5.7 V8 LS1 Engine
Motors of LS series, nicknamed by GM as Gen-III Small-Block, first appeared in 1997. They were available in iron-block variations for trucks while all-aluminum LS1 was applied for C5 Corvette automobile.
While the company prefers to call its contemporary V8 motors Gen III and Gen IV, the real car enthusiasts, who has got excited by the high-productive motors, prefer to refer to all the engines of platform as LS.
LS1 engine specs
Keeping 5.7-liter displacement, LS1 is the 3rd generation of GM’s Small Block V8 motors. The fresh engine had much in common with its predecessor, Gen II LT1, but featured modified displacement, external dimensions plus rod bearings.
The first LS1 motor was employed for 1997 Chevrolet Corvette C5, reaching 345 hp (257 kW) at 5,600 rpm with torque of 350 lb/ft (470 Nm) at 4,400 rpm. After some modifications in 2001, the motor gained restyled intake and exhaust manifolds, increasing its power to 350 hp (260 kW) with torque of 365 lb/ft (495 Nm). Corvette automobiles were equipped with LS1 motors from 1997 to 2004.
General Motor’s F-Body automobiles, such as Chevrolet Camaro and Pontiac Firebird Trans Am, also obtained LS1 motors, but in 1998 and were applied till 2002. Those LS1 achieved 305-310 hp, considered to be rather moderate rated power.
Additionally, Pontiac GTO plus Holden Commodore, Ute and Caprice used LS1. GM’s Australian brand Holden made some other improvements of the motor. Thus, HSV YII range reached 382 hp (285 kW) while Callaway’s C4B variation had output of 402 hp (300 kW) in HSV GTS models.
|Throttle Body, Fuel Injectors, Oil Pan Specs & More|
|Throttle Body||78mm, 3-Bolt|
|Throttle Control, Corvette||Drive-by-Wire|
|Throttle Control, GTO, Camaro/Firebird||Throttle Cable|
|Fuel Injector Flow, 1997-98||29.6 lbs.|
|Fuel Injector Flow, 1999-2000||27.3 lbs.|
|Fuel Injector Flow, 2001-04||30 lbs.|
|Fuel Injector Length (between O-Rings)||2.5 in.|
|Fuel Injector Connector||EV1|
|Crankshaft Reluctor Ring||24x|
|Camshaft Sensor||Rear Mount, 1x on cam|
|Oil Pan, Corvette||Batwing Rear Sump|
|Oil Pan, Camaro/Firebird||Rear Sump|
|Oil Pan, GTO||Front Sump|
|Oil Pump||Standard Volume|
- 1997–2004 Chevrolet Corvette
- 1998–2002 Chevrolet Camaro
- 1998–2002 Pontiac Firebird Formula
- 1998-2002 Pontiac Firebird Trans Am
- 2004 Pontiac GTO
- 2001 Opel Omega (prototype)
- 2001–2005 CSV Mondo
- 2001–present Mosler MT900
- 2006–present Elfin MS8 Streamliner
- 2006–present Elfin MS8 Clubman
Head and Block Peculiarities
Though LS1 kept aluminum block and cylinder head, it proved to be very strong and durable. Sometimes, engineers apply very unusual and non-traditional materials in the search of the best way to improve engine’s performance. And they may succeed though such modifications can be pretty expensive. However, it’s much more significant to have a really solid construction to feel all the benefits of materials applied.
LS1 is provided with a regular valve train featuring pushrod overhead valve. That valve construction keeps two valves per cylinder, 1 intake plus 1 exhaust.
Undoubtedly, LS1 engines were a real breakthrough in the world of small block V8 motors. Among the key modifications were increased block strength plus removal of the ignition system with distributor. Some amateur mechanics still employ these motors to demonstrate their power in their project vehicles.
|LS1 Cylinder Head Specs|
|1997-1998 Casting Numbers (Perimeter Valve Cover Bolts)||10215339, 12550592, 12558806|
|1999-2004 Casting Numbers (Center Valve Cover Bolts)||12559853, 12558805, 12560621, 12562174, 12564241|
|Combustion Chamber Volume||67cc|
|Intake Port Shape||Cathedral|
|Intake Runner Volume||200cc|
|Exhaust Port Shape||Oval|
|Exhaust Runner Volume||70cc|
|Intake Valve Diameter||2.000 in.|
|Exhaust Valve Diameter||1.550 in.|
|Cylinder Head Bolt Style||Torque to Yield (TTY)|
|Cylinder Head Bolt Size (1997-2003)||(8) M11 x 2 x 155, (2) M11 x 2 x 100, (5) M8 x 1.25 x 45|
|Cylinder Head Bolt Size (2004)||(10) M11 x 2 x 100, (5) M8 x 1.25 x 45|
LS1 engine problems and reliability
LS motors are pretty durable and reliable, but, of course, some troubles may occur especially if we consider them as high-productivity engines. Among the key shortcomings of these motors are:
Piston Ring Seals. A part of LS modifications are provided with low-quality piston ring seals, which may lead to troubles with increased oil consumption. Moreover, consequently, you may face engine blowing.
Oil Pump Cavitation. The original oil pump may start to cavitate above 6,000 rpm. As LS motors have rather limited revolutions abilities, this trouble isn’t critical for a production variation of the motor. Nevertheless, performance versions reach more than 6,000 rpm and that may lead to troubles with oil pressure when the pump begins to cavitate (You can research this issue in more detail by having a look at the list of restyled and improved pumps).
Non-Priority Main Oiling in OEM Blocks. The majority of aftermarket blocks feature updated priority oiling. Priority main oiling guarantees that oil gets to the mains and only after that, it reaches the heads. It helps to minimize oil pressure drop. Meanwhile, all original LS blocks go without this system. And actually, if you opt for OEM settings, there is no need in priority main oiling as motor will spend too little time at high revs.
Skirted Cylinder Block. Though skirted block proves to be more solid, it restricts the opportunity to decrease windage in classic ways. Thus, crank scrapers and power pouches can’t be utilized, reducing the efficiency of windage trays.
Despite being convenient for packaging, the push rod design is among the most substituted parts of the motor as its valve train is its main shortcoming. To be exact, the valve train system is so complex that it restricts the revs range.
Comparing to overhead camshaft engine, a push rod motor needs more valve train details. Thus, the big number of moving details leads to their failure due to high friction in the valve train.
Restrictions of the actual valves which can be utilized are another common problem of LS and push rod motors. Thus, volumetric effectiveness may be limited due to the application of 1 intake and 1 exhaust valves in push rod versions. For instance, overhead camshaft engine keeps better productivity thanks to utilization of up to 5 valves.
It’s pretty hard to reach camshaft because of the push rod design. Thus, in case you want to substitute camshaft, you need to remove either motor or radiator to reach it.