destroking a ls1
Thread Starter
Teching In
Joined: Oct 2012
Posts: 11
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From: pnw
destroking a ls1 i'm new to lsx engines but not to the old gm engines so please be kind,
i'm trying to figure out if i can use the crank and rods out of a 4.8 and use the pistons from a ls1 in the ls1 block.
is the pin height the same on both pistons?
and how much can a early ls1 block [originally with perimeter valve cover bolt heads] take for and over bore? i've been told the iron liners can take a +20, is this true.
i need to find this out before i pull the trigger on a deal i have come across.
i know you all are gonna ask "why destroke it"! well i plan on using it in a very lightweight sports car and really dont want alot of torque. this application will be better with a quick reving motor that will be more forgiving to lighter weight drivetrain.
i'm trying to figure out if i can use the crank and rods out of a 4.8 and use the pistons from a ls1 in the ls1 block.
is the pin height the same on both pistons?
and how much can a early ls1 block [originally with perimeter valve cover bolt heads] take for and over bore? i've been told the iron liners can take a +20, is this true.
i need to find this out before i pull the trigger on a deal i have come across.
i know you all are gonna ask "why destroke it"! well i plan on using it in a very lightweight sports car and really dont want alot of torque. this application will be better with a quick reving motor that will be more forgiving to lighter weight drivetrain.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
i'm new to lsx engines but not to the old gm engines so please be kind,
i'm trying to figure out if i can use the crank and rods out of a 4.8 and use the pistons from a ls1 in the ls1 block.
is the pin height the same on both pistons?
and how much can a early ls1 block [originally with perimeter valve cover bolt heads] take for and over bore? i've been told the iron liners can take a +20, is this true.
i need to find this out before i pull the trigger on a deal i have come across.
i know you all are gonna ask "why destroke it"! well i plan on using it in a very lightweight sports car and really dont want alot of torque. this application will be better with a quick reving motor that will be more forgiving to lighter weight drivetrain.
i'm trying to figure out if i can use the crank and rods out of a 4.8 and use the pistons from a ls1 in the ls1 block.
is the pin height the same on both pistons?
and how much can a early ls1 block [originally with perimeter valve cover bolt heads] take for and over bore? i've been told the iron liners can take a +20, is this true.
i need to find this out before i pull the trigger on a deal i have come across.
i know you all are gonna ask "why destroke it"! well i plan on using it in a very lightweight sports car and really dont want alot of torque. this application will be better with a quick reving motor that will be more forgiving to lighter weight drivetrain.
Absolutely not 20 thou.
I'm sure if yo search online you'll find the pin height of a standard LS1 piston
Why not just start with a aluminum 5.3? It'll be a lot cheaper and still be light weight and take the revs with a good valve train without having to much low end grunt. You never mention exactly what its going in care to share?
I think this is right.
4.8 stroke: 3.27
4.8 rod : 6.276
4.8 deck height: 9.240
5.7 stroke:3.62
5.7 rod: 6.098
5.7 deck height: 9.240
3.62/2=1.81
3.27/2=1.635
5.7:
1.81+6.098=7.908
9.240-7.908=1.332
4.8:
1.635+6.276=7.911
9.240-7.911=1.329
4.8 stroke: 3.27
4.8 rod : 6.276
4.8 deck height: 9.240
5.7 stroke:3.62
5.7 rod: 6.098
5.7 deck height: 9.240
3.62/2=1.81
3.27/2=1.635
5.7:
1.81+6.098=7.908
9.240-7.908=1.332
4.8:
1.635+6.276=7.911
9.240-7.911=1.329
Thread Starter
Teching In
Joined: Oct 2012
Posts: 11
Likes: 0
From: pnw
thanks guys.
the ls1 ended up not being available any more...... i was quoted a price and when it came to wanting to look at it, it was "sold" already.
the car i plan on building is a v8 porsche 914. [yes there is room to put it in there, more so than the sbc for the lack of a distributor... oh and you have to delete the water pump on both and use an outboard water pump.]
i have had this car for several years and have always intended on doing this to it.
