Torque curve for 2.5 L Forester donk?

[Ratbag]

G'day again Taz

Ratbag, after having issues before hand and spending a few thousand on her im not replacing the engine. She just runs out of puff both on and offroad thus my reasoning for the SC, im not looking for turbo power either, just enough to have power on demand when its needed. From doing some calculations the SC should give me similar power to an EJ25 found in the eirlier Foresters but with more torque, mainly low down and in the mid range.

A supercharger gives you an increase in power and torque that is exactly proportional to the boost. e.g. a 7 psi boost will lift power and torque at the same revs by 50% (approx, of course); 3.5 psi by 25%, etc.

The valve stem/guide seals are completely r**ted, I have had a compression test done which came back almost like a new enigne on all 4 cylinder which means all the internals are fine.

There's your oil burning problem.
Replace the valves/valve guides and stem seals.


These being buggered has several effects:

1. Excessive direct injection of oil into the cylinders when the valves are open on the inlet stroke;
2. This oil is burned during the combustion (power) stroke; adding to carbon deposits throughout the internals of the engine; and causing the cops in the big city to pull you up and slap an "unroadworthy" certificate on you ... ;
3. It also allows the sump to be pressurised during the exhaust cycle, forcing more oil up past the oil scraper rings - and more burned oil ...
4. The additional oil during combustion leads to loss of power, and will also fool the combustion chamber sensor into firing the plug the second time at the wrong time ... This will lead to loss of power and torque.

Might try and clean a few of the sensors and just hope for some improvment.

From the compression test coming back at 230PSI on average for all 4 cylinder im guessing the rings are fine??

Should be. But then I don't know what it's supposed to be :iconwink:.
Remember that the inlet and exhaust valves are both closed during the compression stroke. This means that the compression (and rings) can be excellent, but the problems you are having will be occurring.

I know everything else is. She just burns through massive amounts of oil. I have gone through over 5L of oil just this year alone, in aorund 5000km!!

This can't be fixed though until the engine is out and apart, which will happen sometime this year. I need to chat to some of the Ausubaru guys in Perth and see if they can help.... don't really want to pay 10hours labour for a mechanic at $100 an hour.

Muzzle not the kine that tread the grain, mate! Even though I am a devout atheist, I have actually read the Bible. It sure has some good quotes in amongst the rest of it ...

If it were the sprk plugs wouldn't the engine just misfire and the likes? She used to run quite abit better mid last year even with the bigger tyres and roofs racks, etc... on the roof and front of the car.
The last time I changed the plugs was 25,000km ago or there abouts.

When I sold Roo1, the plugs had done somewhere over 100,000 kms. However, it was rather sluggish over 150 km/h when passing (and fully loaded). 25,000 kms ought to be fine if you are using spec. NGKs.

On my last trip in it, I did about 4,300 kms and did not use a drop of oil or water. The air-conditioner ran for all but about 2~300 kms of that (35~40+°C ... ); with most of it just under 20 km/h over whatever the speed limit was (mostly ).

 

[Ratbag]

G'day mate

When I did check the plugs just the other day though the were covered in quite abit of carbon/dry oil. I know this is due to the valve stem seals being worn.

The same can be said for your rings ...
High compression readings can also be caused by serious carbon deposits around your rings ...

EDIT: atfer reading through my Haynes rapair manual its given me some extra ideas of what to look at. How often should the fuel filter be replaced? Ive done just over 50,000km in the foz and it hasn't been replaced while ive had it.

With mine, it should be replaced every 62,500 kms or 30 months.

It also never had a proper 100,000km service. Could that have anything to do with it?

Taz, I would have that done ASAP. How many kms have your car done?
I don't know about your engine, but if mine drops the camshaft timing belt, it takes the donk apart ... .

Opps thread hi-jack, i'll stop after this post.

It's my thread, hi-jack it all you like ... . All valuable stuff for everyone.

