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4jg1t "franken-engine"

Share and discuss mod ideas here that make your Isuzu safer, faster, more homely, more user friendly or just crazier! The best from here will be made into a full DIY write up for the FAQ and DIY mod section.

Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Tue Jul 28, 2020 8:13 pm

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
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Re: 4jg1t "franken-engine"

Postby handymanny01 » Sat Aug 01, 2020 1:13 pm

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
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Re: 4jg1t "franken-engine"

Postby MISTIRIODES » Wed Aug 19, 2020 6:30 am

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
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Re: 4jg1t "franken-engine"

Postby MISTIRIODES » Wed Aug 19, 2020 7:07 am

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)
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Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Wed Aug 19, 2020 4:53 pm

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
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Compound twin Turbo
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Re: 4jg1t "franken-engine"

Postby handymanny01 » Mon Aug 24, 2020 8:02 pm

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 ,,
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Re: 4jg1t "franken-engine"

Postby handymanny01 » Mon Aug 24, 2020 8:08 pm

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!!
handymanny01
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Country: NZ
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Tue Aug 25, 2020 9:39 pm

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
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Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Tue Aug 25, 2020 9:56 pm

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
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Compound twin Turbo
12mm fuel Pump
+50 injectors
Water/meth injection
14s 1/4 Mile

Re: 4jg1t "franken-engine"

Postby handymanny01 » Tue Aug 25, 2020 10:44 pm

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!
handymanny01
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Posts: 68
Joined: Tue Jul 12, 2016 9:39 pm
Age: 43
Country: NZ
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Wed Aug 26, 2020 5:30 pm

handymanny01 wrote: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!
yep ok, forgot the JG1 was another style bowl. One other thing to play with is your injector height in the head. You can use 4H1E1T copper injector seals, same profile and diameter but about 1mm shorter.
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Compound twin Turbo
12mm fuel Pump
+50 injectors
Water/meth injection
14s 1/4 Mile

Re: 4jg1t "franken-engine"

Postby handymanny01 » Wed Aug 26, 2020 9:10 pm

Cheers Paul, yes I have access to several different height injector washers, plus my own brass shims too,, I tried raising and lowering the 4jh1 injectors when I tried them,, Made noticeable differences to the smoke level,,, but power remained similar,,, it maybe just shifted the peak around ?.... but then they were really not the right injectors for my pistons,,, so who knows really? I've sourced 1.5mm copper sheet for the gasket now,,, So just gotta draw it up,, and get it water jet cut.. then machine head for o-rings,,,, Then I can try again!! Lol. The other parts of this hybrid build are in perfect condition though,,, pistons, head, valves , hybrid turbo , bores,, all mint,, so that's pleasing at least ! Hahahaha.
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby jackapoo » Sun Jul 11, 2021 8:43 pm

is there any news on how this build is going??
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Re: 4jg1t "franken-engine"

Postby handymanny01 » Fri Aug 20, 2021 10:36 am

much news! some good some bad,, lol Yes its still going! so it got water methanol this year,, and 4JG1 single spring injectors.. power dropped off a bit with the single spring injectors, dynoed at 90KW at wheels and 411 NM (on 33'' wheels mind, so still not bad) then 115kw / 495NM on 50/50 water meth,,, then a whopping 133KW 510NM on 25/75 water meth,, needless to say, it felt pretty grunty! that was running at 29 lbs boost... The whole project has been hampered by the mods i made to the pistons (de-lipped) which means it won't ever run to its full potential until i build the next one with un-modified pistons... I've been having to run excessive advance to combat the poor burn, which causes excessive "nailing" and has ultimately ended in a snapped crank, (no 1 big end) a very old harmonic balancer , and over tensioned belts, prob hasn't helped here either... important to note this wasn't a power related failure, it failed under light load and low boost.. although the standard aluminium big end bearings weren't up to the job, so these have been replaced with copper lead bearings...
Its now back together with a new (second hand) crank, new solid copper head gasket, and running brand new 4jb1 153 degree nozzles in twin spring bodies... and its going great! seat of the pants says 110kW and 500 nm.. so will book dyno again, and put results up...
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Country: NZ
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby handymanny01 » Fri Aug 20, 2021 10:50 am

One broken crank! waaaaaa
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handymanny01
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby handymanny01 » Fri Aug 20, 2021 11:06 am

solid copper gasket - O ring head mods
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handymanny01
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Posts: 68
Joined: Tue Jul 12, 2016 9:39 pm
Age: 43
Country: NZ
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Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Fri Aug 27, 2021 2:54 pm

handymanny01 wrote:solid copper gasket - O ring head mods

What are you planning for a crank upgrade? I haven’t gone the copper gasket or o-rings yet, ARP studs are holding the factory gasket ok.
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Posts: 109
Joined: Thu Apr 05, 2018 8:56 pm
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Vehicle: 1995 Isuzu Rodeo 2.8d
Compound twin Turbo
12mm fuel Pump
+50 injectors
Water/meth injection
14s 1/4 Mile

Re: 4jg1t "franken-engine"

Postby paulthepilot5 » Fri Aug 27, 2021 8:47 pm

handymanny01 wrote:much news! some good some bad,, lol Yes its still going! so it got water methanol this year,, and 4JG1 single spring injectors.. power dropped off a bit with the single spring injectors, dynoed at 90KW at wheels and 411 NM (on 33'' wheels mind, so still not bad) then 115kw / 495NM on 50/50 water meth,,, then a whopping 133KW 510NM on 25/75 water meth,, needless to say, it felt pretty grunty! that was running at 29 lbs boost... The whole project has been hampered by the mods i made to the pistons (de-lipped) which means it won't ever run to its full potential until i build the next one with un-modified pistons... I've been having to run excessive advance to combat the poor burn, which causes excessive "nailing" and has ultimately ended in a snapped crank, (no 1 big end) a very old harmonic balancer , and over tensioned belts, prob hasn't helped here either... important to note this wasn't a power related failure, it failed under light load and low boost.. although the standard aluminium big end bearings weren't up to the job, so these have been replaced with copper lead bearings...
Its now back together with a new (second hand) crank, new solid copper head gasket, and running brand new 4jb1 153 degree nozzles in twin spring bodies... and its going great! seat of the pants says 110kW and 500 nm.. so will book dyno again, and put results up...


Old harmonic balancer will do that, mine snapped with a loose balancer. New one on now and it’s been fine. You would have had some crazy advance timing running 25/75, even 50/50 will advance too much if you get carried away. Probably best looking at running a lower comp ratio of you want to do that.
paulthepilot5
Isuzu Junior
 
Posts: 109
Joined: Thu Apr 05, 2018 8:56 pm
Age: 34
Country: Australia
City: Brisbane
Vehicle: 1995 Isuzu Rodeo 2.8d
Compound twin Turbo
12mm fuel Pump
+50 injectors
Water/meth injection
14s 1/4 Mile

Re: 4jg1t "franken-engine"

Postby handymanny01 » Tue Aug 31, 2021 10:42 pm

That's interesting you should say that Paul, as all my research suggests that methanol actually retards the combustion event , due to its low Cetane rating, ie it is slow to burn, and has a high auto ignition point,,, Further to that, methanol will ONLY burn once the diesel has ignited , it will not burn with compression alone, I think the issue (in my case) was I was already running excessive advance, and the better burn I got with the water meth, resulted in excess peak cylinder pressure, worth noting this "only" blew a head gasket, it didn't break the crank, the water meth had been turned off for weeks prior to the crank breaking,,
As for the crank, no plans for anything but stock crank, it's crazy strong, I had a go at my old one with a huge hammer for "research purpose" and they are TOUGH!!
handymanny01
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Posts: 68
Joined: Tue Jul 12, 2016 9:39 pm
Age: 43
Country: NZ
City: Wellington
Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

Re: 4jg1t "franken-engine"

Postby handymanny01 » Tue Aug 31, 2021 10:50 pm

On a side note Paul, you may be interested to know, when I built this thing with Alibaba pistons, I got them hard anodised locally, and can confirm TOTALLY worth it! I'd rate it as 2-3 times better than "ceramic coating" ,the anodising "grows" out of the aluminium, it cannot flake or chip off,, And after 3 blown head gaskets, and a broken crank worth of abuse, there isn't so much as a hint of colour on the underside of the pistons! And the crowns are 100% like new! Very impressed,, I actually tested some factory pistons before I had mine hard anodised, and the only way you can get the anodising off is sand blasting , Obviously just my opinion, but though you might find it interesting : )
handymanny01
Isuzu Junior
 
Posts: 68
Joined: Tue Jul 12, 2016 9:39 pm
Age: 43
Country: NZ
City: Wellington
Vehicle: Isuzu MU 3.1 Direct injection 4JG1 conversion, Vf10 hybrid, ported wastegate, mild port head, custom 12mm pump, 3"dump and system, 3" inlet / pod filter, EGR delete, 2" body lift, 2" (ish) suspension lift, 33" on 15" steelies , recaro seats, nardi wheel,,, rear LSD , front "lokka"

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