i have several friends that have done the sbc version and that is what i first wanted to do but when i realized that the ls motors are making stupid power pretty easily and cheaply i started keeping an eye out and inquiring around to friends and other car guys around for what i was looking for.
my first plan was a alloy 5.3 block with the 4.8 internals and that is still a fall back, but a ls1 block would open up more choices for heads. and i would think that the mind set for cars with ls1's is that when the need to upgrade or overhaul the 5.7 the logical step would be to go to a larger bore block and dump the 3.898 block..... so the ls1 market should not be all that expensive and be readily available.
this project is not on the front burner and i can and have sat on it, i can wait until the right deal comes around.
i have heard of all the cheap deals that have been had but have not found the sources for said deals. craigs list people seem to think that the ls motor in the 150,000k truck that is totaled is worth more than a whole unwrecked truck is worth [screwy].
so any one up in the pnw know of a alloy block in either a 5.3 or 5.7 that is available?
the ls1 ended up not being available any more...... i was quoted a price and when it came to wanting to look at it, it was "sold" already.
the car i plan on building is a v8 porsche 914. [yes there is room to put it in there, more so than the sbc for the lack of a distributor... oh and you have to delete the water pump on both and use an outboard water pump.]
i have had this car for several years and have always intended on doing this to it.
i have several friends that have done the sbc version and that is what i first wanted to do but when i realized that the ls motors are making stupid power pretty easily and cheaply i started keeping an eye out and inquiring around to friends and other car guys around for what i was looking for.
my first plan was a alloy 5.3 block with the 4.8 internals and that is still a fall back, but a ls1 block would open up more choices for heads. and i would think that the mind set for cars with ls1's is that when the need to upgrade or overhaul the 5.7 the logical step would be to go to a larger bore block and dump the 3.898 block..... so the ls1 market should not be all that expensive and be readily available.
this project is not on the front burner and i can and have sat on it, i can wait until the right deal comes around.
i have heard of all the cheap deals that have been had but have not found the sources for said deals. craigs list people seem to think that the ls motor in the 150,000k truck that is totaled is worth more than a whole unwrecked truck is worth [screwy].
so any one up in the pnw know of a alloy block in either a 5.3 or 5.7 that is available?
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On The Tree
Joined: Jan 2010
Posts: 168
Likes: 1
From: Fort Campbell, KY
I found my LS1 short block off craigslist for $100.00. Look through parts listings and take a good look at the ones that need a rebuild. My block has some vertical scratches in one of the cylinders, that may be able to be honed out.
If I can hone it, I'll use it as is. If not, companies like Earl's sell blocks that are re-sleeved with 4.165 bores for $2,200.00, and they give you $1,300.00 core for an aluminum block..... yeah I will pay $1,000.00 in the end for a big bore block.
And btw, if you used a 4.8L crank in a block with a 4.165 bore, you get a 354ci motor. I bet this combo would have plenty of torque and be fairly rev-friendly. In my build I will save $$$ and just re-use the LS1 crank, which nets a 395ci.
Just one way to be thrifty with aluminum LS blocks........
If I can hone it, I'll use it as is. If not, companies like Earl's sell blocks that are re-sleeved with 4.165 bores for $2,200.00, and they give you $1,300.00 core for an aluminum block..... yeah I will pay $1,000.00 in the end for a big bore block.
And btw, if you used a 4.8L crank in a block with a 4.165 bore, you get a 354ci motor. I bet this combo would have plenty of torque and be fairly rev-friendly. In my build I will save $$$ and just re-use the LS1 crank, which nets a 395ci.
Just one way to be thrifty with aluminum LS blocks........
