How to replace the timing chain? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OregonC20 · 03-21-2009, 07:52 PM

I'm going to be replacing the timing chain in my 70 big block truck. Can someone tell me the step by step process of doing this? how long should I expect for this project
to take if you know what you are doing? and what else should I replace while in there?

Thank you guys!

cdowns · 03-21-2009, 08:50 PM

STEP 1 //buy service manual

STEP 2 read same

OregonC20 · 03-21-2009, 09:08 PM

STEP 3 // don't count on cdowns

stockish shawn · 03-21-2009, 10:35 PM

I would recomend buying a book but heres a step by step
find top dead center
remove the water pump
remove the harmonic balancer ( puller required )
remove the timing cover
find the timing marks on cam and main sprocket
LINE THEM UP TO MEET IN THE MIDDLE ( CLOSEST TOGETHER )
CHECK TIMING MARKS
remove the cam sprocket by taking the three bolts off
remove the crank sprocket
install new crank sprocket
put the chain on both sprockets
roll the cam sprocket onto the cam ( dowel in slot between 2 holes)
tighten 3 bolts using blue lock tite
check timing marks
CHECK TIMING MARKS
clean gasget surfaces
reinstall in reverse order

spinning wheels · 03-21-2009, 10:49 PM

Get a good engine gasket kit.
Get yourself a good roller timing set or gear drive.
You might have to heat up the crank sprocket to help slide it on the crank. Some people heat it up with the use a butane torch, I used the boiling pan with water, so I only got it to 120 degrees.
I had to, ahem..... use some BFH help. I used a plumbing pipe about the same diameter of the sprocket to tap it in. Watch the sprocket teeth, they chip off easy..... don't ask how I know this

just trust me on that.

Since you are doing this on your truck. Just take your time and do it with love

Just remember all the $$$$ you are saving, compared to paying a shop to do the work. That always helps, when things don't come together as smoothly as one had hoped.

stockish shawn · 03-22-2009, 12:05 AM

the wifes new frying pan with some 30 wieght oil and a torch work well for heating the sprocket, warm until the sprocket barely turn colors and grab with a some channel locks and slide it on in a hurry. make sure the timing marks face out. have fun

spinning wheels · 03-22-2009, 12:14 AM

Quote:

Originally Posted by stockish shawn

the wifes new frying pan with some 30 wieght oil and a torch work well for heating the sprocket, warm until the sprocket barely turn colors and grab with a some channel locks and slide it on in a hurry. make sure the timing marks face out. have fun its not a day in the shop unless you throw a tool

I never tried that way. You learn something new everyday.

Just wondering, could you substitute the 30wt engine oil, with extra virgin olive oil?

**El Jay** · 03-22-2009, 12:17 AM

And, as a side note, I'd replace the water pump since the old one is already sitting on the floor.

stockish shawn · 03-22-2009, 12:21 AM

good call on the water pump. and throw some mushrooms in with the sprocket to not waste the olive oil. but it would make disposal of the oil easier

03-21-2009, 07:52 PM	#1
OregonC20 Registered User Join Date: Oct 2006 Location: Salem, Oregon Posts: 250	How to replace the timing chain? I'm going to be replacing the timing chain in my 70 big block truck. Can someone tell me the step by step process of doing this? how long should I expect for this project to take if you know what you are doing? and what else should I replace while in there? Thank you guys!

03-21-2009, 08:50 PM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: How to replace the timing chain? STEP 1 //buy service manual STEP 2 read same __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-21-2009, 09:08 PM	#3
OregonC20 Registered User Join Date: Oct 2006 Location: Salem, Oregon Posts: 250	Re: How to replace the timing chain? STEP 3 // don't count on cdowns

03-21-2009, 10:35 PM	#4
stockish shawn Registered User Join Date: Mar 2009 Location: paso robles ca. Posts: 20	Re: How to replace the timing chain? I would recomend buying a book but heres a step by step find top dead center remove the water pump remove the harmonic balancer ( puller required ) remove the timing cover find the timing marks on cam and main sprocket LINE THEM UP TO MEET IN THE MIDDLE ( CLOSEST TOGETHER ) CHECK TIMING MARKS remove the cam sprocket by taking the three bolts off remove the crank sprocket install new crank sprocket put the chain on both sprockets roll the cam sprocket onto the cam ( dowel in slot between 2 holes) tighten 3 bolts using blue lock tite check timing marks CHECK TIMING MARKS clean gasget surfaces reinstall in reverse order

03-21-2009, 10:49 PM	#5
spinning wheels Registered User Join Date: Sep 2001 Location: Hacienda Heights, California USA Posts: 474	Re: How to replace the timing chain? Get a good engine gasket kit. Get yourself a good roller timing set or gear drive. You might have to heat up the crank sprocket to help slide it on the crank. Some people heat it up with the use a butane torch, I used the boiling pan with water, so I only got it to 120 degrees. I had to, ahem..... use some BFH help. I used a plumbing pipe about the same diameter of the sprocket to tap it in. Watch the sprocket teeth, they chip off easy..... don't ask how I know this just trust me on that. Since you are doing this on your truck. Just take your time and do it with love Just remember all the $$$$ you are saving, compared to paying a shop to do the work. That always helps, when things don't come together as smoothly as one had hoped. __________________ '72 GMC custom camper 350/350

03-22-2009, 12:05 AM	#6
stockish shawn Registered User Join Date: Mar 2009 Location: paso robles ca. Posts: 20	Re: How to replace the timing chain? the wifes new frying pan with some 30 wieght oil and a torch work well for heating the sprocket, warm until the sprocket barely turn colors and grab with a some channel locks and slide it on in a hurry. make sure the timing marks face out. have fun Last edited by stockish shawn; 03-22-2009 at 12:18 AM.

03-22-2009, 12:17 AM	#8
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: How to replace the timing chain? And, as a side note, I'd replace the water pump since the old one is already sitting on the floor. __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck

03-22-2009, 12:21 AM	#9
stockish shawn Registered User Join Date: Mar 2009 Location: paso robles ca. Posts: 20	Re: How to replace the timing chain? good call on the water pump. and throw some mushrooms in with the sprocket to not waste the olive oil. but it would make disposal of the oil easier



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