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Jet Valves
Posted: Thu Sep 14, 2006 8:20 am
by gjgnz
Finally stripped down my motor for a rebuild. What should I do about the jet valves?
1. Keep them
2. Get a Jet Valve elimination kit
3. Have the holes welded up
4. Get a non Jet Valve head
Any good advice is appreciated
Posted: Thu Sep 14, 2006 8:26 am
by Starion VR4
Option 4, any of the other will stuff up eventually. :beer
Posted: Thu Sep 14, 2006 10:06 am
by AB
You shouldn't have any problems finding a non-jet valve head in NZ, in fact I'd say a jet valved head is much more uncommon here than the non-jet valved head because I've never seen one except in pictures.
Posted: Thu Sep 14, 2006 10:50 am
by kiwi_EX
Posted: Thu Sep 14, 2006 11:12 am
by gjgnz
Are there likely to be any problems with running a FWD or non turbo head? I was told that some later single cam motors have roller rockers. Will one of these heads require any changes and would it be worth getting one?
Posted: Thu Sep 14, 2006 4:19 pm
by kiwi_EX
I was told the RWD and FWD heads of the same vintage were the same and the only difference was in the manifolds, but hey I could easily be wrong! :D
Posted: Fri Sep 15, 2006 12:29 am
by Starquest86
Im going to jave to say option 1. Mitsubishi put them there for a reason. The car withought them would run real lean. The jet valves put in a rich af mixture back into the cylinder head. So i would say keep them.
Garrett G$
Posted: Fri Sep 15, 2006 5:34 am
by JD_Stazza_Brendan
They are an emission control device that can lead to cracking in the head in modded motors... And not all heads are Jet Valve so you dont have to have them.
Posted: Fri Sep 15, 2006 6:08 am
by AB
I was under the impression that an ultra lean mixture is injected through the jet valves? I've never had a look at them but I assume that with them blocked up the air/fuel mix will just go through the main inlet valve therefore causing no affect to the air/fuel ratio.
Posted: Fri Sep 15, 2006 7:57 am
by ProZac
The roller rocker information turns out to be incorrect... they come on a 4g37 1.8 SOHC, completly different motor :(.
I put blanking plugs in my head. It dosent go yet however, so no idea if it'll crack or not.
FWD and SOHC heads are the same, the turbo ones have a big T embossed on the back of them, but ive never noticied any difference other than that between the turbo and non turbo ones.
Posted: Mon Sep 18, 2006 7:21 am
by BDperformance
if the head is off just have a local head repair shop weld up the
jet valve openings. no harm done as i have done this. i have no hot spot to worry about nor emissions. if you have to worry bout emissions.
dont do this, unless your running a hot ignition, some sort of fuel controler
