Quote:

Originally Posted by austex66

PHP Code:


			
ive hand an engine with the tab on the side 

but ran with the mark on 12oclock

ive seen some engine have tab on 12oclock

right behind the water pump

Thats the problem I have....

i hated that lmao
cause the engine ran really good
like that
could never get timed right i just gave it to my brother and he just timed it by ear
RUNS GREAT still to this day
if i wanted to really fix that first i would try to get engine numbers find out what yrs it is and what it came out of ! get more info on the engine

edszuk · 03-31-2010, 12:04 AM

Quote:

Originally Posted by Sick5

i hated that lmao
cause the engine ran really good
like that
could never get timed right i just gave it to my brother and he just timed it by ear
RUNS GREAT still to this day
if i wanted to really fix that first i would try to get engine numbers find out what yrs it is and what it came out of ! get more info on the engine

Where are the engine numbers? I found some number on the passenger side in the middle of the engine below the side covers. It was 348675 and had GM stamped over it.

Sick5 · 03-31-2010, 12:18 AM

Quote:

Originally Posted by edszuk

Where are the engine numbers? I found some number on the passenger side in the middle of the engine below the side covers. It was 348675 and had GM stamped over it.

in the front right under the heads or in the back driver side might need to get a flash light for that one

markeb01 · 03-31-2010, 01:28 AM

To locate the timing groove in the balancer, just slide under the truck with the engine off and look around the entire balancer, even if you have to bump the engine over. Once it is located, if everything is orange, a black sharpie will highlight the line. If everything is black or cruddy, a white, yellow, or silver crayon can help find the groove when using the timing light. If you still can't find the groove on the balancer with the timing light, it's likely be the distributor is installed 180 degrees out.

It's also possible to have a mismatch of parts on an engine with an unknown history. The factory spot welded timing tabs are not always in the same position on the cover. Depending on what was correct for that engine, the aftermarket bolt-on tabs may or may not accurately identify the correct setting. If this turns out to be the case, timing by ear is closer to accurate than using a light with incompatible parts. If there's any doubt the best solution would be to pull the plugs, find top dead center, and add a timing tape to the balancer in the correct relationship to the timing tab on the cover.

Sillyoldman · 03-31-2010, 01:57 AM

Quote:

Originally Posted by DPowers

283

Non threaded crank snout?

**DPowers** · 03-31-2010, 09:27 AM

Quote:

Originally Posted by Sillyoldman

Non threaded crank snout?

Yes- not really too concerned about it, it was put back together pretty much stock and not planning on running down the track.

steveb64 · 03-31-2010, 12:39 PM

Your harmonic balancer may have spun on it's rubber core. This happened to mine. When I had #1 at TDC, the mark was about 90 degrees away. At the time, I had no idea that the outer ring of the HB with the timing mark could actually spin on it's hub due to the rubber going bad with age and either cracking or letting loose where it connects to the hub/outer balancer.

edszuk · 03-31-2010, 01:57 PM

Quote:

Originally Posted by steveb64

Your harmonic balancer may have spun on it's rubber core. This happened to mine. When I had #1 at TDC, the mark was about 90 degrees away. At the time, I had no idea that the outer ring of the HB with the timing mark could actually spin on it's hub due to the rubber going bad with age and either cracking or letting loose where it connects to the hub/outer balancer.

Did your engine run? My engine runs, but pops out the exhaust. One of my problems is the carb. The engine will idle high then even out and idle for about 2 minutes then die. I turn the key and it will start without having to give it gas.

edszuk · 03-31-2010, 01:59 PM

Quote:

Originally Posted by edszuk

Where are the engine numbers? I found some number on the passenger side in the middle of the engine below the side covers. It was 348675 and had GM stamped over it.

I looked up the casting today and it shows to be a 250 engine between 73-79.

Sick5 · 03-31-2010, 09:27 PM

Quote:

Originally Posted by edszuk

I looked up the casting today and it shows to be a 250 engine between 73-79.

good you found them

steveb64 · 03-31-2010, 11:16 PM

Mine did run once I ignored the timing mark and just found TDC and set the distributor to #1. I would not run using the timing mark, it was spun way too far from real TDC. I ended up replacing my HB with a rebuilt one from Damper Doctor.

