MASH4077

I think I might have broken my timing chain (or jumped a tooth)
I was getting on the freeway and I floored it, then all of a sudden it started backfiring really bad out the exhaust. I pulled it over and tried cranking it numerous times, and it kept back firing. I had it taken to a shop that I know and they were the ones that told me it might be a broken timing chain . Does anyone know a fair price including parts and labor I should expect to pay to have this done?.
Im about ready to cry. It was running so good to.

compedgemarine

first I would find another shop. there is no way the timing chain could be broken because if it did the cam would not turn so the distributor would not turn so the ignition would not do anything at all so it could not backfire. it is possible that the chain jumped a tooth if it still has an old nylon coated upper gear. I would have someone who is knowledgeable on old motors check it out first.

MASH4077

Yeah they said it might have jumped a chain but if thats the case they said you might as well replace it.

fourtwenty

Check your coil. Mine did the same thing and all I had to do was put in a new coil and go.

bil

I doubt the chain actually broke.I have only seen that once,and it took more than flooring it.If the timing gear is original,they had some kind of hard plastic coating on the gear,when it gets old and brittle,it can strip off and the timing will be way off,needs replacing of the timing set.I think you can check by pulling the fuel pump and checking the chain,it has been a while,so someone jump in.But check the cheap stuff first! ---bil

joe_padavano

Semantics aside, you need a new timing set.

442scotty

Seems to be happening a lot right now...good wake up call for all of us who have never done it to our cars...Be proactive and get er done...save a lot of grief down the road...

OLD SKL 69

I would definitely check or replace the coil 1st. Chances are that if it is the original one, it is toast. Had a problem similar to that in an old Ford years ago. Replaced the coil and it was running like a champ again.

MASH4077

how do you check the coil?.

MDchanic

If it's the timing chain, it will sound wrong when you crank it.
Normally when you crank it over, it will have a smooth rhythm (sort of a "WAHwahwahwahWAHwahwahwahWAHwahwahwah," if I may try to describe it).
If the chain jumps, it will sound a bit stuttery or unsteady (more of a "WAHbudabumWAHbudabum...").

Also, since the distributor is connected to the camshaft, you should see a change in timing from your previous settings of about 20° (18 teeth on crank gear, each tooth = 20°) if you put a timing light on it (Am I right about this guys?).

Is your motor high or low compression?
When the chain slipped on my high-comp. '70 Cutlass 22 years ago (but who's counting?), I also bent four valves.

- Eric

MASH4077

yeah the car has the normal sound while cranking, just with the added backfiring.

Rickman48

A timing light and compression tester will tell you everything!!

Lady72nRob71

Replace it.
If it is original, it is proably due. If that is not the problem, store the extra one in the trunk for any roadside emergency.

joe_padavano

Unless you have money to burn (in which case, send some to me), why should anyone spend a dime BEFORE doing some simple diagnosis. Geeze, we all complain about idiot mechanics who are simply parts replacers and now we're giving the same advice here.

Checking if the timing chain has slipped is trivially easy. Simply connect a timing light to the car and check the timing mark while cranking. If the mark is even close to where it's supposed to be, the problem is not the timing chain and you should THEN replace the coil (or at least do diagnostics on the ignition system). If you can't see the timing mark or it is waaaay out of place, it's time to pull the front cover.

oldcutlass

What year and size is your motor. I agree with Joe. I hate spending money on parts for no reason!!! I've run into issues in the past that were ignition related, where a problem with the dwell, coil, condenser, or points can give an erratic timing issue when just cranking, that looks like a timing chain but really is something else. I think we need to do some additional diagnostics here before tearing the front off the motor.

rustyroger

I hope its a simple fix like a bad coil or similar.
But how many miles has your timing chain done?, several experienced mechanics have advised me to replace chain & sprockets at 100k miles.
If it turns out you don't have a chain issue today but have a lot of miles on the car it might be a good idea to plan changing it when convenient to you, that is before it quits on the road.

joe_padavano

I'd do it at 80K miles if it still has the OEM plastic cam gear. On the other hand, the all-metal gears and single roller chain in my Chevy truck looked new at 150K miles (though I replaced them anyway as preventative maintenance).

fourtwenty

I usually find that timing chains slip or skip a tooth when you shut off the motor then try and start again. You can pull the number 1 plug move your timing by hand so that the mark lines up check the distributor rotor to see if it is pointing at number one wire and if the piston is all the way to the top of the cylinder. If all is well borrow a coil and try it out. Check your points for wear. I went to electronic points and better coil after mine coughed and backfired then at 100k went to roller gears and chain. Should have done the gears earlier as all the plastic was gone and could have done some damage if they had slipped. Cost me about 130 for points coil cap rotor and wires and about 125 for timing set. Took a few hours to install but not that bad to do. cheers

MASH4077

Sorry I forgot to mention what year it was. Its a 1983 oldsmobile delta 88 with the 307 5.0 motor.
Its only got 57,000 original miles. Yes the coil is original. I did replace the cap, wires, and plugs about 8 months ago though.

I just wanted to thank you guys for taking the time to help me out here. I pray it is just the coil.

Thank you..

D Appeldorn

you can bring the coil to a autoschop or read the olds manual and test it with a Ohm reader. ( 3 ohms?? standard?)
or multi tester.

check sparkplugs, feel the ignitionwires, check timing or check a manual of your car.
to find a solution.



