CAV filters and Lancruisers

Submitted: Saturday, Mar 18, 2006 at 10:26
ThreadID: 31863 Views:7099 Replies:6 FollowUps:8
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This is a bit of a follow up to post 31658 where there was discussion about whether to use 2 (one CAV+original) or 1CAV filter in the Landcruiser diesels. I was also interested in Peter2's comment about running the fuel flow opposite to that recommended by the manufacturer.
I contacted a well known diesel servicing company (that cannot be mentioned on this site by name) and they forwarded an interesting and helpful response that is reprinted below, with their permission.

The CAV type filter system is called and agglomerator. This means that the
fuel passes THROUGH the filter media FIRST. Any micro droplets of water
agglomerate as they pass through the filtering media to larger ones and then
combine to a larger droplet which then falls to the bottom of the bowl. This
type of filtering is, from what I can remember is about 99% efficient at
trapping water particles.

IF the filter is plumbed up for REVERSE flow then the micro droplets of
water have a higher chance of continuing up through the filter media and on
their way to the pump and injectors. This is classified as about 95% or less
efficient in water trapping.

The Toyota factory manual suggests 'for mining use only' that the 2 filters
be left in place from the factory on the 75/78/79 series. It is suggested
for road use to remove the steel pre filter canister (the one with the paper
element in it only) to reduce fuel flow restrictions at road use (revs). If
this is not done the fuel flow can be reduced leading to higher than normal
fuel pump temperatures. Case in point is to look at the 100 series. Same engine
but different application (road use) and only ONE filter.

We suggest remove the paper element from the primary filter and leave the
canister empty and just run the ONE spin on fuel filter.

For the adaptor you will be looking at $140.80.
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Reply By: glenno(qld) - Saturday, Mar 18, 2006 at 11:39

Saturday, Mar 18, 2006 at 11:39
Firstly , let me say that i paid less than $100 for the aluminium adapter .
Then i took the primary cannister off and put it in the shed .
Delphi filters cost me about $5 .

AnswerID: 161324

Reply By: Pterosaur - Saturday, Mar 18, 2006 at 12:10

Saturday, Mar 18, 2006 at 12:10
Quote :

"The Toyota factory manual suggests 'for mining use only' that the 2 filters
be left in place from the factory on the 75/78/79 series. It is suggested
for road use to remove the steel pre filter canister (the one with the paper
element in it only) to reduce fuel flow restrictions at road use (revs). If
this is not done the fuel flow can be reduced leading to higher than normal
fuel pump temperatures. Case in point is to look at the 100 series. Same engine
but different application (road use) and only ONE filter.

We suggest remove the paper element from the primary filter and leave the
canister empty and just run the ONE spin on fuel filter."

Can anyone vouch for this ? (Not having a go MichaelR, just making sure before I do anything :-)).

Should I remove the prefilter from my 78 series?
If so, the whole assembly, or just the filter element ?

I presume the adaptor being referred to is so that the canister can be removed too ?
thanks
Terry
AnswerID: 161328

Follow Up By: Bob Y. - Qld - Saturday, Mar 18, 2006 at 21:31

Saturday, Mar 18, 2006 at 21:31
Those people considering dropping the element out of the pre-filter, might be interested in using the genuine tojo filter used on the turbo wagon models, instead of the normal filter. Part Number:23303-56040

They are a bigger filter than the normal one, and still have the water trap section, so should last a bit longer, between services.

Hooroo...

Seen it all, Done it all.
Can't remember most of it.

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FollowupID: 416146

Reply By: Bob Y. - Qld - Saturday, Mar 18, 2006 at 20:09

Saturday, Mar 18, 2006 at 20:09
Michael,

Interesting thread, as we have 2 79 series and a 100 series here, with filter details mentioned above. Always wondered about the "security" of the 100 system, without the pre-filter.

The turbo 79 series I've been driving for 3 years, invariably has a partially dirty pre-filter, sometimes the dirt is only on 30% of the filter surface. With filtered fuel, one could run only the main/water-trap filter, and get reliable service.

Restrictive fuel systems can be detrimental to Toyota fuel pumps, they like plenty of clean, cool fuel.

Hooroo...
Seen it all, Done it all.
Can't remember most of it.

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AnswerID: 161388

Follow Up By: Tim HJ61 (WA) - Saturday, Mar 18, 2006 at 23:36

Saturday, Mar 18, 2006 at 23:36
Bob Y,

Interested in your comment about plenty of clean, cool fuel.

I'm running my fuel through a heat exchanger to raise to around 60 to 70 before it goes through a CAV and into the lift pump - then onto the main fuel filter and into the injection pump. Yes, I'm running a vege oil blend and the oil needs to be heated to approx 70° to reduce the viscosity to be similar to diesel so it sprays through the injectors properly.

There's often discussion on the vege oil forums about IP's capacity to handle heated fuel. I've not got thousands of km's up yet with my 12HT, but many Mercedes diesel users have clocked up 20k plus. The MErcedes diesels use a Bosch pump, on which the Nipppondenso are modelled I am led to believe.

I also hear of the need to keep diesel cool, such as you're saying. One of the things that will help IP's with heated oil is the higher lubricosity of a vege oil blend, whereas, I am led to believe, diesel loses lubricosity at higher temperatures so the two may balance each other out. In fact, one of the common comments on vege oil forums is the benefits to all IP's by adding a litre of so of new supermarket vege oil to each fuel fill to increase the slipperiness of the diesel and benefit the pump.

