Re: question re timing belt change for subaru legacy wagon 92, ASAPplease?

> If you do the oil pump, recommend cranking the motor with coil disconnected
> until oil light goes out, to avoid a dry start. Also, after flushing and
> refilling your radiator, "burp" it by letting it run open loop for a while and
> then letting it cool off: when cool, remove radiator cap and fill to the top;
> repeat until the level does not go down after the motor has been run.
>
what does running the radiator 'open loop' mean?

thanks for all the advice. I am fairly mechanically inclined and have no
trouble following a manual (I'm an engineer, have followed way more
complicated instructions than a car manual). If I buy the car today, I
will be picking up a timing belt and Chilton's on the way home.
thanks,
k wallace

Wallace,

Here is a web document that should help. At least the pictures will
let you know what you are looking for

endwrench.com/images/pdfs/2.2Liter.pdf

ceraboy@yahoo.com wrote:
> Wallace,
>
> Here is a web document that should help. At least the pictures will
> let you know what you are looking for
>
> endwrench.com/images/pdfs/2.2Liter.pdf
>

Sounds like you know this make/model- something I recently read about
interference engines is that most cars with two valves per cylinder are
non-interference, while cars with 4 valves per cyl. ARE interference.
This subaru legacy 1992 is a 16-valve (so, 4 per cylinder).
I'm just going to have to pick up the manual tomorrow, but is the one
that you changed the timing belt on also a 16-valve? And it's a
non-interference engine?
Why would anyone use the interference design? It doesn't sound like it
increases performance. It just sounds like (from the bit of reading i've
done today) that you can make the engine physically smaller and get the
same power out of it. Is that right?
If I find that this IS an interference engine, I don't think i even want
to drive it until I change the timing belt. If it's not, I'll still do
it, but I won't be paranoid about it, as the car will just stop if the
belt were to break.
thanks again,
k wallace

All the 2.5L DOHC subie engines are interference. The 2.2L was non
interference until 1996 at which point it is a bit hazy as to exactly
when the interference design was brought in. Yes most SOHC engines are
2 or 3 valves per cylinder, but the subie went with 4. I admitt that I
sure like the idea of a non interference engine, but with the DOHC it
is a bit tough to pack everything in without utilizing an interference
design. Regarding the use of DOHC arguments can go either way, but
valve float can be minimized more easily in the DOHC design (as
oppossed to using very stiff springs in the SOFC), valve placement and
angle can be better optimized, and further the use of DOHC allows the
spark plug to be centered in the combustion chamber which can improve
flame propagation. Yes the difference could be quite small in the
scheme of things unless you lean towards racing performance. The good
news is that with the current timing belts that use curvilinear teeth,
timing belts intervals have been upped to 100K, but even then as long
as you have no oil or antifreeze leak issues your belt will probably
hold out for a while yet. Regarding the valves issue indeed the
original 2.2L engines had 16 valves, however, the cylinder was designed
with clearance between the valves and piston. I do not believe there
is any rule that 4 valves per cylinder indicates interference. The
1990 - 1994 engines are without a doubt non-interference type. If you
had an outback with the 2.2L in 1995 you should be ok as well, but
after that use caution. I spun my camshafts several times in my 1992
Subaru Legacy AWD manual looking for the timing marks with no problems.
If you are worried just change the belt ASAP and spin the cam shaft
real carefully. Although to the untrained, the force of the valve
springs could feel like some sort of interference.

ceraboy@yahoo.com wrote:
> All the 2.5L DOHC subie engines are interference. The 2.2L was non
> interference until 1996 at which point it is a bit hazy as to exactly
> when the interference design was brought in. Yes most SOHC engines are
> 2 or 3 valves per cylinder, but the subie went with 4. I admitt that I
> sure like the idea of a non interference engine, but with the DOHC it
> is a bit tough to pack everything in without utilizing an interference
> design. Regarding the use of DOHC arguments can go either way, but
> valve float can be minimized more easily in the DOHC design (as
> oppossed to using very stiff springs in the SOFC), valve placement and
> angle can be better optimized, and further the use of DOHC allows the
> spark plug to be centered in the combustion chamber which can improve
> flame propagation. Yes the difference could be quite small in the
> scheme of things unless you lean towards racing performance. The good
> news is that with the current timing belts that use curvilinear teeth,
> timing belts intervals have been upped to 100K, but even then as long
> as you have no oil or antifreeze leak issues your belt will probably
> hold out for a while yet. Regarding the valves issue indeed the
> original 2.2L engines had 16 valves, however, the cylinder was designed
> with clearance between the valves and piston. I do not believe there
> is any rule that 4 valves per cylinder indicates interference. The
> 1990 - 1994 engines are without a doubt non-interference type. If you
> had an outback with the 2.2L in 1995 you should be ok as well, but
> after that use caution. I spun my camshafts several times in my 1992
> Subaru Legacy AWD manual looking for the timing marks with no problems.
> If you are worried just change the belt ASAP and spin the cam shaft
> real carefully. Although to the untrained, the force of the valve
> springs could feel like some sort of interference.
>
thanks a lot, that's just the info I wanted. I have the exact same car
now, and I think I'm going to be very happy with it. OTOH, it did just
cost me $32 to fill up. (wondering if I should have just fixed the old
Kawasaki Ninja in the garage- would have been cheaper for commuting...)
thanks again for the details. I do appreciate it.
k w.

k wallace <wallace.k@engr.orst.edNOSPAMu> writes:

> what does running the radiator 'open loop' mean?

Shorthand for "let the engine warm up until the thermostat opens and water
starts circulating through the radiator".

k wallace <wallace.k@engr.orst.edNOSPAMu> writes:

>Why would anyone use the interference design? It doesn't sound like it
>increases performance. It just sounds like (from the bit of reading i've
>done today) that you can make the engine physically smaller and get the
>same power out of it. Is that right?

I don't know what I'm talking about, but I would speculate that it allows you
to get higher compression out of a shorter stroke or a smaller cylinder bore.
The piston at TDC is flush with the top of the cylinder, so removing room in
the cylinder head part of the combustion chamber increases the compression.
And brings the valves closer to the piston.