What would it take to get my 200 to rev to 6500RPM

[Anonymous]

Hey, i was just wonder what it would take to get my 200 to rev up to 6500RPM safely

also, what is the highest that i could rev my 200 up to without it blowing up? i've got it to 5500rpm before but that was on accident, was surprised it didnt blow up

 

[addo]

Why 6500? Do you want high shifts or something? A lightened flywheel and full balance will always help. Beyond that, a windage tray and internal polishing/smoothing.

 

[Anonymous]

working on getting a cylinder head that's got quite a bit of port work to it and would be running around a 280 cam

 

[Anonymous]

Considering the American 200 has about the same ratio as an Aussie 250 "maybe" it could rev to the same. Ive heard from a number
of good sources that a 250 will do between 7500-8000 rpm (assuming it is all in balance properly) before flying to bits. I suspect "if it managed to survive the ordeal" it would result in a lot of damage (still its a lot higher than a clevo 351 with a better rod ratio).
I would never rev a 250 this high the rod ratio would cause the wear and strain on the engine to be phenominal. Its a real credit to the engine than it can hold together at this rpm with the above mentioned factors involved. Dont do it.
I wont rev my 250 2V above 5000 rpm

 

[Anonymous]

i think i can pry step down a cam to get it under 6

 

[Anonymous]

ARP rod bolts for insurance, a must for high rpm. Someone might be able to advise if your pushrods will be OK?. And Addos recommendations.

 

[Anonymous]

I'd be surprised if you could get a 200 to rev that high under load with the original log intake and carby. That having been said, in addition to things previously mentioned, you'd need shorter-than-stock rear gears.

 

[Anlushac11]

8)

The 200 I6 properly built can rev to 7500rpm safetly.

A stock 200 aint gonna do it.

You need the following to rev to 6500 SAFETLY

1) A good port and polish on the log head, a Oz or Argie head would be better. A Holley 5200 carb minimum, 350cfm 2 bbl would be better.

1A) A good aftermarket cam. Even a 264 deg cam can rev that high but it would not make power at that rpm. And the cam kit for the cam with the HD valve springs, anti-pump up lifters.

2) Header and a high flow exhaust

3) Forged pistons if you plan to hit that rpm regularly. Cast pistons MIGHT take that rpm once or twice but you are taking a chance each time.

4) Custom balancing. The worst enemy of the I6 is harmonic vibrations and custom balancing will reduce vibrations.

5) ARP HD rod bolts and main bolts is extra insurance that things will remain together.

 

[Anonymous]

The 200 i6 (providing it was built in 65 or later) has 7 main bearing underneath it. - This makes it virtually indestructable. Bore it .060 over, deck it .040, new cam bearings and freeze plugs installed. Turn the crank (and straighten) .010-.010, balance the whole thing, new rods, ARP rod bolts, new flat top pistons, rings, etc. (=really strong rebuild)

along with all of your upgrades for HP (and larger valves if it is an early six) will give you excellent results. A really strong rebuild (hardened, chrome molly, etc.) will allow you to turn over 6,000 with out trouble - I have heard people talk up to 7500, but I wouldn't take it past 7,000.

 

[Anonymous]

well i've got some top secret plans for the motor, lol.....


but the thing is, my motor is rebuilt and i'm not really sure what they have put back in it, probably just a stock rebuild with nothing strengthened, now i'm pissed at myself for not having it all strengthened when it was rebuilt

 

[Kstang]

o ooo i know i know , yeah shhhhh got to keep the secret!! i wont tell on ya !! lol

kevin

 

[Anonymous]

dont worry, you keep it a secret and ill keep off the gas so you can keep up

 

[addo]

Look at it this way, AC: If you do the things you can afford right now, and it hangs together, fine. If it grenades, well, you're unlikely to have destroyed the recent investments (save maybe a valve or two), only older, less suited parts.

This approach (or something like it) has kept importkiller happy for quite some while. As for "keep off the gas", is this what you mean?

Adam.

 

[Anonymous]

Hm Anlu, u mentioned forged pistons, what I've been told is that, in high RPMs, the rods r what gets stresst the most, so I would think, forged steel rods would be in order, atleast ?
I know its a lil diff but my daily driver 4 cyl has cast pistons w\ forged steel factory rods and its red line is at 6800, I've been up to 6500 many times over the yrs w\ out any problems to pistons etc.
I have heard forged pistons r good mainly for nitrous and blower engines, thats jus what I have seen. I think I'd want to go w\ upgrading all critical parts of these 30+ yr old engines if its gon see high RPMs specially on a regualr basis, like my lil car, it has to, to get it moving lol.

 

[Anonymous]

sorry to interupt your thread, but i always wanted to know what rpm a stock 200 i6 thats in pretty good shape could pull without messing anything up?

 

[Anonymous]

My bone-stock 200/C4 would rev to a little over 5000 in 2nd gear, but you could tell it was out of air above about 4 grand.

 

[Anlushac11]

Hm Anlu, u mentioned forged pistons, what I've been told is that, in high RPMs, the rods r what gets stresst the most, so I would think, forged steel rods would be in order, atleast ?
I know its a lil diff but my daily driver 4 cyl has cast pistons w\ forged steel factory rods and its red line is at 6800, I've been up to 6500 many times over the yrs w\ out any problems to pistons etc.
I have heard forged pistons r good mainly for nitrous and blower engines, thats jus what I have seen. I think I'd want to go w\ upgrading all critical parts of these 30+ yr old engines if its gon see high RPMs specially on a regualr basis, like my lil car, it has to, to get it moving lol.

Actually I intend to upgrade both parts. I want to run forged pistons and polished rods with ARP rod bolts.

 

[Anonymous]

Someone mentioned the pushrods. That is important. Also the Valve Springs. At what RPM do you start to get valve float. Are the Pertronix, and/or Duraspark rated for this RPM level? These are questions I would ask just out of my ignorance. How about the fuel pump? If i am asking these questions improperly just let me know.


Bill

 

[Anonymous]

so you guys all have tachs?

I really need to get one of those.

 

[Anlushac11]

8)

Factory tach in the dash. Its good enough for my purposes.