 

[taza]

Thanks Ratbag!!!

I was told 150PSI compression would be good for an engine of my age and km. So with 230PSI so I can't complain. Im guessing then the massive amounts of burning oil would be effecting my power greatly.
It seems to burn much more when highway driving to around town anyway.

I might start looking inot the valve stem seals/guides when I move down in a week. I never used to have to drop back to 3rd or 4th to overtake like I do now and she used to move along fine. I remember when both myself and my mother were driving to look down and were doing about 150km/hr and didn't even realise. She just climbed up there with ease, now im lucky to reach 140 on a flat.

I would hate to put her on a dyno, I would probably only get about 75-85Kw on the flywheel. rofl

Will stop hi-jacking now but this does have to do with torque and power figures

Taza

 

[Ratbag]

Hi Taz

Thanks Ratbag!!!

I was told 150PSI compression would be good for an engine of my age and km. So with 230PSI so I can't complain. Im guessing then the massive amounts of burning oil would be effecting my power greatly.
It seems to burn much more when highway driving to around town anyway.

If your engine is supposed to have a compression figure of 150 psi (which sounds very reasonable to me), then having a reading of 230 psi is just as bad as it being 110 psi ... I hate to tell you this.

That additional compression can only come from there being very significant carbon deposits on the heads and piston crowns and valve heads. Probably also bad carbon build up on the valve seats as well. This latter leads to serious heat build up in the valve (carbon is a flaming good insulator ... ); and also reduces the amount that the valves open, thereby seriously reducing the ability of the engine to inhale petrol/air, and to clear the exhaust gasses efficiently.

ALL of these things will negatively impact economy, power and oil consumption ...

Since the heads have to be removed to fix the valve guides/seals anyway, sounds like a good idea to do a thorough de-coke while they are off. Seems that it would be sensible to do this when the timing belt is done, as the front of the motor is out of the way when that happens.

I might start looking inot the valve stem seals/guides when I move down in a week. I never used to have to drop back to 3rd or 4th to overtake like I do now and she used to move along fine. I remember when both myself and my mother were driving to look down and were doing about 150km/hr and didn't even realise. She just climbed up there with ease, now im lucky to reach 140 on a flat.

I would hate to put her on a dyno, I would probably only get about 75-85Kw on the flywheel. rofl

Will stop hi-jacking now but this does have to do with torque and power figures

Taza

Yes, mate, it does have a lot to do with the subject of the thread. No worries about that.

 

[taza]

The previous owner never took the car to a mechanic, not since it had its 1000km server back in 2001.
The owner did the timing belt himself with a cheap chinese one. I just had the belt replaced along with the water pump which was leaking and about to fail. My mechanic said the belt was quite worn (being a cheap piece of crap) or that the owner never actually did it. I didn't get one piece of service history. Never again will I buy a car without it!
The compression for my engine new is 250PSI so 230PSI is good, not bad. Its different with the EJ25's and depending on SOHC or DOHC, etc...

Since she had never had been properly service, just bits and pieces done everynow and again ive had LOTS of work done from the clutch through to belts, leaks fixed and the likes.
I decided to run through a can of Subaru Upper Engine cleaner (mid 2011) which cleared out all the carbon build up(since it was never done) but since the seals had gone hard it ment that oil could/can escape and burn. Thus causing my massive amounts of burning.
But nothing can really be done until you crack open the engine itself, it's easier with a boxer motor to do it with the engine out so it looks like it will be a weekend job with a few other Subaru nuts and a few cartons of beer.

Im keen to get it done because the car just runs like crap and I only realised this after driving 2 other 1st gen Forester. They seemed to go much better than mine does.
But if some other things need to be done while the engine is apart I will do them, atleast that way it will be like new out of the factory and good for another 600,000km (hopefully).
By the way my Forester done 168,000km.

