s70 timing belt one notch off question

gojoaddict · Post by **gojoaddict** » 09 Oct 2009, 23:06

I aligned the crank with one of the notched teeth to the mark on the engine block instead of the right way which is aligning to the valley between the two notched teeth. So would being off by half a tooth at the crank (with the cams aligned properly) cause the engine to run rough when started?

Post by **MadeInJapan** » 10 Oct 2009, 06:34

Yes, you'll have to take the belt off and align correctly. Also, make sure that the marks at the bottom (crankshaft) are aligned correctly as well- these marks are hard to see but very important as well.

Post by **Ozark Lee** » 10 Oct 2009, 06:37

If the timing is off a tooth it will run rough and lack power. The good news is that, at one tooth off, it won't hurt the valves.

The hardest part of fixing it is re-compressing the tensioner - take your time and do it in a series of small steps waiting a few minutes between each step.

Set the crankshaft correctly on the marks, release and remove the tensioner, and then move the camshafts to their marks. You don't need to completely remove the belt, just slide it off of the cam sprockets once the tensioner is released.

...Lee

gojoaddict · Post by **gojoaddict** » 10 Oct 2009, 07:12

Thanks, I was worried that I bent some valve after the engine ran rough for about 5 seconds but as said I was only off by one tooth. I did pull the head and the valves all look seated properly. Just to cover all the bases, the tops of the pistons look as though they have slight notches in them that would match the edge of the valves (both intake and exhaust), I am worried that these were hit marks from the valves but all the pistons have them and they are still coated with the normal carbon build up, are the pistons made this way or did my valves hit them and put those indents into the tops of the pistons, as said the valves all look seated and show no air gaps between their seats and the valve head edge? thanks gojo

Post by **Ozark Lee** » 10 Oct 2009, 09:07

The pistons are made that way.

...Lee

gojoaddict · Post by **gojoaddict** » 10 Oct 2009, 18:29

Many thanks,I thought the 1/4 grooves in piston heads looked factory.
Made progress re-assembling it today, used my digital camera to image the crank and got it spot on. Installed the head, exhaust and intake mani and of course all the hoses and brackets and a gazillion bolts, I've found a Volvo goes together a lot easier than it comes apart.
Now I directed myself back to the original problem, over pressure in the crank case and thus a couple oil leaks, when running the dipstick tube has like a small bit of oil vapor that comes out and doesn't have a negative pressure.
So I learned about the oil trap and PTC, I checked both and they seemed fine I cleaned the PTC with brake cleaner and it appears fine..
Now to a question on the oil trap.
I removed it and it seemed fine, very light like it is empty, all the ports were clear including those in the engine block, I sprayed brake cleaner into the top of the oil trap it and it immediately ran out the bottom oil return port as it should, I then had someone else help and held our fingers over the oil return ports and applied low pressure with my air hose in the top vaper inlet port and I could easily feel the air coming out the other port (the one that goes over to the PTC so in essence it seems to pass the smell test as far as functionality , or am I wrong? thanks gojo

Post by **Ozark Lee** » 11 Oct 2009, 05:58

Other than the PTC I don't even mess with cleaning the PCV system components. For about $150.00 you can replace the whole system, the interconnecting lines have a tendency to get clogged and real brittle anyway.

How is your compression? Your pressure might be blow-by.

When I serviced the PCV on the Platinum turbo it went from have a ton of positive pressure to a very slight negative pressure. On the '96 N/A, which wasn't all that bad to begin with, it remained slightly positive even after the service was done. I have no history on the 96 N/A and apparently it had an engine change at some point in its life, the engine doesn't match the rest of the car when it comes to buying parts based on the year. The positive pressure isn't bad enough that I worry about it anyway since that was a $350.00 car in the first place that we have had running otherwise great for over 2 years.

I guess what I'm trying to say is that just servicing the PCV doesn't really assure no positive crankcase pressure. The '96 N/A isn't around very much since it is my son's car and he is off at college. I may try to Seafoam it over one of his breaks when he is back home.

...Lee

gojoaddict · Post by **gojoaddict** » 11 Oct 2009, 06:15

Again thanks, one quick question on the PTC.
Just trying to understand what it does.
The PTC has a vac fitting that goes to the intake mani, a larger hose fitting that goes to the oil trap, a wire connector that connects to who knows where (is probably a feedback sensor) and the PTC port itself gets stuck into the intake manifold plastic hose. I see the PTC has a small hole straight thru it that vents the fumes from the oil trap into the intake plastic pipe, so my question is does this hole expand when vac is placed on the smaller line or maybe from an electrical signal on the connector? Just trying to understand the function of the PTC? thanks gojo

Post by **Ozark Lee** » 11 Oct 2009, 07:16

The PTC nipple is the Positive Temperature Coefficient heater. The wires leading to it are nothing more than supply current for a heater to keep it from icing up.

Here is link that explains it a bit better.

http://www.volvoclub.org.uk/faq/EngineF ... #PTCNipple

...Lee

Post by **Brucebo** » 11 Oct 2009, 14:17

gojoaddict wrote:I aligned the crank with one of the notched teeth to the mark on the engine block instead of the right way which is aligning to the valley between the two notched teeth. So would being off by half a tooth at the crank (with the cams aligned properly) cause the engine to run rough when started?

FYI: You can't be off by "half a tooth". You can only be off by whole numbers of teeth.

-Bruce