SBC to LS swap - and what LS?
Discussion
Just had another glitch on the small block; not too epensive this one (I hope), but just more time and money to be spend fixing the car and not driving it 
On the last engine build I pretty-well went for 'cost no object' on the parts, but it's clear that the SBC isn't a fully reliable proposition at big(ish)-power, capacity and revs.
Plotting now just to put in a bog-standard GM crate engine - and I mean a bog-standard engine, from GM. Not a lookee-likee build from an engine builder, but the kosher GM article with the intention of keeping it totally unmodified. I've a couple of trips to the US coming up in the next few weeks to will try to drop in to a dealer and see what the score is with the warranty...and maybe just buy one then and there if the price is right damn that exchange rate right now - Brown you clown!.
OK, so first off what's involved in the swap? More importantly will it drop straight in? I see there are conversion engine mounts available, so will that put the motor in the same position? I'm tight for space so I need to know if there are any dimensions where the LS is bigger than a SBC. Particularly width at rear of the block/heads, and how far out the balancer/pulleys at the nose stick out.
I'm guessing that the SBC bellhousing won't fit? And presumably the clutch backplate will be different, although I hope I can re-use the clutch [McLeod Magnum Force]. Happy to go with the drive-by-wire throttle pedal, and I gather the FI will operate without a return-to-tank line so presumably rather than replace all the fuel lines I can just add a high pressure pump close to the engine (fuel system is currently low pressure with a carb).
Cooling system will hopefully just plug in to what I have (just a radiator - no heater in car).
Instrumentation is a Pi data logger, so I don't anticipate too many problems there. And I want to run the stock GM ECU, so I'm guessing it's all pretty self contained - hopefully just giving it 12v!
I know the exhaust will be different, so I'll have to make up new headers. Car doesn't run (or need) cats, but will an LS need cats with the standard ECU?
So am I right in thinking I definitely need the crate motor and all ancillaries, ECU, throttle pedal, SBC conversion engine mounts, new bellhousing, clutch backplate, high pressure fuel pump, headers, cats?, dry sump tank? Is it reasonable to think this will drop in pretty easily in place of the SBC?
Next - what LS?
I really do want to keep this thing standard, and as the current SBC was dyno'd at just a few HP under 500 and 485 FT/LB, the LS376/480 isn't a million miles off. The LS376/515 and LS7 would be a nice wee power boost, but I'd need to weigh-up the costs. I'm more interested in reliability (and cost) than power - given the power differences are stated within 35HP of what I currently have, and I'll lose quite a few Kg moving to an all-alloy engine. This is primarily a track day car, so it'll have a harder life than a road car.
The current motor is a wet sump (big baffled Canton race thingy) but the data logs show no pick-up problems even cornering on slicks. But it is a baffled race unit. I know the LS7 is a dry sump unit as supplied, and I think the LS376 is wet? Assuming the LS376 is a wet sump, is it up to hard cornering/track use?
Oh, and I don't need to drive power steering or air conditioning
So, what LS? And any good experiences of GM dealers in/near San Francisco or Atlanta?
Thanks
On the last engine build I pretty-well went for 'cost no object' on the parts, but it's clear that the SBC isn't a fully reliable proposition at big(ish)-power, capacity and revs.Plotting now just to put in a bog-standard GM crate engine - and I mean a bog-standard engine, from GM. Not a lookee-likee build from an engine builder, but the kosher GM article with the intention of keeping it totally unmodified. I've a couple of trips to the US coming up in the next few weeks to will try to drop in to a dealer and see what the score is with the warranty...and maybe just buy one then and there if the price is right damn that exchange rate right now - Brown you clown!.
OK, so first off what's involved in the swap? More importantly will it drop straight in? I see there are conversion engine mounts available, so will that put the motor in the same position? I'm tight for space so I need to know if there are any dimensions where the LS is bigger than a SBC. Particularly width at rear of the block/heads, and how far out the balancer/pulleys at the nose stick out.
