Timing Chain broke @130kph, engine gone? worth repairing?

[lbrowne]

I had a post going already because my 91 Saab shut off on the highway and we couldn't get her started.

Well I took off the valve cover and there it was, bare cam sprokets. The timing chain is nowhere to be seen.

This happened while travelling 130kph. Is it worth getting a timing chain kit and repairing? I know with SOHC and DOHC motors the timing chain breaking while driving can be catastrophic to the motor.

I'm afraid if I do the repair theres internal damage that I can not see that will keep the car from functioning properly, if at all.

I have no idea what a timing chain kit goes for....and most likely would be a dealer only item.

[Wamphyri]

dunno the price of the timing chains but one things for sure you timing is off so either your going to need a timing light, if you havn't used one before you want a digital one, $$$ you might be better off towing it to a garage and having them doing it but your motor should be just fine

[lbrowne]

I would have thought at that speed, with that snapping everything would go whichever way it wanted....I know it can be very bad news, what makes you think its not?

Is there anything I can check to make sure the engine is still good?

Isn't there timing marks and marks to line up when putting her at TDC? I know when I did a timing chain kit in my 240sx SOHC there were markings I used to line everything up....

[Marrk]

dunno the price of the timing chains but one things for sure you timing is off so either your going to need a timing light, if you havn't used one before you want a digital one, $$$ you might be better off towing it to a garage and having them doing it but your motor should be just fine

You do not require a timing light, there is nothing to time on these motors. The crank position is picked up from a crankshaft sensor and the ignition timing determined from this. Earlier models might have the distributor but 1991 models are usually Direct Ignition.

When a timing chain goes you get 2 conditions, first is the valves are left in an open position and the pistons come up a smack them and you end up with bent valves and usually a scrap head as it usually takes out the guides and damages the top of the piston also.
Secondly, you might be lucky and find the cams stopped with valves in a position not to hit the still moving pistons.
If you have been trying to turn the motor over and I think you have then if it spins you might be one of the lucky ones.

For piece of mind you will have to take the head off and check for damage, then see if its worthwhile to replace the chain and guides etc. Lining the cams etc up is straight forward with new chain as it marked clearly but you need the timing cover and all the other items off the engine first though.

[benji9k]

You said the tach moved when you tried to crank it, right? That would make me believe everything still moves ok, and the valves are fine, at least by what Marrk said, I couldn't tell you beyond that.

Sorry to hear the news, BTW. Hope you're back on the road soon.

[lbrowne]

The tach needle still moves when trying to start, and she sounds no different than if the chain was still on.

How much involved in taking the head off? Is it safe to believe the chain is down in the oil pan somewhere?

I have Direct Ignition yes. But there must be some timing marks on those cam gear and then crank gear to line up....it wouldn't make sense if there wasn't

[Marrk]

I have Direct Ignition yes. But there must be some timing marks on those cam gear and then crank gear to line up....it wouldn't make sense if there wasn't

Yes there is, from memory and don't quote me....this might be for the balance chain! you put the crank shaft with no.1 piston at TDC, the woodruff key in the crankshaft holding the timing chain drive sprocket is at the top or is it bottom, the cam shaft sprockets have a little line on them and these need to be at the top. The chain has 3 coloured links and all the marks co-inside with the middle of the coloured links.

I don't have a manual handy but its easy to do and as you mentioned you've done it before on another type of engine then you will be capable of sorting this out. The chain will be in the sump, hopefully it won't have done any damage on the eay down.

Clyinder head removal is pretty straightforward but one thing to remember, the cylinder head cannot be removed without removing the camchain tensioner which is locatedf at the back of the engine and needs a large socket and extension bar to get to. Remove the false bulkhead first to give you more clearance to get tools in a see what you are doing.
Good luck!

[lbrowne]

sump = oil pan? How hard to remove that?

When you say markings on the cam sprockets pointing straight up, you mean perfectly vertical with relation to the car being on level ground? (I would assume so)

This cam tensioner one got me worried, not sure how to go about that. I do have a breaker bar and all the tools etc, but wouldn't it all have to be put back a certain way - to a certain spec after?

[Wamphyri]

like usual i was talking out of my ****.. lol

[Marrk]

This cam tensioner one got me worried, not sure how to go about that. I do have a breaker bar and all the tools etc, but wouldn't it all have to be put back a certain way - to a certain spec after?

No, it just needs to be tight, if it has a copper washer seal replace it, if its a dowty seal reuse. The threads on the block and tensioner are cut so the tensioner 'foot is square on the tensioner when tightened up. It becomes clearer when you actually see it.

