Help Piston out of hole 150 thou on my 408
11-14-2005, 02:12 AM
#1
Staging Lane
Thread Starter
Join Date: Jun 2005
Location: Australia victoria
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
Help Piston out of hole 150 thou on my 408 Hi, my engine builder did a dummy assembly and has informed me that the pistons I am using sit out of the hole 150thou 
. I am using the 6L cast iron block bored 30thou with a 4.000 stroke, no decking to the block at this point. What have I done wrong.
I first had 6.125 rods, then went down to 6.100 rods and they are still 150thou out. have I got the wrong pistons hight, piston specs are Probe SRS 4.030/1.295/Flat top/.927/-4cc. If the pistons are wrong what are the correct piston as I want to keep compression around 10.6-10.8 thanks.
Iron block 6l
4.000 crank
h beam scat forged rods
25% pully
cam 244/248-613/615 @50 LSA 112
dual chain
forged pistons/rings 4.030
head gaskets cometic 4.030-0.051
Ported Heads LS6 LQ4 (soon)
comp cam pushrods
stainless valves
dual valvesprings
titainium retainers
yella terra roller rockers
arp head bolt
arp main studs
injectors 42lb
LSX fast manifold
Fast 90mm
malboro fuel pump
diff 4.11:1
stage3 clutch
. I am using the 6L cast iron block bored 30thou with a 4.000 stroke, no decking to the block at this point. What have I done wrong.I first had 6.125 rods, then went down to 6.100 rods and they are still 150thou out. have I got the wrong pistons hight, piston specs are Probe SRS 4.030/1.295/Flat top/.927/-4cc. If the pistons are wrong what are the correct piston as I want to keep compression around 10.6-10.8 thanks.
Iron block 6l
4.000 crank
h beam scat forged rods
25% pully
cam 244/248-613/615 @50 LSA 112
dual chain
forged pistons/rings 4.030
head gaskets cometic 4.030-0.051
Ported Heads LS6 LQ4 (soon)
comp cam pushrods
stainless valves
dual valvesprings
titainium retainers
yella terra roller rockers
arp head bolt
arp main studs
injectors 42lb
LSX fast manifold
Fast 90mm
malboro fuel pump
diff 4.11:1
stage3 clutch
11-14-2005, 04:52 AM
#2
TECH Senior Member
Shave them .14>.143, I've done it before, no biggie. (machine shop)
Not necessarily increase you compression . It all depends if the notch area shaved is less or greater than the out of hole area.
Just check PTV again.
Probably has to do with pin hole placement/ or pin hole to piston deck height on those.
Not necessarily increase you compression . It all depends if the notch area shaved is less or greater than the out of hole area.
Just check PTV again.
Probably has to do with pin hole placement/ or pin hole to piston deck height on those.
Last edited by PREDATOR-Z; 11-14-2005 at 10:08 AM.
11-14-2005, 06:52 AM
#4
Staging Lane
Thread Starter
Join Date: Jun 2005
Location: Australia victoria
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
Hi well as it turns out I need a piston with around 1.115 comp hight, the only piston that I can find is a Wiseco reverse dome 4.030/6.098 with a comp hight of 1.115 with 4.000 stroke -8cc with a zero deck hight of 9.213, is this what I am looking for as I want the compression around 10.6 as I have room to move decking the block and milling the heads, can anyone else recommend a piston. thanks
11-14-2005, 10:08 AM
#5
TECH Senior Member
Originally Posted by Wet 1
Wouldn't you want to shave a lot more than that?!?!
Sounds like the pin is in the wrong location on your pistons.
Sounds like the pin is in the wrong location on your pistons.
Of course shaving is OK if piston dome height thickness allows it.
I had this issue on one of my ex Skylines.
11-14-2005, 11:36 AM
#7
TECH Fanatic
iTrader: (1)
Join Date: Nov 2002
Location: Venice, Ca
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
Compression will depend on head gasket, piston dish, head cc and how much the piston comes out of the deck. The compression height on the piston is off. My pistons with a 4.075 stroke and 6.125 rods is 1.077. Subtracting for my longer stroke and rods gives you 1.177 with a 4" stroke and 6.100" rods for .002" out of deck. You need to measure the block height before ordering any more pistons.
