timing bouncing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Broken_down? · 11-19-2006, 06:07 PM

timing is boucing between 6 and 8. Could that be caused by a bad timing chain or distributor or much worse?

Livrat · 11-19-2006, 09:42 PM

The timing bouncing is usually caused by the timing chain having some slack.

Two degrees of variation is probably not much to worry about since the minute you start up a chevy even new the chain will stretch to a certain degree, But if the truck still has the original timing chain and gears you might think about changing it just in case, the factory set had an aluminum cam gear with plastic/nylon teeth and are prone to stripping off the teeth, It won't do any serious damage other than stop running and leave you stranded.

72 cheyenne pdx · 11-19-2006, 10:08 PM

How old is the gas in the truck? When I picked up my truck, I ran it home, it was missing and so I had a buddy of mine take a look. He said that the timing was jumping around and the distributor was fluctuating as well. by the time I got home and we messed around with it, I was almost on empty. I filled up the tank, and after about 15 minutes of running it while checking other things, the truck started running better. The distro wasn't fluctuating anymore and the timing wasn't jumping as well. My buddy and I have never seen that before, and not sure if that was a fluke incident or not, but that may be the problem.

Broken_down? · 11-19-2006, 11:53 PM

Well considering I have had the truck gas syphend out 3 or 4 times without me knowning I cannot say the gas is that old. I went and bought some fuel addative and will put in tomorrw when I fill her up. Also put some new plugs in so gonna see how that goes also. Is there any real major gain from running hei then points? If so I may just fork out the $ for it.

wibilly · 11-20-2006, 03:28 AM

hei is the way to go, and i would guess your problem is coming from a warn distributer shaft anyway, perfect time to upgrade to hei

Broken_down? · 11-20-2006, 03:34 AM

any recommendation on hei? I am not draggin my truck just looking for a stock engine upgrade.

*Billla* · 11-20-2006, 10:33 AM

Quote:

Originally Posted by Broken_down?

any recommendation on hei? I am not draggin my truck just looking for a stock engine upgrade.

One of the aftermarket replacements are a pretty good deal from Summit or JEG's. Step up from there if you want adjustable vac. advance, etc.

junkyardjohn · 11-20-2006, 10:44 AM

http://cgi.ebay.com/ebaymotors/CHEVY...-COIL-350-400-
I BOUGHT TWO OF THESE & THEY WERE NICE. BRAND NEW BILLET HEIs WITH CAP, ROTOR & COIL FOR THE PRICE OF A JUNKYARD UNIT. THIS GUY HAS ALMOST 8000 POSITIVE FEEDBACKS WITHOUT A SINGLE NEGATIVE. I'M SURE YOU CAN'T FIND A BETTER DEAL.

JOHN
URRRRRR... THE LINK DIDN'T WORK. HEREs THE AUCTION # Item number: 260041881956 . THEY ARE $45 OR $46. JOHN

Broken_down? · 11-21-2006, 12:52 AM

Now $45 is im my price range, thanks john!

Well the plugs help out hughly. The ping is almost gone. Going to fill up tonight and hope that will take the restof the ping away.

**VetteVet** · 11-21-2006, 01:20 AM

the ebay store is whiteperformance1, They are located in Kingsport Tennessee. If you go into ebay and type ( HEI ) in the search box it will take you to many sales of the HEI distributors.

http://http://stores.ebay.com/whiteperformance1

Huck · 11-21-2006, 09:24 AM

Just a thought--if your block has mega miles on it--it is possible that the chain/gear wear can be a real issue that a new HEI wouldn't fix. Had a 307 or 305 in a super nice 68 truck where the nylon gear teeth cover worn off and it eventually threw the timing chain. In my case, the valves and pistons crashed into each other causing significant valve, push rod, rocker arm, failure. I installed reconditioned heads and then the new higher compression began pushing oil past the rings~~ Wound up just selling off the truck which in retrospect was really dumb as the body was excellent~~~!!!!

11-19-2006, 09:42 PM	#2
Livrat Member #1049 Join Date: Jun 2000 Location: Troy Montana Posts: 3,940	Re: timing bouncing The timing bouncing is usually caused by the timing chain having some slack. Two degrees of variation is probably not much to worry about since the minute you start up a chevy even new the chain will stretch to a certain degree, But if the truck still has the original timing chain and gears you might think about changing it just in case, the factory set had an aluminum cam gear with plastic/nylon teeth and are prone to stripping off the teeth, It won't do any serious damage other than stop running and leave you stranded.

11-19-2006, 10:08 PM	#3
72 cheyenne pdx Registered User Join Date: Nov 2006 Location: Portland Posts: 382	Re: timing bouncing How old is the gas in the truck? When I picked up my truck, I ran it home, it was missing and so I had a buddy of mine take a look. He said that the timing was jumping around and the distributor was fluctuating as well. by the time I got home and we messed around with it, I was almost on empty. I filled up the tank, and after about 15 minutes of running it while checking other things, the truck started running better. The distro wasn't fluctuating anymore and the timing wasn't jumping as well. My buddy and I have never seen that before, and not sure if that was a fluke incident or not, but that may be the problem.

11-20-2006, 03:28 AM	#5
wibilly Senior Member Join Date: Nov 2005 Location: northwestern wi Posts: 2,111	Re: timing bouncing hei is the way to go, and i would guess your problem is coming from a warn distributer shaft anyway, perfect time to upgrade to hei __________________ common sense isn't so common anymore

11-20-2006, 10:44 AM	#8
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,427	Re: timing bouncing http://cgi.ebay.com/ebaymotors/CHEVY...-COIL-350-400- I BOUGHT TWO OF THESE & THEY WERE NICE. BRAND NEW BILLET HEIs WITH CAP, ROTOR & COIL FOR THE PRICE OF A JUNKYARD UNIT. THIS GUY HAS ALMOST 8000 POSITIVE FEEDBACKS WITHOUT A SINGLE NEGATIVE. I'M SURE YOU CAN'T FIND A BETTER DEAL. JOHN URRRRRR... THE LINK DIDN'T WORK. HEREs THE AUCTION # Item number: 260041881956 . THEY ARE $45 OR $46. JOHN __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST Last edited by junkyardjohn; 11-20-2006 at 10:51 AM.

11-21-2006, 01:20 AM	#10
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,709	Re: timing bouncing the ebay store is whiteperformance1, They are located in Kingsport Tennessee. If you go into ebay and type ( HEI ) in the search box it will take you to many sales of the HEI distributors. http://http://stores.ebay.com/whiteperformance1 __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

11-21-2006, 09:24 AM	#11
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,269	Re: timing bouncing Just a thought--if your block has mega miles on it--it is possible that the chain/gear wear can be a real issue that a new HEI wouldn't fix. Had a 307 or 305 in a super nice 68 truck where the nylon gear teeth cover worn off and it eventually threw the timing chain. In my case, the valves and pistons crashed into each other causing significant valve, push rod, rocker arm, failure. I installed reconditioned heads and then the new higher compression began pushing oil past the rings~~ Wound up just selling off the truck which in retrospect was really dumb as the body was excellent~~~!!!!



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