3900 Specs (LZ9)

[Blackrider]

Engine Type
60 degree V-6

Displacement
3.9L
238 cu in

RPO
LZ9

VIN
1

Bore
99 mm
3.90 in

Stroke
84 mm
3.31 in

Compression Ratio
9.8:1

Firing Order
123456

Spark Plug Gap
1.00 mm
0.040 in

Block

Camshaft Bearing Bore Diameter - Front and Rear
55.26-55.31 mm
2.175-2.177 in

Camshaft Bearing Bore Diameter - Middle #2, #3
54.75-54.80 mm
2.155-2.157 in

Crankshaft Main Bearing Bore Diameter
72.1535-72.0695 mm
2.840-2.841 in

Crankshaft Main Bearing Bore Out-of-Round
0.008 mm
0.00031 in

Cylinder Bore Diameter
99.000-99.018 mm
3.897-3.898 in

Cylinder Bore Out-of-Round - Diameter - Production
0.026 mm
0.0010 in

Cylinder Bore Out-of-Round - Diameter - Service
0.030 mm
0.0011 in

Cylinder Bore Taper - Production
0.026 mm
0.0010 in

Cylinder Bore Taper - Service
0.030 mm
0.0011 in

Cylinder Head Deck Height
224 mm
8.818 in

Cylinder Head Deck Surface Flatness
0.05 mm per 150 mm
0.0019 in per 5.905 in

Valve Lifter Bore Diameter
21.417-21.455 mm
0.843-0.844 in

Camshaft

Camshaft Bearing Inside Diameter
51.500-51.525 mm
2.028-2.029 in

Camshaft Journal Diameter
51.415-51.440 mm
2.024-2.025 in

Camshaft Journal Out-of-Round
0.025 mm
0.001 in

Camshaft Lobe Lift - Exhaust
6.9263 mm
0.2727 in

Camshaft Lobe Lift - Intake
6.9263 mm
0.2727 in

Cooling System

Capacity
12.4 liters
13.1 quarts

Thermostat Full Open Temperature
195 degrees

Connecting Rod

Connecting Rod Bearing Clearance
0.18-0.062 mm
0.0007-0.017 in

Connecting Rod Bore Diameter
60.322-60.338 mm
2.375-2.376 in

Connecting Rod Bore Out-of-Round
0.006 mm
0.00023 in

Connecting Rod Length - Center to Center
150 mm
5.9 in

Connecting Rod Side Clearance
0.200-0.241 mm
0.008-0.009 in

Crankshaft

Connecting Rod Journal Diameter
57.122-57.138 mm
2.248-2.249 in

Connecting Rod Journal Out-of-Round
0.005 mm
0.0002 in

Connecting Rod Journal Taper
0.005 mm
0.0002 in

Connecting Rod Journal Width
21.92-22.08 mm
0.863-0.869 in

Crankshaft End Play
0.060-0.210 mm
0.0024-0.0083 in

Crankshaft Main Bearing Clearance - Except #3
0.019-0.064 mm
0.0008-0.0025 in

Crankshaft Main Bearing Clearance - #3 Thrust Bearing
0.032-0.077 mm
0.0012-0.0030 in

Crankshaft Main Journal Out-of-Round
0.005 mm
0.0002 in

Crankshaft Main Journal Taper
0.005 mm
0.0002 in

Crankshaft Rear Flange Runout
0.04 mm
0.0016 in

Cylinder Head

Combustion Chamber Depth - at Measurement Point
2.2 mm
0.087 in

Surface Finish - Maximum
2.8 RA

Surface Flatness - Block Deck
0.08 mm per 152 mm
0.003 in per 6 in

Surface Flatness - Exhaust Manifold Deck
0.1 mm
0.004 in

Surface Flatness - Intake Manifold Deck
0.1 mm
0.004 in

Valve Guide Bore - Exhaust
8.01 mm
0.315 in

Valve Guide Bore - Intake
8.01 mm
0.315 in

Valve Guide Installed Height
16.6 mm
0.654 in

Lubrication System

Oil Capacity - with Filter
3.8 liter
4.0 quarts

Oil Pressure - @ 1850 RPM
207-310 kPa
30-45 PSI

Oil Pump

Gear Diameter
38.05-38.10 mm
1.498-1.500 in

Gear Pocket - Depth
30.52-30.58 mm
1.202-1.204 in

Gear Pocket - Diameter
38.176-38.226 mm
1.503-1.505 in

Gears Lash
0.094-0.195 mm
0.0037-0.0077 in

Relief Valve-to-Bore Clearance
0.038-0.089 mm
0.0015-0.0035 in

Pin

Piston Pin Clearance to Connecting Rod Bore - Press Fit
-0.004 to -0.021 mm
-0.0001 to -0.0008 in

