Member Profile - Yowie's SH Forester XT

[Yowie]

Engine Rebuild

This will be an interim update with no pics.

I've finally joined the Subaru Club properly by having a head gasket issue. Both drivers-side cylinders (road/exhaust) side as it turns out. The symptoms were pushing a load of coolant out at the last Dirt Day, although there has probably been a mild head gasket leak for some time on account of the slightly scummy coolant overflow water.

The engine had been consuming oil for a while, so a bottom-end freshen-up is also needed if the heads are coming off.

There was a fair amount of carbon deposit in the combustion chamber from the oil-burning. The bores are in excellent condition however. Presumably we're just looking at oil control ring wear/failure. Pistons haven't come out yet, so ring land condition TBA.

After considering the options, I went for a factory brand-new EJ257 bottom end.

Despite the weight of opinion I went against a forged pistons option due to the fact that it's a daily driven car running factory-ish boost levels and knock-resistant E85 fuel. Also, the rarity of the lower-expansion 4032 alloy pistons would have added a month to the whole process.

I'll add an 11mm oil pump, some aftermarket sump goodies and other minor freshen-up old-for-new replacements for hoses etc.

Heads are being reconditioned and will go on with ARP head-studs.


Lessons so far

1. You do indeed need to run upper-engine cleaner in a car running full-time E85.

2. The catch can/s are certainly not 100% efficient at scrubbing the oil out of the blow-by gas. I already knew this from the clear hoses and intercooler contents, but it's interesting seeing the cooked oil residue in the inlet manifold. When my budget recovers in the year 3000 it's tempting to add additional catch cans in series to try to scrub the air more. Having said that, a brand-new hypereutectic-piston bottom end might have significantly less blow-by.

[probably to add to this list as the process continues]

[Ric]

Good luck, I hope it goes well!

[Stifull]

Sorry to hear about your engine failure but I guess in the long run it will be good because you can build one exactly how you want. You still haven't had a drive in my GTsince the vf52 upgrade. I think you would like it..a lot..

[Yowie]

Thanks Ric & Stifull. I am indeed keen to drive your car with the VF52, dump pipe & tune. Of course anything would feel fast at the moment compared to the 1994 Corolla I'm currently borrowing.

--

So, the old block has excellent bore condition, but a fair bit of carbon on the pistons (almost certainly from all the oil it was burning).








This small, soft, non-ferrous chip was found in the sump (which was otherwise pretty clean as far as metal particles go). Perhaps it is bearing material?




The stock pickup and windage tray will be replaced with Killer B items. For budget and "realistic G-forces in a Forester" reasons that will be the extent of the sump upgrades. The stock pickup did not have any cracks forming, but apparently it is a known issue.






The new-from-factory EJ257 is much cleaner of course.









You can see the dark colour of the nitride treated crankshaft in this one:




Not critical but interesting, one of the old case halves had quite a poor surface casting on one part (see cracking type look). The new block has no such surface roughness.






More to follow in due course. The heads are currently with the head reconditioner. We'll also do some mild porting and port-matching with the heads (inlet and exhaust) plus the factory cast iron exhaust manifolds.

Thanks for reading.

[Stifull]

That's coming along nicely. The bore does look good. Are you doing it all yourself. I have never been gme to touch engines except the one in my first car but it was a lot less complicated. The 179ci in my Holden panel van blow up so I did a new 186ci block (new) with the 179ci head. but it was just a matter of head gasket, etc and resetting tappets. I hope your continues to be so good. Who has the heads ??

[Yowie]

My dad (who has some engine building & porting experience - but not yet Subarus) and his retired mechanic mate are doing most of the work. We're making it a bit easier for ourselves by not having a bottom end to build.

A Brisbane southside cylinder head shop (Coorparoo?) is doing the head work. I don't know the exact shop but can find out if that is useful to you.

[Yowie]

Porting

The inlet ports in the head seem pretty good. We did some porting on the far side of the inlet valves. Work-in-progress shots below:






On the exhaust side, the head-to-manifold match was quite poor from factory. Both the head and manifold ports were brought out to 41mm diameter:







(apologies for low-light poor quality photos)


We also cleaned up the entrance to the up-pipe, noting the evidence of greater heat on the outside of the bend (where you would expect the exhaust gas to be concentrated - 1st pic):






Heads & timing gear on

We're getting there. When some more replacement OEM hoses come in we'll be able to assemble more of the fruit on top of the engine.