 

[mr turbo]

Where's the hi-jack ? Because I can't see it
Just keep going guys, I'm thoroughly enjoying the read

Regards
Mr Turbo

 

[Ratbag]

Gidday Taza

According to this:
https://forums.nasioc.com/forums/showpost.php?p=27273522&postcount=2

Your compression should be between 142 and 171 psi.
Minimum is 128 psi.
Maximum difference between cylinders is 7 psi.

At 230 psi, it confirms at least much of what I have said.

I agree about buying cars with such a RS "service history" as yours has apparently had. Don't worry, we all get burned like this at one stage or another in life. Better to learn it early, rather than later ...

If it's any consolation, I have helped to explain to a customer at a Subaru dealer how her engine could be stuffed at under 100,000 kms. Carbon build up from driving it too gently!

 

[taza]

Since the engine will be out to do the valve stem/guide seals I should clean out all the carbon too?

 

[Ratbag]

Gidday Mr T & Taza

Where's the hi-jack ? Because I can't see it
Just keep going guys, I'm thoroughly enjoying the read

Regards
Mr Turbo

LOL! Feel free to contribute. It's been a bloody long time since I stripped and rebuilt any engine. At least 30 years ...

Since the engine will be out to do the valve stem/guide seals I should clean out all the carbon too?

Yeah. And ream out the extractors as well. Depending on how smooth they are on the inside, a bit of a polish up with carbide grinding wheels wouldn't hurt your exhaust extraction either.


It was amazing the difference the following made to my Mum's Morris 1100:

• Stage 6 (full racing spec) port and polish. Porting involved reaming out the inlet and exhaust ports to the maximum while leaving enough metal behind so that the separators didn't crack. Cross-flow heads were very rare in those days. Polishing involved making the inlet and exhaust ports so shiny you could see your reflection in them.
• The ports on the head were then matched exactly to the inlet/exhaust manifolds.
• The combustion chambers in the cylinder head were all taken out to the same volume (capacity). The piston crowns were always the same volume, but the head combustion chambers varied with the rough cast iron castings of the day. Sometimes up to 2 ccs or more. Very specialized machining work done by an artist - NOT me!!
• Stage 6 inlet valves (they can stand being enlarged this much as the incoming fuel cools them - another reason for running E10 is that metho evaporates faster than petrol, so cools the valves better). My father's supercharged Mark V Jaguar had a metho injector setup fitted for this reason.
• Stage 2 exhaust valves. Smaller valves have a larger seat contact area to head area ratio, so transfer heat into the cylinder head faster than larger valves. Exhaust valves run far hotter than inlet valves. The oil and water circulating in the head then remove this heat.
• Wade 104 full race camshaft. 25/65 overlap, with a 0.4" lift at the valves. The full race BMC one was 20/60, with a 0.38" lift.
• Very cold plugs. Champion N3. Champion N5s were standard. I had to clean and gap them every 1,500 miles. Useless in traffic - would carbon up within about 3~5 minutes idling (replaced often ... every 7~10,000 miles).
• Full flow sports air cleaners.
• Sewing machine oil in the carburettor dampers instead of engine oil.
• Meticulous attention to valve clearances, plug gaps and carburettor cleanliness, sync and mixture. ALL adjusted about every 1,000 miles.
• Ran the ignition timing static advance at around 10~12 degrees BTDC instead of 5~7.
• Ventilated distributor points (replaced often ... ).
• High voltage sports ignition coil.
• Full-bore BMC Works extractors from the 1340 cc racing Mini Cooper S.
• 2" straight through exhaust, with a token torpedo muffler.

It was so quick it would hold an 1800 cc standard MG-B all the way from 0 to 105 mph (my top speed, at 7,000 rpm in 4th ... ). You have to remember that these engines were positively agricultural by comparison with modern donks. The 1100 engine only had three main bearings ...