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TECH Addict
Joined: Sep 2009
Posts: 2,481
Likes: 5
From: PA/MD
thanks guys.
the ls1 ended up not being available any more...... i was quoted a price and when it came to wanting to look at it, it was "sold" already.
the car i plan on building is a v8 porsche 914. [yes there is room to put it in there, more so than the sbc for the lack of a distributor... oh and you have to delete the water pump on both and use an outboard water pump.]
i have had this car for several years and have always intended on doing this to it.
i have several friends that have done the sbc version and that is what i first wanted to do but when i realized that the ls motors are making stupid power pretty easily and cheaply i started keeping an eye out and inquiring around to friends and other car guys around for what i was looking for.
my first plan was a alloy 5.3 block with the 4.8 internals and that is still a fall back, but a ls1 block would open up more choices for heads. and i would think that the mind set for cars with ls1's is that when the need to upgrade or overhaul the 5.7 the logical step would be to go to a larger bore block and dump the 3.898 block..... so the ls1 market should not be all that expensive and be readily available.
this project is not on the front burner and i can and have sat on it, i can wait until the right deal comes around.
i have heard of all the cheap deals that have been had but have not found the sources for said deals. craigs list people seem to think that the ls motor in the 150,000k truck that is totaled is worth more than a whole unwrecked truck is worth [screwy].
so any one up in the pnw know of a alloy block in either a 5.3 or 5.7 that is available?
the ls1 ended up not being available any more...... i was quoted a price and when it came to wanting to look at it, it was "sold" already.
the car i plan on building is a v8 porsche 914. [yes there is room to put it in there, more so than the sbc for the lack of a distributor... oh and you have to delete the water pump on both and use an outboard water pump.]
i have had this car for several years and have always intended on doing this to it.
i have several friends that have done the sbc version and that is what i first wanted to do but when i realized that the ls motors are making stupid power pretty easily and cheaply i started keeping an eye out and inquiring around to friends and other car guys around for what i was looking for.
my first plan was a alloy 5.3 block with the 4.8 internals and that is still a fall back, but a ls1 block would open up more choices for heads. and i would think that the mind set for cars with ls1's is that when the need to upgrade or overhaul the 5.7 the logical step would be to go to a larger bore block and dump the 3.898 block..... so the ls1 market should not be all that expensive and be readily available.
this project is not on the front burner and i can and have sat on it, i can wait until the right deal comes around.
i have heard of all the cheap deals that have been had but have not found the sources for said deals. craigs list people seem to think that the ls motor in the 150,000k truck that is totaled is worth more than a whole unwrecked truck is worth [screwy].
so any one up in the pnw know of a alloy block in either a 5.3 or 5.7 that is available?
I dont know why you would want to go through the trouble of building an oddball destroked deal when you can use a standard LS engine and just pull alot of timing from the areas you dont want torque via tuning to have the same effect. Later on if you want the power down low you can just add the timing back in without having to build a new engine.
Thread Starter
Teching In
Joined: Oct 2012
Posts: 11
Likes: 0
From: pnw
Thread Starter
Teching In
Joined: Oct 2012
Posts: 11
Likes: 0
From: pnw
I dont know why you would want to go through the trouble of building an oddball destroked deal when you can use a standard LS engine and just pull alot of timing from the areas you dont want torque via tuning to have the same effect. Later on if you want the power down low you can just add the timing back in without having to build a new engine.
i will be some what traction limited and do not need a high torque engine. the gearing will favor running around at 3000-4000rpm and not looping around at 1500rpm.
this is not the type of car that you guys are used to, no burn outs, no clutch drop launches, this will be a car that will chase down crotch rockets on the twistys. and confuse the chit out of most people when it rolls though the local cruise lot.
This is a good reference regarding stroke, bores, etc.
http://www.nookandtranny.com/Info_LSx.html#LSxBlock
http://www.nookandtranny.com/Info_LSx.html#LSxBlock
The ls1 pistons and 4.8 should have relatively the Same compression depth on the pin. The 5.3 uses the same crank and rod length as the ls1 and the 4.8 uses the same pistons as the 5.3 without the dish.
So logic would tell you that you can use the 4.8 crank and rods with the ls1 pistons and end up with the piston in the same position.
So logic would tell you that you can use the 4.8 crank and rods with the ls1 pistons and end up with the piston in the same position.
FormerVendor
Joined: Nov 2012
Posts: 185
Likes: 0
From: Sacramento, CA
One of the local tuners built a de-stroked 5.3 using an Eagle forged 3.622 crank, and did a custom offset grind. Went mid/low 10's NA.