I'm guessing that the SBC bellhousing won't fit? And presumably the clutch backplate will be different, although I hope I can re-use the clutch [McLeod Magnum Force]. Happy to go with the drive-by-wire throttle pedal, and I gather the FI will operate without a return-to-tank line so presumably rather than replace all the fuel lines I can just add a high pressure pump close to the engine (fuel system is currently low pressure with a carb).
Cooling system will hopefully just plug in to what I have (just a radiator - no heater in car).
Instrumentation is a Pi data logger, so I don't anticipate too many problems there. And I want to run the stock GM ECU, so I'm guessing it's all pretty self contained - hopefully just giving it 12v!
I know the exhaust will be different, so I'll have to make up new headers. Car doesn't run (or need) cats, but will an LS need cats with the standard ECU?
So am I right in thinking I definitely need the crate motor and all ancillaries, ECU, throttle pedal, SBC conversion engine mounts, new bellhousing, clutch backplate, high pressure fuel pump, headers, cats?, dry sump tank? Is it reasonable to think this will drop in pretty easily in place of the SBC?
Next - what LS?
I really do want to keep this thing standard, and as the current SBC was dyno'd at just a few HP under 500 and 485 FT/LB, the LS376/480 isn't a million miles off. The LS376/515 and LS7 would be a nice wee power boost, but I'd need to weigh-up the costs. I'm more interested in reliability (and cost) than power - given the power differences are stated within 35HP of what I currently have, and I'll lose quite a few Kg moving to an all-alloy engine. This is primarily a track day car, so it'll have a harder life than a road car.
The current motor is a wet sump (big baffled Canton race thingy) but the data logs show no pick-up problems even cornering on slicks. But it is a baffled race unit. I know the LS7 is a dry sump unit as supplied, and I think the LS376 is wet? Assuming the LS376 is a wet sump, is it up to hard cornering/track use?
Oh, and I don't need to drive power steering or air conditioning
So, what LS? And any good experiences of GM dealers in/near San Francisco or Atlanta?
Thanks
Gen3 stuff, ls1, ls6, lq9 etc use cable and not drive by wire, which might help with costs.
What power are you after?
Speartech do good ecu kits with wiring loom, ecu etc.
Personally Id look at the LS3 engine as its got all the latest tech in it. Heads etc.
Circa 435bhp
Old LS1 is around 315bhp
Trans is hydraulic, so you will need to sort that side of things out. Might be better off to get a T56 while you are at it.
There are a few Monaro's at wreakers.
What power are you after?
Speartech do good ecu kits with wiring loom, ecu etc.
Personally Id look at the LS3 engine as its got all the latest tech in it. Heads etc.
Circa 435bhp
Old LS1 is around 315bhp
Trans is hydraulic, so you will need to sort that side of things out. Might be better off to get a T56 while you are at it.
There are a few Monaro's at wreakers.
ringram said:
Gen3 stuff, ls1, ls6, lq9 etc use cable and not drive by wire, which might help with costs. .
Are you sure? My understanding is that the LS3 (and LS7) are supplied as drive-by-wire, but can be converted to cable operation with some after-market parts. I’m not fussed either way – it it comes drive-by-wire I can use it.ringram said:
What power are you after?
tvrolet said:
I really do want to keep this thing standard, and as the current SBC was dyno'd at just a few HP under 500 and 485 FT/LB, the LS376/480 isn't a million miles off. The LS376/515 and LS7 would be a nice wee power boost, but I'd need to weigh-up the costs.
..so 485BHP as about as low as I want to go.ringram said:
Speartech do good ecu kits with wiring loom, ecu etc.
Ideally, I want to use the standard GM ecu – I’m on a ‘keep it standard’ trip now.ringram said:
Trans is hydraulic, so you will need to sort that side of things out. Might be better off to get a T56 while you are at it.
The car has a TKO600 box already, put in new when I put the SBC in and I’ll reuse it.I'll take it as a vote for an LS3
Unless you went custom the LS3 mentioned has to be the unit of choice.
Roadcraft (they go under another name too) do kits (speedeight mentioned this) for the transmission, so if in any doubt am sure they could say what is needed to change from SBC to LS transmission wise. Just in case you've not encountered them before.
http://www.roadcraftuk.co.uk/
Roadcraft (they go under another name too) do kits (speedeight mentioned this) for the transmission, so if in any doubt am sure they could say what is needed to change from SBC to LS transmission wise. Just in case you've not encountered them before.
http://www.roadcraftuk.co.uk/
I'm of the exact opposite view of Richard.
