Will My Crank Break? (need help kinda quick please)

SQUEEZE&STROKE

New Member

Jun 24, 2005

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SOUTHERN CA

Sep 9, 2005

#41

• Sep 9, 2005

• #41

Start over...But I personally wouldnt order a 4340 crank...for that much money I could do alot of things. The problem with a forged $500 crank is that the stock block is the weak point in that setup. If you break the block you run a good chance of goring/really F'Ing up the crank. Just my 2 cents...When I rebuilt mine I bought a 331 kit, cast crank. My motor has seen in excess of 7500 RPM all the time...with nitrous (250 HP wet unit) and not a single problem. Check out my sig below...

 

1EVIL88VERT

New Member

Jul 12, 2004

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Dyess AFB, TX

Sep 9, 2005

#42

• Sep 9, 2005

• #42

it seems to me like your crank has been balanced to 28OZ...when they do that the take alot a metal off the counter weights, like the picture you put up. I would go to another machine shop....if you are low on cash stock rods and cranks can be had cheap at a local engine reman shop, they will do fine with your hp levels, but if your going to throw down 900.oo on a crank and rods why not go 331/347.....

 

TrickFlow

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Jan 20, 2003

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Bossier City, La

Sep 9, 2005

#43

• Sep 9, 2005

• #43

1EVIL88VERT said:

it seems to me like your crank has been balanced to 28OZ...when they do that the take alot a metal off the counter weights, like the picture you put up. I would go to another machine shop....if you are low on cash stock rods and cranks can be had cheap at a local engine reman shop, they will do fine with your hp levels, but if your going to throw down 900.oo on a crank and rods why not go 331/347.....

Click to expand...

The only reason is because i have damn 500 dollar 10:1 pistons that wont be worth crap if i do a stroker.... grrrrrr i should have done a 331 from the start

 

1EVIL88VERT

New Member

Jul 12, 2004

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Dyess AFB, TX

Sep 9, 2005

#44

• Sep 9, 2005

• #44

then use what you have.....i really don't see the point in going with a super mega bad ass crank when the block is still the weak point and your power levels are not that high. I'm sure some of the guys on this site have spare stock cranks and rods around that you could pick up cheap, but like some of the other guys said invest in ARP hardware...its worth it.

 

TrickFlow

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Jan 20, 2003

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Bossier City, La

Sep 9, 2005

#45

• Sep 9, 2005

• #45

1EVIL88VERT said:

but like some of the other guys said invest in ARP hardware...its worth it.

Click to expand...

I made sure they were on there when they built it the first time.. im just questioning everything now. I have way too much going on at 1 time



Ok, let me ask this... How much HP will a stock crank hold up to if i can get my hands on one?

 

SQUEEZE&STROKE

New Member

Jun 24, 2005

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SOUTHERN CA

Sep 9, 2005

#46

• Sep 9, 2005

• #46

Just start over. Sell those new pistons (or return em if possible?) Buy a set of SRP/JE 331/347 pistons, some decent rods and my crank that is still in the plastic and bam you got a 331 stroker kit. $200 shipped-get it out of my garage!

 

txstang84

15 Year Member

May 21, 2005

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Tuscola, tx

Sep 9, 2005

#47

• Sep 9, 2005

• #47

methinks you got it bassackwards Paully, when you have a 28oz crank, you actually take weight out to equal out the heavier imbalance on the flywheel and balancer-the 50oz crank is actually lighter than the 28oz...

and using a 4340 crank in a stock block is a waste...the block will break before the crank. if the stock crank is cut up that much though, just go with the 28oz crank/balancer/flywheel like Thumper said and you'll be fine...

 

TrickFlow

Member

Jan 20, 2003

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Bossier City, La

Sep 9, 2005

#48

• Sep 9, 2005

• #48

i need some damn asprin

 

1EVIL88VERT

New Member

Jul 12, 2004

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Dyess AFB, TX

Sep 9, 2005

#49

• Sep 9, 2005

• #49

txstang84 said:

methinks you got it bassackwards Paully, when you have a 28oz crank, you actually take weight out to equal out the heavier imbalance on the flywheel and balancer-the 50oz crank is actually lighter than the 28oz....

Click to expand...

