squirrelybird

how do you know when your timing chain is going bad? any particular symptoms or way to check??

my car just seems kind of rough. not like it used to. thanks.

Mark A Shields

What do you mean by rough exactly? When is it rough, stuff like that.

ede

if you're holding it in your had horizontaly and it deflect more than the thickness it's bad. if it's still installed not holding timing would be a good indicator, more than likely your problem lies else where.

ctandc

Hmm... lets see. I've seen timing chains make a noise VERY similar to a rod knock...that was an interesting problem to troubleshoot. I've seen worn timing chains cause false knock in the engine, causing the ECM to massively retard timing.


A bad timing chain won't make a engine run "rough". The more loose the chain gets, the timing gets more erratic , more so when the RPM's get higher.

A good way to tell on slack in the chain is to pop the distributor cap, and then watch the rotor as you turn the engine over by hand. There shouldn't be ALOT of movement by the engine before the rotor starts to turn.


Although, I have seen some of the factory GM plastic timing gears crack off and cause a chain to "jump" a tooth. This will result in retarded or advanced timing.


Safe rule of thumb? If YOU didn't rebuild the engine, and you know it's got more than 90k miles or so, then it couldn't hurt to install a new setup. Of course, while you have all that off, now's the time to install a better cam and lifters


HTH

squirrelybird

thanks guys.

well i have 140ooo miles, so maybe i should change it...no cam and lifters though--it's only a 3.1.

how do you "turn the engine by hand?"

and can you change the timing chain without pulling the engine?? (v6 keep in mind)

thanks.

Mark A Shields

Wouldn't that have a belt and not a chain?

squirrelybird

i dont know, you tell me! so you are thinking i a 91 3.1 has a timing belt, not a chain??? anyone know??

ede

unless you have over head cam(s) you should have a chain in any vee type engine, far as i know. i'm sure someone will dig around and find an exception. actually i've wrenched a few over head cam engines with chains too, 4 cylinder mazda truck and 4 cylinder mercades to name a couple.

86SCBNJ

The Nissan SRD- 4 cyl. have chains too...........

Vader

The top ten signs of a timing chain that has "gone bad" :

10. Sneaks out at night and holds up convenience stores for all the sprockets they have on hand;

9. Sleeps with your neighbor's timing chain;

8. Trys to vote more than once for it's favorite chain for governor;

7. Doesn't claim "additional stretch" on its tax return;

6. Conspires with Honda timing chains behind your back;

5. Whines and kicks and complains that it isn't well enough to go to school, then acts perfectly normal when it visits the timing chain doctor;

4. Doesn't even try to hold its oil until it gets to the drain pan;

3. Runs backwards when you're not watching;

2. Beats on the cover like a mariachi band all night long, while you're trying to sleep;

1. It says "Ford" on it.

Vader

BTW - A 3.1L uses a chain, not a timing belt.

dimented24x7

iTrader: (2)

Haha... lol... I like that even better then the bad torque converter one you posted a while back.

camaronewbie

90 305 TBI LO3
My timing chain told it's own tale - I could hear it. At first, I thought it was a bad idler pulley - I could hear this clicking sound at idle. However, I took a very long screwdriver, and put the plastic handle to me ear (actually against it), and put the metal end (tip) against various engine parts while at idle. When I touched the timing cover, I could definitely tell that was it.

The screwdriver acts as a stethescope and relays the vibrations straight to your ear. JUST MAKE SURE YOU use a long screwdriver, stay out of belts, and be very careful! I've actually done the same 'test' on the road, in the middle of nowhere, by unscrewing my antenna and using it. YOU JUST HAVE TO BE CAREFUL!

Also, for the future, Harbor Freight www.harborfreight.com sells an automotive stethescope for dirt cheap.

gruveb

Shouldn't someone LOCK you up?

dimented24x7

iTrader: (2)

or... if you have a serpintine belt, just pop the belt off and start the motor while its still relativly cold and then take a quick listen.

squirrelybird

i do have a serp belt...how does that trick work??

Vader

That may or may not work effectively, since some chains have a tensioner (not on the Chevy V-6, but some do). Probably the best method to determine the amount of slack is to check the lag in distributor movement as someone described earlier. You can turn the engine back and forth with a strap wrench over one of the accessories with the belt still attached.

The V-6 uses a longer chain than the V-8s, so stretch can be a greater problem.

zupmanZ28

so if timing fluctuates a few degrees when i'm looking at the balancer with a timing light, thats an indication of a bad timing chain? Hmmm, mines been doing that for over a year, maybe thats one of my problems...

Eric