Stan944

So I put things together after resealing the front end and the balance shaft covers, but there are two problems:
1. the engine doesn't start. It cranks, feels like it will pick, but dies a few seconds later. I tried 3 times, the last time added a little gas, and the oil light finally went off, but it still died. Should I keep trying?
2. When I looked at the belts after that, it appears the tracking of the timing belt is different than before (new timing belt and seals, but old sprockets, old water pump-1year old). It used to be that the timing belt on the camshaft was flash with the front of the camshaft sprocket. Now the belt is about 2mm towards the engine. It rubs(?) or is very close to the rear plastic cover of the belts. I looked and it appears there is about 2mm of space for the timing belt to move sideways between the flange of the water pump pulley and the flange of the tensioning pulley (there is no later-model tensioner). Is it normal? Could you describe tracking of the timing belt in your cars?

austin944

Here's mine:
http://home.att.net/~porsche944/seals/dscn0474-1-0.html

I don't think the 2mm is significant, so I think as long as you're not rubbing, you should be OK. My guess is that the timing is off by a notch.

Stan944

is your belt flush with the front of the camshaft sprocket?
I'll check the timing tonight.

tkacki

Re-check ignition / coil wires.

austin944

No, the link I provided shows it's not flush.

xsboost90

first off, make sure the timing is correct. Set it back at TDC by looking at the flywheel through the hole in the belhousing, then double check that all your timing marks are lining up still. Now make sure your pullys are on correct, i believe someone has had problems before w/ putting pullys on backwards or something. If all this is ok and your belt is tight, and she still wont fire, i say check the ref sensor wires to make sure they are plugged in, and make sure your cap rotor wires are on correct. Could be DME also but alittle too convenient that you had the front of the engine apart.

Stan944

Thanks. I looked at the link before (nice pictures), but for some illogical reason it didn't appear to me this was what I asked; sorry.

Stan944

Yeah, I'll start with checking the timing and the ignition connections. And maybe it just needed more cranking to pump the oil up after 2 weeks break, and there was too much friction?
But this belt tracking bugs me a lot. I'll check if it's consistent. If it's rubbing the rear cover, would it make sense to put a washer behind the tensioning pulley? Because the flange on this pulley is on the engine side, bringing the pulley forward would move the belt forward too. Or the flange is not for positioning the belt sideways, just a safety precaution?
The problem is why wasn't it like this before?

austin944

I wouldn't put a washer back there. That's not part of the normal maintenance procedure on these cars. I don't think you want the tensioner flange "pushing" the timing belt out. That would probably cause the belt to wear on the outside edge -- not good.

I suppose if the cam sprocket sat more away from the block, or the crank sprocket sat more towards the block than before, then you could have a situation like yours. But honestly I don't see a problem with a 2mm change. Could just be the belt tension is different.

Only thing I can think of that might cause the difference is putting the crank sprocket on backwards. As I recall the flange end goes on the outside.

Can you post a pic? If it's anything like the pic I posted, you're fine!

Stan944

... I don't have a camera now.
I said 2mm, but I didn't actually measure it. Should have said about 2mm.
In any case, I put the crank sprocket flange to the outside (there would be no way to use a gear puller in the future otherwise), a washer between this sprocket and the oil pump sleeve, and the tensioning sprocket - flange towards the engine.
I have the tool for gap measuring. I can check if there is clearance or not between the belt and the rear cover.
I also wonder if the belt could be defective?

Stan944

Update:
The timing alignment is fine.
The belt bareley or not rubs the rear cover - this is fishy to me. It could be more than 2mm ...

I can start the engine and keep it running by adding gas. As soon as I let off the gas pedal it dies.
After it dies I can hear a pssssss for about 10 seconds, so it sounds like I have an air leak. But it sounds like a small air leak, and I'm not sure if this could explain dying on idle.

Could mechanical rubbing of the belt cause too much friction that it dies unless it's reved up?

Zero10

Check the intake boot for leaks (loose clamps) and make sure that the AFM is plugged in properly.

IIRC if one of the tensioners and/or idlers is installed backwards it will cause the timing belt to rub on the rear cover. If left uncorrected it can cause the car to repeatedly throw timing belts.

Stan944

Thanks Zero10, I might have two independent problems: vacuum leak and belt tracking. I don't think the rollers are installed backwards. I don't think you can pug the AFM backwards, can you?

My plan is to connect a vacuum gauge and see how fast I loose vacuum, and try installing the old timing belt (with the balance and alternator belt removed).

I worry a little about the valve condition. I tried cleaning the head before removing the intake manifold, but maybe some debries got in? I presume a compression test would clarify it, but I never done it before.

I'll be out of town for a couple of days, and any other thoughts would be appreciated.

Zero10

Nope, can't plug the AFM in backwards.
It sounds to me like a big vacuum leak. Hopefully it's something simple.

Doesn't sounds like a foreign debris problem, so I wouldn't worry too much there.
As for the belt tracking funny, a long time ago somebody on Clark's had the same problem, and I thought I remembered it being a roller on backwards. But it could have been one of the crank pulleys. Their problem was that every time they installed a timing belt, it would wander back, then grind itself to bits on the rear belt cover.

Stan944

yep, it was a vacuum leak, it idles fine now. the large hose under the intake was unplugged. This is probably from the air valve for extra air on start up. Must have slipped off when I was moving the intake manifold. And 2 other small hoses were unplugged too - they actually looked too short, and that's why they slipped off during the work.

The belt still rubs agains the rear cover, and with the engine running I could do some testing: I could see some irregular motion of the timing belt. I could also hear a rubbing sound 3 times per 5 secods, while idling, which corresponds to the frequency of 900 rpm. So one "rubbing" event per full length of the timing belt. Because of the frequency match with the idle rpm, it is clear to me the belt is defective, i.e. has one irregularity in its entire length. Any problems with the sprockets would show at higher frequency. Do you agree?