Ok so its a 28oz crank balanced to 50? i was trying to think of walkers since his looked like that, my bad

 

TrickFlow

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Jan 20, 2003

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Bossier City, La

Sep 9, 2005

#50

• Sep 9, 2005

• #50

Ok so this is where i stand:


Stock block bored .030 over
TFS 10:1 forged pistons
Trackheat heads
new timing chain
TFS stage II cam
TFS 6.700 pushrods
FRPP balancer
Stock resurfaced flywheel
stock resized rods
AirGap intake
holley double pumper
BBK shorties
h-pipe


And a possibly fubared crank

I dont have the money for a stroker kit
i have a whopping total of 900 bucks to get my motor running.

Please help

 

TrickFlow

Member

Jan 20, 2003

340

0

16

Bossier City, La

Sep 9, 2005

#51

• Sep 9, 2005

• #51

this is what ive come up with

Im probably buying a 5140 crank (good to 600hp) = $369.00 from brothers

but do i need rods? How much Hp will the stock 1991 rods handle?

ill have under 400 fwhp, but eventually will spray it with at most a 150 shot.

do i need H-beam rods?

 

T

tjm73

Founding Member

Aug 3, 2000

2,418

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48

Rush, NY

Sep 9, 2005

#52

• Sep 9, 2005

• #52

TrickFlow said:

......And a possibly fubared crank

I dont have the money for a stroker kit
i have a whopping total of 900 bucks to get my motor running.

Please help

Click to expand...

ANY 302 crank from 87-up (to be sure) will work. They are ALL the same material.

He'll you can buy a brand new crank from FRPP for $280 bucks and that's MSRP. pn M-6303-A50

http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=2855

 

TrickFlow

Member

Jan 20, 2003

340

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Bossier City, La

Sep 9, 2005

#53

• Sep 9, 2005

• #53

tjm73 said:

ANY 302 crank from 87-up (to be sure) will work. They are ALL the same material.

He'll you can buy a brand new crank from FRPP for $280 bucks and that's MSRP. pn M-6303-A50

http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=2855

Click to expand...

I thought about that, but... the stock crank is rated to 400hp from what ive read... i should have 350-370 at the flywheel as it is now. if i spray it, ill probably kill it. so for $369 for the 5140 crank, im safe to 600hp

 

thumper460

Founding Member

Jul 24, 2000

3,022

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56

Orange Park , Fl

Sep 9, 2005

#54

• Sep 9, 2005

• #54

yeah.. do the crankshaft !! I didnt, ran high 10s on 200 shot of juice with ARP rod bolts , stock crankshaft 10.1 Forged piston , Ported Heads and bottom end, with NO girdle!! Had Main cap walk ( No Girdle) observed after 1st 6 month tear down.. and that was all!! Street drove and raced for OVER 3 years.. NO failure!! But then that is Just me..............

Thumper

 

TrickFlow

Member

Jan 20, 2003

340

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Bossier City, La

Sep 9, 2005

#55

• Sep 9, 2005

• #55

thumper460 said:

yeah.. do the crankshaft !! I didnt, ran high 10s on 200 shot of juice with ARP rod bolts , stock crankshaft 10.1 Forged piston , Ported Heads and bottom end, with NO girdle!! Had Main cap walk ( No Girdle) observed after 1st 6 month tear down.. and that was all!! Street drove and raced for OVER 3 years.. NO failure!! But then that is Just me..............

Thumper

Click to expand...

So wait, was that on stock rods? this is one of the last questions, i promise

 

Rick 91GT

Mustang Master

Nov 29, 1999

9,692

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99

PA

Sep 9, 2005

#56

• Sep 9, 2005

• #56

a 50oz balance will have more meat taken out of the crank depending on the rod and piston combo, you go 28 so the crank doesn't look like swiss cheese.

Don't worry about those holes. I am interested in how you press a wrist pin in a full floating piston when the pistons are pin fit? Or did they not fit the rods so they are full floating?

I build cast crank strokers starting at $1950 that will take more power then a stock block, how much do you have invested in that 306?

 

thumper460

Founding Member

Jul 24, 2000

3,022

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56

Orange Park , Fl

Sep 9, 2005

#57

• Sep 9, 2005

• #57

Stock "Non- Ribed " C8OE rods w/ARP bolts, ARP main Studs, stock .030 Block, Stock Early 302 (2MA) crankshaft.. 7500 RPM shift points!! Cool??

Just me..........................

Thumper

PS.. just because the H beams and steel crankshafts are becoming pleantiful and reasonable on prices.. Doesn't mean YOU Need them.. cool??