Cobalt LNF MPx Lightweight crank pulley - testing going very well!
its not called a harmonic balancer, it's an ISOLATOR the entire purpose of the pulley is to isolate the a/c and alternator intermitten loads from doing bad things to the rest of the engine over an extended period of time (usually a year or two) having a bad isolator or substituting for one without can cause decreased a/c clutch, alternator bearing, tension pulley life. It may also cause the seal to leak (I've actually seen this a couple times on underdrive pulleys without an isolator present).
Just be aware that all your doing is eliminating the ability to isolate sudden loads such as the a/c clutch and times when you do things like turn the headlights on and off, turn on the defogger, even stepping on the brakes (the electrical load). And for what it's worth there is no discernable gain from reducing rotating mass that is this close to centerline (less than 4 inches).
On the flip side, if it's underdrive you can get a little gain in power from bottom to top.
i forgot to mention the obvious, it's going to significantly reduce belt life.
Just be aware that all your doing is eliminating the ability to isolate sudden loads such as the a/c clutch and times when you do things like turn the headlights on and off, turn on the defogger, even stepping on the brakes (the electrical load). And for what it's worth there is no discernable gain from reducing rotating mass that is this close to centerline (less than 4 inches).
On the flip side, if it's underdrive you can get a little gain in power from bottom to top.
i forgot to mention the obvious, it's going to significantly reduce belt life.
I remember posting a TSB about lightened flywheels and crank pulley's ......something about misfires .
I've read a review from someone who did the MRZ pulley and he swore it was a noticeable difference in performance , he posted 6 months later with no problems with it ..... just a heads up.
EDIT: Found it .... now this could be a true concern OR GM just trying to blame something they cant find a fix for . My stock LSJ had an Idle misfire since the day it was new , it wouldn't set a code but I could see it on a Tech 2 . So take it for what it's worth .....
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models: 2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
I've read a review from someone who did the MRZ pulley and he swore it was a noticeable difference in performance , he posted 6 months later with no problems with it ..... just a heads up.
EDIT: Found it .... now this could be a true concern OR GM just trying to blame something they cant find a fix for . My stock LSJ had an Idle misfire since the day it was new , it wouldn't set a code but I could see it on a Tech 2 . So take it for what it's worth .....
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models: 2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
The engine is calibrated for a certain amount of speed up/slow down or "hiccup" in the rythym of the engine based upon the factory rotating assembly. Reducing the weight of the flywheel or crank pulley can change how quickly the bottom end reacts to a misfire and can set a code.
Is it something to worry about? Not really since its only at idle appearently. But yes its a genuine concern.
Senior Member
Joined: 10-05-10
Posts: 805
Likes: 1
From: A.B.E. PA & Jacksonville FL
This bulletin is legit. Its not just GM shuffling blame off on aftermarket parts.
The engine is calibrated for a certain amount of speed up/slow down or "hiccup" in the rythym of the engine based upon the factory rotating assembly. Reducing the weight of the flywheel or crank pulley can change how quickly the bottom end reacts to a misfire and can set a code.
Is it something to worry about? Not really since its only at idle appearently. But yes its a genuine concern.
The engine is calibrated for a certain amount of speed up/slow down or "hiccup" in the rythym of the engine based upon the factory rotating assembly. Reducing the weight of the flywheel or crank pulley can change how quickly the bottom end reacts to a misfire and can set a code.
Is it something to worry about? Not really since its only at idle appearently. But yes its a genuine concern.
This bulletin is legit. Its not just GM shuffling blame off on aftermarket parts.
The engine is calibrated for a certain amount of speed up/slow down or "hiccup" in the rythym of the engine based upon the factory rotating assembly. Reducing the weight of the flywheel or crank pulley can change how quickly the bottom end reacts to a misfire and can set a code.
Is it something to worry about? Not really since its only at idle appearently. But yes its a genuine concern.
The engine is calibrated for a certain amount of speed up/slow down or "hiccup" in the rythym of the engine based upon the factory rotating assembly. Reducing the weight of the flywheel or crank pulley can change how quickly the bottom end reacts to a misfire and can set a code.
Is it something to worry about? Not really since its only at idle appearently. But yes its a genuine concern.
