Project Hakosuka may be many things, but one thing is for sure is that in the past 6yrs, it's certainly never been boring
Like the time I found a 4 inch long piece of sheetmetal floating about inside the sump...oh, wait...that was today
I guess I better start at the beginning....
This morning, I used my engine beam to raise the motor off its mount. Basically to fit new engine mounts and a new oil pickup.
On the one side, I hook a chain to an unused bolthole on the cylinder head...
...and on the other side I used a hole on the side of the block.
Then slowly twist those big handles on the engine bar, and the engine rises off its mounts (which I unbolted from before). A few inches is all it needs before there's enough room to wiggle out the old mount.
The main reason for this job in the first place, was to investigate an oil surge issue. It mainly happens on the track, where I can see the oil pressure falling in hard left hand turns. But unless the oil level is all the way full, I can reproduce the effect on a winding road taken reasonably fast. So off comes the sway bar, which is necessary to make room to slide out the sump (after its gazillion bolts have been undone)
And straight away, I think the mystery is solved...with the sight of the oil pickup at an er, shall we say...rakish angle.
You can kinda see how it would affect the oil pressure in hard turns. On right hand turns, the oil pickup acts like a scoop for any oil sloshing to the right side of the sump. But on left handers, the hat on the oil pickup acts like a shield for oil sloshing to the left, which temporarily starves the pickup of oil.
I've sourced a new pickup, specifically for Hako Skyline, from Kameari Engine Works, and what a lovely bit of gear it is.
And, you can see straight away, that it's at a somewhat different angle to the pickup tube off the car
I guess I can't be too hard on the guy who built the engine. When the motor is on an engine stand and is bolt upright, the angle of the pickup probably looks quite okay. I imagine it didn't occur to him that the L-series sits on quite a slant in a Hako.
Next step is to make a new gasket for the Kameari pickup, which is easy to do. Just take some gasket paper, and gently tap around the pickup (use the old pickup of course!) with a ballpein hammer
This will make an imprint on the gasket paper, and in fact will usually partially cut the holes as part of the process.
Finish the job with a blade, and hey presto, new gasket.
It's a good time to fit up the new engine mounts, which are much softer and fatter than the old ones.
Slot them in place, but leave them unbolted for now...all set, right? Just button it all up and look for the nearest winding road? Well, yeah. That was the plan
So I start to clean up the sump, so that I can fit up a new gasket and get it all back together. That's when I notice something rattling around inside one of the wings.
It took a bit of wiggling to get it out, but...here we are
Righto. What the hell is that doing in there.
I think the answer is this. The sump has a plate just behind the bowl, to prevent oil from sloshing to the back of the sump during acceleration. In Japan, the middle section of this plate was cut out to accommodate a really kludged up oil pickup tube which fouled against it.
During the rebuild, a new plate of steel looks like it was welded across that gaping hole. But, it looks like the welds didn't hold and that plate of steel went for quite a tour around the inside of the engine. But rather shockingly, all I can see in the way of damage to the rotating assembly, are a couple of nicks in a few of the crank weights.
And the odd scrape mark.
But the bores, rods and pistons looks to have escaped unharmed. My theory is that the crank swings below the gasket line of the sump. The builder probably didn't measure things right, and shortly after the rebuild...or maybe during the rebuild, the crank hit the new steel plate and tore it free of its welds.
The mind boggles as to how the engine is still a happy healthy running motor today. The thought of that plate getting whacked up into the bores, or sliding down into the bowl of the sump and getting sucked up into the pickup tube...thus blocking it off...is quite sobering. There's plenty of engine-kaboom scenarios which could have played out...but I reckon we've had quite a measure of blind luck here, and if the Hako sump was a conventional one, that bit of steel might have bounced around for a long time, causing more and more damage. But I think that shortly after that plate of steel came loose, got clobbered by the crankshaft and began its new life as a metal pretzel, it was sufficiently twisted that it fit into one of those holes that lead to the sump wing. And it probably never came back out again.
I suspect that this probably all happened a very long time ago, and that bit of steel has been trapped in the wing of the sump for years. You can see the witness marks on the inside of the sump as it got reshaped by the crank...
The question now is...what do we do? (It's not a rhetorical question...if you have an opinion please do share
I think that the engine is...rather amazingly...okay. The question is whether we need to reinstate that plate across the back of the sump. Naturally, I would like to hear that it's not necessary and we don't have to tempt fate again by welding something in its place. Or...would it be okay to rivet say some 2mm aluminium in its place?
Let's discuss. It's good to talk