Engine - "Well I'm impressed..."

IN THE BEGINNING...

We acquired the car with a very mildly-worked Holden 308.  The thing was stock aside from some YellaTerra heads and a CDI system.  Induction was via a standard air-cleaner mounted directly onto a Rochester 4-barrel carburettor.  Not particularly inspiring, but admittedly the thing did have a bit of grunt.  The engine always had a tendency to die coming into a corner (restarted usually by simply dropping the clutch exiting the corner); this being somewhat annoying to say the least.  We never got to the bottom of it as we found too many other things to break.  Another problem was the rather close proximity of the starter motor to the exhaust.  After a short duration on the track, the starter would be cooking and unable to crank the engine (if for example it stalled coming into a corner).  We eventually replaced the unit with a geared version from Castle Auto Electrical and Exhaust Service that allowed us to rotate the starter away from the exhaust.

As things go, the ol' 308 threw a connecting rod out through the side of the block, also taking out the oil pan.  It was time for a new engine, and the choices were not limited.  Replace the 308, drop in some other motor we happened to have kicking around (253 or a 3.8L V6) or drop something completely different in.  Before making the jump, a spare 253 was bolted into the car, however sitting around for several years had killed the bearings, so it only lasted a single race.  After seeing what a guy called Max ("Mad Max") could do with a Lexus 4.0L quad-cam, we decided to take that route.

AND THEN THERE WAS...

So out came the broken 308 (to be stored under the workshop bench for several years for some unknown reason) and in went the quad-cam.  There were the usual issues with exhaust clearances, oil pan reversal (to clear the K-frame cross member), custom solid engine mounts, and some minor relieving of the firewall to accommodate the slightly larger motor.  A Dellow bell-housing and Ford Toploader were then bolted to the engine, complete with a custom clutch.  The entire unit was fuelled by a Holley Blue scavenging pump feeding a Bosch high-pressure pump, via a swirl pot and filter.  Ignition and fuel management were provided by a Link ECU and a dual igniter pack (due to the quad-cam running two distributors).

The wiring looks like a bit of a nightmare, but most of it gets chopped out and you're left with 4 injector wires (4 cross-engine pairs) and 2 commons.  The ignition wiring is similarly reasonably simple; especially with the dual igniter that came with the Link.

One of the reasons we went with the quad-cam was due to their relative cheapness.  Rebuilding a 308 race motor was going to cost upwards of $8k, whilst we could land these in Perth for $1.5k.  Of course in hind-sight it's obvious why they're so cheap; it's simply because nobody ever has to replace the things.  The quad-cam ran in the Commodore for 4 years (between '02 and '05) without missing a beat.  It was run up to redline (7500rpm) consistently during all races and never failed.  I am somewhat amazed at the punishment it endured in our hands and yet kept going.  Much respect...

Bottom-end of a Lexus Quad-cam (1UZ-FE) Note the 6-bolt mains and the rather large oil pickup inlet (top-left).  The engine also has a low oil level sensor (LHS), however we didn't use this.  The sump required no modifications to fit into the Commodore engine bay; and before you ask, no this wasn't a dry-sumped engine, it ran the stock sump.  I seem to vaguely remember there being an oil baffle (large tin sheet with holes for the oil pickup and low level sensor) sitting just below the crank, which would've restricted the movement of oil around the pan.