timing belt skipped Re: How was your trip home?

[SJ]

>From: "Denis" <sparkplugvw at hotmail.com>
>To: "SJ" <syljay at optonline.net>; <quattro at audifans.com>

  >Hmmmmm, what about opened valves ?
  >I tried and the air goes trought the opened valves.....
**** I may be wrong on this, but the standard 5 cylinder engine has no
overlapping valve timing. On any cylinder, either both valves are closed, or
either one open, but both valves are never open at the same time.

We need some expert opinion here from engine builder type listers.

You may have leaking valves. In other words, the valves do not seal
completely.

You can test for this with a leakdown tester. Its a simple device that you
can build yourself.
The principle of operation is simple.
Pipe divided in half by a plug(epoxy) in center.
A 0.040 inch hole is drilled in the plug.
Pressure guages are installed in each half of the pipe.
One end of the pipe (X) has air hose connnector.
Other end of pipe (Y) has a valve on it.
Attach air compressor to X side.
Shut off the valve on Y side.
Set air regulator on compressor for 100 PSI

Both pressure gauges on pipe will read 100PSI.  Makes sense . . .closed
chambers . .same air pressure on both sides..

Slowly open the valve on Y side of pipe.
The pressure on Y side of pipe will drop, but pressure on X side will remain
constant at 100 PSI.
With valve all the way open, you will get 100 PSI on X side and 0 PSI on Y
side . .. makes sense . Y side is open to the atmosphere.

Adjust valve so you get 80 PSI on Y side gauge.
X side gauge reads 100 PSI, Y side gauge reads 80 PSI - - - you have 20%
leak.
This is how you read a leakdown tester.

To test cylinder leakage:
Connect Y side of leak down tester to spark plug hole of cylinder under
test.
Remove coolant reservoir cap. (in case you have head gasket leak)
Cylinder at TDC.
Lock the engine so it will not spin!!!! ( I set TDC carefully and never had
a cylinder go down with compressed air)
Connect X side to air compressor set for 100 PSI
Slowly open valve on Y side until its fully open.
If the cylinder is not leaking any air, the Y gauge will read 100 PSI
If you do have some leakage, the Y guage will read lower than 100 PSI
All engines leak will leak some air . .past the rings or past the valves.
10% leak for an older engine is not unusual.

To determine where its leaking.
Put some oil in the cylinder . .if leak stops, it was the piston rings.
Put ear at tailpipe, if you hear air rushing out, leak is at exhaust valve.
Put ear at Throttle body with valve open, if you hear rushing out, leak is
at intake valve.


 > The air goes to the intake then trought the valves. If i dont want air
goes trought the valves i must remove the cam to let >all valves at rest.
**** Air is not supposed to go thru the valves. One or both valves are
always closed.
How bad a leak is it?
Are you sure its not leaking thru some hoses?
You said you had an air leak at the intake manifold. Did you spray some
soapy water there and look for bubbles?

SJ

  >Ðenis
    ----- Original Message ----- 
    From: SJ
    To: Denis J
    Cc: quattro at audifans.com
    Sent: Sunday, December 26, 2004 12:52 AM
    Subject: Re: timing belt skipped Re: How was your trip home?


    How about using a pressurized intake manifold to find the vacuum leaks?
    You put in pressurized air at 3 PSI . .and look, listen, feel for leaks.
You
    can use a soapy water solution(dishwashing liquid detergent) to spray
around
    and look for bubbles.
    You can also use a rubber hose as a stethoscope to listen for escaping
air
    at various places.

    The intake manifold and engine is a sealed system.(NO)  The only free
opening is
    the fuel regulator sensor plate plenum.
    Pressurized air wont get past the valves in the combustion chamber in
each
    cylinder.
    Both valves are never open at the same time . . . unless you have a Hot
Rod
    for the drag strip.

    Sealing the regulator can be simple, or a little more complicated .
depends
    if you have that domed screen that sits on top of the regulator
plenum.(Yes i have)

    -------Simple method----------.
    Remove the "air bonnet".
    If you have the domed screen -
    Take a plastic shopping bag, or garbage bag
    Place over the regulator screen and down the sides
    Replace the "air bonnet"
    The intake system is now sealed.

    ------More complicated Method-------

    If you dont have that domed screen, you need to make a plate to support
the
    plastic sheet so it doesnt burst.
    A round piece of thin plywood or plastic or metal should do. A trip to
the
    junkyard to find a screen might be a good idea.
    Place the round piece of wood on top of the plenum, cover with plastic
sheet
    and put on air bonnet.

    Rig something up so you can let in compressed air at 3 PSI into the
intake
    manifold. Schraeder valve in a hose maybe, with a T you can also hook up
a
    pressure gauge. You can use a bicycle pump of you dont have a
compressor.


    SJ
    85 Dodge PU, D-250, 318, auto
    85 Audi 4k - - sold but still on the road
    88 Audi 5kq
    90 Audi 100q


    ----- Original Message ----- 
    From: "Denis J" <sparkplugvw at hotmail.com>
    To: <syljay at optonline.net>; <quattro at audifans.com>
    Sent: Saturday, December 25, 2004 11:20 PM
    Subject: Re: timing belt skipped Re: How was your trip home?


    > I did tried with ether andit accelerate but i cant know where is it
    exactly.
    >
    > As i said i ll change injectors O rings and intake gasket.
    >
    > I ll do the cam cover gasket too.
    >
    > So anything around the place where are leak, i ll change gaskets and O
    rings...
    >
    >
    >
    > Denis
    >
    >
    >
    > >From: SJ <syljay at optonline.net>
    > >To: Denis <sparkplugvw at hotmail.com>
    > >Subject: Re: timing belt skipped Re: How was your trip home?
    > >Date: Sat, 25 Dec 2004 18:58:22 -0500
    > >
    > >Denis
    > >
    > >Here is a trick to help find vacuum leaks.
    > >
    > >Mix solvent(carb cleaner) with ATF(auto transmission fluid). I guess
a
    50/50
    > >mix should work.
    > >
    > >Spray this mix around gaskets.
    > >When you hit the leak, the engine RPM's should go up . .AND . you
will
    see
    > >white smoke out the exhaust.
    > >
    > >As a test, spray the mix into a vacuum connection just to see what
effect
    it
    > >has on the exhaust.
    > >
    > >Disconnect the ISV valve, otherwise you wont notice the RPM changes.
    > >
    > >SJ
    > >85 Dodge PU, D-250, 318, auto
    > >85 Audi 4k - - sold but still on the road
    > >88 Audi 5kq
    > >90 Audi 100q
    > >
    > >
    > >
    >