Ai 300-400 question

[Nsfr1206]

I’ve found an ai300 with much lower hours than my poor running 400. Are there physical differences between these engines besides injector nozzles? Are the pistons etc going to be different?

[Mackpro]

All AI engines internals are the same except the for turbo and injectors and download that determine horsepower ratings.  I will have to find my AI horsepower charts to see the difference between 300 and 400 , sometimes the turbo has to be changed along with the injectiors  . 

[fjh]

11 hours ago, Mackpro said:

All AI engines internals are the same except the for turbo and injectors and download that determine horsepower ratings.  I will have to find my AI horsepower charts to see the difference between 300 and 400 , sometimes the turbo has to be changed along with the injectiors  . 

And Some times the cam key

[Mackpro]

Cam key swaps were only on early ETECH 1998.5 till around 2001. Beginning with the CCRS engine sometime in 2002 , all key ways are straight regardless of HP. But good on reminding us !

[Mackpro]

According to my AI HP chart , if you have a AMI-300 you will need injectiors and download to go to 400HP. If you have a AI-300 Engine you only need the download To get to 400. 

[Nsfr1206]

Thanks. I found out the engine I was interested in doesn’t have engine brake so I guess I’ll pass. 

[Nsfr1206]

Could a weak check valve on fuel

return line affect my engine power? 

[Nsfr1206]

Also, my truck has the fuel line plumbed out of the end of tank at bottom. I’m wondering if I’m picking up a lot of trash this way. It seems like filter would get more and more plugged though. 

[Mackpro]

For CCRS and ASET style engines the fuel pressure regulator starts opening at 59 psi. Early ETECH engines had an 59 psi and later a 100 psi valve . The 100 psi valve caused some fuel in the oil issues on some trucks . If the valve sticks it causes low power and in most cases hard starting as the fuel in the injection galley flows bank to the tank 

[Nsfr1206]

Thanks.