If you want to keep everything absolutely stock, fitted to a race-car-for-the-road which also does track work on slicks, then the engine most likely to be reliable is in my opinion the LS7. And I say that as someone who has just bought an LS376/480 for installation in a full-on race car.
The LS7 is closer to a race engine in stock form than the LS3 - it has better internals and a dry sump. Its not the best dry sump in the world, but numerous Britcar teams and all the Moslers (as far as I am aware) use the stock sump with no issues.
The LS3 has a wet sump and I wouldn't use it for heavy track work without a revised wet sump or a dry sump system.
Neither the 3 or 7 has the best pistons, and for serious track work forged pistons would be better. The LS7 has titanium rods and therefore higher max revs.
If you were to dry sump the LS376/480 and change the pistons and rods, then I think you've got at least as good, if not a better, track/race engine than the stock LS7, with very little difference in power. As an aside, the LS376/480 has slightly more torque than the LS7 in stock form
If you take price into account then the LS376/480 is £4,700, the LS7 £8,400 both plus VAT. Put another way you can have almost 2 of the 6.2 engines for the price of the 7.0. But does that help you if the former goes pop due to oil surge every time you corner with slicks?
In my case, because I already have a very good dry sump system I can bring the LS3 up to a spec I need for far less than the cost of an LS7 (which I would still want to modify in any case)
If I understand Willie's requirements, he's interested in reliability and retaining any warranty available - pushing him down the absolutely stock route. In my book that's the LS7 all day long - if the warranty stacks up.
As far as sources of engines are concerned, there are a number of specialist crate engine outlets in the US. The cheapest I found for the LS376 was crateenginedepot.com, but with the somewhat parlous state of the £ versus $, adding in shipping and import duty (2.7% to save you looking it up), I found that it was only £40 cheaper to import my own compared to buying one from Partsworld Performance in Cannock.
In terms of warranty, the US GM warranty on engines is 24 months or 50,000 miles. It applies only to street legal applications and excludes track use. It does not apply to vehicles registered and normally operated outside the US. I don't think you'll have any comeback via a GM warranty from an engine bought in the US, and even if you did you'd invalidate it by going on track. Worth checking with GM though
According to my invoice, Partsworld give no warranty of their own, except that the goods are free of defect when they arrive and you have 7 days to notify them if not. Otherwise they refer to the manufacturer's warranty. Having said that their website states a 12 month 12,000 mile warranty, but no reference to terms and conditions. My own view is that the moment you take the car on a track, you have little chance of later claiming on a warranty unless there is demonstrable component failure due to a manufacturing fault - which is tricky in itself.
So, where does that leave you.... if I were you I'd do the maths - what is the cost of an LS376/480 + pistons, rods and a dry sump, plus labour to fit them, versus the cost of an LS7. To help you out, a set of Compstar rods and Mahle forged pistons with rings if just over US $1,000. Can't help on the dry sump I'm afraid. Mine is from Dailey Engineering and is a stunning bit of kit, but I think they are ~$2k for the (billet) sump and the same again for the oil pump. ARE also do them and are cheaper. You may find that when it all adds up the LS7 actually a good option price wise.
Hope that helps Willie. You've got bit of homework to do on the warranties I think!
Cheers
Andy
If you want to keep everything absolutely stock, fitted to a race-car-for-the-road which also does track work on slicks, then the engine most likely to be reliable is in my opinion the LS7. And I say that as someone who has just bought an LS376/480 for installation in a full-on race car.
The LS7 is closer to a race engine in stock form than the LS3 - it has better internals and a dry sump. Its not the best dry sump in the world, but numerous Britcar teams and all the Moslers (as far as I am aware) use the stock sump with no issues.
The LS3 has a wet sump and I wouldn't use it for heavy track work without a revised wet sump or a dry sump system.
Neither the 3 or 7 has the best pistons, and for serious track work forged pistons would be better. The LS7 has titanium rods and therefore higher max revs.