Rightly or wrongly, for simplicity I decided to put back all the stock emissions gear (TVGs and secondary air pump system). Budget and time are already stretched without turning it into more of an R&D project.


Turbo replacement

I should have checked earlier, but the VF46 turbo has obviously had a long and fulfilling life since being rebuilt by GSG because there is a lot of side-to-side play in the shaft.

I'm now looking at VF52 "or thereabouts" replacement turbos, noting that this is a stock bottom-end, daily driven car & auto gearbox (and I like responsiveness). The VF46 plus E85 was probably a little too responsive (and choked-up at the top end) so moving boost threshold and die-off point a couple of hundred revs higher should be a good thing.

Currently I'm looking into a new Kinugawa TD05H big 16G 7cm but we'll see how research & enquiries go.

There are so many options it's a bit "paralysis by analysis". Eg:
- 12, 11 or 9 blade turbines?
- billet compressor wheels?
- 1.0 bar standard wastegate (0.5bar recommended from my research)
- 8cm hot side?
- 18G compressor side?

Any comments on this are very welcome.

[Stifull]

When the stock turbo in our Delica failed (blew the exhaust billet out the end of the tailpipe) I did a lot of research and ended up buying a Kinagawa cartridge, which is all the moving parts, bearings, oil and coolant in/out etc and it fitted straight into the existing turbo shell and the downpipe and inlet manifold pipe all stayed connected .... long story short... Kinagawa make a great product. They are a Japanese owned company in Taiwan and they provide turbos for several car companies including Hyundai and others. Mine has done many klms in the 7 years since that cartridge was fitted with no problems ..

[JezzaH6]

It's a shame about your engine but nice to see you putting the effort into the new one! Those old bores did look pretty great. Interesting observation re the poor quality casting- I have noticed this on a friend's car in the past as well. Porting looks great!

I'll add an 11mm oil pump, some aftermarket sump goodies and other minor freshen-up old-for-new replacements for hoses etc.

Have you been monitoring oil pressures previously? IIRC Turbolag (on a very similar engine setup, stock oil pump) was sitting above 75psi while cruising on the freeway, and even on track with stupidly high (145c+) oil temperatures it never dropped low enough to be of concern. Very curious to see what your pressures are like with the 11mm pump!

[Yowie]

Cheers JezzaH6

Interesting observation re the poor quality casting- I have noticed this on a friend's car in the past as well.

It's external and buried under all the cr@p on the top of the engine, so it doesn't matter, but most of us would still prefer nice-looking alloy casting.

I'm curious about the market (if any) for used EJ25 blocks, and whether it's affected by splitting the case halves. After all the main activity is out of the way I'm tempted to strip the old block further for curiosity's sake.

Porting looks great!

Honestly, it's a bit rough, but I'm not the one doing it, beggars can't be choosers etc. In theory even a rough port in key areas should be better than stock. The internet can argue about smooth finishes vs rough.

The stock exhaust manifold mismatch does point to the value of a simple port job - easily enough done by a garage amateur.

Have you been monitoring oil pressures previously? IIRC Turbolag (on a very similar engine setup, stock oil pump) was sitting above 75psi while cruising on the freeway, and even on track with stupidly high (145c+) oil temperatures it never dropped low enough to be of concern. Very curious to see what your pressures are like with the 11mm pump!

Yes to monitoring. The only written record will be in this build thread, so not scientific.

The 11mm oil pump was one of many recommendations I adopted from a local performance shop operator (the deal being advice as well as parts) without a great deal of research or second-guessing on my part.

I am aware of the down-sides of going too big with the oil pump (especially with a new tight-clearance engine). Apparently 11mm is standard with an STI, so it must not be catastrophic.

Agreed that it will be interesting to monitor once the car is going again.