If you can't vind anything, than think of checking te timingbelt.
I'l always start with checking the simpel things before tearing it appart.

knighthawk

can't believe the timing chain is bad at 57,000 miles, more like 150,000 . But the they did that nylon cam gear, that gets pretty brittle after with age, . Jf the chain is loose enough to slip, you can check it easy enough. put a socket and breaker bar (flex hanldle) on the damper pully from under the car, rock the crank back and forth, you'll feel when it starts to turn the cam, at the end of your flex handle you should have about 1'' total movement max

MASH4077

Well I just got off the phone with the shop. I asked them to check the coil, but they already checked the car out and they said its definately the timing chain. I didnt ask them any questions if it jumped or actually broke, but they quoted me $345.00 including parts. My old honda accord was only $218.00 with parts, so i thought the older oldsmobile would be cheaper than a honda.

I cant afford to pay $345.00 right now.
Is that to much or does that seem right?.

joe_padavano

That's probably not unreasonable for a shop to do it. Keep in mind that your Accord has a timing BELT, not a chain. I'll also say that 57,000 mi is low for needing a chain replaced. Are you sure it's not 157K?

MASH4077

Yeah its only 57,000. It was owned by an elderly couple, then a college student then me.

joe_padavano

By the way, don't get hung up on whether the chain broke or jumped a tooth. The result and needed repair are the same, so the actual failure mode is irrelevant.

oldcutlass

A honda timing belt is a royal pain in the keister. Your in a tuff spot, I can't give financial advice other than beg, borrow, or steal (this one generally turns out bad). See if there is any negotiating room.

A crying woman at your side works too!!

MASH4077

I just made an ad up on craigslist so hopefully someone will call.
I should beable to find someone to do it for $250.00 including parts.
I checked the parts and its only about $25.00 for the timing chain set.

oldcutlass

Remember you get what you pay for! Yes the timing set is about $25 + gaskets and shop supplies, labor avg $80/hr with a 4 hr minimum. It can add up! What about you towing it to the house and doing it yourself. It's not rocket science!

Rickman48

I've a policy with the front of ANY motor:
If it needs a water pump, also do a timing set.
If it needs a timing set, also do a water pump!
I've never done one without the other, as with a pump, you're 2/3 of the way there,
and with the timing set, you've got the pump off aready! $25 is well spent!
I really hate doing things twice, and found the timing chain to be bad every time!

coltsneckbob

I have had 2 Pontiacs where the timing chain started to go at around 60K. It started to sound like a marble rattling around in side an iron can. Changed out the chains and all was great again.

Higgins

Does anyone know when they started using the plastic on the timing gears? My 394 c.i. Starfire has 106,000 miles on it, just wondering if I should be concerned about the gears.
Higgin

Destructor

Yes, but I had a 72 caddy skip at 120 K and I rebuilt a caddy motor at around 100 K and the timing set was still fine. I'm sure a gently driven vehicle is less stressfull to the timing set. My 88 Caprice had an all steel set so I never worried about it. My 70 Cutlass is at 79 K so I'm beginning to get concerned, I'm not going to let it accumulate a whole lot more miles on the stock timing set.

MDchanic

Wise words.

- Eric

Stattiolds69

[QUOTE]Wise words./QUOTE]

Indeed, I only had 75K mile on my 98 when i replaced the water pump that was leaking and did the timing chain too on a hunch. Good thing i did the chain had tons of slack and all the nylon teeth had cracks in them!

bcroe

I don't see the engine type, but I'll assume its a 60s or 70s Olds V8. There
are a couple ways to treat a car. You can make it reliable by doing your
periodic maintenance, or just keep driving it till it strands you somewhere
(again). GMs of the era all had plastic teeth on the cam sprocket. At this
age its brittle and about to fall off; likely worn enough to throw off the
timing as well. So you can get a new roller chain NOW (that will outlive
all of us) and install it at your convenience and have best possible timing.
Or you can wait till the car forces you to change it (at the side of the road)
and fills your oil pickup with plastic and possibly bang pistons on valves.

Every Olds I have got a new timing chain as soon as I got it. Cured pinging
in one case. I drive them coast to coast. Please don't cry that its a lot of
work, you ought to try it on a front driver. Driving an old car, be good at
fixing it, or pay a lot of money to someone who is good at it. Can't afford
that, you can't afford the car.

To check the chain, take off the distributor cap and hand crank it around
so the timing mark is by the degree scale. Note the degrees and carefully
back the crank the other way. If the crank goes 6 degrees before the
rotor starts to back up, the chain set is completely shot. 2 degrees shows
some wear, but not ruining the timing yet. But plastic could fail anytime.

Todays problem might not be the chain. Take care of all the maintenance,
and "todays problem" will be infrequent, less inconvenient, and less costly.
Bruce Roe

MDchanic

You do realize that this thread is just shy of four years old, right? It enrolls in kindergarten next year.

- Eric

RROLDSX

Now that's funny, I don't care who you are!

bcroe

Somebody, not sure who, sent me a message, and this was the first search
that came up. I hope they see it; its valid regardless. Bruce

RROLDSX

No prob, I've revived a few oldies myself, I just thought Eric's comment was hilarious.

MDchanic

Hey, it's a good thread, just letting you know before you wonder why he's not answering you.

Welcome to ClassicOlds.

- Eric