scat cast iron cranks??

M

mitchboy

Active member
looking at a bluprint motor 383 stroker it has a cast scat crank,will it hold up in a airboat with gearbox application??
 
Cast cranks no matter who makes 'em(imports 'em)......ya get what ya pay for. That being said, there's lots of boats out there with cast cranks that will run a long time.
 
I dont very often post about our companies engines, but you did ask a direct question. We have built thousands of 383 engines with that crank and never had a crank break. While most aftermarket cranks come from overseas, not all are the the same. We have had great luck with SCAT. I am an airboater and I wouldnt worry about that crank in my mothers boat. Keep in mind lots of stock cranks, (most) are cast. I am not sure what exactly your looking for from that 383, but I would be happy to discuss further with you. Just pm me. We will be coming out with a line of airboat specific engines later in this year, I would be happy to discuss your needs and make sure you get what your needing.. Norris Marshall, President, Blue Print Engines
 
thanks guys!! i am going to go with it it does make sense most oem is cast,i had a stock 350 ran good for 4 years. anybody went from a 300hp to a 400 hp stroker is a big change in push?? i know i would love to have a 550 plus hp set up just cant afford it.
 
I HAVE A SCAT 4340 40LB CRANK IN MOTOR I BENT A SPORTSMAN ROD AT 5000RPM AN THE CRANK IS STILL GOOD BUT I WILL SAY IM GOING TO A DIFFERENT COMPANY NEXT MOTOR I BUILD JUST BECAUSE



PERHAPS THEY KNOW ME BETTER THEN I KNOW MYSELF GEN ROBERT E LEE
 
Balance and quality bearings is the key as far as I'm concerned. If an engine will spin up like an electric motor then (guessing) more than 90% of the failures after that will either be valve train, timing, insufficient carburation, or operator abuse. Some people can tear up an anvil.
 
Olf Art said:
Balance and quality bearings is the key as far as I'm concerned. If an engine will spin up like an electric motor then (guessing) more than 90% of the failures after that will either be valve train, timing, insufficient carburation, or operator abuse. Some people can tear up an anvil.
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FUNNY YOU SHOULD SAY IT WAS A INTAKE VALVE THAT DONE ME IN :lol: :lol: :lol: A SCAT IS A GOOD CRANK NO MATTER HOW YOU LOOK AT


PERHAPS THEY KNOW ME BETTER THEN I KNOW MYSELF GEN ROBERT E LEE
 
At 5000 rpm i would say the vavle springs did you in. The valve floated and the piston slapped it. The cast crank will work fine as long as you have main studs and good rod bolts. If the crank and rods and piston assemblies are balanced then the cast combo will run for years without Crank induced problems.
 
no it was the intake valve it was in two pieces the piston had holes in it an the head had a hole from bottom to top an the cylinder wall had a big hole from the piston



PERHAPS THEY KNOW ME BETTER THEN I KNOW MYSELF GEN ROBERT E LEE
 
When the valve floats it's in the way of the piston even with mild cams. The piston touchs the valve and it's not dead on straight. The piston bends the valve and it woundnt close. The piston comes up again and brakes the vavle in 2. The loose piece ( the valve head ) now roams around the cylinder for three or more more cycles or until it has bent the rod , broken the piston , Cylinder wall is cracked and the rod comes off the jammed ,destroyed piston and roatates around the crank case till it puts a hole in the block. all in about 1 second before the engine can stop. I'll bet that a weak spring which can be measured is the cullprit. Ultimately rpm higher than the vavle spring float rating.
 
gjperkins1 said:
When the valve floats it's in the way of the piston even with mild cams. The piston touchs the valve and it's not dead on straight. The piston bends the valve and it woundnt close. The piston comes up again and brakes the vavle in 2. The loose piece ( the valve head ) now roams around the cylinder for three or more more cycles or until it has bent the rod , broken the piston , Cylinder wall is cracked and the rod comes off the jammed ,destroyed piston and roatates around the crank case till it puts a hole in the block. all in about 1 second before the engine can stop. I'll bet that a weak spring which can be measured is the cullprit. Ultimately rpm higher than the vavle spring float rating.
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the valve broke because it was a pos an what happens when this is true








perhaps they know me better then i know myslef gen robert e lee
 

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the spings were on a motor turning 7000rpm before i put them on the heads their on now so i cant see valve float because of rpm rating now did the spring go weak could be but i have not check them to see what the pressure is so i cant say



PERHAPS THEY KNOW ME BETTER THEN I KNOW MYSELF GEN ROBERT E LEE
 
it was just a cheap valve i let it to someone else to buy them when i should have done so myself oh well we live n learn



PERHAPS THEY KNOW ME BETTER THEN I KNOW MYSELF GEN ROBERT E LEE
 
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