- Is this the most unique engine that's ever been swapped into a Nissan S chassis?
The bespoke five litre V12 built by Hartley Engines and Motorsport has to be pretty close.
Finding a V12 of any nature as a donor engine is, let's face it, going to be pretty tricky.
And when Hartley Engines and Motorsport were looking for a base to develop
a bespoke engine that they could provide to prototype, kit car manufacturers
all around the world, the Toyota Century V12 became the go to option.
These engines are available in reasonable numbers and they're also available
for a reasonably modest price.
Don't let that fool you though.
There's not a lot of original Toyota Century V12 left in this engine behind me.
The only components left over from the Toyota factory catalog include
the bare casting for the engine block, the crankshaft and the bare cylinder heads.
Every single component other than those, has been manufactured and designed
by Hartley Engines and Motorsport.
Despite the base engine having five litres of capacity and 12 cylinders,
it's actually been shown that the base engine doesn't produce amazing power
and it can be a struggle to get really large improvements in power from these engines.
That didn't deter Hartleys though and they've gone through some extensive development
and some serious modification to get what has ended up being 700 horsepower
in naturally aspirated form from these engines, at a whopping 9500 RPM.
A lot of this work really has come down to the head flow.
Which in stock form is quite poor.
Getting the heads to support this sort of air flow has required an extensive
amount of modification and development on the flow bench.
In the end, the ports have been enlarged by around about four millimetres.
There's also a completely new valve train consisting of larger valves and double
valve springs.
Since Hartleys have an in house CNC head porting machine,
this then allows them to replicate that porting program on any future heads.
Another modification made to the cylinder heads is the replacement of the stock
aluminium bucket actuation for the valves.
Now this wasn't going to be reliable at the sort of RPM range that Hartleys were
intending from these engines, so they've been swapped to a steel bucket,
and this is a one piece bucket, and the bucket is chosen to also set
the valve lash.
Now in terms of getting air flow through those heads, it's not just about the port flow,
the cam profile is also essential here.
And because the Century V12 isn't really very well supported in the aftermarket,
options here for aftermarket cams were essentially non existent.
Again this didn't deter Hartleys though, and they've taken to the process of
building up the original cam lobes and then having them reground
to their own specifications.
This allows the flexibility to achieve the sort of valve lift and duration that they need.
The cam drive system on the Century V12, is also a little unique,
although it's relatively common on a range of Toyota engines.
While it is a true quad cam engine, there is only one cam drive pulley
for each bank of cylinders.
The other cam is then driven off the intake cam via a scissor drive arrangement.
The bottom end of the engine retains the stock Toyota crankshaft as I've already
alluded to, as it's been proven to be up to the task of delivering the power
and RPM Hartleys were looking for.
The conrods and pistons however have been changed out, and again this consists
of a bespoke set of rods and pistons manufactured in house from blanks
by Hartleys.
The compression ratio here has been bumped up to a pretty massive 13:1 and this is well
suited however to the E85 fuel that this particular engine is designed to run on.
Lubrication is another key consideration here to get an engine like this to be
reliable and provide a long service life.
And here Hartleys have reached straight for the top shelf with a complete
dry sump lubrication system.
So this consists of an external pump that is driven straight off the nose of
the crankshaft.
This includes a number of scavenged stages which are designed to suck oil
and air out of the crank case and then return it to an external oil reservoir.
From here, the air is removed from the oil, and oil is then sucked from the bottom
of that reservoir forward, to a pump stage or pressure stage of that dry sump pump,
where it's then pumped through the engine.
Now this ensures that regardless of the sort of forces involved in cornering,
braking or acceleration, there's always going to be a consistent and uninterrupted
supply of high pressure oil delivered to all of the internal components of the engine.
On the intake side of the engine is another bespoke component CNC machined
by Hartleys in house, which is the individual throttle body mechanism.
Another aspect that's worth mentioning here is the extent that Hartleys have gone to
in modelling this engine in CAD.
Every single measurement, every single component that goes into this engine,
has been modelled in CAD, so they've got a full three dimensional model.
This gives Hartleys the confidence that when the engine, the exhaust manifolds,
and the intake are shipped to the other side of the world, that everything is going to fit
perfectly.
Now while Jaron's Silvia might not be the most powerful car competing here
at World Time Attack, it is definitely one of the most unique engine combinations
and we're looking forward to seeing how he goes in competition tomorrow.
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