[J0386]

A couple nights ago i went to drive home from work and as i steped on the gas in my truck it backed fired and stalled i do it again and it backfires again then dies but the third time it started up and drove but it was missing like crazy and had no power so i thought it might have been the carb maybe some gaskets blew out and sucking air checked it and it was fine same with the intake manifold so i decided to hook up a timing light to it and its way off time the line on the balancer is almost under the truck i tryed to set it but it will not even go to the scale on the timing cover it dies and wont start but it runs if i turn it back to the place it was before and the dist. vacuum advance it almost touching the carb so im guessing that night it jumped time real bad or maybe a bad cam or dist. gear? how would i set it back on top a buddy of mine said i could just pull the dist. out and rotate it on tdc and drop it back in straight? not sure any help would be great. heres a pic of where the line is at, u cant see it but its right about where the shadow on the balancer is. also it still runs but it has a bad miss to it and heres a pic of the dist

[sam_bo3]

That way would work if you jumped time on the distributor. It would be an easy way see if that is all. You will probably want to into gettting a new gear for your distibutor if it did jump back there.

If the timing chain jumped you will be pulling off the the front of the engine.

[lg1969]

It's more common the timing chain has jumped then a bad distributor gear.
Most likely the nylon teeth for the cam gear is chewed up.

[J0386]

would i have to pull the engine to replace the timing gears the engine is in a 1990 1500 so there is a good amount of room in the front and is there a guide anywhere that a can look at on how to change it?

[T-bucket23]

Originally Posted by J0386

would i have to pull the engine to replace the timing gears the engine is in a 1990 1500 so there is a good amount of room in the front and is there a guide anywhere that a can look at on how to change it?

It is a fairly straight forwad job. You will need to pull the water pump and damper pulley. Then lower front of the oil pan. Remove the front cover and everything is right there.
You will need a few tools that you probably dont have. A puller/installer for the damper and crank gear. You can most likely borrow or rent these from the parts store. The only tricky part is putting the front pan seal back on. This is why you need to lower the oil pan. Some people will modify the front cover by removing some of the inner lip. This eliminated the need to lower the oil pan but can make it difficult to get the cover back on. Be sure you put some rtv in the corners where the fron cover meets the pan or it will leak.

[J0386]

ok i should be able to handle that and as for the tools i got them and the dist. if i need to change the gear on that will i have to pull the engine or if i take the cap off will there be enough room to pull it out?

[T-bucket23]

Originally Posted by J0386

ok i should be able to handle that and as for the tools i got them and the dist. if i need to change the gear on that will i have to pull the engine or if i take the cap off will there be enough room to pull it out?

I doubt if it is the distributor gear unless the pin sheared partially. The distributor is easy to get out. all that holds it in is the clamp bolt. It can be tricky to get back in right. From the questions you are asking I am guessing you dont have any experience with this. It can be very frustrating to try to re-install a distributor is you have not done it before.

[oldbogie]

Originally Posted by J0386

ok i should be able to handle that and as for the tools i got them and the dist. if i need to change the gear on that will i have to pull the engine or if i take the cap off will there be enough room to pull it out?

Don't let anybody kid you, while not a really hard job, this ain't no walk in the park either.

I'm guessing this is a small block Chev from the picture, but even a BBC will be similar.

You'll need a gasket set for the front end and it's a good idea to invest in a pan gasket set, you'll use all or part most likely. For the timing set itself I can't recommend anything with the factory plastic gear, for a more or less stock engine that doesn't get rev'ved much a silent link chain type is fine. If the engine is pulling a cam against some stiff valve springs and you like to provoke the rev limit than a two row real roller chain and matching gears is the way to go. If you do that get an extra timing cover gasket as sometimes the roller chain will rub the cover with just one gasket.

You've got to have working space which means the radiator has to come out and all those brackets that hold the accessories and the accessories with the serpentine belt system has to come off.

You can now remove the damper, this uses a removal tool, you can rent or but at your choice if you don't have one. While we're here you might as well lay your hands on an installation tool as well because the damper doesn't take kindly to being beat back on with a hammer. There will be a Woodruff key that keeps the damper aligned to the crank, try not to loose it.

You will probably have to disconnect the exhaust and engine mounts to raise it up a bit to loosen the pan around the front.

Once this is done you can pull the timing cover. Now you're stairring at the disaster. Put some rags under the crank gear and over the pan to keep anymore crap from falling into the pan.

Remove the gears and chain, watch out for the Woodruff key that holds the crankshaft timing gear to the crank, don't loose it into the pan. Scrape the old gasket material off and clean everything.

Put the new crank gear onto the shaft with its Woodruff key. Install the damper's retaining bolt into the end of the crankshaft. Rotate the crankshaft till the pip mark on the gear is straight up.

Put the cam gear onto the cam and tighten its bolt, rotate the cam to one of two possible places. With cam gear's pip mark facing that of the crank gear's mark; the engine is now timed to fire number 6, it is 180 degrees away from number one, if you remember this position it's fine to work from here to time the distributor. But I'd recommend turning the gear so the pip mark is facing upward in the 12 o'clock position, for the Chev this is now timed for number one to fire at TDC.

Remove the cam gear and drape the timing chain over it and around the crank gear. Bring the cam gear to the position you've chosen to start the timing sequence, again the choice can be pip marks facing each other crank's up, cam's down for firing number 6, this is easy to see the alignment. Or with both pip marks up to fire number one. Harder to see the pip mark alignment this way, use a straight edge from a small carpenters square with to get this. Everything depends on getting this right so mess around for as long as it takes to be satisfied with the alignment. I recommend timing the distributor to the selected cylinder at this point, firing #6 if the pip on the crank is up and the cam gear down or firing # 1 if both marks are up.

