[GNU]

Hi all, I'm having a TD42 head tidyed up and as it's fitted with an aftermarket turbo I was going to get the head guy to fit TD42t pre comp chambers, as they have a bigger opening and the std one's are cracked, Anyone done this?? is it a good idea??

 

[sudso]

No brainer, if they're cracked replace them.

 

[GNU]

No brainer, if they're cracked replace them.

Not trying to be smart mate but read the question

 

[GRUBBIES MOBILE MECHANICS]

not trying to be smart mate but read the question

x 2

 

[BeNos]

I can't see any reason why you wouldn't go with turbo precomp chambers. They shouldn't crack at least.

 

[GNU]

I can't see any reason why you wouldn't go with turbo precomp chambers. They shouldn't crack at least.

The only reason I ask is i'm sure I've heard of this being done before, but One head work shop I spoke with did not recommend it, He thinks it plays havic with the injector spray patten's??? But I just don't think he was keen due to having not done so before.
Anyone shed and 1st hand light on this???

 

[sudso]

What I should have said was, it is a good idea to replace cracked chambers while the head is off. Have never heard of there being any difference in the TD42 chambers though.
Happy?

 

[GNU]

Yes the factory turbo TD42t pre comps are bigger, but trying to work out if they can be used safely in a non turbo TD42 head due to it having a aftermarket turbo anyway, Of corse they are getting changed but with what one's is what I'm trying to work out??

 

[BeNos]

I'm fairly sure td42 and 42t injector nozzles are the same with the only difference being pressures so I shouldn't Imagine any dramas with that. But I'm happily corrected.

 

[GRUBBIES MOBILE MECHANICS]

injectors same as i have my standard 4.2 diesel pump and injectors in my 4.2 turbo just that when i had them recoed they were done to suit turbo so yeah different pressures so i dont see a problem with those chambers. let me know how u go as motor in project grubster is coming out for rebuild and im thinking of doing the same.

 

[insane_patrol]

the injectors on td42 n/a and turbo are the same everything is exactly the same, increasing crack presure is recommended on turbo ones only to help atomise the fuel under boost, the heads for td42 n/a and turbo are exactly the same castings the pre comps are larger in the turbo version and thats the only difference. would see if its cheaper to have your head reco with turbo precomps or get an exchange head last time i saw it was 1800 for exchange head and thats new valves and guides etc and new casting. do your research and find what best suits you and your setup as their is few ideas you can adopt with td42 head if your going to be reco or replace

cheers

 

[GNU]

Cheers Insane, thats the info I was after, the head is fine apart from the pre comps so i'll get him to put the GU turbo one's in. Anyone know what psi the injector's should be set to crack at for say around 14 psi?? Might as well shim up a bit to as they were only rebuilt around 30k ago

 

[ToughDiesels]

Cheers Insane, thats the info I was after, the head is fine apart from the pre comps so i'll get him to put the GU turbo one's in. Anyone know what psi the injector's should be set to crack at for say around 14 psi?? Might as well shim up a bit to as they were only rebuilt around 30k ago

Just set them at 115 bar mate

 

[GNU]

Just set them at 115 bar mate

Thanks Man

 

[sudso]

the injectors on td42 n/a and turbo are the same everything is exactly the same, increasing crack presure is recommended on turbo ones only to help atomise the fuel under boost, the heads for td42 n/a and turbo are exactly the same castings the pre comps are larger in the turbo version and thats the only difference.

cheers

The TD42's used in Nissan trucks, buses, and O/seas GQ Safari's were mostly factory turbo'd too.
They just went bigger precomps in GU TD42t's?

 

[Tracteur Tom]

It's probably an emissions refinement thing ? I note that there is a fraction difference on the comp ratio too between factory turbo and na versions - or again, that might just be a update / revision thing. Whatever, I doubt you'd notice the change !

 

[GNU]

No I don't think so eather, it was more so they may not crack again as easy

 

[Rhysta]

anyone know the size difference between the two?

 

[Dye-04]

Did you go ahead with this GNU? did it work out ok?