Jumped timing ? - Team Camaro Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Display Modes
post #1 of 15 (permalink) Old Sep 25th, 04, 10:11 PM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

My friend has an 84 camaro with a 2.8 litre V6, he was out driving around and the car developed a knock, so he brought it over and hooked up the timing light. With the vacume advance unhooked the knock got better but still there, The timing is off by about 1/3 of the balacer(quite a bit) turning the distributor makes the car run worse and backfires through the carb. Could the timing chain have jumped a tooth or two. On this 2.8 litre is the firing order 123456, and which is number 1(front passenger side?) thats the one I thought was #1 so thats where I hooked the timing light to. Hope I was right.
If It jumped a tooth or two what are the options to get it running properly again.

Thanks
Dino
CanCamaro is offline  
Sponsored Links
Advertisement
 
post #2 of 15 (permalink) Old Sep 26th, 04, 04:16 AM
Senior Tech
Steven
 
Join Date: Jan 2001
Location: Raleigh, NC
Posts: 1,046
Post

If he has a knock, such as coming from rods, the first thing I would do is check the oil level and oil pressure. If by knock, you are actually refeering to pinging or detonation, then look at the timinig. The firing order is 123456 ... #1 is right front ... Try to set the timing to wherever it runs best, then proceed from there. If timing chain or gears are damaged, you need to go ahead and replace them.
sdtsdt is offline  
post #3 of 15 (permalink) Old Sep 26th, 04, 06:28 AM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

By right front do you mean sitting in the car or standing in front of the car. If I hook the timing light to #2 sparkplug wire(drivers front) the timing is a lot closer, whats that all about. Is that because the timing has jumped. The car belongs to a 16 year old and I would like to help him as much as possible.

67 camaro 462 BB 9.6 CR Compcams 314HR 252 @ 50 612 lift, Port+Polish Oval port 2.19 1.88, Edelbrock RPM intake, 850 Holley DP, 3" exhaust, turbo 400 TCI 4000 stall, Dana 60 4.10 posi, 315/60/15 BFG M/T drag Radials, 3650lbs. w/driver. [email protected]
CanCamaro is offline  
 
post #4 of 15 (permalink) Old Sep 26th, 04, 06:56 AM
a67
 
Join Date: May 2003
Posts: 416
Post

Right front as sitting in the car (passenger side). It is common on these engines for the damper ring to come loose. This throws the apparent timing all a-kilter.

The timing chains on these engines don't last long either.

To check the timing chain remove the distributor cap, while observing the rotor turn the crank backwards until the rotor moves.

Mark the damper.

Now rotate the crank forward until the rotor moves and mark the damper. Check the distance between the marks. That will be the amount of timing chain slack. Shouldn't be more then a few degrees.

Bob.
a67 is offline  
post #5 of 15 (permalink) Old Sep 26th, 04, 08:06 AM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

If it was the dampener that moved could that affect the way the motor ran and the knocking that all of a sudden started.
When I hook the timing light to #2 cyl. the timing is close, is this another indication that the chain has jumped.
Is changing the timing chain on one of these cars as simple as tearing off the front of the engine and pulling off the chain and gears and lining up the dots on the new one?

Thanks for all the great replys
Dino

67 camaro 462 BB 9.6 CR Compcams 314HR 252 @ 50 612 lift, Port+Polish Oval port 2.19 1.88, Edelbrock RPM intake, 850 Holley DP, 3" exhaust, turbo 400 TCI 4000 stall, Dana 60 4.10 posi, 315/60/15 BFG M/T drag Radials, 3650lbs. w/driver. [email protected]
CanCamaro is offline  
post #6 of 15 (permalink) Old Sep 26th, 04, 04:34 PM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

The timing chain could very well have jumped, especially if the engine has a lot of miles on it. Theres nothing special about working on them...they are pretty much like a little mini metric small block. Like a67 posted, remove the distributor cap and rotate the engine back and forth, noting how far you can turn the crank before the rotor moves. I have seen engines do this, and they sound like they are knocking when really it is firing thru the open intake valve. That is harder than hell on an engine. If the rotor responds quickly to a change in crankshaft direction, I would remove the balancer and check for a broken key and/or a torn rubber ring between the inner and outer hubs of the balancer. I seems like those engines are partially internally and partially externally balanced IIRC. If the hub slipped on the balancer, they will shake and rattle.

"This is not a cheerocracy...I make the cheercisions around here"
travis is offline  
post #7 of 15 (permalink) Old Sep 26th, 04, 08:51 PM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

I checked the slack on the timing chain and came up with about 10-12 degrees. How much slack is too much? If it jumped could the timing be off so much that it could hurt anything inside the engine like valves and stuff. I don't want to get him to put money into the engine to find out that everything else in the engine is toast.

