Direct Injection in 4JG2T

[dani4JB1T]

Just would like to know if anyone has fitted 4JB1T´s cylinder head on 4JG2T´s Block ??

This can be possible ??


cheers !!!
Dani

[MattMU]

Even if the head does bolt up, it would not work well at all. You would have a far too high compression ratio and the piston design is suited to the application. Depending on the engine being direct or indirect the pistons are shaped differently to give different compression ratios and flamefront travel patterns.
A direct injection engine is built from the start to be direct and vice versa for an indirect injection engine.

Sorry, not a chance!!

Matt.

Here you go and exert from an RMIT exam!
Direct injection diesels inject the diesel fuel directly onto the piston crown. Most direct injection diesels have a swirl chamber designed into the piston. Due to the high compression required for a direct injection diesel engine to operate diesel noise is usually more pronounce. The higher compression creates more compression heat so the use of glow plugs is not required for cold starts.
Indirect injection diesel engines inject the diesel fuel into a pre- combustion chamber. This chamber has a glow plug that aids the compression heat to assist with cold starts. Indirect injection diesels usually have a lower compression ratio and are much quieter running.

[jjcymru]

is it bore/stroke or both the diff between the 2.8/3.1?

[shinz]

Hi JJ, I see you've found us out here & still want to go faster. ;D
re you question about bore & stroke. The 4jb1 (2.8) is 93mm x 102mm & the 4jg2 (3.1) is 95.4mm x 107mm. Although there is no way to fit the 2.8 head to the 3.1, there is such a thing as a 4jg1 motor which is a direct injected 3.1 but I've never found any info to support that it was ever used in automotive apps, only ever seen it listed as an industrial engine at relatively low revs so don't know whether its pistons would be up to road speeds ie 3600 rpm at times. I believe the injectors can be used in the 2.8 as an upgrade but suspect yours may already have something close anyway. The block for the 3.1 & 2.8 are the same in most dimensions other than bore & stroke I believe. HTH
Cheers, Steve.

[stephanbotswana]

Sorry even the injectors do not fit.
I have replaces the 3.1 with a 2.8 since the 3.1 is not local in South Africa or Botswana and parts is a pregnant dog. The Diesel pump do not fit, the 2.8 turbo uses bushes and the 3.1 bearings. I hade to change the manifold, rebuild the diesel pump (Hybrid between the 2.8 and 3.1 since I have an Auto Box) The Oil sump is different if you do a complete change, so you have to modify the oil pump to get the engine in. As they say hind sight is an exact science. You must either be mad, love your Isuzu lots to attempt it. The 3.1 felt more alive then the 2.8 after I have done the conversion. I hope to get my love back on the road (once the auto box is working properly) for many happy driving hours.