Hey guys I'm just curious as i seen in a recent post that they revved their 3k to 9000rpm i would just like to know how many of you have actually done this as it is a pushrod ohv setup, Thanks

I've got a 5k getting built at the moment which is having a full balanced, blue-printed bottom end with a big cam which were expecting to rev to 9000.

I've hit almost 8000 with a pretty mild 5k so yeah i don't see 9000 being an outrageous value. :jamie:

Sure you can get them to rev that hard, But they won't last terribly long if you keep it there all day..

Keep in mind that revving to 9000rpm on a daily basis will do some kind of damage fairly quickly.....these engines arent unbreakable.

I only ask cause i know that 9000rpm is fairly high for a 4AGE and i have only taken mine to around 7k, id be worried about bending a push rod and so on in a 3k.

would clock the tacho with my 5K. Thats 8000rpm with a standard bottom end

The tacho in my 4k reckons its been to 9750 but i don't know how accurate it is when bodgerly hooked up.

Hi,

don't know how hard my 3K has rev trev as I have no tacho. But too quick you said ur tacho is done bodgerly if it is on the coil and held firm with no other wires crossed can't see why even if it looked messy isnt readign the right RPM unless gauge is out or shit it's self..lol

 

Cameron

You wouldn't want to have a loose tappet at those revs thats for sure

Hi,

don't know how hard my 3K has rev trev as I have no tacho. But too quick you said ur tacho is done bodgerly if it is on the coil and held firm with no other wires crossed can't see why even if it looked messy isnt readign the right RPM unless gauge is out or shit it's self..lol

 

Cameron

I don't know what the ppm is of a 4k so i just set it to 1.5 i think and it worked ok.

Hi,

don't know how hard my 3K has rev trev as I have no tacho. But too quick you said ur tacho is done bodgerly if it is on the coil and held firm with no other wires crossed can't see why even if it looked messy isnt readign the right RPM unless gauge is out or shit it's self..lol

 

Cameron

 

Set your tacho to 6 or 8 when on a 4 cylinder and it will read alot more revs.

umm, it will read less

 

4 sparks per rpm

if set to an 8 cyl motor its expecting 8 sparks per rpm

 

so your poopy k motor is doing 6000 rpm. this equals 400 sparks per second

a v8 at 6000 rpm would produce 800 sparks per second

 

therefore the tacho if hooked to poopy K motor but set to 8cyl will read 3000 rpm when real engine speed is 6000.

Been there done that.

 

My 3K had a 7K change mark, but would go out to 9K, but not something I did everyday, funnily enough. Wouldn't go any harder than that as the valve springs wouldn't let it. Readings as per an Autometer Tacho. Pulled 8K cheerfully on the dyno.

 

A 4AG should be able to crap 7K in all day everyday. 9K I believe on a decent one is a very realistic achievement.

 

Build them right and they don't break.

Edited October 13, 200620 yr by Redwarf

I have had a throttle linkage jam whilst my foot was meshed against the floor. As I switched the engine off, I saw the tacho falling from 12,000RPM. The only damage was 3 snapped valve springs. Actually it was only the inner springs, as they were aftermarket dual valve springs. That was in my 5K.

My 5K now happily goes to 8000RPM.

 

My first engine was a standard 3K. Not a day went past where that motor didnt see 7000+RPM with a 32/36 weber. It was still fine when i pulled it out after many years of abuse. Never burnt any oil either.

Edited October 13, 200620 yr by kangaroosa

The moral of the story is that K motors don't tend to bend pushrods.