3.8 to 4.2 Stroker
- Thread starter monti83
- Start date
EEEK, taking the builders advice?
Did you ask him his opinion again after he was done taking your money?
IIRC the original kit was a re-worked stock crank, and what james is referring to is probably why they broke it... this car needs a 2.43 final drive with all that torque... for a DD, the added torque of the stroker motor would be pretty nice though.....
If all else fails, you were different, and I give you credit for that
If all else fails, you were different, and I give you credit for that
good point, that's what it comes down to and i completely agree i'm
right with you.
the older Series 1, LN3, LG3 and the GN's LC3 all have a 1 inch taller deck height and longer rods, piston acceleration at tdc/bdc is slower which means at high rpm there's a bit more time for the cylinders to fill, plus the reduced drag as short rod/high angularity engine tend to waste power trying to push the piston through the side of the bore.i didn't know the 3800, in any series, was capable of high rpm anything.
additionally due to the shorter package the SII has a much shorter piston skirt to clear the crank throws, meaning its more prone to rocking/ring flutter. the only good thing to really be said is when GM redesigned the engine for it's mid/fullsize cars they were willing to sacrafice high rpm power for more tq down low as well as the weight/material savings that the beancounters wanted. in this case the short rod and faster piston acceleration enhances low rpm breathing and interestingly enough the faster piston acceleration is generally accepted to reduce cylinder pressure spikes from detonation as combustion volume increases faster to 90* past tdc than a long rod motor.
i dont have my notes close by but the L67 has damn near a 1.5 to one rod/stroke ratio (NA slightly better due to the .1inch longer rod) and the stroker calced at less than that. where the SI was 1.7+
i do recall that for my research is that the SI with SII pistons would let me use off the shelf chrysler 440 rods and end up with a rod stroke ratio of 1.95 (indycar rotating geometry territory)
it would lose a bit on the bottomend but would breath damn well over 5k for a traction limited fwd this would be far more ideal at the line.
besides the SI block has FARRR more meat inthe main webs and front/rear bulkheads than the SII, though it doesnt have 2 bolt + 2 side bolt maincaps it can be retrofited and actually fit 6 maincap bolts 4+2 side on the middle two, plus the GN pistons/rods can be made to work in the SI block fairly easily. the SI's primary downside is the dismal flowing asymetrical port heads, in this respect he SII outshines it's predecessor as GM was wise enough to use the best head design that the GN stage II head (symetrical port) motors had evolved to.
IIRC the original kit was a re-worked stock crank, and what james is referring to is probably why they broke it... this car needs a 2.43 final drive with all that torque... for a DD, the added torque of the stroker motor would be pretty nice though.....
If all else fails, you were different, and I give you credit for that
i dont think that crank was a 4.2L crank but i may be mistaken, the worst thing ever is to weldup and ofset grind any cast iron/nodular iron crank, there's almost no way to stop crack propogation from the stresses of welding combined with metalurgical issues, just ask eric his reman crank broke right where it was welded up and reground...and that was with a vs camed 4inch pulley whipple...destroyed his rods/diamond pistons/timing chain/valves
the problem with stroking a split journal crank is that without enlarging the bearing journal dia (resulting in less than desirable bearing surface speeds) you loose significant journal to throw overlap, which means a std and stroker crank with identical journal size that is cast the stroker crank will be weaker and prone to splitting between adjacent rod journals. increasing the journal radius can help negate the lost overlap area but at increased bearing/film loading due to smaller bearing area.
diffent is good, the road less traveled is one with fewer fartcan honda's
1 1/16th > 7/8thsBah the 1" chain is over rated, 7/8" chain is more than enough for what his builders told him he'll do.For real though, the 7/8" chain has proven to be a very strong chain, prob not the best chain for 500+whp cars but it's a champ.
im also curious as to what oiling system mods were done and whether they built it or tischler.
to the OP dont let us debbie downers get on yer nerves we're just pissed that your bigger than a gallon
the older Series 1, LN3, LG3 and the GN's LC3 all have a 1 inch taller deck height and longer rods, piston acceleration at tdc/bdc is slower which means at high rpm there's a bit more time for the cylinders to fill, plus the reduced drag as short rod/high angularity engine tend to waste power trying to push the piston through the side of the bore.
additionally due to the shorter package the SII has a much shorter piston skirt to clear the crank throws, meaning its more prone to rocking/ring flutter. the only good thing to really be said is when GM redesigned the engine for it's mid/fullsize cars they were willing to sacrafice high rpm power for more tq down low as well as the weight/material savings that the beancounters wanted. in this case the short rod and faster piston acceleration enhances low rpm breathing and interestingly enough the faster piston acceleration is generally accepted to reduce cylinder pressure spikes from detonation as combustion volume increases faster to 90* past tdc than a long rod motor.