----

General update

The turbo question has resolved in favour of a new VF52. The tuner's comment was:

"I’ve never been overly impressed with TD based turbos, excluding the FP Reds, but the 200-250kw TD’s always need more boost for the same power [than] IHI and Garrett based, even copies of."


For start-up, running-in and getting around until a mid-November tune I'll run vacuum hose directly from the compressor housing to the wastegate control (keeping boost at its lowest possible level). Apparently that won't be a problem, noting that the injectors and/or Inlet (in the MAF area) have not changed since the last tune.

Also, lower compression (EJ257), bigger turbo and E85 should keep knock well away if I don't drive like an eejit.


More generally, this whole engine rebuild exercise is eye-wateringly expensive by my modest standards, even when trying to be as sensible as possible about needs-based upgrades only, with some free labour, re-using a lot of things, etc.

There is a lot to be said for treating one's car well, going for long life & reliability and not turning power up to eleventy.

In many respects I have treated this engine with a lot of mechanical sympathy, but at the end of the day a small-med turbo (VF46) and E85 is going to put a lot more wear on a drivetrain for a lot more of the time spent driving, as is any type of motorsports fun.

[Yowie]

VF52 pictures, dimensions and instructions

...for weirdos into this sort of thing. You disgust me.


















The transition to the wastegate hole in the cast housing:





The 45mm diameter of the turbine housing inlet shouldn't be a problem when you consider the 39mm or 41mm (depending if inner sleeve or inner diameter at the join) up-pipe:

[bigBADbenny]

Great updates!
What was your oil consumption rate prior to the teardown?

[Yowie]

Great updates!

Very kind of you to say. Hopefully more of substance to follow when the engine is back in the car, run-in & tuned.

What was your oil consumption rate prior to the teardown?

"A lot". Don't take this as gospel, but perhaps 2 litres over a 5000km change interval?

I still ponder where it was being lost. Presumably worn rings were a big factor, combined with other sources (eg valve guides). The extra blow-by may have added more oil to the catch can contents. It will be very interesting to see the catch can pattern with a new tight engine (noting that summer "new" versus winter "old" is not apples-to-apples).

Does a loose/worn set of turbine shaft bearings mean oil is lost out the exhaust? The back of the turbo and the cat did not seem particularly oily, so my guess is "no".

[JezzaH6]

You'll never see the imperfections in the casting, but I am more interested in the fact that it is on more than one engine- I though they were just unlucky or it was perhaps a result of his failure mode. Shouldn't make a difference either way but interesting none the less.

I'm curious about the market (if any) for used EJ25 blocks, and whether it's affected by splitting the case halves. After all the main activity is out of the way I'm tempted to strip the old block further for curiosity's sake.

Would definitely be interested to see the results of this- but I am also unsure of the value of a split vs complete short block assembly, broken or otherwise.

Yes to monitoring. The only written record will be in this build thread, so not scientific.

The 11mm oil pump was one of many recommendations I adopted from a local performance shop operator (the deal being advice as well as parts) without a great deal of research or second-guessing on my part.

I am aware of the down-sides of going too big with the oil pump (especially with a new tight-clearance engine). Apparently 11mm is standard with an STI, so it must not be catastrophic.

Agreed that it will be interesting to monitor once the car is going again.

That's fair. If anyone is going to know the benefits of such a change it will be them! My knowledge is very limited with the 4 cylinder engines so am definitely curious to see if you notice a significant or meaningful difference or not.

2 litres over 5000kms, whilst a lot, doesn't seem catastrophic. IIRC the 'acceptable' level of consumption speaking to Subaru is 1l per 1000km, which mine was getting close to using before the HG blew. I luckily didn't have to touch the block itself, but my oil consumption is now less than 100ml per 1000km which points to very leaky valve stem seals- but again I am not sure if this is a H6 thing or common amongst Subaru's in general. With rebuilt heads and a new short block yours should be very close to zero, but interested to see if the increase in oil flow and pressure has an impact on this.

[Stifull]

I think the important thing is that the inside is as close to perfect so oil flow is not impeded. I haven't seen a subaru block yet that is polished on the outside. It would be soo time consuming to make the outside smooth. They would cost a lot more for no real improvement in performance an a smooth surface is good for oil flow, it is not as good at dispersing heat.