Time Chain....?

>Speaking as an electrical engineer and fair mechanic,
>removing the wire from a functioning plug does cause excessive high voltage
>which can damage the spark coil and more importantly, kill the transistor
>that drives the coil. Since the transistor is likely in the ECU, that can be
>a big oops!
>This is not to say that I have never removed a plug wire from a running
>engine either, it is just good to know what the potential damage might be.
>The coil drive transistor is actually pretty well protected but having a
>plug wire disconnected does cause abnormal stress on the components... and
>stuff happens.
>

You can definitly hurt a coil by pulling a plug wire and not grounding it. But
as long as you keep the wire near the head so the spark jumps into the head,
you should be ok.

"BANDIT2941" > wrote in message
...
> >Speaking as an electrical engineer and fair mechanic,
>>removing the wire from a functioning plug does cause excessive high
>>voltage
>>which can damage the spark coil and more importantly, kill the transistor
>>that drives the coil. Since the transistor is likely in the ECU, that can
>>be
>>a big oops!
>>This is not to say that I have never removed a plug wire from a running
>>engine either, it is just good to know what the potential damage might be.
>>The coil drive transistor is actually pretty well protected but having a
>>plug wire disconnected does cause abnormal stress on the components... and
>>stuff happens.
>>
>
> You can definitly hurt a coil by pulling a plug wire and not grounding it.
> But
> as long as you keep the wire near the head so the spark jumps into the
> head,
> you should be ok.
>
>

Also remember that the Saturn uses a waste spark ignition system. If you
remove a wire and don't ground it you will actually have two cylinders
misfiring.

>Also remember that the Saturn uses a waste spark ignition system. If you
>remove a wire and don't ground it you will actually have two cylinders
>misfiring.
>

Thats correct. There are 2 coils. When a coil fires it simply completes the
circuit between the 2 posts. One cylinder will be on compression stroke, the
other will be on exhaust.

"BANDIT2941" > wrote in message
...
> >Also remember that the Saturn uses a waste spark ignition system.
If you
> >remove a wire and don't ground it you will actually have two
cylinders
> >misfiring.
> >
>
> Thats correct. There are 2 coils. When a coil fires it simply
completes the
> circuit between the 2 posts. One cylinder will be on compression
stroke, the
> other will be on exhaust.

What I've done in situations like this is to connect a spark plug to
the disconnected wire and then ground out that spark plug.

Ken

I've never seen a busted chain. On the engines I've worked with in the past,
the most likely culprits were the camshaft sprocket (with nylon teeth that
wear) and hydraulic chain tensioner (getting slack due to low oil pressure
or binding). All contribute to a loose chain that will start to skip a tooth
here and there. One tooth off can make a big difference in the way the
engine runs. 10 teeth and you've likely got a bent valve and a dented
piston.
_________________
"BANDIT2941" > wrote in message
...
|
| There is no service interval. The chain is supposed to last the life of
the
| engine. If it does need to be replaced it will make lots of clattering
noise
| alerting you to impending doom. Oppie is correct in that it is and
interference
| engine. If the chain snaps it'll bend the valves.

>I've never seen a busted chain. On the engines I've worked with in the past,
>the most likely culprits were the camshaft sprocket (with nylon teeth that
>wear) and hydraulic chain tensioner (getting slack due to low oil pressure
>or binding). All contribute to a loose chain that will start to skip a tooth
>here and there. One tooth off can make a big difference in the way the
>engine runs. 10 teeth and you've likely got a bent valve and a dented
>piston.

Yeah. I don't think I've ever seen a busted chain either. Usually the chain
stretches with age and the tensioner stops tightening it up leaving slack in
it, which lets it skip a tooth. It is interesting how much difference one tooth
can make.

In article >, bandit2941
@aol.comNHRA says...
> >I've never seen a busted chain. On the engines I've worked with in the past,
> >the most likely culprits were the camshaft sprocket (with nylon teeth that
> >wear) and hydraulic chain tensioner (getting slack due to low oil pressure
> >or binding). All contribute to a loose chain that will start to skip a tooth
> >here and there. One tooth off can make a big difference in the way the
> >engine runs. 10 teeth and you've likely got a bent valve and a dented
> >piston.
>
> Yeah. I don't think I've ever seen a busted chain either. Usually the chain
> stretches with age and the tensioner stops tightening it up leaving slack in
> it, which lets it skip a tooth. It is interesting how much difference one tooth
> can make.
>

Engine timing is such a precise thing. This is why I will never trust a
"belt" for keeping it in time.

how do you know if a car has a belt or a chain? i mean like on the new
cars.

Why not? Timing belts usually have a Kevlar core and are stronger than steel
belts.

"Blah Blah" > wrote in message
...
> Engine timing is such a precise thing. This is why I will never trust a
> "belt" for keeping it in time.

Steel "belts"? Yeah probably so but Kevlar core or not, the outside is
still made up of decomposing rubber and has a life span even when
sitting still. (remember that the belt still makes contact with
unlubricated steel pulleys) Timing Chains that are well lubricated,
along with the valve train, wear out when the rest of the engine wears
out. By then who cares.

In article <1096324040.LYq2TvgQ8lMyVoc3/KY9ow@teranews>, boppie@-nospam-
ludl.com says...
> Why not? Timing belts usually have a Kevlar core and are stronger than steel
> belts.
>
> "Blah Blah" > wrote in message
> ...
> > Engine timing is such a precise thing. This is why I will never trust a
> > "belt" for keeping it in time.

In article <2e9855196c14b8639d5909eec23cd090
@localhost.talkaboutautos.com>, says...
> how do you know if a car has a belt or a chain? i mean like on the new
> cars.

I usually do a google search if its an engine I'm not familiar with. If
you can look at a owners manual it will say in the maintinance portion
if a "timing belt" is due for service.