How much should a timing chain move?...

[Mark B]

Hey guys,
I had a feeling that my timing chain had streched. So I pulled the cover off last night and this is what I found...




I dont think the chain is susposed to move 3/4"

hahaha


I am lucky I checked it when I did. Any suggestions for a replacement? Jegs has one that is made by Edelbrock for about $60. Any good? I need one that will work with my roller block

[Mark B]

I showed these pictures to a friend of mine. He seems to think the timing chain is fine? Im really confused now. Is this kinda play in the chain normal? If so, what else could be causing my scratching sound? Here are the symptoms:

-1991 305 TBI/auto with 125,000 miles.
-It sounds like metal-to-metal scratching
-It only happens at idle when the trans is in park
-Its not constant. It will turn on & off quickly & randomly.
-Its coming from the harmonic balancer area. (I used a piece of vacum hose to track it down)
-I removed the belt to see if it was another pulley... But even with the belt off, it didnt go away.
-I want to say that its the timing chain. I sounds like the chain is loose and is floping around scraping against the timing chain cover.
-The car seems to run fine even with the problem.

[M3EATER - GG '00 WS6 T/A]

I dont think the chain is susposed to move 3/4"

hahaha

Mark,

"How much should a timing chain move?"
..... all the way around both gears !


The factory link-belt chains do stretch. That one looks like it wouldn't hurt to replace it. Get a good roller chain ... which means new gears too, as a set.

A stretched chain will cause cam and ignition timing to jump around ... and will wear the gear teeth more quickly.


Gordon

[Coop '02Z]

If it was hitting the cover that often there should be a shiny area where it removed some of the metal of the cover. I would def. replace it since you are in there now, but looking for the scratches would give you a definite answer to the source of your noise. If no scratches keep looking since you have it apart.

Just a thought

[Joe 1320]

I've seen worse. Time for a replacement though.

[Mark B]

There are no scratches on the inside of the cover. So I was wrong on that one. I am going to replace the chain with a kit from Edelbrock. I am hoping that I will see something when I get the timing chain gears off that will tell me what the sound is.

Here is what I am worried may be the problem:

My brother drove this car for about a year. During this year, he ran the car into a mound of snow. This bent the radiator support & broke the fan housing. I wonder if he somehow bent something on the crank (or mabey the crank itself). Is it possible for a harmonic balancer to make this sound? I am sure that there is some sort of a bearing at the front of the motor where the crank comes out, is this replaceable without removing the motor?

[detroitgene]

I seriously doubt that anything crank or damper related is bent. You'd have noticed more serious problems long before now.

This may be a long-shot, but I recall doing a 'snow-job' much like you describe in my old Nova that fortunately only put a slight bend in my flywheel inspection cover. Gave me a random 'metallic scraping' noise much like you describe. The cover was made of steel and upon removing it, you could easily see the scrapes from the flywheel. Made the diagnosis easy.

If there was enough snow jammed up front to do the damage you indicate, there's a good chance the flywheel cover took some abuse as well. I don't know for sure if your cover is made of metal (could be plastic), but i'd have a look here before I went any further.

[fastTa]

The factory hypoid chains will stretch after a few miles. Like mentioned before, a loose chain will create premature wear on the crank and cam sprockets and will cause erratic timing issues. A stretched chain will even retard the camshaft timing a little as well. (This isn't so bad though).

While you're there go ahead and get a good roller setup. They can be had for about $80.

[Mark B]

I put a new chain on last night... And I would say somewhere between 1/4-1/2 of the play in the old one is gone. I looked all over to see scratch marks... But I couldnt find any. So I am puting everything back together tonight. Hopefully my scratching sound is gone. If not, the sound must be from withing the engine. This motor isnt work taking apart, so I will drive it till it dies. (In the mean time be saving for a 406 small block!!!)

[Mark B]

ITS FIXED!!! I got everything together last night and started her up!!! NO SCRATCHING SOUND!!! The engine is quieter in general too. Im so glad that was the problem. I just hope that I dont have any problems with oil leaks now. The car runs good too! While everything was apart, I removed the A.I.R. pump, raised the fuel pressure, ported my Throttle body, and bumped up the timing. Car runs really strong now. Im very Happy

[fastTa]

ITS FIXED!!! I got everything together last night and started her up!!! NO SCRATCHING SOUND!!! The engine is quieter in general too. Im so glad that was the problem. I just hope that I dont have any problems with oil leaks now. The car runs good too! While everything was apart, I removed the A.I.R. pump, raised the fuel pressure, ported my Throttle body, and bumped up the timing. Car runs really strong now. Im very Happy

Good to hear Mark! It always feels good to get the car back together and have her running strong.