Thread: OKA owners

I've always admired the OKA, being a parochial West Aussie possibly also helps... I'm currently building a poor man's baby OKA in the form of a series Forward Control landy instead, with a myriad of modern updates.

Originally Posted by oka374

Tins you had better join the Oka forum and come to next years get together, we had one earlier this year and over 30 Oka's turned up, no two the same and a wide variety of bodies and all models from XT's right through to an NT.
There have been a few fit a 6 cylinder Perkins but the 5.9 6BT's seem to be more popular with in excess of 40 that we know having been fitted to Oka's.
374 is happier at 110 on the freeway as it is spot on max torque at 1850 rpm, 100kph which is legal maximum for heavy vehicles is 1750rpm.
I've only recently gone to the 17" Method alloys with the 37x12.5 Yokohama G016 AT's and was worried that it would be too tall as 5th and 6th gear in my Allison are .71 and .61 but it doesn't seem to worry the engine at all, it still pulls well up hills. The 19.5's when fitted with the 315 tyres are about the same diameter as my 37's.
When ours had the Perky we reckoned we should cover the headlights so it couldn't see the hills coming up and slow down. With the 6BT it will only change back to 5th on the steepest hills at touring speeds but still at the legal speed limit. In travelling trim loaded we weigh in at around 5.5 tonne but still well shy of the 6 tonne GVM.
My 6BT started life as a genset, I scrounged all the Ram bits to turn it into a vehicle engine and changed the CAV IP to a VE IP, a well tuned VE pumped 5.9 can easily put out in excess of 350hp without serious mods. I still have the original non wastegated turbo, injectors and the engine internals were not touched and it's still probably putting out around 250hp with the W2A intercooler. Needs a 4" exhaust to allow it to breather better and possibly enable another turn of the fuel screw ;-)) but really it goes well enough as is with a straight through 3".
There are a few things you can do to a Perky to get back to something approaching its rated output, 1/ ensure that when the pedal is flat to the floor that you are getting full throttle at the engine, the pedals bend over time and hit the floor before full throttle is reached, just bend the top section rearwards on the shaft, 2/ fit a bigger air cleaner (a lot are running Optiair 1100 series) and simplify and enlarge the snorkel setup, 3/straight through exhaust and possibly ditch the existing muffler and/or fit a straight through muffler. On the last point a lot of Perky's had a narrow section in the exhaust as it joined the engine, removing that will allow it to breath better.
A standard Perky should pull around 17-18lb of boost at WOT with around 650 C post turbo under load and can do that all day, coming from Landcruisers I was horrified when I fitted an EGT and boost gauge and saw the temps and pressure it was putting out but all the spurts assured me it was fine.
The 6BT is a similar temp but max boost is currently around 28lb the 3" exhaust limits it but they can handle well over 30 in standard form.

Just seen your ad on the OKA forum. I would love to see how you built the slide out bit. Sadly, the money you ask, while completely reasonable, would in my case need to go to the 6BT/Allison.

Tins as I said on the Oka forum make an offer as I don't want it sitting around forever and can remove and reuse some items to make the package cheaper as well.
Saying that, at the moment the plans for the new body are on hold due to the panels being made in fortress Qld so actually getting up there to pick them up is nigh on impossible for me, plus any thoughts of getting it all built and sorted before next years travelling season have now gone with the wind. As we want to travel next year the existing setup will likely not be available until 2/3rds of the way through next year now.
To answer the other question yes an intercooler will wake the Perky up as does the aircleaner, turbo and exhaust mods but it still lacking in a 6 tonne vehicle.