SCAT 9000 Limits

[GARY C]

If you know any credible long standing dirt track engine builders then you will here plenty of broken crank stories that were virtually eliminated when they started using the 9000 crank, these would be 7000 ish 500 hp ish engines. At that point the main webs are probably weaker than the 9000 crank. RPM seems to be harder on cranks and rods then power and load.

At one time I was well connected with builders and racers. That all changed when I moved across the country. I'm kind of my own out here and am trying to find the right people to help me along.
I've paid attention the circle track guys and what works for them. But as was posted earlier the longevity is the concern for what I'm putting together. I've no interest in having to do a season ending tear down because I'm running components to the edge.
I will say I'm not building a rocket ship (my first post mentioned "another pedestrian 383 build" ) but at the same time I don't want to have to rebuild anything. Or worse.

If the fact that you can't find any failure story's and chances are you will not get a failure rate on this thread but if you are still in fear then just buy a 4340... All people can do here is answer your questions but at some point you have to decide what to do with those answers.

The Interweb is not great for positive feed back but you can guarantee that every problem someone wants to bitch about is posted daily!

[skinny z]

[quote="GARY C" post_id=855019 time=1585014174 user_id=21117]
then just buy a 4340...
[/quote]

That is entirely likely. Seeing that that was the plan is the first place but then along came this pretty good deal which included the 9000...

[GARY C]

viewtopic.php?f=1&t=23938&hilit=2814


This is an old engine of mine that had one of those cast cranks in it, may have been an eagle...but cast.

Is that the one you had in the Chevell?

[GARY C]

then just buy a 4340...

That is entirely likely. Seeing that that was the plan is the first place but then along came this pretty good deal which included the 9000...

I have run enough stock stuff both NA and Nitrous that I wouldn't hesitate to run a 9000 on an NA 500 hp/7000 RPM or a 700 hp Nitrous application 1/8th mile drag race.

[CGT]

I probably wouldnt choose that crank for 5 minute wot....although i feel it would be fine if it was all in good tune. Id want forged for piece of mind more than anything.

[skinny z]

I have run enough stock stuff both NA and Nitrous that I wouldn't hesitate to run a 9000 on an NA 500 hp/7000 RPM or a 700 hp Nitrous application 1/8th mile drag race.

It seems as far as drag racing is concerned and the on street performance, it's a capable component.
But, entry level at the Nebraska Sandhills open road event is 110 MPH average with a Tech speed of 140. That's pretty close to 5000 RPM in overdrive. Taking everything else into consideration, is that crank capable of that sustained RPM for minutes at a time? That's the question I have to ask myself.
I'm leaning towards no.

[skinny z]

I probably wouldnt choose that crank for 5 minute wot....although i feel it would be fine if it was all in good tune. Id want forged for piece of mind more than anything.

I appreciate that thanks. And I'm thinking the same way.
Now, to find a home for the forged crank and rods in the 355...

[GARY C]

I have run enough stock stuff both NA and Nitrous that I wouldn't hesitate to run a 9000 on an NA 500 hp/7000 RPM or a 700 hp Nitrous application 1/8th mile drag race.

It seems as far as drag racing is concerned and the on street performance, it's a capable component.
But, entry level at the Nebraska Sandhills open road event is 110 MPH average with a Tech speed of 140. That's pretty close to 5000 RPM in overdrive. Taking everything else into consideration, is that crank capable of that sustained RPM for minutes at a time? That's the question I have to ask myself.
I'm leaning towards no.

At that point for me it becomes a race engine that may see the street and longevity is more important than budget. Although it may due more street time than race time the street time does not define this build...Which leads back to why I said before that application dictates a large part of what you need for that "application"

[skinny z]

...Which leads back to why I said before that application dictates a large part of what you need for that "application"

Sometimes, and not in this thread, when you ask a question you have to clear away all the baggage. If I set some strict guidelines, sometimes that's necessary to get an answer that's clear and not cluttered with what if's. Then, the real result can start to take form.
This thread is a little different in that the question was not, for example, which cam is best, but rather, will this part survive what I'm asking it to.

And I'll say this, there are a lot of opinions here at ST that I respect a great deal. Some of the PMs I've received have been outstanding and immensely helpful.

[GARY C]

Another pedestrian 383 in the works and I've a quick question regarding SCAT's 9000 series crankshafts. Plenty of hits here searching but nothing specific.
The collection of parts is looking to keep peak RPMs to 6000. Maybe a couple of hundred more for some overspeed headroom. HP and TQ are not going to exceed 500. In street trim, I'd expect 450-475.
The proposed build direction will include drag racing and may include an open road event or two. It'll certainly be going across the country once or twice. The open road event gives me the greatest concern. That could be steady state 5000 RPM+ for minutes at a time.
So the question is: Is this power and RPM approaching the limits of the 9000 series crank? SCAT's Pro Comp rods w/ 7/16ths hardware are part of the pile.

