4jg1t "franken-engine"

[paulthepilot5]

handymanny01 wrote:cheers paul, good to know!,, i just got cheapish ali-express nozzles, for the purpose of testing,, will see if my fuel tech can make them work or not.... my current and bigger problem is keeping the head on it! lol another blown head gasket! curses! (even with ARP studs) im actually thinking of making a solid copper one, and fitting steel o rings into the head... then sealing all coolant and oil passages with viton o rings.. begining to wonder if the 2.8 head gasket with its smaller bores is less prone to failure? im pressing on with this 3.1 direct injection engine none the less! my other thought is maybe the toyota cam plate in my injection pump is too aggressive ,, i (MAY) also be running too much advance... which is prob adding to my excessive cylinder pressures..
Are you using genuine MLS type head gaskets? If not you will probably have failures. Could also got to the higher grade arp studs as well (ARP 2000) about 20% more clamp pressure. I would say it is most likely injection advance causing the issue though. I am just running stock pump timing, but also have reduced compression so peak cylinder pressure would be significantly less, water methanol is also pretty hard on head gaskets, as it will cause advance too. I was also thinking copper gasket is eventually the way to go for high boost build. If you o-ring the head make sure it is inline with the liner protrusion so it seals on that. If I build another engine I’m going to modify the top flange of the liners to taper more of a point and run a little more liner protrusion, this would provide a similar crush effect to seal the gasket and not have an o-ring wire

[handymanny01]

Hey Paul, yes was a quality steel shim gasket, permaseal brand , looked very well made,, But I guess the peak cylinder pressure I seem to be generating was just too much for it,, So going to make up a copper gasket, and yes, will have a careful look at the best place to position the steel oring relative to the cylinder liner protrusion, as well as backing off the advance, we might need to put the pump back on the test bench, and check how the advance is actually coming in,,, maybe there is too much down low, and not enough up top, Fingers crossed the head stays on this time! Lol

[MISTIRIODES]

Hi there. I successfully make the conversion too some years back and I have some helpfull info 4 you... Also I need some info from you:) I currently use 4jb1 pump and with 4jb1 injectors(2 stage) is powerfull but... I ve tried 4jh1 injectors and is more quied, no smoke compared to 4jb1 but... Less power.. I believe I must try to upgrade my pump to 4jg2 but do I have to change something in the pump? With 4jh1 injectors is less responsive

[MISTIRIODES]

Sorry I stayed on the first page and replied before, now I saw all three I just order a turbo from a w163 mercedes (VGT) and I have some ideas for control the vanes, but definitely need help on correct fueling as I successfully used 4jb1 pump + nozzles. I don't know much about pumps internals, so will a 4jg2 pump work? And what nozzles will fit 4jb1 2 stage nozzle body? Have in mind that on my first attempt, I fitted 4JH1 Pistons and it was way more powerfull, but I ended with a broken con rod and a hole an the cylinder. Now I suspect it was due to wrong injection angle (I didn't have the 4jh1 injectors then)

[paulthepilot5]

MISTIRIODES wrote:Sorry I stayed on the first page and replied before, now I saw all three I just order a turbo from a w163 mercedes (VGT) and I have some ideas for control the vanes, but definitely need help on correct fueling as I successfully used 4jb1 pump + nozzles. I don't know much about pumps internals, so will a 4jg2 pump work? And what nozzles will fit 4jb1 2 stage nozzle body? Have in mind that on my first attempt, I fitted 4JH1 Pistons and it was way more powerfull, but I ended with a broken con rod and a hole an the cylinder. Now I suspect it was due to wrong injection angle (I didn't have the 4jh1 injectors then)
4JH1 injectors will not work well with the VE44 pumps, smaller nozzle size designed for higher pressures of the vp44 electronic pump. What year engine were your JB1 injectors out of? The late JB1 and The JH1 have the same style combustion bowl so spray pattern will suit both. Early 4JB1 pistons are square bowl and use a different spray pattern

[handymanny01]