Sillyoldman · 03-31-2010, 11:32 PM

Quote:

Originally Posted by DPowers

Yes- not really too concerned about it, it was put back together pretty much stock and not planning on running down the track.

Mine (327) too. Id be a little more at ease about it if the snout was flush with the end of the balancer. Oh well no need to re invent the wheel.

tapeworm · 03-31-2010, 11:40 PM

Quote:

Originally Posted by Sick5

could never get timed right i just gave it to my brother and he just timed it by ear
RUNS GREAT still to this day

and hence the reason why I don't use a light.

Its one thing if you are tuning high $$ race motor, high comperssion, or looking for hp numbers on the dyno

but if you want to get that old, simple, low $$, just drive it around trusty SBC running good, forget the light.

And yes, I will know I will get a little flack for saying it

edszuk · 04-01-2010, 12:40 AM

That's normally how I time my VW bug.

63 & 64 Bowties · 04-01-2010, 07:41 AM

Quote:

Originally Posted by edszuk

That's normally how I time my VW bug.

Don't mean to hijack the thread, but older VW's are supposed to be timed with a trouble light (not a timing light) with the engine not running. I was a mechanic at a VW dealership in the late 60's (yup, I'm an old fart)

edszuk · 04-01-2010, 08:33 AM

That is right. I think in the manual it is referred as static timing. This will get you started at TDC.

Ed

fleetsidelarry · 04-01-2010, 09:08 AM

edszuk, does your damper look like the V-8 one pictured above or is the pulley made right on the damper? reason I ask is that the manual for our trucks shows the 6 cyl timing mark to be just a small v-notch on the rim of the pulley. But your engine is 10 years newer so might be different.

My first thought, as mentioned earlier by steveb64, was that the damper has spun, which happens, especially if the engine ever backfired hard.

As you know, fuel and electrical issues can often mimic each other and you can't easily chase down both at the same time. To me it sounds like a carb problem but until the timing thing is resolved you won't know for sure.

If you have the type with the notch in the pulley, I can copy the picture from the manual and post it, just for your reference.

**DPowers** · 04-01-2010, 09:26 AM

Quote:

Originally Posted by Sillyoldman

Mine (327) too. Id be a little more at ease about it if the snout was flush with the end of the balancer. Oh well no need to re invent the wheel.

I know what you mean, but as far as I know they weren't flush from the factory.

03-30-2010, 10:10 PM	#2
DPowers One foot in front of the other Join Date: Aug 2008 Location: Parrottsville, TN Posts: 5,443	Re: Timing Marks and Timing No groove line on the pulley? Do you have a timing tab on the timing gear cover? __________________ DP's 66 Build http://67-72chevytrucks.com/vboard/s...d.php?t=361556

03-30-2010, 10:25 PM	#3
JRBECK64 Registered User Join Date: Sep 2008 Location: Cornelius Oregon Posts: 1,073	Re: Timing Marks and Timing The groove is actually on the Harmonic Balancer and the marks should be on a tab that is on the timing gear cover. If you have a lot of paint build up or grease on the Harmonic Balancer you might not be able to see the grove on the Balancer.

03-30-2010, 10:59 PM	#5
DPowers One foot in front of the other Join Date: Aug 2008 Location: Parrottsville, TN Posts: 5,443	Re: Timing Marks and Timing 283 Attached Images __________________ DP's 66 Build http://67-72chevytrucks.com/vboard/s...d.php?t=361556

03-30-2010, 11:08 PM	#6
Sick5 C10 CLUB Y QUE! Join Date: Mar 2010 Location: Here Posts: 2,770	Re: Timing Marks and Timing ive hand an engine with the tab on the side but ran with the mark on 12oclock ive seen some engine have tab on 12oclock right behind the water pump __________________ C/10 CLUB http://67-72chevytrucks.com/vboard/f...play.php?f=148

