Belt Skipped a Few Teeth

[CharlieB]

Hi Again,
As I was fixing my valve shim issue, I accidentally rotated the engine the wrong direction, maybe 1/4 turn (please don't ask why I did this). As a result, my timing belt jumped a few teeth and now I can't rotate the engine by hand.
So, at the risk of sounding like a complete idiot, what should I do now?
Until recently I had someone to take care of timing the engine, etc... That guy moved away, so I need to try figure this out myself.
One of the problems is I don't have the timing cover or the cam pointers.
I know I need to loosen the timing belt and rotate the cam? Which cam do I rotate?
Or, have I caused catastrophic damage?
Any advice is greatly appreciated.
Thanks
Charlie

[18Fiatsandcounting]

No worries, Charlie, it's very unlikely that you have caused major damage if you just rotating it by hand. Here's what I would do:

Remove the timing belt, although you don't have to fully remove it from the crankshaft pulley. Just remove it from the two camshaft pulleys. Locate the the Auxiliary Shaft pulley and turn the pulley a few times slowly by hand. If it binds, let us know. Now turn the auxiliary shaft pulley so that its timing mark is at about the 1 o'clock position when looking at it from the front (ask if this doesn't make sense). See if you can turn the crankshaft a small amount by hand (do NOT use the starter motor), and you might need a wrench or socket on the pulley or the like. Either direction is fine. If you can't turn the crankshaft by hand, let us know. All of the above it to make sure that you haven't wedged a connecting rod against the lobe of the auxiliary shaft, which can happen in some engines if the timing belt is way off.

I'll let you respond as to whether your auxiliary shaft pulley spins freely by hand and whether your crankshaft turns by hand, and we'll go from there.

-Bryan

[CharlieB]

Bryan,
Thanks for the response. I'm in my office for a little while this morning but I'll work on the car when I get home.
Your directions make perfect sense, I'll report back soon.
Thanks again
Charlie

[18Fiatsandcounting]

Sounds good Charlie. The first step is to make sure that the engine hasn't got an interference issue which has caused it to "jam", and the next step is to get it timed right and get you back on the road.

I've never damaged a Fiat engine just by turning it by hand, but I have bent a valve when I tried to start a rebuilt engine while having serious brain fade on getting the timing belt right. But, I put in a new valve and all was well again. I learned my lesson, and that's why I always rotate the crankshaft a few times by hand* to make sure all is well, before using the starter motor.

*in practice this means slowly rotating the crankshaft by using a socket or wrench on the pulley nut.

-Bryan

[CharlieB]

Ok, I got the belt off the cams, the auxiliary pulley turns easily, no binding there.
I turned the crankshaft a few rotations slowly by hand and there is a point where it stops turning.
I did have the auxiliary pulley pointed at 1 o'clock before I rotated the crankshaft.
Thanks again for the help
Charlie

[18Fiatsandcounting]

Excellent! OK, here's the plan: Rotate the crankshaft so that pistons #1 and #4 are at TDC. If you have a timing mark, you can use that, but if not, remove the #1 spark plug and put a pencil or screwdriver down the hole. If you rotate the crankshaft, you should be able to find the point at which the #1 piston is at the top of its rotation. It takes some practice, and sometimes I find this top of rotation (TDC) by feel more than anything else. Then make sure the auxiliary shaft pulley alignment hole is roughly at 1 o'clock. Then, turn the camshaft pulleys so that the holes in them line up with the pointer bracket or, if you don't have that bracket, with the nubs on the camshaft housing. Install the timing belt. Verify that the distributor rotor is pointing towards the #4 spark plug (NOT the #1), and put that back together.

All should be timed properly at this point, although you will likely need to fine tune the ignition timing once you get it running.

-Bryan

[CharlieB]

Thanks Bryan, I'll do that after work today. I'm glad to hear it's not a lost cause.
I'll let you know what happens.
One question though. Will I be able to turn the cam pulleys by hand? Without the timing belt?
Thanks
Charlie

[RRoller123]

+1, just be very sure that the distributor is pointed at the contact for NUMBER 4 cylinder, NOT number 1, which is more common. If not, there will be a huge backfire after a few tries starting it, the big black hose will blow off, and shatter your brittle, old overflow bottle. I somehow know this to be true....

[CharlieB]

Ha, I'll certainly make sure I do that.
Thanks

[18Fiatsandcounting]

Will I be able to turn the cam pulleys by hand? Without the timing belt?

Yes. Usually, you can just grab the pulley with both hands (wrap the pulley in a rag first to avoid nicks and cuts), and slowly turn it. If you have an old timing belt, you can wrap that around the pulley and pull on it from the right direction and that will inch the pulley along. Or, you can use a wrench and use the bolt in the center to slowly turn the camshaft. If you use a wrench, I suggest not turning the pulley in a counterclockwise direction, as that might loosen the nut and then you have a new problem. So just turn it clockwise. I suppose one of those "chain vise grip" tools might also work, but you want to be careful not to gouge the pulley teeth so that they could damage your timing belt over time.

For all these methods, slow and steady is the operative word. Well, OK, two operative words.

-Bryan

[CharlieB]

Ok, I just wanted to make sure, I know the cams are pretty tight. I'll try to avoid using tools just to be safe.
Thanks gents,
Charlie

[CharlieB]

Well I've got #1 at TDC, and the auxiliary shaft at 1 oclock and the intake pulley on its mark. Now, on the exhaust pulley i have to sets of marks. Each set is 2 small dots (looking at the backside of pulley. One of those sets also has a small dot on the front of the pulley. Is that the mark I'm aligning to?
Thanks
Charlie

[18Fiatsandcounting]

Gosh, you got me there, Charlie. The timing marks on both the intake and exhaust camshaft pulleys should be a hole (about 1/8" diameter) drilled all the way through the pulley from one side to the other. That hole is what you should be aligning to. Are you saying that you don't have that hole in either camshaft pulley?

-Bryan

[CharlieB]

This photo shows the back of the exhaust pulley.
Here is the front of the exhaust pulley.
I'm 90% sure that is the correct mark, well actually on the front it is the only mark.
Just making sure.
Here is the back of the intake pulley, that one is pretty obvious...I think.
I have a spare set of pulleys around here somewhere, I'm trying to find them to help verify the marks.
Thanks for the clear instructions by the way, I hope to get it all back together today.
Charlie

[18Fiatsandcounting]

Those sure look like the timing marks (holes) as far as I can tell. One trick, when you get to this stage, is to insert a suitably sized metal rod through the hole from the front, like a drill bit. It's easier to then line up the hole with the raised nub on the cambox. Be careful that the drill bit doesn't stick out from the back too far while you're rotating the pulley, as you can easily break a drill bit that way.

-Bryan