They have the same type of bowl (round) and not the early square bowl, but the spray angle is WAAAY wrong, 4jh1 is 144 degrees , 4jb1 is 154 degrees,, So it's unlikely that 4jh1 injectors would work in anything but 4jh1 pistons... I tried 4jh1 injectors in the 4jg1 hybrid, And not good results,,, Changed to 4jb1 injectors (only 2 degrees wrong on spray angle) and picked up 140 NM and 13kw at wheels, with no other changes,, which shows how important matching the bowl to spray angle is,,, I did not find any difference in amount of fuel delivered between 4jh1 and 4jb1( late) injectors,, Each build is different though, and what works for one, might not be best for another,,,, but the one constant is that the bowl design MUST match injector spray angle,,, MUCH smarter people than us have spent millions testing this ,,

[handymanny01]

Oh, and Paul, you are bang on with the 6 cylinder excavator injectors I mentioned .. they are absolutely 180 degrees out! But because the early injector bodies are top feed, I may be able to drill through the body, and re-braze the return pipes on the opposite side.. which will swap them 180 degrees again, making the spray angle and position correct again,,, Worth a try!!

[paulthepilot5]

handymanny01 wrote:They have the same type of bowl (round) and not the early square bowl, but the spray angle is WAAAY wrong, 4jh1 is 144 degrees , 4jb1 is 154 degrees,, So it's unlikely that 4jh1 injectors would work in anything but 4jh1 pistons... I tried 4jh1 injectors in the 4jg1 hybrid, And not good results,,, Changed to 4jb1 injectors (only 2 degrees wrong on spray angle) and picked up 140 NM and 13kw at wheels, with no other changes,, which shows how important matching the bowl to spray angle is,,, I did not find any difference in amount of fuel delivered between 4jh1 and 4jb1( late) injectors,, Each build is different though, and what works for one, might not be best for another,,,, but the one constant is that the bowl design MUST match injector spray angle,,, MUCH smarter people than us have spent millions testing this ,, The bowls are the same between the late JB1 and JH1 but the difference may lay in the injection timing and it’s relationship to the spray angle and targeting the correct part of the combustion bowl at the correct time. You would have definitely had bigger orifice size on the JB1 injectors as well when you ran them in the 4JG1, there is a substantial difference in hole sizes between the JH1 and JB1

[paulthepilot5]

handymanny01 wrote:Oh, and Paul, you are bang on with the 6 cylinder excavator injectors I mentioned .. they are absolutely 180 degrees out! But because the early injector bodies are top feed, I may be able to drill through the body, and re-braze the return pipes on the opposite side.. which will swap them 180 degrees again, making the spray angle and position correct again,,, Worth a try!! would just cut off the return line and braze a banjo fitting over the body of the injector over the hole at the angle needed. I’m still sure those nozzles are the same sizing as the JB1 nozzles, at least that’s what the injection shop found when they looked them up

[handymanny01]

Yes, 5 x 0.22 mm that's the DLLA144PN309 (4jh1) And 4jb1 is typically DLLA154PN (XXX) 4 x 0.28mm , (several different nozzles) so yes, you're totally correct that (area wise) , the 4jh1 are smaller,, However.. In my application with the custom pump,, The 4jh1 injectors were CHUNDERING out fuel... HUGE clouds of grey smoke,,, So fuel was def being delivered, but the spray angle didn't suit the 4jg1 pistons ,and is wasnt burning properly ,, they are a different profile to both 4jh1 and 4jb1.. going to build up a 12mm pump "based" on a standard 4jb1 now though, And match nozzles to my pistons.. I DO like your idea with the banjos though! Might even be able to machine circlip grooves, and use them to retain banjos with o rings ?? This is why it's GREAT to bounce ideas around with like minded people! I totally hear ya that on paper going for the 6 cylinder excavator nozzles seems like a lot of effort for same nozzle size,,, but as this 4jg1 hybrid seems to be very particular on spray angle,,, I have to at least try the 152 degree nozzles!