[PinHead]

Originally Posted by Rock-It Man

The problem is that they don't hold pressure and collapse when the engine is off.

That's not the root cause of the AFM failing.

Do a little reading about GM V8s and AFM/DoD failures.

Think physics, you cannot maintain balance in a reciprocating assembly(engine) when you start shutting/turning cylinders off.

It causes all kinds of mechanical harmonic disturbances that will eventually kill parts via self destruction. Harmonics also kill HP gains and turn them into loses. It might only be single digit losses at the beginning, but a high percentage end in a catastrophic failure.

Some of the former aviators on the board can tell you about a problem harmonic in an aircraft's drive or propulsion systems. Same end result.

Why AFM = Only for improving Emissions and Mileage.

So why are we still putting up with AFM when we still have to pay the gas hog tax? GM Politricks.

If my project car disn't have to maintain a factory engine config, I'd hard delete the AFM and use a full roller valvetrain.

A full roller system is basically bullet proof and is also low friction and light weight. Low friction/Light valve actuation = HP gains and high durability.

[LibertyHill]

I did some research and it does seem to confirm the failure would be less likely to happen to the manual cars where the system is disabled. There are a lot of recommendations out there to disable it ASAP for long engine life. Most of the failure history is on the old engines though.

"Doing a bunch of research, found this page. There have been instances of AFM lifters collapsing because of failed oil control solenoids or the lifter guides allowing the lifter to rotate. Other than that, design flaws were noted. Normally, oil pressure collapses the lifter in V4 mode and when it switches back to V8 mode, relieves that pressure in the lifter to allow it to come back to full height. When they fail, it's an internal mechanical failure preventing them to return. In that same page, it says that deactivation should prevent the AFM lifters from failing. But, this is assuming that the lifter guides are good."

[PinHead]

Originally Posted by LibertyHill

I did some research and it does seem to confirm the failure would be less likely to happen to the manual cars where the system is disabled. There are a lot of recommendations out there to disable it ASAP for long engine life. Most of the failure history is on the old engines though.

"Doing a bunch of research, found this page. There have been instances of AFM lifters collapsing because of failed oil control solenoids or the lifter guides allowing the lifter to rotate. Other than that, design flaws were noted. Normally, oil pressure collapses the lifter in V4 mode and when it switches back to V8 mode, relieves that pressure in the lifter to allow it to come back to full height. When they fail, it's an internal mechanical failure preventing them to return. In that same page, it says that deactivation should prevent the AFM lifters from failing. But, this is assuming that the lifter guides are good."

You're still focusing on the secondary failures not the root cause.

It would take an extremely long and technical post to get into harmonic distortion of hydraulic systems. GM won't admit this as it embarrass their Engineering and Development Teams.

I'll see if I can put into a Cliff Notes version.

A engine's oil system is hydraulic. FACT: The GM AFM is hydraulically controlled and causes harmonic distortion.

Harmonic distortion disrupts and destroys a hydraulic system as well as disrupts a reciprocating assembly's balance.

Lifters without constant pressure cause wear. Excessive wear causes catastrophic failures.

A reciprocating assembly out-of-balance will eventually destroy itself.
http://www.enginebuildermag.com/2013...increase-life/
These two conditions exacerbate the other.


The ONLY fix is to eliminate the harmonic distortion, (i.e. eliminate the AFM system and hard parts).

Btw, Internet Writers also avoid posting about this issue as GM won't play nice ever again.

[Camarolover85]

This makes me feel better about my new purchase...

[RS-Chevy-SS]

Originally Posted by LibertyHill

I did some research and it does seem to confirm the failure would be less likely to happen to the manual cars where the system is disabled. There are a lot of recommendations out there to disable it ASAP for long engine life. Most of the failure history is on the old engines though.

"Doing a bunch of research, found this page. There have been instances of AFM lifters collapsing because of failed oil control solenoids or the lifter guides allowing the lifter to rotate. Other than that, design flaws were noted. Normally, oil pressure collapses the lifter in V4 mode and when it switches back to V8 mode, relieves that pressure in the lifter to allow it to come back to full height. When they fail, it's an internal mechanical failure preventing them to return. In that same page, it says that deactivation should prevent the AFM lifters from failing. But, this is assuming that the lifter guides are good."

My car is an M6

Originally Posted by Camarolover85

This makes me feel better about my new purchase...

I hear you man. But hey, while this one is in the shop I'm driving around my '89 Third Gen.

[Burly]

Is it true that running an auto in manual shifting mode disables AFM? I think I've noticed this but haven't really proved it.

[Stex]

Originally Posted by Camarolover85

This makes me feel better about my new purchase...

Yes GM has caused a lot of hardship and stress for many with this AFM mess. GM did shorten their mileage warranty from 100,000 to 60,000. Gee.

[Camarolover85]

Originally Posted by Stex

Yes GM has caused a lot of hardship and stress for many with this AFM mess. GM did shorten their mileage warranty from 100,000 to 60,000. Gee.

Did they really!? I didn't know that...

[CruzySS]

I understand why AFM is put in vehicles for gas mileage. But why would you put it in a v8 muscle car. I bought the car for the power not the mpg. If people are worried about gas buy the V6 or I4.

[Camarolover85]

Originally Posted by CruzySS

I understand why AFM is put in vehicles for gas mileage. But why would you put it in a v8 muscle car. I bought the car for the power not the mpg. If people are worried about gas buy the V6 or I4.

It's not GM, I'm fairly certain it's the EPA forcing all the rules on mpg.

[reeper]

Boy, the way this thread is going i should just trade in. Sounds like this is a wide-spread issue with these motors.

[trz174]

.

[Chutzpah]

See older post below... the OP looks like he may still have his car, I don't see an engine replacement, lifter / rocker arm repair when following the OP. It appears he may even be adding upgrades (after the post)...


http://www.camaro6.com/forums/showth...ht=engine+tick

[RS-Chevy-SS]

Originally Posted by Chutzpah

See older post below... the OP looks like he may still have his car, I don't see an engine replacement, lifter / rocker arm repair when following the OP. It appears he may even be adding upgrades (after the post)...


http://www.camaro6.com/forums/showth...ht=engine+tick

That's incorrect. That's same OP posted in here. His engine was replaced and the dealer forgot to put oil in his replacement engine. Not good.

Originally Posted by reeper

Boy, the way this thread is going i should just trade in. Sounds like this is a wide-spread issue with these motors.

I am feeling the same way man.