Thanks for helping

Dino
CanCamaro is offline  
post #8 of 15 (permalink) Old Sep 27th, 04, 01:48 AM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,715
Garage
Post

If there is over 150K miles, I'm surprised the 2.8L is still running, but, they were/are dependable engines if maintained in its life. You fix this problem, what & when is the next one?

They are throw-away engines. You can get a replacement and also, since its is carb'd, GM has a 3.1L & 3.4L to replace it. GM still sales 2.8L long block for about $1600 USD.

If you are contemplating a V8, you will need a different transmission, as the bellhousing bolt pattern is a 60* V6. A standard SBC trans will not bolt up.

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - Thank you, Joe Madden enjoy your next chapter.
Everett#2390 is online now  
post #9 of 15 (permalink) Old Sep 27th, 04, 03:03 AM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

10-12 degrees is way too much. The timing chain must just be flopping around in there. If the timing chain is smacking the side of the timing cover or block, it will making a kind of a knocking sound. And if it is hitting the timing cover, it will wear a hole in the cover and you will have a big oil leak.
Like Everette said, gm makes a HO 3.4L replacement engine for these things, and the price is barely more than the base 2.8 goodwrench engine.

"This is not a cheerocracy...I make the cheercisions around here"
travis is offline  
post #10 of 15 (permalink) Old Sep 29th, 04, 06:28 PM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

We took the cover off and tuned the engine over till the marks lined up. Since the marks line up does that mean the timing chain didn't jump at all.
fun fun fun

Thanks Dino

67 camaro 462 BB 9.6 CR Compcams 314HR 252 @ 50 612 lift, Port+Polish Oval port 2.19 1.88, Edelbrock RPM intake, 850 Holley DP, 3" exhaust, turbo 400 TCI 4000 stall, Dana 60 4.10 posi, 315/60/15 BFG M/T drag Radials, 3650lbs. w/driver. [email protected]
CanCamaro is offline  
post #11 of 15 (permalink) Old Sep 29th, 04, 06:40 PM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

How do the teeth on the upper gear look? That is where 90% of the wear occurs. Does it have the plastic/nylon coated top gear, or is it all metal? Teeth still sharp and well defined, or rounded off? How much slack in the chain?

"This is not a cheerocracy...I make the cheercisions around here"
travis is offline  
post #12 of 15 (permalink) Old Sep 29th, 04, 07:16 PM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

I wasn't there when the cover came off but I was told that the chain was extreamly loose. Before we took it apart we found that there was about 12 degrees of slop in the chain. Am I to beleive that the chain probably didn't jump.

Thanks for your time

Dino

67 camaro 462 BB 9.6 CR Compcams 314HR 252 @ 50 612 lift, Port+Polish Oval port 2.19 1.88, Edelbrock RPM intake, 850 Holley DP, 3" exhaust, turbo 400 TCI 4000 stall, Dana 60 4.10 posi, 315/60/15 BFG M/T drag Radials, 3650lbs. w/driver. [email protected]
CanCamaro is offline  
post #13 of 15 (permalink) Old Sep 29th, 04, 07:40 PM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

It is possible the chain didn't jump (sounds like it didn't), but a seriosuly loose chain will make all kinds of noise when it gets to slapping around in there. Did they say that the marks lined up perfectly up and down? Any signs of wear on the block or timing cover where the chain could have been hitting?

"This is not a cheerocracy...I make the cheercisions around here"
travis is offline  
post #14 of 15 (permalink) Old Sep 29th, 04, 08:04 PM Thread Starter
Senior Tech
 
Join Date: Apr 2002
Location: Kindersley Canada
Posts: 223
Post

I'll find out more about what it looks like tommorrow and let you know, is your idea about the chain slapping the case and block consistant with the way it just started knocking all of a sudden, hope so. The chain and gears are about $50 so we will probably change it and hope for the best. Probably the smartest thing would be to swap to a sbc and have a better engine/drivetrain.

Travis, thanks for taking time to answer my posts

Dino

67 camaro 462 BB 9.6 CR Compcams 314HR 252 @ 50 612 lift, Port+Polish Oval port 2.19 1.88, Edelbrock RPM intake, 850 Holley DP, 3" exhaust, turbo 400 TCI 4000 stall, Dana 60 4.10 posi, 315/60/15 BFG M/T drag Radials, 3650lbs. w/driver. [email protected]
CanCamaro is offline  
post #15 of 15 (permalink) Old Sep 30th, 04, 01:30 AM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,715
Garage
Post

Usually a loose timing chain sounds like taking a bicycle chain fully extended and dropping it into a shoebox.

Its a good decision to replace the timing chain and sprockets. Twelve degrees is the max limit, more like 8 degrees is max.
Everett#2390 is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome