4jg1t "franken-engine"

[paulthepilot5]

isuzurob wrote:I use autometer gauges not cheap rubbish, keep putting fuel in it will get way hotter than what I said, ie seen the manifold go white from the heat, turbo builder was worried it would melt the wheel

Even good gauges can fail though. What sort of power and torque are you getting from that setup?

[isuzurob]

Have run 3 different brand egt and all well over 900 degree celcius, never run on a dyno, has average power, goes far better than my stock 4jj1 colorado and have blown 5 gearboxes in it and 3 clutches to pieces so must have some power

[paulthepilot5]

isuzurob wrote:Have run 3 different brand egt and all well over 900 degree celcius, never run on a dyno, has average power, goes far better than my stock 4jj1 colorado and have blown 5 gearboxes in it and 3 clutches to pieces so must have some power
Yes clutches are a issue with the JB1 when pushing them, too small diameter for the torque really. Went through several types before I could find one that did the job. NPC cushioned ceramic with a doubled up diaphragm spring is what solved my problems. What has been the failure on your gearboxes? I have dramas with the input shafts snapping I believe it’s the weakest part. Even so they are surprisingly strong gearbox given its size and weight particularly behind a 4cylinder diesel.

[isuzurob]

I run a 8 button clutch plate and custom 3000lb pressure plate, also running a bigger diameter flywheel to run bigger clutch setup, normally strips 5th gear first and spreads the main and lay shafts apart, then just works it's way down till I only have fourth to limp home

[paulthepilot5]

handymanny01 wrote:Dyno run with the 4jh1 injectors ... you can see the solid hit of power and torque,,, then it just can't burn the fuel properly,,, Will book a dyno run with the 4jb1 injectors and post results,,, expect to see much better result! ,,,, (sorry, pic is kinda fuzzy) red and green runs are 4jg1, the blue line was the old 4jg2 on 20lb and maxed out standard pump ,,,.

The 4JH1 injectors are a smaller nozzle oriffice than the JB1 nozzles. Might explain the better low rpm and running out top end. The +50 nozzles I’m running on my JB1 perform mid to top end more so than low rpm.

[handymanny01]

Hey Paul, I think it was just due to the terrible mismatch between the 4jg1 pistons and the 4jh1 injectors... 4jg1 is a 152 degree injector spray angle, 4jh1 is 144 degrees ... the 4jh1 injectors were flowing plenty of fuel,,, just wasnt burning it,, Now running 4jb1 injectors,,(154 degrees) and shes MUCH happier!! A best of 112KW at wheels and 501NM on 33 inch tyres, so pretty respectable.... next couple of runs will be with narrow body injectors and actual 4jg1 nozzles, then some hopefully perfect nozzles from a Komatsu 6 cylinder,(these took some searching!)
And then water meth injection! yuuussssss

[paulthepilot5]

Handymanny that’s some good output there now, you will see some good gains with water/meth as well, particularly top end. Seems the 6cylinder engines offer a better selection for better flowing nozzles, I’ve been looking at some Isuzu 6cyl options, what Komatsu engine nozzles were you looking at? I’m just in the process of fitting up a in-line P-Pump after doing a belt drive conversion. Going to the +50 nozzles didn’t get me anywhere near the fuel I wanted, but then they are just the 4hole nozzles. What sort of W/M setup will you be running?

[handymanny01]

Hey Paul, the Komatsu nozzles are DLLA152PN009 4x.30 @ 152degrees. These are at (least in theory) the perfect nozzles for a hot rod 4JG1 Standard 4JG1 nozzles being something tiny like 4x0.17 (don't quote me on that, I just remember them being tiny) Hopefully they fit a set of narrow body 4JB1 injectors I have coming ,,, Def looking forward to the water meth! I've got bits coming from ProMeth (great selection!)in the states, have readied manifold for port injection, 4 x 95cc nozzles, For a total flow of 380cc/min @ 100 psi, or approx 700cc/min @ 200psi. Will test on dyno to see how much is needed

[paulthepilot5]

handymanny01 wrote:Hey Paul, the Komatsu nozzles are DLLA152PN009 4x.30 @ 152degrees. These are at (least in theory) the perfect nozzles for a hot rod 4JG1 Standard 4JG1 nozzles being something tiny like 4x0.17 (don't quote me on that, I just remember them being tiny) Hopefully they fit a set of narrow body 4JB1 injectors I have coming ,,, Def looking forward to the water meth! I've got bits coming from ProMeth (great selection!)in the states, have readied manifold for port injection, 4 x 95cc nozzles, For a total flow of 380cc/min @ 100 psi, or approx 700cc/min @ 200psi. Will test on dyno to see how much is needed

My injection shop had a set of those Komatsu nozzles to look at. same hole size as the 4JB1, and orientation is out 180deg.

[handymanny01]

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..