Piston Pin Clearance to Piston Pin Bore
0.002-0.010 mm
0.00008-0.0004 in

Piston Pin Diameter
23.952-23.955 mm
0.942-0.943 in

Piston Pin Length
64.21-64.44 mm
2.57-2.53 in

Piston

Piston Diameter - Production
98.970-99.008 mm
3.896-3.897 in

Piston Diameter - Service Limit
98.950 mm
3.895 in

Piston Pin Bore Diameter
23.957-23.962 mm
0.943 in

Piston Ring Groove Width
1.22-1.24 mm
0.048-0.049 in

Piston to Bore Clearance - Production
-0.008 to +0.048 mm
-0.0003 to +0.0018 in

Piston to Bore Clearance - Service Limit - Maximum
0.080 mm
0.003 in

Piston Ring End Gap

First Compression Ring
0.15-0.30 mm
0.006-0.011 in

Second Compression Ring
0.25-0.45 mm
0.009-0.017 in

Oil Control Ring
0.15-0.65 mm
0.06-0.025 in

Piston Ring to Groove Clearance

First Compression Ring
0.03-0.065 mm
0.001-0.002 in

Second Compression Ring
0.02-0.055 mm
0.0007-0.002 in

Oil Control Ring
0.01 mm
0.004 in

Piston Ring Thickness

First Compression Ring
1.175-1.190 mm
0.046-0.047 in

Second Compression Ring
1.475-1.490 mm
0.058 in

Oil Control Ring - Maximum
2.50 mm
0.098 in

Valves

Valve Face Angle
45 degrees

Valve Seat Angle
46 degrees

Valve Seat Depth - Exhaust - From Deck Face
8.9-9.1 mm
0.350-0.358 in

Valve Seat Depth - Intake - From Deck Face
7.9-8.1 mm
0.311-0.318 in

Valve Seat Width - Exhaust
1.70-2.0 mm
0.067-0.079 in

Valve Seat Width - Intake
1.55-1.80 mm
0.061-0.071 in

Valve Stem-to-Guide Clearance
0.026-0.068 mm
0.0010-0.0027 in

Valve Lifters/Push Rods

Push Rod Length - Intake
146.0 mm
5.75 in

Push Rod Length - Exhaust
152.5 mm
6.0 in

Valve Springs

Valve Spring Free Length
48.5 mm
1.89 in

Valve Spring Installed Height
43.2 mm
1.701 in

Valve Spring Load - Closed
320 N 43.2 mm
75 lb 1.701 in

Valve Spring Load - Open
1036 N 32 mm
230 lb 1.260 in

Valve Spring Total Number of Coils
6.55

[LoJac963]

How about a comparison table between the 3.5 and the 3.9? It think that would be kinda cool just so everyone knows what the exact differences are between the two engines. I would say throw in the GXP also but I don't think the actual specs are out-just the horsepower. Good job though.

[Blackrider]

How about a comparison table between the 3.5 and the 3.9? It think that would be kinda cool just so everyone knows what the exact differences are between the two engines. I would say throw in the GXP also but I don't think the actual specs are out-just the horsepower. Good job though.

Good idea, dont have time right now, but anyone can do it!

[LoJac963]

yeah true, lol-didn't mean to come across as pushy or anything

[Blackrider]

yeah true, lol-didn't mean to come across as pushy or anything

lol dont worry about it man, I was just leaving for a 7 hour drive when i posted last.

[v6h.o.]