If you were to dry sump the LS376/480 and change the pistons and rods, then I think you've got at least as good, if not a better, track/race engine than the stock LS7, with very little difference in power. As an aside, the LS376/480 has slightly more torque than the LS7 in stock form
If you take price into account then the LS376/480 is £4,700, the LS7 £8,400 both plus VAT. Put another way you can have almost 2 of the 6.2 engines for the price of the 7.0. But does that help you if the former goes pop due to oil surge every time you corner with slicks?
In my case, because I already have a very good dry sump system I can bring the LS3 up to a spec I need for far less than the cost of an LS7 (which I would still want to modify in any case)
If I understand Willie's requirements, he's interested in reliability and retaining any warranty available - pushing him down the absolutely stock route. In my book that's the LS7 all day long - if the warranty stacks up.
As far as sources of engines are concerned, there are a number of specialist crate engine outlets in the US. The cheapest I found for the LS376 was crateenginedepot.com, but with the somewhat parlous state of the £ versus $, adding in shipping and import duty (2.7% to save you looking it up), I found that it was only £40 cheaper to import my own compared to buying one from Partsworld Performance in Cannock.
In terms of warranty, the US GM warranty on engines is 24 months or 50,000 miles. It applies only to street legal applications and excludes track use. It does not apply to vehicles registered and normally operated outside the US. I don't think you'll have any comeback via a GM warranty from an engine bought in the US, and even if you did you'd invalidate it by going on track. Worth checking with GM though
According to my invoice, Partsworld give no warranty of their own, except that the goods are free of defect when they arrive and you have 7 days to notify them if not. Otherwise they refer to the manufacturer's warranty. Having said that their website states a 12 month 12,000 mile warranty, but no reference to terms and conditions. My own view is that the moment you take the car on a track, you have little chance of later claiming on a warranty unless there is demonstrable component failure due to a manufacturing fault - which is tricky in itself.
So, where does that leave you.... if I were you I'd do the maths - what is the cost of an LS376/480 + pistons, rods and a dry sump, plus labour to fit them, versus the cost of an LS7. To help you out, a set of Compstar rods and Mahle forged pistons with rings if just over US $1,000. Can't help on the dry sump I'm afraid. Mine is from Dailey Engineering and is a stunning bit of kit, but I think they are ~$2k for the (billet) sump and the same again for the oil pump. ARE also do them and are cheaper. You may find that when it all adds up the LS7 actually a good option price wise.
Hope that helps Willie. You've got bit of homework to do on the warranties I think!
Cheers
Andy
Interestingly its not smiles all round for the LS7:
"Many of the LS7 owners were and are still disappointed with the performance of the oil system GM let slide out the door"
Search for ARE dry sump to find ARE and prices.
Of course you'll need a separate oil tank and associated pipework with an LS7 or a dry sumped LS3 variant. Costly, and you've got to find somewhere to put the thing - a bit tricky in your application
"Many of the LS7 owners were and are still disappointed with the performance of the oil system GM let slide out the door"
Search for ARE dry sump to find ARE and prices.
Of course you'll need a separate oil tank and associated pipework with an LS7 or a dry sumped LS3 variant. Costly, and you've got to find somewhere to put the thing - a bit tricky in your application
teamHOLDENracing said:
...lots of good stuff...
Thanks for taking the time with that. Lots to ponder 
.But even with the LS7 you're saying it could do with better pistons 'for serious track work'? I guess it boils down to what's 'serious'. I've already had piston crown failures on 5 and 7 on the SBC, but in truth that was down to a problem with the cooling system and hot spots - now solved. Assuming a decent cooling system (and I'll no doubt have more questions on that too) and the temperature running normally, and with a standard ECU are you still of the opinion the the pistons may not be up to it? I'd kind of naively thought since Corvette folks could expect to thrash their cars round a track all day without mishap that the LS7 would be pretty much bulletproof?
then again, everyone I spoke to up-front said a SBC was bulletproof
If it were me Willie, I'd probably change the pistons in the LS7 for forged, though how much of that is because I'm only using it for racing and I'm now super cautious because I munched through 3 pistons through det in the LS6 I'm not sure. (They were forged too!!).