Hooroo too ...

Tim
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FollowupID: 416169

Follow Up By: Bob Y. - Qld - Sunday, Mar 19, 2006 at 21:44

Sunday, Mar 19, 2006 at 21:44
Tim,

Thought about the "cool" fuel thing after I'd posted it, and thought it would be difficult to keep the fuel cool most of the time. With large amounts being bypassed to the tank/s, the supply would gradually heat up. Much would depend on ambient temp, at the time.

Maybe what I should have said was "heaps, and heaps of clean fuel".

Believe hot diesel does ignite much better, than cold stuff.

Hooroo...
Seen it all, Done it all.
Can't remember most of it.

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FollowupID: 416298

Reply By: dieselup - Saturday, Mar 18, 2006 at 22:12

Saturday, Mar 18, 2006 at 22:12
Can some one tell me what the attraction is in fitting these CAV filters in place of the original filter?
When you sit back and look at it you are only replacing the original with with exactly the same thing
The only difference is the glass bowl,they eliminate the float switch that indicates water in the filter so if you do get a bad batch of fuel with heaps of water in it and the filter fills up with water the indicator light on the dash wont come on , so by the time you realise it's too late , the water's reached the fuel pump
Filters and oil are cheap , fuel pump and engine parts are expensive
AnswerID: 161411

Follow Up By: MichaelR - Sunday, Mar 19, 2006 at 00:09

Sunday, Mar 19, 2006 at 00:09
I'm considering fitting one of these filters for a few reasons.
1. The water sensor in my original filter has failed and is expensive to fix
2. I believe (and happy to be corrected) that the CAV type filters are a finer filter (5 microns) as opposed to the original filter (15 microns) and therefore superior filtration.
3. Have had a bad batch of fuel previously that did make its way past the filter (before water sensor failed) and resulted in expensive pump repair.
4. A bonus is the filters are cheaper to replace.

I am happy to regularly check the glass bowl for water regularly, especially on a trip where fuel might be a bit dodgy. I would imagine the chance of ingesting large amounts of water is small if you don't run your fuel tank too low.
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FollowupID: 416172

Reply By: glenno(qld) - Sunday, Mar 19, 2006 at 21:11

Sunday, Mar 19, 2006 at 21:11
If you have never experienced fuel contamination where you live and travel and not likely too then maybe fit the cav .
If however you think that fuel contamination will be a problem then dont fit one .
AnswerID: 161565

Follow Up By: MichaelR - Monday, Mar 20, 2006 at 22:43

Monday, Mar 20, 2006 at 22:43
Hey Glenno
That's a bit of a provocative statement. Could you explain your reasoning as I have been lead to understand that the CAV filter is a finer filter than the OEM stuff and therefore should be superior? Look forward to your response
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FollowupID: 416462

Follow Up By: Member - Andrew W (SA) - Monday, Mar 20, 2006 at 22:59

Monday, Mar 20, 2006 at 22:59
but you have to watch it ... if you are used to doing 1400km days you will know that you stop to sleep, stretch and if you absolutely have to refuel.

I lift the bonnet once a day ...

on one of those days the water sensor went bananas ... after 1100 ks' and I had the pleasure of it bleating six times after that.

Damned Dalby Truck stop Queensland Fuel crap ...

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FollowupID: 416465

Follow Up By: glenno(qld) - Tuesday, Mar 21, 2006 at 11:30

Tuesday, Mar 21, 2006 at 11:30
MichaelR , want i was trying to say is if you think you need the sensor with the dash warning light then keep the original unit . Does this make sense .
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FollowupID: 416532

Reply By: Tim HJ61 (WA) - Wednesday, Mar 22, 2006 at 10:20

Wednesday, Mar 22, 2006 at 10:20
Stating the obvious, the micron rating of the CAV unit is dependent on the filter you stick inside the housing, not on the CAV unit itself.

I've asked several filter manufacturers for details on their fuel filters with regard their ability to cope with heated fuels for people running their vege oil through a heat exchanger and also the micron rating of the CAV type filters.

I only got one decent response and that was from Ryco, who said amongst other things that the Ryco filter for the CAV unit was 15 microns at the start of it's life.

I've asked Cooper, Delphi and Valvoline and not been given micron ratings. Valvoline say they manufacture to Original Equipment Specs. I don't know what they standard Toyota filter micron rating is.

IMHO, having two filters is better than one. If you get a bad load of fuel, or water mixed in, then you need all the weapons you can have to stop the s..t getting into the injection pump. Users picking up fish shop vege oil are a bit careful about filtering and typically filter at 5 microns before tipping it into the fuel tank. But you never know when a bit of other stuff gets in their as well and the CAV works well for me - normally. I'm having a hell of a job tracking down an air leak at the moment, and it's not the CAV.... But that's another story.

Tim
AnswerID: 162176

Follow Up By: Member - Roachie (SA) - Wednesday, Mar 22, 2006 at 11:48

Wednesday, Mar 22, 2006 at 11:48
Tim,
Just a note regarding air leak......
I have a CAV adaptor on the the OE primer head unit. Some CAV filters I've tried WILL NOT seal up properly onto the aluminium machined adaptor. Looking at the top of the filter, some have a series of small nodules/bumps/lumps or whatever you want to call them. These are the ones that will not seal up properly on my adaptor unit. I have to use the filters that have a series of crescent shaped slots around the top of the filter....they seal up perfectly.
Hope this helps a bit.
Cheers
Roachie
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FollowupID: 416867

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