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From Tony Lee:

Before leaving Kalgoorlie for the trip back to NSW in 123, I checked to make sure the air filter was in its right place.

Written on the end of the filter cartridge was "Checked 23-2-94".

Filter is clean and the safety filter is spotless so I guess there is some benefit in having to put up with the drone of the air intake just next to the driver's right ear.

BTW. I turned the air intake grill so it faced the rear as per recommendation from Collyn Rivers I read somewhere. Seemed to make a difference but since the noise level is highly dependent on several factors (wind direction, engine speed and loading etc), it is hard to tell.

Anyone done any objective tests?

From David Ribbans:

Tony,

I suffered from a noisy sucking popping noise from the air inlet as well (I don't understand why some people do and some don't) so I extended my air intake to the front and fitted an air scoop to it (using 90mm plumbing fittings). I also doubled the thickness of sound insulation on the down pipe behind the drivers seat. It's very much quieter now unless the window is down, we can even hear the radio. It probably helps the fuel consumption too, it certainly doesn't adversely affect it.

See also David Hallandal's new air box design which is much larger and he swears it improves engine efficiency, ie power.

Hope this helps.

David

From Peter_n_Margaret:

Tony, I replaced mine with a washable foam filter.

Several people advised me against doing this because of the "higher resistance", so I checked the Perkins specs (they quote maximum resistance somewhere) and installed a vacuum gauge in the air intake system to check.

There was no problem. The resistance is quite low.

That original filter only lasted 150,000 km and five years of bush travel. BUGGA. So last week I bought a new one. Unifilter UC185 390S, about $100 direct from Unifilter. I actually bought two, because they wanted about $150 (including freight) for one and $200 (including freight) for two.

I wash them regularly in the bush with turps and re-oil with light oil (I use hydraulic oil).

I keep hearing these stories about noisy air intakes.

Mine is not noisy. Never has been. The air intake is still standard. Check the insulation under the snorkel cover.

Cheers,

Peter

BTW...Why do you want those SS jerries? Plastic is much better IMHO...

From Tony Lee:

>> I keep hearing these stories about noisy air intakes. Mine is not noisy. Never has been.<<

Yes, I must be the absolutely unluckiest bloke around. Everyone has totally quiet generators, webasto heaters, compressor fridges, dogs, children and now OKA intakes while I consider all the above to be relatively noisy -- OR more likely, everyone else has undiagnosed industrial deafness.

From Tony Lee:

> >Check the insulation under the snorkel cover.

Cheers,

Peter

BTW...Why do you want those SS jerries? Plastic is much better IMHO...<<

Yes, if the insulation is anything similar to the insulation above the perforated head-lining, it will have deteriorated a fair bit. Betty was ready to open an umbrella to stop all the little bits of foam trickling through the holes on to her head.

The two SS cans will become de-facto permanent auxiliary fuel tanks. Oka 123 has two standard tanks and you and others advised carrying a bit more as safety for long trips. Also I will be installing a webasto water heater and a webasto diesel cooktop, so rather than them sucking out of a possibly dirty main tank, I will be mounting the two thirty-litre SS tanks firmly on the back of the dual cab and using a separate electric fuel pump and filter to fill them from the main tanks. With a bit of extra plumbing, this will also allow me to drop that fuel into the main tank if required (and to turn the fuel over rather than run into trouble with algae as many vanners do, and also allow me to suck a near-empty main tank bone dry and transfer it over to the other tank thus getting the maximum possible range out of the main tanks.

(also the SS ones are near to 30 litre capacity so they are close to equivalent to three standard 20L ones)

Coming back from Perth I decided to see how accurate the standard gauges are and was surprised at how good they were. Left it on one tank until the gauge was a whisker off the zero mark before I chickened out (middle of the desert not an ideal place to learn how to re-establish fuel prime on an OKA) and swapped tanks. Doubt whether there would have been more than a couple of litres left when I checked later. The gauge on the other tank was equally accurate.

(Now we can have that discussion about sucking all the crap out of the bottom of the tanks when they get near empty.)

From Tony Lee:

Amazing how minor an adjustment is needed to change the air intake noise from something resembling an 18-wheeler under full exhaust braking to no noise at all.

I took the cover off and yes, the insulation was a bit ratty although most of it was there. What I did notice though was that the rubber washer that fits over the rubber elbow was not hard up against the inside of the side wall of the cab and there was a 10mm gap in places. I guess the noise coming out of the pipe was reflecting off the outside cover back through the gap inside the cab, and the insulation and cover were not tight-fitting enough to keep it from reaching the drivers ear.

I filled up the gap with non-setting mastic and pressed the rubber washer back against the cab wall and now there is no noise at all - even with the cover still off.

Very strange -

-

-

although I must admit that a small part of the reason the noise is not apparent might be the fact that all the ceiling lining is out which does make the cab a bit more boomy than normal.

Bought enough lining to do the roof and the plywood sheet I fitted between the cab and the crew cab as well as a sheet of the heavy filled foam to replace the engine bay insulation so hopefully that $400+ investment will make a bit of difference.

From David Ribbans:

>>Now we can have that discussion about sucking all the crap out of the bottom of the tanks when they get near empty<<

I was brought up thinking it was bad to let the fuel level get too low because muck will get sucked up, although it's now difficult to justify.

If crap is floating then it might get sucked into the pick-up pipe as the level drops.

If it's laying on the bottom, it should stay there since the pick-up pipe is above the bottom of the tank, (until the level of crap exceeds the level of the pick-up pipe). eg I don't get any tea leaves if I don't take the last suck from the tea cup.

If it's just wafting around, or gets stirred up by fuel slopping around, it's going to get sucked up eventually. That's why we have lots of fuel filters.

Despite the arguments, I still like to keep the tanks well above empty because, irrespective of crap, you really don't know how much is left.

David

How often does one change the inner safety air filter? or do we assume it doesn't get dirty because the primary filter does the cleaning.

The outer air filter I get sent off for "dry cleaning" which costs about $20. I think from memory that it can be done about 6 times, but they test the filter anyway.

I toss the outer once a year and the inner every other year and keep a pair  as 'spares' just in case they get them wet or something. Probably overkill but something I don't have to worry about any more.

As to air intake noise, wasn't a problem untill the cabin was dynamatted, then I could hear the air inlet noise. Took the cover off and covered the PVC pipe with about 4 layers of the left over Dynamat scraps, problem fixed.

Can now hear the radio and have a normal conversation.

Dean

It is a bit permanent, but we fixed the inlet noise issue by removing all of the insulation around the air pipe, refitted the plastic cover and then drilled a few small holes in the cover. I then filled the entire space with expanding foam.