 

[NachaLuva]

My 2.0l is just crap, I am really starting to hate the darn thing. My ratios are fine but its just crap on the highway, around town shes quite pokey for a 2.0l but once you get past 90 its just like hell.... Even with an empty load and nothing on the roof I can't even hold 110km/hr on small inclines.

I find mine's not too flash around town but on the freeway its good. Just today I wanted to zoom around a driver doing 95 in the right lane on the freeway, before he had a chance to speed up. Just left it in 5th & it zoomed by... Above 3000rpm has heaps of grunt.

Yup. That's towing it up Skene's Creek Road to Birregurra from Apollo Bay (actually, from Skene's Creek, LOL); here:

https://maps.google.com/maps?ll=-38...e=-38.81630401,143.705635,20328.42,0,44.822,0

A steep climb from sea level to the top of Mount Sabine of around 500 metres. Bloody near straight up ... :iconwink:. Sure felt like it with the trailer on and the car packed to the gills with stuff.

Skenes Ck Rd is pretty steep! I wouldnt want to tow anything up there lol

Have you had a compression test done?
Sounds as if the rings are stuffed (all of them; compression and oil scrapers); valves not seating properly, or dead; worn valve guides (or spark plugs ... ) are buggered. Maybe the engine sensor is out of whack (next to the front crankshaft pulley on the Impreza).

His compression is awesome...valves maybe? I think he's gonna do them soon

Just doesn't sound right to me.

+1, def some probs there

You might well be better off dropping an EJ-254 into it, if that can be done easily ...

It sure can :biggrin: Not easy, but is a very popular mod on here...

 

[NachaLuva]

Since the heads have to be removed to fix the valve guides/seals anyway, sounds like a good idea to do a thorough de-coke while they are off.

+1

How often should the fuel filter be replaced? Ive done just over 50,000km in the foz and it hasn't been replaced while ive had it. It also never had a proper 100,000km service. Could that have anything to do with it?

yep I would def do the fuel filter when you do the valves...

The previous owner never took the car to a mechanic, not since it had its 1000km server back in 2001.
The owner did the timing belt himself with a cheap chinese one. I just had the belt replaced along with the water pump which was leaking and about to fail. My mechanic said the belt was quite worn (being a cheap piece of crap) or that the owner never actually did it. I didn't get one piece of service history. Never again will I buy a car without it!

Thats a bugger but it doesnt mean with a bit of work you cant have a great, reliable engine

I nkow its a pain & very disappointing, not to mention expensive, but I really would get this sorted out before you do the supercharger

 

[taza]

I find mine's not too flash around town but on the freeway its good. Just today I wanted to zoom around a driver doing 95 in the right lane on the freeway, before he had a chance to speed up. Just left it in 5th & it zoomed by... Above 3000rpm has heaps of grunt

If I want to overtake someone on the highway doing say 70-90km/hr I have to go back to 3rd, rev her upoto 55000rpm, quickly change upinto 4th and reach about 120km/hr then into 5th.

If someones doing 90-110km/hr and I want to get past I drop back to 4th plant my foot and slowly get upto 140 then drop her into 5th and by then im usually just past the car/s. I used to be able to just plant it in 5th if I was doing more than 90km/hr and I could pull like I was in 4th at the moment.

His compression is awesome...valves maybe? I think he's gonna do them soon

Its something along thoses lines but defernately the seals because of the burning oil. I won't know until she comes out and is on a bench :iconwink:

+1, def some probs there

Yes but will be worth the time, effort and money when done. Especially for the 25-25% power and torque increase from the supercharger. Should put along nicely in all situations :biggrin: Plus since I will assist some of the more mechanically minded people to do it I will learn a hell of alot :iconwink:

It sure can :biggrin: Not easy, but is a very popular mod on here...

Yes but I want the SC, plus its something different to just swapping to a H6 or 2.5. Plus with the heat I live in (reached 47degrees here today and was just under 40 at 8pm tonight) I don't think the H6 in a forester would do very well. I would be concerned about driving to the post office let along going on the soft beach sand.