We have the capability of making a custom crankshaft for your application if you are interested.
We have the capability of making a custom crankshaft for your application if you are interested.
Teching In
Joined: Jan 2017
Posts: 9
Likes: 0
nice! ive been looking for this kind of build since i changed the route of my build, at first it was drifting pourpuse but it took a radical change to a roadracer/weekend ride, so im aiming for more revs than torque, i have the old trusty 240sx build so its light, all fiberglass pannels, seats, half cage & tubefront.
Ive made the reasoning behind this so a LS1 Block will have same dimensions as the LR4 but the Bore right? so we can use The LR4 Crank & rods (these are longer than the LS1/5.3) so the pistons wil be safe inside the sleeves & as far as i know the wrist pin is just 0.0001" thicker in the ls1 piston so no real difference there, it'll be just a little hooning on the Rod for it to fit properly, also, the only thing that will change will be the intake valve diameter and if you get the LS1 heads you just need to change springs for the ones on the 4.8 heads and as far as my logic tells me you can also use the same camshaft as the 4.8... im planning on doing this just also looking for the right price of combo ls1 parts... aluminum 5.3 are rare on my side of the border...
what are your thoughts on this? any info photos & vids will be appreciated...
Ive made the reasoning behind this so a LS1 Block will have same dimensions as the LR4 but the Bore right? so we can use The LR4 Crank & rods (these are longer than the LS1/5.3) so the pistons wil be safe inside the sleeves & as far as i know the wrist pin is just 0.0001" thicker in the ls1 piston so no real difference there, it'll be just a little hooning on the Rod for it to fit properly, also, the only thing that will change will be the intake valve diameter and if you get the LS1 heads you just need to change springs for the ones on the 4.8 heads and as far as my logic tells me you can also use the same camshaft as the 4.8... im planning on doing this just also looking for the right price of combo ls1 parts... aluminum 5.3 are rare on my side of the border...
what are your thoughts on this? any info photos & vids will be appreciated...
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
nice! ive been looking for this kind of build since i changed the route of my build, at first it was drifting pourpuse but it took a radical change to a roadracer/weekend ride, so im aiming for more revs than torque, i have the old trusty 240sx build so its light, all fiberglass pannels, seats, half cage & tubefront.
Ive made the reasoning behind this so a LS1 Block will have same dimensions as the LR4 but the Bore right? so we can use The LR4 Crank & rods (these are longer than the LS1/5.3) so the pistons wil be safe inside the sleeves & as far as i know the wrist pin is just 0.0001" thicker in the ls1 piston so no real difference there, it'll be just a little hooning on the Rod for it to fit properly, also, the only thing that will change will be the intake valve diameter and if you get the LS1 heads you just need to change springs for the ones on the 4.8 heads and as far as my logic tells me you can also use the same camshaft as the 4.8... im planning on doing this just also looking for the right price of combo ls1 parts... aluminum 5.3 are rare on my side of the border...
what are your thoughts on this? any info photos & vids will be appreciated...
Ive made the reasoning behind this so a LS1 Block will have same dimensions as the LR4 but the Bore right? so we can use The LR4 Crank & rods (these are longer than the LS1/5.3) so the pistons wil be safe inside the sleeves & as far as i know the wrist pin is just 0.0001" thicker in the ls1 piston so no real difference there, it'll be just a little hooning on the Rod for it to fit properly, also, the only thing that will change will be the intake valve diameter and if you get the LS1 heads you just need to change springs for the ones on the 4.8 heads and as far as my logic tells me you can also use the same camshaft as the 4.8... im planning on doing this just also looking for the right price of combo ls1 parts... aluminum 5.3 are rare on my side of the border...
what are your thoughts on this? any info photos & vids will be appreciated...
The LS1 block shouldn't be bored.
Everything between the LS1 and LR4 is interchangeable. There are no specific parts other than pistons. Cam, springs, heads, cranks, rods, bearings, sensors, manifolds, oil pans, it all interchanges.
