[ericnova72]

Originally Posted by zildjian4life218

http://www.summitracing.com/parts/SCA-910526/

So like this. What about the cross drilled mains?

Agree, Scat over Eagle...heck, stock over Eagle.
Your linked part will work just fine. I haven't used the one piece seal version yet but can't imagine it is any different in strength from two piece.

You don't want cross drilled mains. It is old tech that has been proven with todays oiling passage orientation in cranks to be more detrimental than it helps, tends to siphon oil away from the bearings due to centrifugal force at higher rpm.

I'll agree the hyper pistons will handle the nitrous load, but you have to do it as F-Bird has said, and you can never detonate it, or you will have a bunch of marble sized aluminum shrapnel in the oil pan. Never to low an octane, never elevated intake air temps, never too much timing, never too lean or too overly rich. Things have to be just right, like Goldilocks.

I agree, use a bigger solid cam if you want to be a man In a Howards, #112081-10 if you need to stay down near .500 lift. Don't forget lash gets subtracted from published lift specs.

[zildjian4life218]

on summits site it says that scat crank i posted has cross drilled mains. Most articles i read say to stay away from them. Does scat offer any other cranks like this without the cross drilled mains?

[cobalt327]

At the RPM level you are talking about, plus w/the "corrected" clocking of the passages, I do not believe being X drilled matters.

[zildjian4life218]

Originally Posted by cobalt327

At the RPM level you are talking about, plus w/the "corrected" clocking of the passages, I do not believe being X drilled matters.

When does it start playing a roll? I understand that the force from the crank spinning prevents the oil from going to where it needs to.

[cobalt327]

I wouldn't begin worrying about it until the need was there for using a forged crank instead of a cast crank. I. e.- if you can otherwise use a cast crank for the engine, I wouldn't let the crank being cross drilled keep me from using it.

I base this on the number of cast steel X drilled Scat cranks that are currently in use, w/o issue. Before this discussion, I wasn't aware the Scat cast steel cranks even WERE X drilled. And I guess I'm not alone...

[zildjian4life218]

Originally Posted by cobalt327

I wouldn't begin worrying about it until the need was there for using a forged crank instead of a cast crank. I. e.- if you can otherwise use a cast crank for the engine, I wouldn't let the crank being cross drilled keep me from using it.

I base this on the number of cast steel X drilled Scat cranks that are currently in use, w/o issue.

Good point. Thanks for the insight.

So fbird thinks i can spray 200 at it. I would start worrying about the block at that point. I wouldn't do it till the end of the season when its time for a better motor anyways. Maybe i do worry too much though.
I think 100-125 will be plenty to play with for now. I guess I can just do it and see what happens. I'm not gonna have a ton of money into this motor anyways so if it hand grenades just gotta watch my feet cause the motor is moved back like 10" and dropped down a couple inches. Without the firewall there i can stretch my legs from the seat and touch the front motor mount lol.

Anyone got some hp/tq numbers with and without the spray? Im thinking like 425ish without spray and maybe 500 with spray.

[ericnova72]

Originally Posted by zildjian4life218

on summits site it says that scat crank i posted has cross drilled mains. Most articles i read say to stay away from them. Does scat offer any other cranks like this without the cross drilled mains?

It is a typo on Summits site. If you go directly to Scat's web site and look it up, none of the cast cranks are crossdrilled.

Summits web side has a lot of typos and bogus info, if you want to know about a part, go straight to the manufacturers web site and get the info, then just order it from Summit if that is where you want to do your business. Don't rely on them for good tech information.

[zildjian4life218]

Originally Posted by ericnova72

It is a typo on Summits site. If you go directly to Scat's web site and look it up, none of the cast cranks are crossdrilled.

Summits web side has a lot of typos and bogus info, if you want to know about a part, go straight to the manufacturers web site and get the info, then just order it from Summit if that is where you want to do your business. Don't rely on them for good tech information.

Got ya ive noticed that a couple times before. Like you said i should have went to scats site and got the info.

[ericnova72]

As a matter of fact, I just had to go and check, just to see if something had changed. None of Scat's cranks, cast or forged, have crossdrilled mains. They use straight shot oiling, which is basically same as stock, they may have refined sizes or angle of drilled passage slightly for different strokes, but it is still as Chevy engineers originally designed( as in "If it ain't broke, don't shade tree fix it" )

[zildjian4life218]

Originally Posted by ericnova72

"If it ain't broke, don't shade tree fix it"

lol. What would you rate one of these scat cast cranks to hp and rpm wise. I believe there site said 500hp and 5000rpm but I know there is a safety factor involved and i am sure will go further than that.

[F-BIRD'88]

200+hp shot:

Run the bigger 256-270 cam and a 5000 stall 8" converter.
The nitrous comes on at 5000rpm (nitrous rpm window switch+WOT switch)
Avoids overstressed parts from over torque.
Caused by hitting it hard from too low an rpm.
Don;t go nuts on cr. 10:1+ is good enough.
Let the nitrous make the power.

Its all about combustion presssure management.
Give it all the nitrous it needs to go fast.
Control the launch by controling when the nitrous comes on
4900 5000 5100 5200........
The rpm window switch does this as well as avoiding over rev on the top end.

Don;t bother with spark retard. Just lock out the advance and run 26 to 32 deg advance. The motor will tell you what it likes. (MPH)

[ericnova72]

Originally Posted by zildjian4life218

lol. What would you rate one of these scat cast cranks to hp and rpm wise. I believe there site said 500hp and 5000rpm but I know there is a safety factor involved and i am sure will go further than that.

I have seen it printed that Speedway Motors has 100's of them in 550-600 hp engines with none broken. Myself and friends have run several 3.48" stroke to 7800-8200 rpm and 540-550 hp with no failures, and several 3.75" stroke, both 350 and 400 main sizes to 550-600+ hp and 7500 rpm without failure for several years, so I can't really say what it takes to break one in a street/strip situation. Some with nitrous up to 200hp shots. Their rating seems to be quite conservative, or maybe based off the rigors of circle track continuous rpm duty(I've heard this mentioned on another forum).

I'm putting one in the 406 going into my Nova next spring, 610 gram Scat I-beam rods and 500 gram pistons, 110 gram pins, and looking for 700hp. We'll see how that holds up, I just couldn't justify putting an expensive steel crank in a stock 400 block, so I'm willing to roll the dice on my own stuff. If it blows, block gets trashed, if block blows, crank gets trashed. I'll go forged in an SHP block if that happens. It was a Swap, Ebay, and existing parts experiment anyway, I don't have $2800 in it intake to oil pan(all i have yet to get is rings, and the valve seats cut/guides honed on the heads), All good stuff, just waited for deals from people abandoning their own projects. Crank and rods are new, as are the bare Canfield 220 heads, just sat in someones closet for a year or two, solid roller is used, pistons were in the engine with stock 400 crank and stock 5.7 rods in my previous solid lifter Sportsman head build that ran 15 years running 11.50's in 3400lb car.

[zildjian4life218]

I have a 2 bolt block right now.......uhoh

[cobalt327]

Originally Posted by cobalt327

Before this discussion, I wasn't aware the Scat cast steel cranks even WERE X drilled.

It seems there was a reason for not knowing, if they aren't!

I forget at the moment what it was, but there was some discussion of Summit's info being "tainted", shall we say, on this forum before. But the same info is all over the internet- not JUST Summit- so good advice to get the info from the maker.