The problem is there is always something available of a better spec than the stock items and how do you know where to draw the line? For me it was not needing more power and already having my dry sump that made it an LS376/480 no brainer.
Some people will tell you the LS7 is the best thing ever and will never fail. I know of numerous failures in Moslers, but I don't know exactly what they were to help you in your decision.
I do think its interesting that GM's flagship engine, the supercharged LS9, is based on the LS3 not the LS7
The problem is there is always something available of a better spec than the stock items and how do you know where to draw the line? For me it was not needing more power and already having my dry sump that made it an LS376/480 no brainer.
Some people will tell you the LS7 is the best thing ever and will never fail. I know of numerous failures in Moslers, but I don't know exactly what they were to help you in your decision.
I do think its interesting that GM's flagship engine, the supercharged LS9, is based on the LS3 not the LS7
RichardD said:
teamHOLDENracing said:
I'm of the exact opposite view of Richard.
LS3 as mentioned was based on OP using the words cost and standard.What I'm saying is I wouldn't go LS3 unless it was modified.
teamHOLDENracing said:
RichardD said:
teamHOLDENracing said:
I'm of the exact opposite view of Richard.
LS3 as mentioned was based on OP using the words cost and standard.What I'm saying is I wouldn't go LS3 unless it was modified.
So the conclusion is for track reliability that both LS3 or either engine should be modified (pistons on the LS7)!?
I've seen Boosted LS1 on PH mention a lot how he doesn't like the standard LS7 pistons.
Speartech harnesses include the OEM ECU dude
Or at least are built for use with the OEM controller.
Also yes you can run cable, but only with the earlier ECU as it came with an OEM cable tune. Later ones are mandatory drive by wire. Though you can run them alpha-n fueling if it takes your fancy, no need for maf or speed density fueling for those crazy cam durations.
In which case you will want a 24x reluctor so you can run cable... which is basically the LS1 ECU. For the price of a crate LS7 you can get a forged LS3 easy. Probably with CNC ported heads and fast102 intake to boot. No dry sump though. Still they work ok in the C6 with wet sumps.
Or at least are built for use with the OEM controller.
Also yes you can run cable, but only with the earlier ECU as it came with an OEM cable tune. Later ones are mandatory drive by wire. Though you can run them alpha-n fueling if it takes your fancy, no need for maf or speed density fueling for those crazy cam durations.
In which case you will want a 24x reluctor so you can run cable... which is basically the LS1 ECU. For the price of a crate LS7 you can get a forged LS3 easy. Probably with CNC ported heads and fast102 intake to boot. No dry sump though. Still they work ok in the C6 with wet sumps.
The OP hasnt specified what he will actually be using the car for.
And I suspect most piston failures are tuning related as opposed to simple failures.
Obvilously buying the best is always nice....but its a bit silly IMO buying the "best" only to start taking it apart and replacing stuff.
May as well just buy "custom" built to your needs in the first place.
As for dry/wet sump...Im sure there are wet sumps capable out there for his needs if the standard system isnt up to the task. But as his seemed to be ok with the SMC, I cant see an LS allowing the car to perform much better in the corners
And I suspect most piston failures are tuning related as opposed to simple failures.
Obvilously buying the best is always nice....but its a bit silly IMO buying the "best" only to start taking it apart and replacing stuff.
May as well just buy "custom" built to your needs in the first place.
As for dry/wet sump...Im sure there are wet sumps capable out there for his needs if the standard system isnt up to the task. But as his seemed to be ok with the SMC, I cant see an LS allowing the car to perform much better in the corners
All stock ls pistons are weak but strong enough to do what's asked of them. GM don't add extra strength because that would add weight. Reason they break is usually down to detonation and the causes of that are numerous but often ignition related. I know the moslers got through a bunch of engines some time back. Mapping has to be very good as these engines are on the 'edge' compression wise and given the weak pistons. Knock detection would be desireable imo as are 'fail safes' to let you know what's been happening inside the engine and EGT's would be nice to monitor. Monitoring things in the chassis are also the way forward as that's a real world environment.
Andy, any news?
Andy, any news?
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff