12 Valve 3.0L Montero working on going to single turbo.

[TainterRacing]

I saw the 4g54 is about .3in longer then the 6g72 ones. MMM wonder how close the mech rockers would be to working.

[Ondonti]

I saw the 4g54 is about .3in longer then the 6g72 ones. MMM wonder how close the mech rockers would be to working.

You will still need a smaller base circle. The longer valves might prevent the rockers from sliding off the valve stem by changing the points at which the adjusterslides on the valve stem but maybe not. They do not work over the long term if they slide off the valve stem...at least on my big cams. Long term = 1 oil change :P

[TainterRacing]

Did you try running any of the 4g54 rockers? I know they fit the shafts.

[Sundance 6g72]

the rockers he tried using were solid lifter from a mitsu 1.5 4cyl i think. it had 2 intake valves and 1 exhaust valve.

[Ondonti]

Did you try running any of the 4g54 rockers? I know they fit the shafts.

Yes, the statement I made above is based on me being the first and only known to run them. They function but they self destruct because they are a little too short (1.5 rocker ratio vs 1.6 oem) and they are a smaller angle. They fall off the valve stem at full lift. I only tried this with a big cam because a stock cam would not be able to use them since the base circle is too large. The less base circle you have, the less likely the rocker would slide off the valve stem because you would get the angle of the rocker more like OEM. They also have to be clearanced a bunch unless you have enough base circle removed or beehive springs (small retainer) or both.

[Sundance 6g72]

wait what about the 1.5 mitsu engine rockerS?

[Ondonti]

wait what about the 1.5 mitsu engine rockerS?

Oh, I guess there is a bit of a disconnect here. 4g54 rockers are slider rockers which ALSO came on 3.0L 87 year motors and I don't know what year they stopped. I have a set but they are 1.4:1 ratio so they are a HUGE downgrade.
What I laugh about is that Starion guys don't even seem to realize that 1.6:1 roller rockers exist.

[Sundance 6g72]

maybe you should go onto starquest and let them know :P

[TainterRacing]

1.6 rockers don't work so well for the 4g54. The lifters can pupmp up at high rpms will not let them close.

---------- Post added at 04:21 PM ---------- Previous post was at 04:17 PM ----------

Why not remachine the top of the valves so they are shorter?

There was a roller rockers for the 4g54 just not in the USA. Got to go down under to get the good stuff

[Ondonti]

1.6 rockers don't work so well for the 4g54. The lifters can pupmp up at high rpms will not let them close.

---------- Post added at 04:21 PM ---------- Previous post was at 04:17 PM ----------

Why not remachine the top of the valves so they are shorter?

There was a roller rockers for the 4g54 just not in the USA. Got to go down under to get the good stuff

So they just need to convert the hydraulic lifter to solid. Quite a few of us want to try that. Weird that they pump up too much. They collapse in 3.0s. Probably because the clearances are preloaded when you put in a 1.6 rocker. What is the highest a 4g54 has been reved?

[TainterRacing]

I cant say what the highest they reved. I know some guys do more then 8500. But I will say not high... Most never see more then 7K. I know some guys do more then 8500 A good stock oil pump will at about 6k be pushing 95psi+ Oil pressure.

[Vigo]

I believe that's what a regulator valve is for.

[TainterRacing]

What is the stock crossover manifold pipe inside diameter?

[Sundance 6g72]

i can check for you later when im out of work.. i have one sitting in my garage

[Ondonti]

I believe that's what a regulator valve is for.

Or a simple restrictor. Thats all the srt-4 heads need to stop from over pumping.

3.0 pumps oil pressure dump works fine :P

[Vigo]

3.0 pumps oil pressure dump works fine :P

Thats what i was talking about. There should be a spring in there you can modify or replace to bring that high rpm pressure down.

[Ondonti]

I actually put a washer in (sometimes) to up the idle pressure because sometimes they don't seat tightly enough.

[TainterRacing]

I never got in to working on the lower end of the motor. I have always taking it to a shop for the short block. With that said.... I have a very low Idle on the 3.0 8-9psi at Idle. Next time I work on it will be sure to address that. It sounds like the lifters collapse at idle.

I should have asked this up at the top. What I am wanting is a turbo that’s going to make full boost at about 2600-2800rpms. I will likely use a external wastegate set to about 6-7psi. I am trying to do this right now for the turbo about as cheap as I can. $$ is very tight right now. The power I am looking for is about 210-230hp with a lot of tq. I am in the 8.9:1 comp motor that stock makes 143hp@5000rpms. I don’t know if its the same cam as any of you so I realize it might be hard to know what would be best. I was thinking a t3t4 with a .63 ar and stage 3 wheel would spool fast. I believe that’s the same turbo as Sundance6g72 is using. Should I run a larger turbo? I can also make is in to a split tag manifold for it as well. I am going to try not to run an IC on it as I don’t every plan on running more then the 6-7psi max.

Thanks so much Matt

[Sundance 6g72]

this is what im running. take it as it is LMFAO

http://www.cxracing.com/mm5/merchant...ode=TRB-T3T4-V

they dont tell you much and i dont get full boost until like 4000rpms but with that said, i have big intercooler piping, probebly an exhaust leak and an intake leak that im too lazy to check right now. sorry

[TainterRacing]

I bet your wastagate is leaking a good deal I think you will realy like the new one your getting on there.