ALH Timing belt - investigate Head

So it all started with the power steering line blowing out while I was a long way from home. Drive the car back while allowing the power steering to run dry for 2-3 hours and park it on the street.

A few days later, start it up to get it another 40 feet into the garage and the belt goes.... car stalls.

So.... It'd due for a timing belt anyways, I tear the whole car apart, and goto manually crank it to TDC and... *clink*... it won't crank.

So I'm thinking that in busting the serpentine belt I made the car skip a tooth or something.. at which point it instantly stalled and some neighbours helped me push it into the garage.

Here are the questions:

1) How is it possible that I lost the timing by snapping the serpentine belt?

2) I'm pretty sure I need to pull the head and check for valve damage, right?

2) Is a head rebuild beyond the DIY pay grade? Background readying suggests once I get it off, assessing the damage will not be that straightforward, so should I be looking at a professional rebuild, or is it simply a matter of buying a rebuild kit, those little spring compressors, and swoping out valves?

It's not uncommon for pieces of a busted serpentine belt to make their way into the timing belt's path.

Before any further guessing your best bet is to pull the timing belt cover and carefully inspect the belt. If it's broken or has missing teeth then yup off comes the head.

However, it may be that you'll find a piece of serpentine belt is what's jamming the works.

The timing belt cover was on at the time of the failure, but it's off now.

As far as I can see there's no damage, no missing teeth or anything. Lifters look right too, as far as I can see.

1) So should I be pulling the head? or would it be good enough to pull the camshaft, and set it back to TDC manually?

2) Is there any reason the car would stall upon breaking the serpentine belt *other* than taking the timing system with it?

3) If I do need to pull the head anyways, would a valve job be enough, or is there anything else I should be looking for?

Sorry for all the question marks but I like to try to get all my bases covered!

Not being able to roll the engine over by hand really ruined by day, and I can't figure out why it's hitting. That said I'm trying now to figure out if that alone is reason enough to a) Pull the head and put new valves in it or b) Put an entirely new head in the car.

Deadend said:

The timing belt cover was on at the time of the failure, but it's off now.

Click to expand...

Yup, but there are pictures on this forum of bits of serp belt making it *behind* the cover and messing up the belt.

I don't know why you won't want to move one step at a time? First remove the belt, see what happens. Then the cam, if need be, see what happens, then pull lifters and see, then the head if all else fails?

EDIT: looks like you've torn the car down some aka "tore the whole car apart". Are you trying to move the engine back to TDC without the timing belt on?

*No* way to guess on any machine work staring at the engine in the engine bay... machinist will make that call when he/she sees the bits, if you get to that point.

Is the engine locked solid... in both directions...or are you meeting with an obstruction at a certain point in the rotation? Nothing else got damaged by the serp belt? Is it clear what caused the serp belt to fail?

Serp belt failed due to seized power steering pump. I drove it back to Calgary from Ponoka with a major power steering leak!

Engine was not locked solid. It hit obstructions within about 90 degrees of camshaft rotation or.

I am going over the areas with a fine-tooth comb looking for anything indicative of damage and I can't find anything!... just the obstructions trying to rotate to TDC with the timing belt on.

*Here's what I was doing while you posted*.

Observed that the obstruction was encountered when the right valve (from the front of the car) on the right most cylinder was almost completely open.

So I backed it off a bit, and loosened the cam sprocket off the camshaft then I advanced the crankshaft a little bit at a time. This was a back and forth for a while. Eventually I could both the cam sprocket back down, and get the engine to TDC. After that I managed to roll it over without any obstructions.. so *knock on wood* so far so good.

At this point I've basically just adjusted back the camshaft position, Flywheel timing mark lined up perfectly with the injection pump.

So I've just come in the house for a quick break, and then I'll pull the belt off, while continuing to look for damage as you suggest. If I can't see any, my plan is to put everything back together (quite a mess right now on account of I'm putting in a new air conditioning system while I'm at it), and see if it works, and do a compression test.

Good Plan? It seems maybe the cam sprocket jumped when the serp belt snapped.... I'm hoping I got lucky in that it didn't cause any damage because it stalled out pretty much instantly.

If the sprocket jumped you almost-certainly had valve contact.

Any damage the serpentine belt might do to the timing belt would likely be at the bottom. I can't interweb figure if and when the timing skipped. Guess I would do the timing belt system, inspect what you see of the cam and stuff.
Maybe the timing belt got drenched but didn't fail until you tried to pull in. If it failed. You'll know when you get it off. Quite the series of events.