Junior Member
Joined: 09-27-08
Posts: 436
Likes: 0
From: delray beach, florida
I remember posting a TSB about lightened flywheels and crank pulley's ......something about misfires .
I've read a review from someone who did the MRZ pulley and he swore it was a noticeable difference in performance , he posted 6 months later with no problems with it ..... just a heads up.
EDIT: Found it .... now this could be a true concern OR GM just trying to blame something they cant find a fix for . My stock LSJ had an Idle misfire since the day it was new , it wouldn't set a code but I could see it on a Tech 2 . So take it for what it's worth .....
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models: 2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
I've read a review from someone who did the MRZ pulley and he swore it was a noticeable difference in performance , he posted 6 months later with no problems with it ..... just a heads up.
EDIT: Found it .... now this could be a true concern OR GM just trying to blame something they cant find a fix for . My stock LSJ had an Idle misfire since the day it was new , it wouldn't set a code but I could see it on a Tech 2 . So take it for what it's worth .....
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models: 2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Senior Member
iTrader: (7)
Joined: 04-06-10
Posts: 3,702
Likes: 0
From: 6000ft on a Mountain in Colorado!
You know, im actually glad you said that. Your chiming in with a prevalent misconception that old schoolers seem to have.
Most modern 4 cylinder motors are internally balanced, and do not have extreme harmonics like v6's and v8's.
Furthermore, we have been selling, using and testing crank pulleys now since the late 90's. You know what? We have never heard of ONE engine failure due to lightweight crank pulleys and we have sold thousands of them.
We offer crank pulleys for the following vehicles:
95-99 Neon
00-05 Neon
03-05 Neon SRT4
08+ Caliber SRT4
08+ Cobalt Turbo
Most modern 4 cylinder motors are internally balanced, and do not have extreme harmonics like v6's and v8's.
Furthermore, we have been selling, using and testing crank pulleys now since the late 90's. You know what? We have never heard of ONE engine failure due to lightweight crank pulleys and we have sold thousands of them.
We offer crank pulleys for the following vehicles:
95-99 Neon
00-05 Neon
03-05 Neon SRT4
08+ Caliber SRT4
08+ Cobalt Turbo
So I tend to believe this statement
Senior Member
Joined: 06-22-09
Posts: 5,989
Likes: 7
From: Kathmandu
Looks like a great way to void your powertrain warranty for only $120.
Seriously, though, why does the stock unit have the rubber portion? Is it because the engineers at GM simply had some excess rubber lying around that they feel like they needed to use? It has to be there for a reason.
Seriously, though, why does the stock unit have the rubber portion? Is it because the engineers at GM simply had some excess rubber lying around that they feel like they needed to use? It has to be there for a reason.
Senior Member
Joined: 06-22-09
Posts: 5,989
Likes: 7
From: Kathmandu
I think the risk reward on this mod is not very good at all. You're not gonna gain that much on this car. It's done all the time and people tell you it's *fine and dandy*...I would not want to find out on this relatively UNTESTED car. You can destroy the motor LONG TERM with an *occult* (time to get your dictionary out guys) imbalance.
As I said before, it's an isolator not a damper/harmonic balancer. The entire purpose of the factory pulley is to isolate the load cycling from the accessory drive, which from calculations in my head can be hundreds of pounds of force just from a/c compressor cycling. The mod is probably not a good idea. Underdrive, isolated pulley, I'd pay for that maybe.
Be wise and spend your money on the ati dampner. Underdrive,overdrive,or stock. All of u can take my advice or not don't matter to me any. But if u like ur car as much as I do ull listen to me. Jbp has a pulley that's actually a very nice piece and balanced but it has no dampner in it. Mrz and c.a also sell a pulley like the one mpx is making. These engines don't like being thrown Outta balance on the factory computer.
Be wise and spend your money on the ati dampner. Underdrive,overdrive,or stock. All of u can take my advice or not don't matter to me any. But if u like ur car as much as I do ull listen to me. Jbp has a pulley that's actually a very nice piece and balanced but it has no dampner in it. Mrz and c.a also sell a pulley like the one mpx is making. These engines don't like being thrown Outta balance on the factory computer.
Everytime you modify a car ........ you take a risk! THE WHOLE GAME of more HORSEPOWER is a risk.