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Hi,

I'm about to pull the head on my 4JB1T to replace a suspected blown head gasket from the previous owner.

Along with getting the head refurbished/replaced, are there any power mods I can carry out while it's apart?
In particular I'm thinking of the camshaft, are there any known replacement cams available that will out perform the stock cam?

So far I have a 2.5 inch exhaust, an EGT guage (it a cheap one), coolant guage and a boost guage.

I also have a front mount intercooler that I have not fitted yet.

I have fitted and timed a new pump and injectors also, but these are all running stock settings at this time.

Vehicle is a 4x4 Isuzu Rodeo.

TIA
Brady

I have 0 experience with this engine, other than the one i am building, but lots with the vm 2.8 crd. My full-time side job is turbos, and from what ive measured in mine, and seen from others on here, is the stock turbo is pretty small. The intake compressor is small and chokes at higher rpms, and the exhaust turbine housing is REALLY small, also choking higher in the revs. Upgrading the turbo would be one of the best bang-for-your-buck mods you could do. I could build you one, but im sure the shipping from US to AUS wouldnt be cheap.

The stock turbo seems to be setup for lower rpm, hi torque, rather than all out wot performance.

Brady93 wrote:Hi,

I'm about to pull the head on my 4JB1T to replace a suspected blown head gasket from the previous owner.

Along with getting the head refurbished/replaced, are there any power mods I can carry out while it's apart?
In particular I'm thinking of the camshaft, are there any known replacement cams available that will out perform the stock cam?

So far I have a 2.5 inch exhaust, an EGT guage (it a cheap one), coolant guage and a boost guage.

I also have a front mount intercooler that I have not fitted yet.

I have fitted and timed a new pump and injectors also, but these are all running stock settings at this time.

Vehicle is a 4x4 Isuzu Rodeo.

TIA
Brady

Not too much you have to do with the head off. Don’t think there is any thing available off the shelf in the way of cams. Not really great gains to be had with cam modification in a diesel like the 4JB1T. Best option is improve breathing through intake and exhaust systems. Intercooler will improve things if you increase fuel to match. TD04H is probably the best bolt on turbo upgrade, again with a significant increase in fuel you will see good performance. If you want to go all out high performance with high boost, replace the head bolts with some ARP studs, will stop you blowing head gaskets.

Thankyou!

I'll almost certainly go ahead and do both of those changes.

It's been a while, but I'm about to pull the cylinder head.

I fitted a front mount intercooler, and I also salvaged a 4JH1 intake manifold so the intake is facing outboard to simplify the plumbing and keep it clean looking. Obviously I ditched the the butterfly assembly and made a new intake elbow that faces forward towards the intercooler.