When you say markings on the cam sprockets pointing straight up, you mean perfectly vertical with relation to the car being on level ground? (I would assume so)

Up in relation to the engine... not the ground. If you do a search there is lots of more info about in previous posts.

[lbrowne]

I've been busy readin archives, and thanks for your input as well Markk.

I'm wondering if theres a way to check to see if everything is ok to put another chain in, without having to remove the cylinder head? Everything *looks* ok from the top...

Whats invovled with removing the oilpan to get the remanants of the old chain? I would imagine I need the chain with the master link...right?

Should I replace the tensioner? Or is it ok? I've found to check if the piston is out - exceeding 11mm, but that only says to then change the chain...not the tensioner.

with 217k on the odometer, I would think I should change that waterpump since I'm in there. All the cam/gear sprockets look perfect, no teeth missing...

[Marrk]

You will have to remove the chain cover to replace the chain now, there will be no way you will be able to thread a split one in now the other chain is in the sump. Take the side cover off, this exposes a section of the sump and you might have enough space to get the old chain out. The cam chain sprocket on the crank is the one that wears so check that...putting a new chain on worn sprockets is asking for trouble IMO and its wise to check the tensioners also....in other words for piece of mind chain the sprockets, tensioners and chain.

[lbrowne]

I need to find a haynes manual, I responded to another thread on here where someone made reference to one, because it would really help.

Do all the pulleys have to come off pretty much? I have the car jacked up with the inner fender trim removed.

I've searched many archiives but found no laid-out process to follow like I did for my other car I did this on.

[lbrowne]

Couldn someone please take a look at the linked picture, resize it since this one is HUGE.......

But look at whats there and tell me what I have to take off. I have to get the correct socket to take off the crank pulley bolt.

What the heck is that large metal bar close to the valve cover running horizontal???? Its not AC....runs to a pump I think..

Side of Engine

Thanks Fellas,

lbrowne

[Marrk]

That pipe is the waterpipe it needs to be disconnected from one end then can be moved up out of the way, if I remember correctly the steering pump needs to be removed also.
Sorry cannot be any more specific, if I was there it would be easy to point to things to remove but....... :wink:

[lbrowne]

How the heck to I take the crank ppppulley bolt off? the crank spins with any force placed on it.

I tried putting the car in Drive and it still won't stop turning when I'm trying to loosen the bolt.

Is there a trick to this?

[Marrk]

You need to use a breaking bar and a lump hammer, lots of sharp thumps with the hammer will loosen it.

[V.J.S]

Originally Posted by lbrowne

How the heck to I take the crank ppppulley bolt off? the crank spins with any force placed on it.

I tried putting the car in Drive and it still won't stop turning when I'm trying to loosen the bolt.

Is there a trick to this?

I'm not sure if this works on automatics, but I reckon it should...
Stuck screwdriver(s) through the front caliper(s) to the venting holes on the disc (gear on D). The screwdriver will block the wheel from turning when it hits the caliper and you're able to put some torque to the bolt.

EDIT: Added pic.


Another trick I've heard utilizes the starter motor and is not for the fainted heart: Take the fuel pump fuse (nr 14) off, crank the car few times so, that you are sure it won't start. Then put the socket on the bolt, use a suitable-length breaker bar, place the breaker bar close to the suspension control arm (A-arm) so, that when you then crank the car for a few clicks, the bar will hit the control arm and the bolt loosens, or most likely, the socket slips off the bolt. Repeat multiple times with an adequate amount of swearing until you finally get the bolt loose and not the socket/braker bar flying all over the place

-Ville

[lbrowne]

Still no dice.

Thanks for putting up the pic and post VJS, however nothing is moving when I'm turning the crank. The wheel hub/rotor etc is staionary. So putting a screwdriver in like you said won't be stopping anything cuz nothing is moving.

The other front tire is on the ground. Remember the chain is broke, I don't know if that means anything in trying to take this crank pulley bolt off.

[V.J.S]

Originally Posted by lbrowne

Still no dice.

Thanks for putting up the pic and post VJS, however nothing is moving when I'm turning the crank. The wheel hub/rotor etc is staionary. So putting a screwdriver in like you said won't be stopping anything cuz nothing is moving.

The other front tire is on the ground. Remember the chain is broke, I don't know if that means anything in trying to take this crank pulley bolt off.

You need to have the car on gear to get the rotor moving, like I said, I'm not sure if this works on automatics...Did you try to use the starter motor technique? A fellow Saabist opened his crank bolt like that (on -87 2,0T automatic), he said it took several tries, but in the end it worked. I think he also covered the part where the breaker bar hits with a piece of wood.

-Ville