Setting the correct bearing clearance is critical for any LS engine build.
This guide provides a comprehensive LS engine bearing clearance chart covering crankshaft main bearings, rod bearings, cam bearings, and thrust clearance for popular LS engine variants.
LS Engine Bearing Clearance Chart
Main Bearing Clearance
| Engine Variant | Journal Size | Stock Clearance | Performance | Racing / Boosted | Max Limit |
|---|---|---|---|---|---|
| LS1 / LS6 | 2.559″ | 0.0015″–0.0025″ | 0.0025″–0.0030″ | 0.0030″–0.0035″ | 0.0038″ |
| LS2 | 2.559″ | 0.0018″–0.0028″ | 0.0028″–0.0032″ | 0.0032″–0.0038″ | 0.0040″ |
| LS3 / L92 | 2.559″ | 0.0020″–0.0028″ | 0.0028″–0.0032″ | 0.0032″–0.0038″ | 0.0042″ |
| LS7 | 2.750″ | 0.0020″–0.0030″ | 0.0030″–0.0035″ | 0.0035″–0.0042″ | 0.0045″ |
| LQ4 / LQ9 | 2.559″ | 0.0020″–0.0030″ | 0.0028″–0.0035″ | 0.0035″–0.0040″ | 0.0042″ |
| LY6 / L96 | 2.559″ | 0.0020″–0.0030″ | 0.0028″–0.0035″ | 0.0035″–0.0040″ | 0.0042″ |
| 5.3L (LM7, LC9, LH6) | 2.559″ | 0.0018″–0.0028″ | 0.0028″–0.0032″ | 0.0032″–0.0038″ | 0.0040″ |
| 4.8L (LR4, LY2) | 2.559″ | 0.0015″–0.0025″ | 0.0025″–0.0030″ | 0.0030″–0.0035″ | 0.0038″ |
Related Engine Connecting Rod Bearing Size Chart(For All Vehicle Brands)
Connecting Rod Bearing Clearance
| Engine Variant | Rod Journal | Stock Clearance | Performance | High RPM / Boost | Max Limit |
|---|---|---|---|---|---|
| LS1 / LS6 | 2.100″ | 0.0015″–0.0022″ | 0.0022″–0.0028″ | 0.0028″–0.0032″ | 0.0035″ |
| LS2 / LS3 | 2.100″ | 0.0020″–0.0025″ | 0.0025″–0.0030″ | 0.0030″–0.0035″ | 0.0038″ |
| LS7 | 2.200″ | 0.0020″–0.0028″ | 0.0028″–0.0035″ | 0.0035″–0.0040″ | 0.0042″ |
| LQ4 / LQ9 | 2.100″ | 0.0020″–0.0028″ | 0.0028″–0.0032″ | 0.0032″–0.0038″ | 0.0040″ |
| 5.3L Series | 2.100″ | 0.0018″–0.0025″ | 0.0025″–0.0030″ | 0.0030″–0.0035″ | 0.0038″ |
| 4.8L Series | 2.100″ | 0.0015″–0.0022″ | 0.0022″–0.0028″ | 0.0028″–0.0032″ | 0.0035″ |
Camshaft Bearing Clearance
| Engine Variant | Stock Range | Performance | Max Limit |
|---|---|---|---|
| LS1 / LS6 | 0.0010″–0.0020″ | 0.0015″–0.0025″ | 0.0028″ |
| LS2 | 0.0012″–0.0022″ | 0.0018″–0.0028″ | 0.0030″ |
| LS3 | 0.0012″–0.0022″ | 0.0018″–0.0028″ | 0.0030″ |
| LS7 | 0.0015″–0.0025″ | 0.0020″–0.0030″ | 0.0032″ |
| LQ4 / LQ9 | 0.0012″–0.0022″ | 0.0018″–0.0028″ | 0.0030″ |
| Gen V LT-based LS architecture | 0.0015″–0.0025″ | 0.0020″–0.0030″ | 0.0032″ |
Related LS Engine Weight Chart(For All Engine Codes)
Thrust Bearing Clearance (Crankshaft Endplay)
| Engine Variant | Stock Endplay | Performance | Racing | Max Limit |
|---|---|---|---|---|
| LS1 / LS6 | 0.003″–0.007″ | 0.004″–0.008″ | 0.005″–0.009″ | 0.010″ |
| LS2 / LS3 | 0.004″–0.008″ | 0.005″–0.009″ | 0.006″–0.010″ | 0.012″ |
| LS7 | 0.004″–0.009″ | 0.006″–0.010″ | 0.008″–0.012″ | 0.014″ |
| LQ4 / LQ9 | 0.004″–0.008″ | 0.005″–0.009″ | 0.006″–0.010″ | 0.012″ |
| 5.3L / 4.8L | 0.003″–0.007″ | 0.004″–0.008″ | 0.005″–0.009″ | 0.010″ |
Piston-to-Wall Clearance (Common LS Pistons)
| Engine Variant | Hypereutectic Pistons | Forged Street | Forged Race |
|---|---|---|---|
| LS1 / LS6 | 0.0010″–0.0015″ | 0.0025″–0.0035″ | 0.0035″–0.0045″ |
| LS2 / LS3 | 0.0010″–0.0015″ | 0.0028″–0.0038″ | 0.0038″–0.0050″ |
| LS7 | — | 0.0035″–0.0045″ | 0.0045″–0.0060″ |
| LQ4 / LQ9 | 0.0012″–0.0018″ | 0.0030″–0.0040″ | 0.0040″–0.0055″ |
| 5.3L / 4.8L | 0.0010″–0.0015″ | 0.0025″–0.0035″ | 0.0035″–0.0045″ |
Related LS Engine Swap Compatibility Chart(For All Models)
How to Measure Bearing Clearance
1. Plastigauge Method
- Place Plastigauge on the journal
- Torque caps to spec
- Measure squish width
2. Micrometer & Dial Bore Gauge
The most accurate method used by professional builders.
