Thread: The importance of clean fuel and good filtration - especially in commonrail diesels!

Originally Posted by Offender90

On the topic of sequential filtration, do the filters need to get progressively "smaller", or if they are the same "fineness", do the subsequent filters do much filtering (especially after the first filter gets a bit clogged)?

Progressively finer is better, however even the same filter in series will still make a big difference.

e.g, for a given size particle, the first filter might remove 50% of the particles, and the 2nd 50% as well, meaning you have overall 75% removal for that size class, rather than the 50% you would get with one filter.

Also, if you leave the changes too long and the (first) filter starts reentraining captured particles as it clogs, they will be captured by the 2nd filter.

Thanks Ben,

Soon I'll be turning my attention to the fuel filtration on my 4BD1. It has the standard 3 now - one near the tank, the one next to the water pump and the fun one behind the engine mount. On two occasions I've had to clean the fun one which has me questioning the first one near the tank. If I convert it to a CAV one, will it perform better filtration or will it just be cheaper / easier to replace? Do you think it is worth putting an other one in line? If so, what and where?

Flagg, is the one near the tank actually a filter or just the standard sedimenter?
If its a filter I'm surprised you're getting that much crap in the gauze filter...

Steve.

Originally Posted by flagg

Thanks Ben,

Soon I'll be turning my attention to the fuel filtration on my 4BD1. It has the standard 3 now - one near the tank, the one next to the water pump and the fun one behind the engine mount. On two occasions I've had to clean the fun one which has me questioning the first one near the tank. If I convert it to a CAV one, will it perform better filtration or will it just be cheaper / easier to replace? Do you think it is worth putting an other one in line? If so, what and where?

If your 4BD1 landie is standard you have:

1. A sedimenter near the tank. This is not a filter. It is a settling chamber designed to remove water. This style of sedimenter is not great for modern diesels which can have up to 5% bio unlabelled.

2. Gauze/Mesh screen. This is not a filter. It is a screen/sieve only. It is designed to remove rocks only.

3. Filter on the inlet manifold. This is the only fuel filter on a stock 4BD1. IMHO it is better to swap this for the truck spin-on version, as it is easier to ensure you don't introduce contamination when changing the filter.


If you have a filter near the tank it has already been converted???
The CAV-style filters are not the best filter, nor the easiest to replace, but they are cheaper than all other options and as an initial filter they work well. If you still have the sedimenter there are a few threads on here showing how to convert them to accept a CAV filter while retaining the metal sedimenter bowl.

Well I'm glad I asked because clearly I have a lot to learn not sure why I thought it was a filter because ive drained the water catcher several times.

Ill have to read up and think about how best to tackle it.

I was thinking it would be best to leave the sedimenter in place and then fit a 30 micron spin-on filter(like a stanadyne one) between sedimenter and final filter. BTW-what is the micron-rating of the final filter- spin-on isuzu one?

TD5 have a good filtration system. My country diesel is full of crap in any pump and never have problems with injectors, none any of the other TD5 I know here. Puma engine in Ford Ranger have really big issued with their injectors, they are almost considered as consumables

oops