You start with what I highlighted and then you move to this...

But, entry level at the Nebraska Sandhills open road event is 110 MPH average with a Tech speed of 140. That's pretty close to 5000 RPM in overdrive. Taking everything else into consideration, is that crank capable of that sustained RPM for minutes at a time? That's the question I have to ask myself.

I think you already know what crank you are looking for.

[skinny z]

Another pedestrian 383 in the works and I've a quick question regarding SCAT's 9000 series crankshafts. Plenty of hits here searching but nothing specific.
The collection of parts is looking to keep peak RPMs to 6000. Maybe a couple of hundred more for some overspeed headroom. HP and TQ are not going to exceed 500. In street trim, I'd expect 450-475.
The proposed build direction will include drag racing and may include an open road event or two. It'll certainly be going across the country once or twice. The open road event gives me the greatest concern. That could be steady state 5000 RPM+ for minutes at a time.
So the question is: Is this power and RPM approaching the limits of the 9000 series crank? SCAT's Pro Comp rods w/ 7/16ths hardware are part of the pile.

You start with what I highlighted and then you move to this...

But, entry level at the Nebraska Sandhills open road event is 110 MPH average with a Tech speed of 140. That's pretty close to 5000 RPM in overdrive. Taking everything else into consideration, is that crank capable of that sustained RPM for minutes at a time? That's the question I have to ask myself.

I think you already know what crank you are looking for.

All of that said, I'm sure there are many here that would say an open road event 383 build IS pedestrian.
But I'll have to say I'm coming into agreement with your last statement.
Now, if someone chimes in and says "Hey man, I've been flat out in the Silver State Challenge with my 9000 series crankshaft and never had an issue.", then I would have to think again. But I doubt that's going to happen.

[GARY C]

Another pedestrian 383 in the works and I've a quick question regarding SCAT's 9000 series crankshafts. Plenty of hits here searching but nothing specific.
The collection of parts is looking to keep peak RPMs to 6000. Maybe a couple of hundred more for some overspeed headroom. HP and TQ are not going to exceed 500. In street trim, I'd expect 450-475.
The proposed build direction will include drag racing and may include an open road event or two. It'll certainly be going across the country once or twice. The open road event gives me the greatest concern. That could be steady state 5000 RPM+ for minutes at a time.
So the question is: Is this power and RPM approaching the limits of the 9000 series crank? SCAT's Pro Comp rods w/ 7/16ths hardware are part of the pile.

You start with what I highlighted and then you move to this...

But, entry level at the Nebraska Sandhills open road event is 110 MPH average with a Tech speed of 140. That's pretty close to 5000 RPM in overdrive. Taking everything else into consideration, is that crank capable of that sustained RPM for minutes at a time? That's the question I have to ask myself.

I think you already know what crank you are looking for.

All of that said, I'm sure there are many here that would say an open road event 383 build IS pedestrian.
But I'll have to say I'm coming into agreement with your last statement.
Now, if someone chimes in and says "Hey man, I've been flat out in the Silver State Challenge with my 9000 series crankshaft and never had an issue.", then I would have to think again. But I doubt that's going to happen.

I have built a lot of stuff on stock parts with no failure but that does not mean I would build it that way again. Although I grew up highway racing and we ran stock cranks 5000 plus for several miles... slowing down was my only concern.

[skinny z]

[quote="GARY C" post_id=855056 time=1585020194 user_id=21117]
Although I grew up highway racing and we ran stock cranks 5000 plus for several miles... slowing down was my only concern.
[/quote]

I shudder to think about what I did with what I had when I was young. And I know first hand what happens when you drop a valve and end up with one cylinder head and an intake manifold as the only surviving pieces.

[RevTheory]

I was with you on the 9000 until you mentioned going flat-out for minutes on end. I'd be too worried about the crank to pay attention to what I'm doing at 140+ mph.

[skinny z]

I was with you on the 9000 until you mentioned going flat-out for minutes on end. I'd be too worried about the crank to pay attention to what I'm doing at 140+ mph.

It's something I've wanted to do legally for a long time.
And to have a lump that's overbuilt is certainly better than the other way around. Keep in mind that flat out might only realize 5000-5500 RPM depending on whether or not the engine package as a whole is capable of pushing the little 3rd Camaro that fast.