What all plays into RPM's of engine?

[streetknight]

If you turn an engine higher than it's RPM range, say a stock 231 6500RPM, you're gonna spin bearings I would think, but I want to know what all is considered when building an engine for higher RPM use.

The stock TR engine in my car is done @ around 5200. Let's say I chose a camshaft that pulled to 6000, is this the only thing that would be changed in the engine to get to the new RPM range or is there gonna be bearing failure if other mods aren't made?

 

[REGAL_SS]

well teachnicaly every thing like the crankshaft rods pistons cam timing chain and gears and heads idealy you would want forged if ur gona run high rpm and trust me it aint cheap i spent 8000 rebuilding my 355 and thats just the motor

 

[BIGPSI]

ported heads will get you some more RPM'S. my motor has stock internals and has seen 6200

 

[Slow91z]

Stock shortblock here (well kinda, NA crank, aftermarket rings and bearings), my motor sees 6000 on a fairly regular basis.

The things that limit your RPM are cam, valve springs, heads things like that.

There are many things that may break if you over rev the motor (I wouldn't go much over 6000 on a stock Buick motor, and no where close to 6000 with stock cam and springs) you could float the valves and they could hit the pistons which could result in anything from a bent valve to a hole in the piston, you should stretch the rod bolts resulting in a spun bearing or worse throw a rod right out the side of the block.

 

[QUIP'6']

If you turn an engine higher than it's RPM range, say a stock 231 6500RPM, you're gonna spin bearings I would think, but I want to know what all is considered when building an engine for higher RPM use.

The stock TR engine in my car is done @ around 5200. Let's say I chose a camshaft that pulled to 6000, is this the only thing that would be changed in the engine to get to the new RPM range or is there gonna be bearing failure if other mods aren't made?

bearings are an issue if your going to turn 6000 rpm and have a poor tune and detonate it

 

[machinegun]

The actual easier qustion to ask is what does not play a factor?

Anything that affects air flow or rotation needs to considered.

 

[A2000RICH]

The actual easier qustion to ask is what does not play a factor?

Anything that affects air flow or rotation needs to considered.

very true-------heres a good physics thing to keep in mind------when the speed of an engine is increased the forces, strains and unbalances go up by the square -------its easy to see how this affects things like connecting rods and valve springs but think about something else, ie BALANCE--------this means that if you have an engine that is at 3000 rpm and you increase the speed to 6000 the forces and unbalances that want to tear it apart are not twice but FOUR times as much--------many production engines (especially ones the age of our 25 year old GN's) are only balanced to 1 or even 2 oz inches--------at 4000rpm a 2oz/in imbalance can result in a hammering force of about 60 lbs at a rate of 60 times a second---------at 6000 that would increase to well over a hundred lbs of force 60 times a second trying to hammer your engine apart---------picture someone under your hood dropping a 100 lb weight on your crank bearings 60 times a second-------not a comforting thought........RC

 

[ULOSE2A6]

Well explained Richard.

Regards,
Shev

 

[TurboBuRick]

Well explained Richard.

Regards,
Shev

X2

I just wish-------he could learn------to post-------so we could read the stuff.

 

[A2000RICH]

X2

I just wish-------he could learn------to post-------so we could read the stuff.

sorry--------i am a poor typer and if i took the time to find capitals and punctuatation it would take twice as long---------and i sort of type as the thoughts come to mind--------

 

[Boost231]

Its ok richard. i can read what you type.

 

[John Wilde]

Thanks Richard!

 

[BEATAV8]

sorry--------i am a poor typer and if i took the time to find capitals and punctuatation it would take twice as long---------and i sort of type as the thoughts come to mind--------

Hahaha it doesn't bother me. Gives your posts some character.