 

[taza]

Nachaluva the chargers going on next weeke, maybe the week after depending how I go when I first move down to Perth. Plus uni doesn't start until the end of feb but I do have some things to organise and do.
The charger and engine should be fine just need to watch the oil level. But once the work is done she will run even better

 

[Rally]

If the existing engine is weak in the top end- including worn rings, then forced induction may hasten it's demise. But since it is low boost, hopefully all will be well.

 

[Ratbag]

Gidday Rally

If the existing engine is weak in the top end- including worn rings, then forced induction may hasten it's demise.

I agree. Or kill it stone dead !

The boost is at normal air pressure at the bottom of the inlet stroke.
Taza's compression ratio is currently about 16.5:1 (230/14) ...

But since it is low boost, hopefully all will be well.

Hopefully maybe. But I wouldn't even think about it until the current engine problems have been rectified personally .

 

[Rally]

That is a more or less what I meant

 

[taza]

Well I will look at getting at issue sorted within the next few weeks . The charger can be there but it doesn't mean I have to use it.

 

[El_Freddo]

My 2.0l is just crap, I am really starting to hate the darn thing. My ratios are fine but its just crap on the highway, around town shes quite pokey for a 2.0l but once you get past 90 its just like hell.

Are you sure this isn't just the P plate racer boy in you wanting an offroad lump to perform like a sports car? I know it happens, I was one of them back in the day, just in a different situation - I killed an engine doing it to - threw two rods out the side and created 5 holes in the block, you can see through the lower end of the block out to the other side I'm not proud of it, but I learned a lot from it. I should pull that engine down to really check it out.

Since the engine will be out to do the valve stem/guide seals I should clean out all the carbon too?

Cleaning out the carbon isn't that easy, you really need to get everything chemically washed, and with the block in one piece it isn't feasible. That said, if it's crusty and flaking you should be able to carefully scratch it off.

Realistically, what Ratbag is saying about your compression and oil usage is ringing true to me. What you'd be better off doing when you've got the engine out is to pull the whole thing down, get a re-bore (40 thou is usually the go), purchase new piston heads and rings that are 40 thou oversize to fit the new bore. Get the head's valve guides replaced - basically a full head service, new seal kit, check out if you need new bearings - probably a good thing to do since you're going to run the SC.

One question I've got for you is: when the compression check was done did you do it twice - once cold and once hot? Also what did the spark plugs look like - you can learn a lot about the engine's running condition by the crud on the spark plug.

If the existing engine is weak in the top end- including worn rings, then forced induction may hasten it's demise. But since it is low boost, hopefully all will be well.

Yeah this is true. And if you were to run with it just to see how it goes Taza, I'd leave off the head work until you need to rebuild the engine - or find a fresh one in good condition and swap that in.

Cheers

Bennie

 

[Ratbag]

Gidday Bennie

Since the engine will be out to do the valve stem/guide seals I should clean out all the carbon too?

Yes. The only opportunity to do it.

SUEC will maintain a clean engine in clean condition, as long as the car is not driven too slowly in the wrong gears all the time ...

It cannot perform miracles, however.

One tends to think of carbon as being soft.
Think "carborundum" instead ... It is harder than the average ball-peened hammer head ...

Very hard, stiff, machine-driven wire brushes that are designed for the job will remove most of it, without the risk of using a scraper, which can create grooves and swarf, both of which can create pre-ignition problems.

Final finish is done with a circular carborundum 'drum' mounted on a fluted rubber drive holder that is itself mounted in the head of the high speed flexible drive unit.

If the existing engine is weak in the top end- including worn rings, then forced induction may hasten it's demise. But since it is low boost, hopefully all will be well.

