A1 timing belt howl, non cat exhaust systems

Last weekend I put the 83 JH code 1.8 I have spent the last 4 months
rebuilding in my 79 Scirocco. Huge improvement over the 1.6, and it
hasnt even been past 3500 rpm yet (100 miles on it). Everything inside
the block is new. The timing belt cover was from the 1.6, the belt and
the tensioner were replaced, and I took the best gears from both
engines. The howl starts about 1000 rpm. You can adjust it out with the
idle screw, but you always hear it somewhere near the perfect idle
speed. The old 1.6 did it, and my brother in law's 83 Jetta (think it's
a 1.7) does it also. The sound drives us both nuts. We thought it was
the position of the tensioner, the 2 manuals we have show different
views. I need to set the idle at 1200 rpm, because when you kick on the
DPD A/C (dealer installed I think) the idle drops to 1000. I have the
idle at 1000 now, not using the a/c. It just howls away. If I set the
idle at 1200, no noise, but turn the a/c on and it howls away. The car
is not smooth unless it idles around 1000 rpm, but the engine is still
tight.

I am one of the few lucky ones that doesn't have to pass emissions,
so I removed the EGR valve when I put the engine back in. Don't need a
cat. The manifolds, double downpipe, and timing cover are from the 1.6.
The exhaust system is stock, with the tiny hole at the bottom of the
downpipe. All the exhaust systems I have seen on the net seem to deal
with cats. I can probably have my brother in law fabricate a 2" or so
flange on the downpipe and have a shop do the rest to the tailpipe, but
i'd rather find something I can bolt in. I want to get the best mileage
with the most power, as I usually drive it on the highway. Any ideas?

Todd,


> Last weekend I put the 83 JH code 1.8 I have spent the last 4 months
> rebuilding in my 79 Scirocco.

> the belt and the tensioner were replaced,
> The howl starts about 1000 rpm.

A few possible options...

1. You have the tensioner too tight. When it is set correctly, you should
just be able to twist the timing belt about 90 degrees at midspan between
the cam and crank pulleys.

2. The timing belt cover is rubbing. Remove the cover and see if it still
rubs. I've had this problem several times and just leave mine off now.

3. The tensioner pulley is bad. I have more than one bad part direct from
the auto supply stores. Rare, but it happens.

> The old 1.6 did it, and my brother in law's 83 Jetta does it also.

My wife's 1986 Jetta GLI makes a lot of belt noises too. I "think" it's a
misalignment of the various pulleys, but I really don't know. I've adjusted
and replaced the parts a few times and hers is still much noiser than my
1976 Rabbit.

> I am one of the few lucky ones that doesn't have to pass emissions,
> so I removed the EGR valve when I put the engine back in. Don't need a
> cat.

I removed all the emission equipment from my 1976 Rabbit years before they
implemented emission checks in our area. To my surprise, I still passed the
emission tests easily without all of that. Of course, now that my car is
more than 25 years old, I'm no longer need to get emission checks anyway.

> All the exhaust systems I have seen on the net seem to deal
> with cats.

Techtonics can probably supply whatever you need.

I'm sure any muffler shop could fabricate a straight pipe replacement for
the cat as well.

Anthony

i'd guess it's a timing belt problem of some sort. either the tensioner is
a bit too tight or the belt is rubbing against the cover somewhere.


"Todd" > wrote in message
oups.com...
> Last weekend I put the 83 JH code 1.8 I have spent the last 4 months
> rebuilding in my 79 Scirocco. Huge improvement over the 1.6, and it
> hasnt even been past 3500 rpm yet (100 miles on it). Everything inside
> the block is new. The timing belt cover was from the 1.6, the belt and
> the tensioner were replaced, and I took the best gears from both
> engines. The howl starts about 1000 rpm. You can adjust it out with the
> idle screw, but you always hear it somewhere near the perfect idle
> speed. The old 1.6 did it, and my brother in law's 83 Jetta (think it's
> a 1.7) does it also. The sound drives us both nuts. We thought it was
> the position of the tensioner, the 2 manuals we have show different
> views. I need to set the idle at 1200 rpm, because when you kick on the
> DPD A/C (dealer installed I think) the idle drops to 1000. I have the
> idle at 1000 now, not using the a/c. It just howls away. If I set the
> idle at 1200, no noise, but turn the a/c on and it howls away. The car
> is not smooth unless it idles around 1000 rpm, but the engine is still
> tight.
>
> I am one of the few lucky ones that doesn't have to pass emissions,
> so I removed the EGR valve when I put the engine back in. Don't need a
> cat. The manifolds, double downpipe, and timing cover are from the 1.6.
> The exhaust system is stock, with the tiny hole at the bottom of the
> downpipe. All the exhaust systems I have seen on the net seem to deal
> with cats. I can probably have my brother in law fabricate a 2" or so
> flange on the downpipe and have a shop do the rest to the tailpipe, but
> i'd rather find something I can bolt in. I want to get the best mileage
> with the most power, as I usually drive it on the highway. Any ideas?
>

Like the others have said about belts and tensioners but it lso might be a
vacuum leak due to a defective hose. I have heard groans or moans coming
from the hose going to the intake manifold near the rear of the valve cover.
Usually I find a split in the hose and it only makes noises close to idle
IIRC.

Use a hose, heater hose is nice, to listen more carefully for this howl.

later,
dave
One out of many daves.