Thread: 4BD1 Knocking

Originally Posted by Dougal

I had funny orange crystal type things in two of my exhaust ports when I stripped the engine and got the injectors done.

Tip ! A bit of petrol in the tank is better than Vodka +orange no nasty orange deposits

Well it lives on we got it started this arvo spluttered for about 20 secs then run fine once the air had bled out

Sounds good no missing or rough running tho its only free spinning tho id say by now mike has driven it and has the smile back on his face

Long live the ISUZU

Woohoo! Good to hear

Excellent. Now stay off the dodgy cooking oil.

Originally Posted by wrinklearthur

Cooking oil! Save money on travelling expenses to spend on engine rebuilds ???
.

It gets really frustrating when people just run with this as the go to fault, because veg oil when filtered and dried correctly and used with a properly set up heated twin tank system is not a problem. I've travelled 30,000km in AU on recycled oil, and countless more at home, without issue. In any case, I hadn't been running veg oil in the 4BD1, just diesel, so that wasn't the fault.

Anyhow, dropped in the pistons yesterday, and reassembled. Did the remainder this morning. Piston #2 had a stuck compression ring with a lot of carbon build up in the groove, took quite a lot of soaking and scraping to get it freed up. #2 piston looks like it may not have a been atomising properly, but hard to say for sure. None of the injectors looked blocked, or any dirtier than the one lokka brought down this morning, and when I cracked them off earlier in the week it didn't affect the knocking. All I can guess is that it wasn't functioning properly at some stage, sized up the ring, and that was giving me knock and blowby.

Bled her up, cranked her over, and all is good, no more knock, and no more oil spraying from the dipstick. :-)

Incidentally, pistons and bores all looked pristine, despite the fact that the engine had been turboed, even before I got it, so it looks like the engine is capable of standing up to the higher temps, within reason of course. Much thanks to Chris and Matt who came over yesterday and made the job of dropping in pistons infinitely easier :-)

Originally Posted by mike_ie

It gets really frustrating when people just run with this as the go to fault, because veg oil when filtered and dried correctly and used with a properly set up heated twin tank system is not a problem. I've travelled 30,000km in AU on recycled oil, and countless more at home, without issue. In any case, I hadn't been running veg oil in the 4BD1, just diesel, so that wasn't the fault.

Anyhow, dropped in the pistons yesterday, and reassembled. Did the remainder this morning. Piston #2 had a stuck compression ring with a lot of carbon build up in the groove, took quite a lot of soaking and scraping to get it freed up. #2 piston looks like it may not have a been atomising properly, but hard to say for sure. None of the injectors looked blocked, or any dirtier than the one lokka brought down this morning, and when I cracked them off earlier in the week it didn't affect the knocking. All I can guess is that it wasn't functioning properly at some stage, sized up the ring, and that was giving me knock and blowby.

Bled her up, cranked her over, and all is good, no more knock, and no more oil spraying from the dipstick. :-)

Incidentally, pistons and bores all looked pristine, despite the fact that the engine had been turboed, even before I got it, so it looks like the engine is capable of standing up to the higher temps, within reason of course. Much thanks to Chris and Matt who came over yesterday and made the job of dropping in pistons infinitely easier :-)

Which engines did you run 30,000km on? Indirect injection or direct injection?

Straight vegetable oil has components which do not burn cleanly in diesel engines. That is the whole reason behind bio-diesel. Indirect injection engines have far simpler injectors and air/fuel mixing methods which are far more tolerant of buildup.

Originally Posted by Dougal

Which engines did you run 30,000km on? Indirect injection or direct injection?

Straight vegetable oil has components which do not burn cleanly in diesel engines. That is the whole reason behind bio-diesel. Indirect injection engines have far simpler injectors and air/fuel mixing methods which are far more tolerant of buildup.

x2 There was some research commissioned by the Australian army using 4BD1/Ts which found carbon trumpets forming on the injectors when using veg oil.

I have emissions measurements from a 4BD1(T) running on D, B20, B100 and virgin/new canola. I will post them up once the paper is published...

Originally Posted by Dougal

Which engines did you run 30,000km on? Indirect injection or direct injection?

Straight vegetable oil has components which do not burn cleanly in diesel engines. That is the whole reason behind bio-diesel. Indirect injection engines have far simpler injectors and air/fuel mixing methods which are far more tolerant of buildup.

Direct in all cases - 300tdi, 200tdi, and Mazda 3.5. Swopped out rubber seals, heated twin tank set up with diesel purge on shut down, regular filter changes and run injector cleaner through the diesel every few tanks, and most importantly good sources of oil.

I agree with your points, but the potential problems can also be offset with a good set up, good oil, and and good maintenance.

It's a moot point in this case, because I haven't run the Isuzu on SVO yet, will set it up at a later time.