i dont have my notes close by but the L67 has damn near a 1.5 to one rod/stroke ratio (NA slightly better due to the .1inch longer rod) and the stroker calced at less than that. where the SI was 1.7+
i do recall that for my research is that the SI with SII pistons would let me use off the shelf chrysler 440 rods and end up with a rod stroke ratio of 1.95 (indycar rotating geometry territory)
it would lose a bit on the bottomend but would breath damn well over 5k for a traction limited fwd this would be far more ideal at the line.
besides the SI block has FARRR more meat inthe main webs and front/rear bulkheads than the SII, though it doesnt have 2 bolt + 2 side bolt maincaps it can be retrofited and actually fit 6 maincap bolts 4+2 side on the middle two, plus the GN pistons/rods can be made to work in the SI block fairly easily. the SI's primary downside is the dismal flowing asymetrical port heads, in this respect he SII outshines it's predecessor as GM was wise enough to use the best head design that the GN stage II head (symetrical port) motors had evolved to.
i dont think that crank was a 4.2L crank but i may be mistaken, the worst thing ever is to weldup and ofset grind any cast iron/nodular iron crank, there's almost no way to stop crack propogation from the stresses of welding combined with metalurgical issues, just ask eric his reman crank broke right where it was welded up and reground...and that was with a vs camed 4inch pulley whipple...destroyed his rods/diamond pistons/timing chain/valves
the problem with stroking a split journal crank is that without enlarging the bearing journal dia (resulting in less than desirable bearing surface speeds) you loose significant journal to throw overlap, which means a std and stroker crank with identical journal size that is cast the stroker crank will be weaker and prone to splitting between adjacent rod journals. increasing the journal radius can help negate the lost overlap area but at increased bearing/film loading due to smaller bearing area.
diffent is good, the road less traveled is one with fewer fartcan honda's
1 1/16th > 7/8ths
im also curious as to what oiling system mods were done and whether they built it or tischler.
to the OP dont let us debbie downers get on yer nerves we're just pissed that your bigger than a gallon
I have a fucking headache. Thanks bro.
the older Series 1, LN3, LG3 and the GN's LC3 all have a 1 inch taller deck height and longer rods, piston acceleration at tdc/bdc is slower which means at high rpm there's a bit more time for the cylinders to fill, plus the reduced drag as short rod/high angularity engine tend to waste power trying to push the piston through the side of the bore.
additionally due to the shorter package the SII has a much shorter piston skirt to clear the crank throws, meaning its more prone to rocking/ring flutter. the only good thing to really be said is when GM redesigned the engine for it's mid/fullsize cars they were willing to sacrafice high rpm power for more tq down low as well as the weight/material savings that the beancounters wanted. in this case the short rod and faster piston acceleration enhances low rpm breathing and interestingly enough the faster piston acceleration is generally accepted to reduce cylinder pressure spikes from detonation as combustion volume increases faster to 90* past tdc than a long rod motor.
i dont have my notes close by but the L67 has damn near a 1.5 to one rod/stroke ratio (NA slightly better due to the .1inch longer rod) and the stroker calced at less than that. where the SI was 1.7+
i do recall that for my research is that the SI with SII pistons would let me use off the shelf chrysler 440 rods and end up with a rod stroke ratio of 1.95 (indycar rotating geometry territory)
it would lose a bit on the bottomend but would breath damn well over 5k for a traction limited fwd this would be far more ideal at the line.
besides the SI block has FARRR more meat inthe main webs and front/rear bulkheads than the SII, though it doesnt have 2 bolt + 2 side bolt maincaps it can be retrofited and actually fit 6 maincap bolts 4+2 side on the middle two, plus the GN pistons/rods can be made to work in the SI block fairly easily. the SI's primary downside is the dismal flowing asymetrical port heads, in this respect he SII outshines it's predecessor as GM was wise enough to use the best head design that the GN stage II head (symetrical port) motors had evolved to.
i dont think that crank was a 4.2L crank but i may be mistaken, the worst thing ever is to weldup and ofset grind any cast iron/nodular iron crank, there's almost no way to stop crack propogation from the stresses of welding combined with metalurgical issues, just ask eric his reman crank broke right where it was welded up and reground...and that was with a vs camed 4inch pulley whipple...destroyed his rods/diamond pistons/timing chain/valves
the problem with stroking a split journal crank is that without enlarging the bearing journal dia (resulting in less than desirable bearing surface speeds) you loose significant journal to throw overlap, which means a std and stroker crank with identical journal size that is cast the stroker crank will be weaker and prone to splitting between adjacent rod journals. increasing the journal radius can help negate the lost overlap area but at increased bearing/film loading due to smaller bearing area.
diffent is good, the road less traveled is one with fewer fartcan honda's
1 1/16th > 7/8ths
im also curious as to what oiling system mods were done and whether they built it or tischler.
to the OP dont let us debbie downers get on yer nerves we're just pissed that your bigger than a gallon
:tmyk:
the older Series 1, LN3, LG3 and the GN's LC3 all have a 1 inch taller deck height and longer rods, piston acceleration at tdc/bdc is slower which means at high rpm there's a bit more time for the cylinders to fill, plus the reduced drag as short rod/high angularity engine tend to waste power trying to push the piston through the side of the bore.