Now put it back together with new gaskets and a crank seal in the timing cover. You'll find non-hardening Permatex to be an asset in resealing the pan gasket, hopefully it survived to be used again, if not you'll have to repair or replace it, this often is the biggest PIA of this job.

Bogie

[timothale]

pull the dist cap and then put a socket on the front pulley nut and see how much rotation you have back and forth before the Dist rotor moves. If ther is a lot of movement and the gear is shot you neet to pull the pan to get all the junk pieces out of the oil paqn.

[willowbilly3]

I've done a bunch of them on the older 350s and never loosen the pan. The timing cover will pry off and pop out of the pan. It's best to 45 the corners of the inside lip on the cover. Use a good grade of RTV instead of the rubber gasket and let it set up over night before you put in the oil or start it. Never had one leak.

[J0386]

guess i should have game more info on the vehicle its a 1990 1500 with a mild built carburetor 350 with headers straight pipes, etc, and only has the power steering pump alt and water pump but ill start getting all the things i need and ill let u guys know what gose down

[willowbilly3]

So this just happened as you were driving along? Hadn't touched anything under the hood? The reason I ask is because it's a repeat of a scenario I have had come into my shops dozens of times over the years. I have never seen a distributor "jump" time. Sometimes they don't get tightened down properly and slip. Also out of all the timing chain/gear failures I have only seen a couple that just slipped a little and still ran. Not saying it couldn't happen. What did happen in about 95% of the "jumped timing" situations was the owner had been fiddling with something and never got it back together properly (which they almost always neglect to tell you up front). I have seen plenty of chevys slip the outer ring on the balancer so no timing marks line up anymore.

[T-bucket23]

Originally Posted by oldbogie

Don't let anybody kid you, while not a really hard job, this ain't no walk in the park either.

I'm guessing this is a small block Chev from the picture, but even a BBC will be similar.

You'll need a gasket set for the front end and it's a good idea to invest in a pan gasket set, you'll use all or part most likely. For the timing set itself I can't recommend anything with the factory plastic gear, for a more or less stock engine that doesn't get rev'ved much a silent link chain type is fine. If the engine is pulling a cam against some stiff valve springs and you like to provoke the rev limit than a two row real roller chain and matching gears is the way to go. If you do that get an extra timing cover gasket as sometimes the roller chain will rub the cover with just one gasket.

You've got to have working space which means the radiator has to come out and all those brackets that hold the accessories and the accessories with the serpentine belt system has to come off.

You can now remove the damper, this uses a removal tool, you can rent or but at your choice if you don't have one. While we're here you might as well lay your hands on an installation tool as well because the damper doesn't take kindly to being beat back on with a hammer. There will be a Woodruff key that keeps the damper aligned to the crank, try not to loose it.

You will probably have to disconnect the exhaust and engine mounts to raise it up a bit to loosen the pan around the front.

Once this is done you can pull the timing cover. Now you're stairring at the disaster. Put some rags under the crank gear and over the pan to keep anymore crap from falling into the pan.

Remove the gears and chain, watch out for the Woodruff key that holds the crankshaft timing gear to the crank, don't loose it into the pan. Scrape the old gasket material off and clean everything.

Put the new crank gear onto the shaft with its Woodruff key. Install the damper's retaining bolt into the end of the crankshaft. Rotate the crankshaft till the pip mark on the gear is straight up.

Put the cam gear onto the cam and tighten its bolt, rotate the cam to one of two possible places. With cam gear's pip mark facing that of the crank gear's mark; the engine is now timed to fire number 6, it is 180 degrees away from number one, if you remember this position it's fine to work from here to time the distributor. But I'd recommend turning the gear so the pip mark is facing upward in the 12 o'clock position, for the Chev this is now timed for number one to fire at TDC.

Remove the cam gear and drape the timing chain over it and around the crank gear. Bring the cam gear to the position you've chosen to start the timing sequence, again the choice can be pip marks facing each other crank's up, cam's down for firing number 6, this is easy to see the alignment. Or with both pip marks up to fire number one. Harder to see the pip mark alignment this way, use a straight edge from a small carpenters square with to get this. Everything depends on getting this right so mess around for as long as it takes to be satisfied with the alignment. I recommend timing the distributor to the selected cylinder at this point, firing #6 if the pip on the crank is up and the cam gear down or firing # 1 if both marks are up.

Now put it back together with new gaskets and a crank seal in the timing cover. You'll find non-hardening Permatex to be an asset in resealing the pan gasket, hopefully it survived to be used again, if not you'll have to repair or replace it, this often is the biggest PIA of this job.

Bogie

Most trucks will not require pulling the radiator as there is plenty of room in the front.

[T-bucket23]

Originally Posted by willowbilly3

I've done a bunch of them on the older 350s and never loosen the pan. The timing cover will pry off and pop out of the pan. It's best to 45 the corners of the inside lip on the cover. Use a good grade of RTV instead of the rubber gasket and let it set up over night before you put in the oil or start it. Never had one leak.

I have done this also, just wanted to keep it less confusing and I couldn't find a picture of a modified vs. stock cover. If you have one it would be helpful if you could post it.

[lg1969]

Things could get worse. Could have a split camshaft. I doubt it.