03-30-2010, 11:16 PM	#7
austex66 Registered User Join Date: Feb 2009 Location: Austin, TX Posts: 78	Re: Timing Marks and Timing PHP Code: `ive hand an engine with the tab on the side but ran with the mark on 12oclock ive seen some engine have tab on 12oclock right behind the water pump` Thats the problem I have.... __________________ 66' Chevy SWB:350ci-th350,frt. disc brakes, pwr steering, 5-lug waltshow.com/Chevy

03-30-2010, 09:57 PM	#1
edszuk Registered User Join Date: Mar 2010 Location: Vandenberg, CA Posts: 80	Timing Marks and Timing After fighting the carb rebuild I finally got the truck to idle and run a bit better. I hooked up a timing light to set the timing but could not find any timing marks on the crank pulley. I brought No. 1 to TDC and checked the pulley again, but nothing. Am I missing something. Ed

03-31-2010, 01:28 AM	#11
markeb01 Senior Enthusiast Join Date: Feb 2007 Location: Spokane Valley, WA Posts: 8,356	Re: Timing Marks and Timing To locate the timing groove in the balancer, just slide under the truck with the engine off and look around the entire balancer, even if you have to bump the engine over. Once it is located, if everything is orange, a black sharpie will highlight the line. If everything is black or cruddy, a white, yellow, or silver crayon can help find the groove when using the timing light. If you still can't find the groove on the balancer with the timing light, it's likely be the distributor is installed 180 degrees out. It's also possible to have a mismatch of parts on an engine with an unknown history. The factory spot welded timing tabs are not always in the same position on the cover. Depending on what was correct for that engine, the aftermarket bolt-on tabs may or may not accurately identify the correct setting. If this turns out to be the case, timing by ear is closer to accurate than using a light with incompatible parts. If there's any doubt the best solution would be to pull the plugs, find top dead center, and add a timing tape to the balancer in the correct relationship to the timing tab on the cover. __________________ My Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=444502

03-31-2010, 12:39 PM	#14
steveb64 Registered User Join Date: Oct 2009 Location: Moline, IL Posts: 157	Re: Timing Marks and Timing Your harmonic balancer may have spun on it's rubber core. This happened to mine. When I had #1 at TDC, the mark was about 90 degrees away. At the time, I had no idea that the outer ring of the HB with the timing mark could actually spin on it's hub due to the rubber going bad with age and either cracking or letting loose where it connects to the hub/outer balancer.

03-31-2010, 11:16 PM	#18
steveb64 Registered User Join Date: Oct 2009 Location: Moline, IL Posts: 157	Re: Timing Marks and Timing Mine did run once I ignored the timing mark and just found TDC and set the distributor to #1. I would not run using the timing mark, it was spun way too far from real TDC. I ended up replacing my HB with a rebuilt one from Damper Doctor.

04-01-2010, 12:40 AM	#21
edszuk Registered User Join Date: Mar 2010 Location: Vandenberg, CA Posts: 80	Re: Timing Marks and Timing That's normally how I time my VW bug.

04-01-2010, 08:33 AM	#23
edszuk Registered User Join Date: Mar 2010 Location: Vandenberg, CA Posts: 80	Re: Timing Marks and Timing That is right. I think in the manual it is referred as static timing. This will get you started at TDC. Ed

04-01-2010, 09:08 AM	#24
fleetsidelarry Senior Car Nut Join Date: Jan 2008 Location: shellman bluff, GA Posts: 1,411	Re: Timing Marks and Timing edszuk, does your damper look like the V-8 one pictured above or is the pulley made right on the damper? reason I ask is that the manual for our trucks shows the 6 cyl timing mark to be just a small v-notch on the rim of the pulley. But your engine is 10 years newer so might be different. My first thought, as mentioned earlier by steveb64, was that the damper has spun, which happens, especially if the engine ever backfired hard. As you know, fuel and electrical issues can often mimic each other and you can't easily chase down both at the same time. To me it sounds like a carb problem but until the timing thing is resolved you won't know for sure. If you have the type with the notch in the pulley, I can copy the picture from the manual and post it, just for your reference. __________________ Larry



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