Subaru sump capacities, syncro ground clearance etc

[silverbullet]

You all know I've got rather mixed emotions about Subaru engines, but since I've just had a couple of EJ's turn up for machining and the donor DG case is still on the floor, I thought I'd run a tape measure over them to see how the raw capacities stack up as it seems to be the biggie when contemplating the swap into a syncro. I never thought to run the numbers, but here are some internal dimensions:

VW wbx pan is 23cm long x 28 wide x 70 deep, judging by the tideline (not inc oil in the timing gear housing, but not a lot) This gives 4.5 litres, surprise surprise! I put exactly this amount into my rebuild but also primed/filled the filter before screwing it on. Aways a good idea.

The Subaru sump is 23 x 23 at widest and longest, narrowing to 16 or 17 at each end but not quite symmetrical. Approximate area 500cm sq. For the same 4.5 litres capacity it's got to be 9cm deep. Now that's pushing it to have any kind of headroom over the bottom of the syncro wbx engine bars, however they are modified.

But...if you run an oil radiator capacity can go up by quite a bit:

2 x 3/4" bore hoses, = 2.8 sq.cm x 2 x 5m long = 2.8 litres plus the capacity of the radiator...who's worried about a small sump? The EJ has a perfectly good windage tray as standard! All this talk of big capacity sumps being a necessity for a good conversion, people hanging on for ages for the goods to arrive or even be made...for what?

Chop the EJ steel sump off at 70mm, plate it, shorten the pickup and run a cooler. Job done.

[lhd]

You all know I've got rather mixed emotions about Subaru engines, but since I've just had a couple of EJ's turn up for machining and the donor DG case is still on the floor, I thought I'd run a tape measure over them to see how the raw capacities stack up as it seems to be the biggie when contemplating the swap into a syncro. I never thought to run the numbers, but here are some internal dimensions:

VW wbx pan is 23cm long x 28 wide x 70 deep, judging by the tideline (not inc oil in the timing gear housing, but not a lot) This gives 4.5 litres, surprise surprise! I put exactly this amount into my rebuild but also primed/filled the filter before screwing it on. Aways a good idea.

The Subaru sump is 23 x 23 at widest and longest, narrowing to 16 or 17 at each end but not quite symmetrical. Approximate area 500cm sq. For the same 4.5 litres capacity it's got to be 9cm deep. Now that's pushing it to have any kind of headroom over the bottom of the syncro wbx engine bars, however they are modified.

But...if you run an oil radiator capacity can go up by quite a bit:

2 x 3/4" bore hoses, = 2.8 sq.cm x 2 x 5m long = 2.8 litres plus the capacity of the radiator...who's worried about a small sump? The EJ has a perfectly good windage tray as standard! All this talk of big capacity sumps being a necessity for a good conversion, people hanging on for ages for the goods to arrive or even be made...for what?

Chop the EJ steel sump off at 70mm, plate it, shorten the pickup and run a cooler. Job done.

You forgot to add "BANG" at the end of it.

[syncropete]

Or run it how subaru intended with the full capacity and smash the "pooh" out of it like I do Seriously we have done uk to gambia, loads of offroading in the Gambia and a return trip to Dakar from the Gambia twice on the most sump bashing roads you could ever imagine and only incurred a few dents to sump and filter. I would rather run this risk and watch the oil light than destroy engines long term as with my previous 2.2s with reduced capacity.

[silverbullet]

You forgot to add "BANG" at the end of it.

Why's that then Rob? If the shortened sump has got decent baffle welded in so the pickup doesn't get exposed in pitch/roll, where's the problem? Can't be any worse than a JX sump withthe van on a 30 degree LH slope, can it?

Ahh, that's the thing isn't it...people don't want to start doing a cut'n'shut to the most vulnerable part of the engine, for fear of what might happen.

Like naturist BBQ's, maybe only for the very skilled or very brave?

(You could dry sump an EJ but it's another drive belt exposed to sand and grit etc. so not ideal for true offroading, never mind the expense and complexity so it's not really a solution)

[silverbullet]

A few more measurements to think on:

WBX crank centreline-to-bottom of sump (at drain plug, internal) ~190mm or to put it another way, 120mm to oil fill level.

