[Aml383]

Bought a balanced rotating assembly for a 385 sbc stroker. .040 weisco pistons ..weisco 6 inch rods..with a 3.75 crank from skip white performance. They balanced it and sent it to me .
The issue is that the piston sticks out of the hole .065 .
The scat crank is for 5.7 .
The rods are 6 inch
Then theres the 040 pistons they sent me .
Does scat make a crank specifically for when a 6 inch rod is used and they sent me the wrong crank ??
Or did they send me the wrong pistons??
And yes the obvious question is why wouldnt I call them and ask?
I did the the first part of that oh about 20 times or so .
Cant reach anyone and I'm not getting a return call.
Quality parts . Low price but here I am .
I do not like skip white sam I am lol

 

[bracketchev1221]

check the number on the crank did they send you a 3.875 stroke crank?

 

[SFD]

what did you order carpenter?

 

[Jim Mac]

no expert here but the piston determins the rod length. so it sounds like you have the wrong pistons.
back in the old days when the 383 was getting popular, you used a 400 crank and 400 rods with the 350 pistons.
jim

 

[68Chevele]

Call them for sure it's their screw up not yours. If the crank is for a 5.7 rod then you need to use a 5.7 rod to correct it.

 

[BillK]

What part number piston ? What number on the front of the crank ? If it was a 3.875 stroke crank the piston would be up about .065 higher. Part numbers off the crank and pistons would help solve the puzzle a lot.

 

[BillK]

By the way the difference in the cranks is the size of the counterweight. Most of the time but not always the counterweights on the 6" crank are too big and will hit the bottom of the pistons if you use a 5.7 rod.

 

[MW69Chevelle]

You either have the wrong pistons (compression height) or as mentioned the crank is 3.875 and not 3.75 stroke what is the crankshaft and piston part numbers?

 

[MW69Chevelle]

According to skip white their pistons for sbc are .015 taller then normal. So if your block was decked without being measured with rotating assemble this could be part of your problem.

 

[Steve69SS396]

check the number on the crank did they send you a 3.875 stroke crank?

That's exactly what it sounds like happened. Popular rod lengths are 5.7" and 6". If the other parts are correct, a 5.7" rod would put the piston below deck. If the crank and rods are correct the pistons would need to have a 1.19" compression height to be above deck 0.065". I don't find an off the shelf 4.040" piston in the Wiesco catalog with a 1.19" compression height. That leaves the crank. If they sent a 3.875" stroke crank with 6" rods and 1.125" compression height 4.040" pistons, that would put the pistons 0.065" out of the hole on a 9" deck height.

 

[Aml383]

Crank is
9 - 103750L scat

Piston is weisco
KP451A4

.but wtf though I'm screwed either way right ??
I mean they balanced this mother fo
So if I need a different piston or a different crank the whole show is out to lunch. They gotta balance again ! No ??
These pos man . You cant even get ahold of em . Idk maybe I tell em stuff the whole deal up thier ass and get the loot back. They suck

 

[Tom Mobley]

you might have noticed that Skip White is sort universally disrespected hare at chevelles.com. I wouldn't buy a spark plug from them.

 

[Aml383]

According to skip white their pistons for sbc are .015 taller then normal. So if your block was decked without being measured with rotating assemble this could be part of your problem. View attachment 706590

Yeah I guess maybe . I'd think machine shop guy mighta checked deck heighth .
The block came outta my 89 k2500.
I bought the truck in 08 on Ebay.
Couple months later I call the guy I bought it from (dont ask me for what) but I remember the dude said ...oh yeah we rebuilt that motor. Thing had 54 k on the dash. I say rebuilt it for what?? One stoner left oil plug out and another drove it too far and wrecked the motor . Then I took the motor out 4 years ago and put in a 99 350 vortek motor.
The 89 engine sat on the floor till I decided to use it for the chevelle . Its got one piece RMS so I figured if I use that then I dont have to go retro roller cam button blah blah.
Tore the motor down and found it had been bored .040 . So that's the block the machine shop has now . I don't know why they would have shaved the deck . Plus you could tell that nothing had been done to the heads but the crank and cylinders looked mint .

 

[Aml383]

check the number on the crank did they send you a 3.875 stroke crank?

Yeah the guy at the machine shop gave me the number I posted below. Maybe that was off the box and not off the crank itself .
I'll call em tomorrow. Good lookin out

 

[Aml383]

what did you order carpenter?

Right length studs but the wall plates arent the standard thickness or somthin or the deck ain't framed at the right heighth . Idk The elevation ain't hittin where the architect said it would . Maybe the owner wont notice lol

 

[Aml383]

Well a buddy of mine said he thinks it's the pistons too . But is a 5.7 crank used when your using 6 inch rods ?? Idk

 

[Aml383]

Call them for sure it's their screw up not yours. If the crank is for a 5.7 rod then you need to use a 5.7 rod to correct it.

Yeah but I wanted a 6 inch rod . It's better if for no other reason than less angularity which is good right ? Who uses a 5.7 rod on a stroker ?

 

[RifRaf]

Based on a deck height of 9.015 (per Skip White instructions when using their custom Wiseco pistons) and the Wiseco pistons having a custom compression height of 1.140... and also using 6" rods, it looks like the crank that was sent/installed in the block has a 3.875 stroke. The crank should have had a 3.750 stroke to "zero deck" for the above pistons and rods.

• Deck height 9.015 + Stroke 3.75 + 6" Rod = Compression height of 1.140 to "zero deck".
• Deck height 9.015 + Stroke 3.875 + 6" Rod = Compression height of 1.078 to "zero deck"... but you have pistons with a compression height of 1.140, so that puts them .062 out of the hole (1.140 - 1.078 = .062).

Piston Compression Height Calculator | UEM Pistons

uempistons.com

Somehow the wrong stroke crank was sent to use with the Skip White sbc custom Wiseco pistons.
Either an incorrectly labeled or incorrectly boxed crank. Scat 9 -103750L should have been a 3.75 stroke crank.

 

[Aml383]

That's exactly what it sounds like happened. Popular rod lengths are 5.7" and 6". If the other parts are correct, a 5.7" rod would put the piston below deck. If the crank and rods are correct the pistons would need to have a 1.19" compression height to be above deck 0.065". I don't find an off the shelf 4.040" piston in the Wiesco catalog with a 1.19" compression height. That leaves the crank. If they sent a 3.875" stroke crank with 6" rods and 1.125" compression height 4.040" pistons, that would put the pistons 0.065" out of the hole on a 9" deck height.

Either way the whole show is temporarily closed now because they gotta balance the whole shootin match again.
I'll call the machine shop tomorrow see what number is on the crank itself.
I posted the number he gave me off the box

 

[Aml383]

Based on a deck height of 9.015 (per Skip White instructions when using their custom Wiseco pistons) and the Wiseco pistons having a custom compression height of 1.140... and also using 6" rods, it looks like the crank that was sent/installed in the block has a 3.875 stroke. The crank should have had a 3.750 stroke to "zero deck" for the above pistons and rods.

• Deck height 9.015 + Stroke 3.75 + 6" Rod = Compression height of 1.140 to "zero deck".
• Deck height 9.015 + Stroke 3.875 + 6" Rod = Compression height of 1.078 to "zero deck"... but you have pistons with a compression height of 1.140, so that puts them .062 out of the hole (1.140 - 1.078 = .062).

Piston Compression Height Calculator | UEM Pistons

uempistons.com

Somehow the wrong stroke crank was sent to use with the Skip White sbc custom Wiseco pistons.
Either an incorrectly labeled or incorrectly boxed crank. Scat 9 -103750L should have been a 3.75 stroke crank.

Thats what the machine shop guy said. He said according to the number it's a 3.75 . Why he didn't look on the crank itself at the number is beyond my limited knowledge lol