At Taza's compression ratio (actually 230/14.7, approx, = 15.65:1), any sort of boost pressure, even only 3.5 psi, will likely tear the engine to bits. Maybe blow the top of the piston/s out. It is already running the equivalent of around a 4 psi "boost" ( (230 - 171)/14.7 = 4.01 psi ... ). The current stress on the motor is around 61% above normal ( ((14.7 + 4)/14.7)^2 ).

This is not a good starting point for adding a SC ... .

Are you sure this isn't just the P plate racer boy in you wanting an offroad lump to perform like a sports car? I know it happens, I was one of them back in the day, just in a different situation - I killed an engine doing it to - threw two rods out the side and created 5 holes in the block, you can see through the lower end of the block out to the other side I'm not proud of it, but I learned a lot from it. I should pull that engine down to really check it out.

Broke the crankshaft in the Morris 1100 I described above. Spent some 5 days in Coffs Harbour watching endless repeats of the first Moon landing ...

That little engine was never designed to withstand what I did to it.
Getting a 16 cwt, 1100 cc car to go nearly as fast as a BMC Works racing Mini Cooper S - 1340 cc; blue-printed engine etc; AND it only weighed around 10 cwt ("cwt" = hundredweight. I am using the Imperial value, which is 112 pounds/cwt) was a big ask. It was fun while it lasted; and it lasted a surprisingly long time!

Cleaning out the carbon isn't that easy, you really need to get everything chemically washed, and with the block in one piece it isn't feasible. That said, if it's crusty and flaking you should be able to carefully scratch it off.

DON'T scratch. See above.

Realistically, what Ratbag is saying about your compression and oil usage is ringing true to me. What you'd be better off doing when you've got the engine out is to pull the whole thing down, get a re-bore (40 thou is usually the go), purchase new piston heads and rings that are 40 thou oversize to fit the new bore. Get the head's valve guides replaced - basically a full head service, new seal kit, check out if you need new bearings - probably a good thing to do since you're going to run the SC.

One question I've got for you is: when the compression check was done did you do it twice - once cold and once hot? Also what did the spark plugs look like - you can learn a lot about the engine's running condition by the crud on the spark plug.



Yeah this is true. And if you were to run with it just to see how it goes Taza, I'd leave off the head work until you need to rebuild the engine - or find a fresh one in good condition and swap that in.

Cheers

Bennie

Thanks for your independent opinion on this, Bennie.

Only problem with a s/h donk is that it may well have the same problems! My brother and some others I know have had this happen. You only find out AFTER you have removed the old donk and re-fitted the new one ... .

If I were Taza, I would carefully consider the likelihood of the engine having other damage and wear issues due to its very poor service history. Considering final cost; it may be worthwhile to get a s/h N/A EJ254 from a wreck, and fit that instead. Has anyone done this? How difficult is it; and how costly?

I can assure him that this engine will give him tons of grunt, unless he wants to do the "hoon-boy racer" stuff; and I don't think that's what he's looking for at all. I am continually amazed at the torque of this engine in my Fox, and its tractability at all speeds, in all gears.

The torque curves in this thread show one reason why ...
The far better chosen gear ratios (compared with my 1993 Impreza) tell the rest of the story.

 

[NachaLuva]

RB, I dont think he wants to swap in a new engine...he wants THIS engine running properly & with a supercharger.

But Taza, I really think you need to get it running properly BEFORE you add extra stress. Subarino would have had his running perfectly before he did his, which is why its lasted. Its great you're getting others to help you & you will learn heaps from, plus its very kind of them for all the offers of help you've had.

What Bennie is suggesting is a full rebuild. I'm guessing you're not so keen on that just yet. So perhaps when you have the engine out doing the seals (do you mean valve guides?) you could clean the pistons as RB said...do some research 1st.

Also use their experience to check valve clearance & anything else that can be easily done.

RB, a supercharger has been done before on a stock EJ20 with exc results incl longevity...Subarino's "Hatchie", still going strong. By all accounts, VERY STRONG lol