EJ series from same axis to sump flange (max realistic fill level/baffle height) ~125mm, so near enough equal.

Both engines drain their oil back into the sump by similar means; WBX uses the pushrod tubes and slots in the lifter bores, the EJ has galleries that connect to the air volume above the sump flange. If anything the WBX has better sump baffling by virtue of the lifter bores being webbed together in each half of the crankcase, allowing the engine considereable tolerance to roll angles before the oil pickup is exposed to air.

The vehicle will probably have overbalanced before the engine is at risk of damage, as a quick look with a protractor indicates a good 45 degrees roll before the oil level gets even near the strainer...

I'll get an EJ sump pan and have a go, to see what's achieveble with modest effort.

[rollercoaster]

I have saved my old steel EJ2.2 sump for just such an opportunity, you are welcome to it..

[silverbullet]

I'll square you for the postage

[silverbullet]

I've been casting an eye over my pdf manual for the early Legacy engines (1992) and oil change capacities are as follows:
SOHC 4.5 litres
DOHC 5.2 litres (oil interwarmer as standard and possibly larger filter)
The pickup and baffle arrangement are impressively well designed! It looks like the baffle will have to be remade with a shortened sump and mounted higher up but that's no bad thing for a syncro (makes greater roll angles possible)
A nice wing-type pan should be possible but...not if you've got a smallcar mounting bracket. The deep-sided wrap-around design just won't allow it.

[Aidan]

98 2.5 dohc has the silly little filter, I'm boggled that anything that small can do 7500 miles the haynes says, let alone the 12k that some service manuals indicate for this engine
you're thinking like me on this Ian, now can we make an integral mount with the pan that replaces the smallcar mount which seems unecessary as it doesn't use the scooby mounts except to attach to, damping is via the vw mounts, I have andy's old sohc 2.5 sump for working over

[silverbullet]

I'll be under the Microbru soon enough, to extract the transmission so will have a good look to refresh my memory.
Seems like we're searching for the "Third way"

[silverbullet]

Just had a glance at the smallcar site and it looks like they have changed the design of their mount bracket (I haven't looked for a while so this may be old news)

There's a useful underside pic of a steel-sumped installation on the "completed conversions" page, but it's been used for ages so safe to say it's the earlier mount.

Compare to the one shown on the 4 cylinder mounting instructions page: it's got a flange welded to the top of the arms to make it T-section, so was there a problem with the earlier design?

Now none of this should be a problem if the steel sump is re-worked to have a wing section either side and to the flywheel end only. It would then make best use of all the available volume between the arms of the bracket. Sump removal in-situ might become a bit of a pig as half of the bolts will only have side access (with use of spanners not socket tools) but who ever does that?

I want to cut and weld something

[silverbullet]

One of the lads from the engine shop called yesterday to pickup the EJ cases. I mentioned this subject to him and speaking as a modified Impreza driver, he says that the standard Subaru windage trays are generally regarded as dustbin filler in tuning circles and the Cosworth "trap-door" type baffle is £200 well spent.
It sandwiches between the sump and block and keeps the oil where it needs to be; it's also used by other firms who make their own wing sumps. Combined with a thermostatic cooler set-up it's the route to reliability for turbo engines that generally go pop by 100k if they haven't had a bottom-end refurb by then...

[rollercoaster]

Hi, sorry only just caught up with this, shall I post the sump to your works address?

[silverbullet]

Hi, sorry only just caught up with this, shall I post the sump to your works address?

Yeah, to the works is fine I'm going to need an oil pickup pipe from somewhere too...

Yet more idle musings:

Cossie trap-door baffle is all well and good for high speeds on long slow turns i.e. on track days, but what a syncro needs is oil control for low speeds in all directions at quite large angles of pitch and roll; up to 40 degrees from horizontal.

This will require a different approach but I do have an idea...

PS anyone know why VW ditched the louvred baffle plate from inside the old type 4 engine when the wbx came along?

[rollercoaster]

Packing it up now,
coming with oil pickup,
not dipstick tube..
Heard that welds can be prone to occasional pinholes,
but perhaps the hot zinc spray would help?