Steps:
- Measure the crank journal with a micrometer
- Measure bearing ID with dial bore gauge
- Subtract values
Related LS Engine Bore and Stroke Chart(For All Models)
Factors That Affect LS Bearing Clearance
1. Engine Power Level
- Stock engines need tighter clearances
- High HP engines require more oil flow
2. Oil Viscosity
- Thicker oil tolerates wider clearances
- Thin oil requires tighter tolerances
3. RPM Range
High RPM engines need more clearance to maintain lubrication.
4. Block Material
- Aluminum blocks expand more → tighter cold clearance
- Iron blocks expand less → slightly looser clearance
Related LS Engine Identification Chart(For All LS Models)
Signs of Incorrect Bearing Clearance
Too Tight
- Low oil flow
- Overheating bearings
- Engine seizure risk
Too Loose
- Low oil pressure
- Knocking noise
- Premature bearing wear
Expert Tips for LS Engine Builders
- Aim for 0.001″ clearance per inch of journal diameter
- Always check clearances during mock assembly
- Use assembly lube during final installation
- Match oil pump capacity to clearance targets
What Is Bearing Clearance?
Bearing clearance is the gap between the crankshaft journal and the bearing surface. This small space allows engine oil to form a protective film that prevents metal-to-metal contact.
Why It Matters
- Maintains oil pressure
- Prevents overheating and bearing failure
- Supports high RPM stability
- Reduces friction and wear
Too tight → oil starvation and seizure
Too loose → low oil pressure and knocking
FAQs
What is the bearing clearance of a LS engine?
Bearing clearance in an LS engine typically ranges from 0.0015″ to 0.0030″, depending on the component and engine use. Stock builds run tighter clearances for stable oil pressure, while performance or boosted builds use slightly larger clearances to improve oil flow and cooling.
How much bearing clearance is acceptable?
Acceptable bearing clearance depends on the engine’s purpose:
- Stock engines: 0.0015″–0.0025″
- Street performance: 0.0020″–0.0030″
- Racing/boosted: up to 0.0035″–0.0040″
Clearance outside these ranges can cause oil pressure problems or bearing wear.
What is 0.002 bearing clearance?
A 0.002″ bearing clearance means there is a two-thousandths-of-an-inch gap between the crankshaft journal and the bearing surface. This is a common target for LS street engines because it balances lubrication, oil pressure, and durability.
Is .003 main bearing clearance good?
Yes, 0.003″ main bearing clearance is considered good for:
- High-performance LS builds
- Forced induction setups
- High-RPM racing engines
However, it may be too loose for a stock daily driver, potentially lowering oil pressure.
What size is a LS 2.2 bearing?
In LS terminology, “2.2” usually refers to the rod journal size of 2.200 inches, commonly found in engines like the LS7. Most other LS engines use 2.100-inch rod journals.
What is the 2:1 bearing rule?
The 2:1 rule suggests that main bearing clearance should be about 0.001″ per inch of journal diameter, and rod clearance slightly tighter. For example:
- 2.559″ main journal → ~0.0025″ clearance target
This rule helps builders set safe baseline clearances.
What is the difference between C1 and C3 bearing clearance?
C1 and C3 refer to bearing internal clearance classes:
- C1: Tighter-than-standard clearance
- C3: Greater-than-standard clearance for high heat or high-speed applications
In automotive engines, C3 bearings are sometimes used in performance builds to accommodate thermal expansion and higher loads.
What is the clearance limit for the main engine bearing?
For most LS engines, the main bearing clearance limit is:
- Service limit: ~0.0035″–0.0040″
- Beyond this range, oil pressure loss and bearing knock may occur.
If measurements exceed the limit, the crankshaft or bearings should be replaced or resized.
Final words
Correct bearing clearance is the foundation of a reliable and powerful LS engine. Whether building a daily driver or a 1,000+ HP race engine, following the clearance ranges in this chart ensures optimal lubrication, durability, and performance.
By carefully measuring and adjusting tolerances, builders can maximize the lifespan and efficiency of any General Motors LS engine platform.