additionally due to the shorter package the SII has a much shorter piston skirt to clear the crank throws, meaning its more prone to rocking/ring flutter. the only good thing to really be said is when GM redesigned the engine for it's mid/fullsize cars they were willing to sacrafice high rpm power for more tq down low as well as the weight/material savings that the beancounters wanted. in this case the short rod and faster piston acceleration enhances low rpm breathing and interestingly enough the faster piston acceleration is generally accepted to reduce cylinder pressure spikes from detonation as combustion volume increases faster to 90* past tdc than a long rod motor.
i dont have my notes close by but the L67 has damn near a 1.5 to one rod/stroke ratio (NA slightly better due to the .1inch longer rod) and the stroker calced at less than that. where the SI was 1.7+
i do recall that for my research is that the SI with SII pistons would let me use off the shelf chrysler 440 rods and end up with a rod stroke ratio of 1.95 (indycar rotating geometry territory)
it would lose a bit on the bottomend but would breath damn well over 5k for a traction limited fwd this would be far more ideal at the line.
besides the SI block has FARRR more meat inthe main webs and front/rear bulkheads than the SII, though it doesnt have 2 bolt + 2 side bolt maincaps it can be retrofited and actually fit 6 maincap bolts 4+2 side on the middle two, plus the GN pistons/rods can be made to work in the SI block fairly easily. the SI's primary downside is the dismal flowing asymetrical port heads, in this respect he SII outshines it's predecessor as GM was wise enough to use the best head design that the GN stage II head (symetrical port) motors had evolved to.
i dont think that crank was a 4.2L crank but i may be mistaken, the worst thing ever is to weldup and ofset grind any cast iron/nodular iron crank, there's almost no way to stop crack propogation from the stresses of welding combined with metalurgical issues, just ask eric his reman crank broke right where it was welded up and reground...and that was with a vs camed 4inch pulley whipple...destroyed his rods/diamond pistons/timing chain/valves
the problem with stroking a split journal crank is that without enlarging the bearing journal dia (resulting in less than desirable bearing surface speeds) you loose significant journal to throw overlap, which means a std and stroker crank with identical journal size that is cast the stroker crank will be weaker and prone to splitting between adjacent rod journals. increasing the journal radius can help negate the lost overlap area but at increased bearing/film loading due to smaller bearing area.
diffent is good, the road less traveled is one with fewer fartcan honda's
I was thinking the same thing...
i admit im not as knowledgible as the next guy and prior to my stoker build i only knew the basics and maybe im just gulliable but i do know i have a great motor that is very few and very far between it produces TONS of power and i get the 22mpg. these threads tend to be "my penis is bigger than yours" discussions instead of advice or even some unheard secrets to get something more. so help me out guys.
We are just trying to keep you from entering a fantasy world of unrealistic numbers man, I don't even think there is a handful of people making 340whp with a 3800 on here so... There's a lot of info we're giving you and you're the one taking it as a pissing contest. Sometimes the reality isn't what you want to hear. None of us said you shouldn't have done it, we all congratulated you on being different and successful at the same time. Expecting low 11 high 10 second 1/4 mile times just because it's .4ltrs bigger is pretty unrealistic. James (turbocharged400stupidname ) was merely just talking about the geometry of the motor and the problems that can be associated with having a stroker. Whether it's something for you to look at now or later it was all useful information and wasn't putting you down in any way. So with this enlightenment, maybe read over the posts again with a different outlook to what people are doing instead of ASSuming we are putting you down. kthx.
) was merely just talking about the geometry of the motor and the problems that can be associated with having a stroker. Whether it's something for you to look at now or later it was all useful information and wasn't putting you down in any way. So with this enlightenment, maybe read over the posts again with a different outlook to what people are doing instead of ASSuming we are putting you down. kthx.
one the things that we found with the stroker is how much more efficient it runs we didnt get the numbers we orginally projected. its only creating 10.6lbs of boost when it should be closer to 18-20. that .4ltrs would surprise you on the big difference it makes.
i never took it as insulting in anyway
i never took it as insulting in anyway
It's copy and pasted from somewhere else 
I think he uses the redneck talk just because, dude's smarter than he types. It's a little over thought, since we're not building motors that sit at 7,000rpm constantly, but he likes to put things together that end up lasting, totally NOT what i do. I'm all about the get it done now and fix all the stuff that breaks as they come, which I usually pay for on a track day or on the way home from somewhere really far away.
I think he uses the redneck talk just because, dude's smarter than he types. It's a little over thought, since we're not building motors that sit at 7,000rpm constantly, but he likes to put things together that end up lasting, totally NOT what i do. I'm all about the get it done now and fix all the stuff that breaks as they come, which I usually pay for on a track day or on the way home from somewhere really far away.that's probably the heads not the .4ltrs FYI this is really confusing why you would think you're getting 18-20psi on a Gen V? WTF?
Thread Info
-
Created -
211Replies
-
23KViews
-
Participants list