3900:
Engine Type: 60 degree V-6
Displacement:
3.9L, 238 cu in
RPO: LZ9
VIN: 1
Bore:
99 mm, 3.90 in
Stroke:
84 mm, 3.31 in
Compression Ratio:
9.8:1
Firing Order:
123456
Spark Plug Gap:
1.00 mm, 0.040 in

The 3900 "LZ9", and the new 3500 "LZ4/LZE" engines (not to be confused with the regular variant 3500 "LX9" engine which is just a larger bore 3400) are what GM is calling the "High Value" engines. These two engines share 80% of the components between each other.
The 3500 shares the same bore as the 3900, But has a much smaller stroke at: 2.99 inch, 76mm (same stroke the original 60v6 the 2.8L had back in the day)

I know most of this is what Jordie already posted from myself on 60v6.

This is info I posted a while back on 60degreev6.com about the Changes GM has made compared to the older 3100/3400/3500 gen3 660's.

Block centerline is changed by 3mm.

Camshaft bearings are larger journal diameter (55mm now up from 51mm we are used to) to accomodate larger camshaft profiles.

9.8:1 compression ratio (at least for the 3900, havn't checked the 3500 yet)

Camshaft phasing, which can advance and retard the camshaft 25 degree's throughout the powerband to create a broad flat torque/powerband.

Tuned Plenum with Intake Manifold Tuning Valve, -opens and closes dual ports in the plenum to create a low and high rpm runners/plenum.
The 3900 uses a larger ported lower Intake manifold,

There is a larger 72mm throttle body on the Plenum,

Heads are different, and do not share any related component with previous 60v6 heads. 47.5mm (1.87inch) Intake valves and 38.7mm (1.52inch) exhaust valves are in the heads which feature revised port shapes and different combustion chamber shapes. as far as the rockers all I know is that "Features rocker arms similar to those found on LS1 V8's" What the actual ratio is not sure if its still 1.6:1 or now 1.7:1 like the LS engines.


Exhaust manifolds are new redesigned and tuned for maximum performance (as per what GM claims anyways)

Each cylinder bores have piston oil squirters to keep pistons cool.
Features a High volume oil pump to accomodate the larger oil system requirements from the squirters and as well as the cam phaser actuator setup. The Oil pump drive gear is different and cannot be interchanged withe the previous engines drive gear.

New style Delphi Multec 3.5 injectors featuring new design features.

New redesigned Cooling system which flows the coolant through and around the block in a different more uniform path through the engine.


There are other small changes and whatnot that I know I'm missing.

[LoJac963]

good info, interesting stuff, thanks for the post!!

[CoupeOfG6]

Re: 3900 Specs.

Firing Order: 1-2-3-4-5-6

WOW!! I don't think I've heard of any other V6 with this kind of firing order! : (Correct me if I am wrong ofcoarse)

I liek the idea of a "Comparison Chart" idea. Hell, if anyone wants to give me all the data they want, I can make up a pretty snazzy chart like in Motor Week or what ever and post it in here to be stickied. All I know abotu the two is 3.9 has 40 extra horsies.

[Blackrider]

Re: 3900 Specs.

Firing Order: 1-2-3-4-5-6

WOW!! I don't think I've heard of any other V6 with this kind of firing order! : (Correct me if I am wrong ofcoarse)

I liek the idea of a "Comparison Chart" idea. Hell, if anyone wants to give me all the data they want, I can make up a pretty snazzy chart like in Motor Week or what ever and post it in here to be stickied. All I know abotu the two is 3.9 has 40 extra horsies.

3100 3400 3500's all have 1-2-3-4-5-6 fireing order

[CoupeOfG6]

Learn a little more everyday!

[LoJac963]

that is an amazingly odd firing order I have to say

[v6h.o.]

Re: 3900 Specs.

Firing Order: 1-2-3-4-5-6

WOW!! I don't think I've heard of any other V6 with this kind of firing order! : (Correct me if I am wrong ofcoarse)

The 60degreev6 has used this firing order since its birth back in the 80's with the 2.8L. Its really nice actually. Simple to remember LOL.

[LoJac963]

yeah it is easy, better than SB chevy's. This is my first V6 other than all the SB350's I've owned and I have to say I love it. I went from small blocks to a 2.2 ecotec and it killed me. That little engine did get up and go though, it will always have a place in my heart as my first car. I can't get over the fact that my G6 doesn't feel like it wants to die when I turn the AC on like the ecotec did

[spoolinturbo]

ya ive seen it a number of times, still odd if you ask me
jeff

[MDMAS13]

I agree that it's odd. I would like to know how the engine stays balanced. Would be some interesting information.