Subaru HO Engine questions

[SoCal LS-L]

Ive always been curious..... since our engines lay flat, does the piston ring and cylinder wall on the bottom side wear out faster since gravity is always pulling the piston down? Or does it balance out from having more lubricant there as opposed to the top of the cylinder for the same reason? And does everyone elses seem to pull much better at high rpm's and feels a little flat in the mid-range??

On a seperate note I had the timing belt yanked and noticed the white lines on the belt did NOT match up to the crank mark and pulley notches, not even close. Is this evidence that it has been replaced previously?? It should come from the factory dialed in right? Ok no more questions from me for a fortnight I swear

[RoughSilver92]

Well, I can't answer about the wear on the bottom, haven't tore that far into one yet, but I doubt it wears any faster. Now on the timing belt lines, those will only line up every X number of rotations(where X equals some fancy equation of teeth on the gears and teeth on the belt). This is easily noticed when you turn the crank 2 full rotations and confirm your timing marks still line up, and the lines on the belt are magically somewhere other than on the timing marks.

[log1call]

What? Wear in a subaru?

I have done a few subarus and at 160,000Km they are still like new inside. Rings and bearigs and off they go for a few more around the clock. Honestly, the wear in them is often unmeasurable with a micrometer.

I don't think, if they were to wear, that gravity would be much of a factor at all. The thrust of the conrod as the crank is out to one side is what forces the piston against the wall of the bore. Knowing subaru they will have it so the thrust is in an upwards direction on both banks... the tricky buggers.

[SoCal LS-L]

Originally Posted by log1call

What? Wear in a subaru?

I have done a few subarus and at 160,000Km they are still like new inside. Rings and bearigs and off they go for a few more around the clock. Honestly, the wear in them is often unmeasurable with a micrometer.

Thats great to hear. My 91 Accord rolled past 250,000 and still didnt burn a drop.... the asians can sure engineer a good powerplant. Im still curious if anyone else's has much better pull at above about 4000 rpm?

[oab_au]

Originally Posted by SoCal LS-L

Thats great to hear. My 91 Accord rolled past 250,000 and still didnt burn a drop.... the asians can sure engineer a good powerplant. Im still curious if anyone else's has much better pull at above about 4000 rpm?

4000 rpm is the change over point of the IRIS. (INERTIA RESONATE INLET SYSTEM). The Inertia system runs from 2200 to when the IRIS valve opens at 4000, to change to the Resonate system, that runs to 5000.
So there is a dip in the torque curve as the rpm rises, the Inertia system runs off it's peak, and the Resonate system starts to build torque to it's peak of 5000.

So yes they do pull better on the Resonate system.

Harvey.

[SoCal LS-L]

Excellent, thanks for the insight on that, was wondering. Now tomorrow out comes the ol resonator. Ive noticed that the splashguard directly below it has already worn a hole from bottoming out.... it seems that this angled protrusion faces forward so that maybe it can be further opened for a better ram-air effect into the wheelwell? Ive researched this topic relentlessly in the mods area but havent seen a mention of this protrusion or modifying of such Guess ill play it by ear tomorrow.

Edit: Included pic of what im referring to, and yes, I know my valve covers are leaking like a sieve

[svxfiles]

Originally Posted by SoCal LS-L

Ive noticed that the splashguard directly below it has already worn a hole from bottoming out.... it seems that this angled protrusion faces forward so that maybe it can be further opened for a better ram-air effect into the wheelwell? Ive researched this topic relentlessly in the mods area but havent seen a mention of this protrusion or modifying of such Guess ill play it by ear tomorrow.

Before I went with forced induction I ran for a time with no airbox resonator, and a 3" truck 90° radiator hose attached to the shortened end of the tube where the resonator was, through the said splash guard, and forward as a cheap, hidden ram air system.





However at the dragstrip it did nuttin!?
On the road in real life it should help.

[SoCal LS-L]

Ahhh then thats what I will do then..... im going to try to find some kind of funnel type inlet to the hose to scoop more air.... something rectangular for the opening that reduces to the 3" hose. Its one of those hunt the shelves at home depot and autozone type things. If it comes out less than ghetto ill post pics and parts info.

[Mike621]

*cue ill-fated copper intake thread from ages ago*

or you could get a Tomyx with CAI

[SoCal LS-L]

Greeeaaat what is it? I saw the thread you were referring to I think but its 98 posts long..... too long to wait for the punch line . It should be a pretty straightforward mod if I can find the right ducting and inlet, the protrusion from the pic below looks like an idea spot for it.

[YourConfused]

Originally Posted by Mike621

*cue ill-fated copper intake thread from ages ago*

or you could get a Tomyx with CAI

kinda like the putting an intercooler on a N/A motor thread.

[SVXRide]

Check my old locker (http://www.subaru-svx.net/photos/user.php?SVXRide|23910) for the only true SVX ram air (with instrumented pressure readings to confirm its benefit) running on the street. Dave H. put together a nice set up on the RaceCar that uses one of the fog light opennings.
-Bill

[longassname]

The tops and bottoms of the cylinders wear more than the sides. When you take them apart you will still see crosshatching all around so many people mistake that to mean the bores are not worn at all. A high miles engine is likely to be .006" out of round.

The lines on timing belt only line up when you install it. As soon as you turn the motor they don't line up anymore except after some magic number of revolutions that puts them back to the original locations.

Originally Posted by SoCal LS-L

Ive always been curious..... since our engines lay flat, does the piston ring and cylinder wall on the bottom side wear out faster since gravity is always pulling the piston down? Or does it balance out from having more lubricant there as opposed to the top of the cylinder for the same reason? And does everyone elses seem to pull much better at high rpm's and feels a little flat in the mid-range??

On a seperate note I had the timing belt yanked and noticed the white lines on the belt did NOT match up to the crank mark and pulley notches, not even close. Is this evidence that it has been replaced previously?? It should come from the factory dialed in right? Ok no more questions from me for a fortnight I swear