So who has broken a stock caged lower or keyway? Big blower guys come on in

[DSGWhippedSnake]

Who has broken a stock caged lower? I know it does happen, just curious how common of an issue it is. I know there are a couple 3.4 guys on here that have broke them and I know Jared from lethal has broken 2 of them with the 4.0

It seems to be a popular topic lately so I figured I'd start a thread to get some info.

Who has had crank issues? My buddy Chris broke the keyway off the snout of the crank a couple weeks ago with his 3.4

It seems like you don't really read about it much although it happens more than we all think.

 

[tarheeltrooper]

And people said cogs were bad lol. Wild i didnt know this was happening on peoples 3.4's

 

[DSGWhippedSnake]

And people said cogs were bad lol. Wild i didnt know this was happening on peoples 3.4's

oh yea lol it's definitely wild. These big blowers take alot of power to spin which puts alot of strain on the crank and lower pulleys

 

[03redfirevert.]

Interested as well although I have an innovators west balancer and a 3.4

 

[DSGWhippedSnake]

Interested as well although I have an innovators west balancer and a 3.4

+1 I know there are guys on here with feedback

 

[SlowSVT]

I think one of the 5.8 Trinity GT500 owners took out his crank running a 4.5 Whipple in short order if I remember correctly. The snout on the 5.8 is the same as the 4.6. I think anything over a 3.4 on a mod motor is a "bridge too far" turning all that mass.

 

[testorossa1989]

I think your referring to "bigger crank pulleys" There was an issue with Metco pulleys snapping the crank snout and causing huge problems, also walking crank in some cases.


As for stock crank caged pulleys, i havent heard of them failing besides people breaking them while trying to remove them due to improper removal practices.


The post below is a email i had with Metco rep awhile back about this matter.

 

[testorossa1989]

Here is the actual email i had with METCO


Hey James.

There is no 'average' failure rate associated with our crank pulley kits.
We have been manufacturing these kits since the Lightning was introduced and
have sold thousands for both the Lightning and Cobra applications.
Speculation on the issue of crank failures surfaces on the internet from
time to time, and there is a lot of misinformation posted.

We have a business relationship with an engine builder who served with Ford
Motor Company as one of the lead engineers for the Terminator engine
application, and he provided specific input to Ford on the design of the
Cobra supercharger drive. He uses our crank pulley kit on every Cobra
engine he builds, and also has our crank pulley kit on his own car.

There have been reports of an issue with the way the oil pump drives were
machined into the Cobra crankshafts that affects a small number of cars.
This machined portion of the crank may represent a potential failure point
in some cars, and we have seen documented cases of crank snout failures in
cars equipped with the original caged crank pulley assembly. I suspect most
cars that fall into this group would have had some sort of failure by now,
but I don't have specific details.

We also have ongoing access to some of our original development cars, and
these are Cobras that have run high boost and severe belt tensions (not
recommended) for close to ten years of extreme service. These cars are run
hard on a regular basis and have suffered no failures of the crankshaft or
any related components, and several are now showing mileage well in excess
of 100K.

Obviously, it is impossible for me to guarantee your results, but I can tell
you very honestly that if I owned a Cobra right now, our kit would certainly
be on my car.








Rick
Metco Motorsports
109 North Park Drive
Anderson, SC 29621
(864) 332-5929
Fax: (864) 332-5930
Metco Motorsports

 

[DSGWhippedSnake]

I think one of the 5.8 Trinity GT500 owners took out his crank running a 4.5 Whipple in short order if I remember correctly. The snout on the 5.8 is the same as the 4.6. I think anything over a 3.4 on a mod motor is a "bridge too far" turning all that mass.

I think your referring to "bigger crank pulleys" There was an issue with Metco pulleys snapping the crank snout and causing huge problems, also walking crank in some cases.


As for stock crank caged pulleys, i havent heard of them failing besides people breaking them while trying to remove them due to improper removal practices.


The post below is a email i had with Metco rep awhile back about this matter.

There have been guys who had issues even with the stock caged lowers. The center recessed Allen stud strips out which causes the pulley to spin freely. You can start the car and the harmonic balancer will spin while the caged lower pulley does not move. Jared from lethal had this happen twice on his grabber blue with the 4.0 on it. He resolved the issue by welding a circular plate on the face of the pulley with a bead around the outside edge as well as the inside around the Allen stud. I'll post the pic he sent me

 

[testorossa1989]

Yeah please, im interested to see this. Also there are TONS of cobras with 3.4s so this sounds like an isolated problem. I wouldnt be worried by this

 

[DSGWhippedSnake]

Yeah please, im interested to see this. Also there are TONS of cobras with 3.4s so this sounds like an isolated problem. I wouldnt be worried by this

That's what I'm thinking. I've been thinking about taking my lower off to modify it before the blower even goes on but I'm probably going to leave it alone as I'm not one to "fix what's not broken"

 

[04torchred]

Frank Yi, I am missing his screen name(had the black Cobra in Vegas running a 3.4L and than a YSI)

He had failures with a stock caged lower, pulling the entire crank forward and damaging the block. It was threading into the stock damper as it spun and pulling forward on everything I believe.

Seems from my memory of the failures all have been with aftermarket tensioners. some manual and some I think still spring loaded. I suspect the manual none spring loaded are going to be the most frequent failures as they have zero give.

 

[SlowSVT]

Here is the actual email i had with METCO


Hey James.

There is no 'average' failure rate associated with our crank pulley kits.
We have been manufacturing these kits since the Lightning was introduced and
have sold thousands for both the Lightning and Cobra applications.
Speculation on the issue of crank failures surfaces on the internet from
time to time, and there is a lot of misinformation posted.

We have a business relationship with an engine builder who served with Ford
Motor Company as one of the lead engineers for the Terminator engine
application, and he provided specific input to Ford on the design of the
Cobra supercharger drive. He uses our crank pulley kit on every Cobra
engine he builds, and also has our crank pulley kit on his own car.

There have been reports of an issue with the way the oil pump drives were
machined into the Cobra crankshafts that affects a small number of cars.
This machined portion of the crank may represent a potential failure point
in some cars, and we have seen documented cases of crank snout failures in
cars equipped with the original caged crank pulley assembly. I suspect most
cars that fall into this group would have had some sort of failure by now,
but I don't have specific details.

We also have ongoing access to some of our original development cars, and
these are Cobras that have run high boost and severe belt tensions (not
recommended) for close to ten years of extreme service. These cars are run
hard on a regular basis and have suffered no failures of the crankshaft or
any related components, and several are now showing mileage well in excess
of 100K.

Obviously, it is impossible for me to guarantee your results, but I can tell
you very honestly that if I owned a Cobra right now, our kit would certainly
be on my car.








Rick
Metco Motorsports
109 North Park Drive
Anderson, SC 29621
(864) 332-5929
Fax: (864) 332-5930
Metco Motorsports

Take it from someone with something to sell you

I'm sure there is some merit on what was said here bet he did not address the fact eliminating the pulley support means the only support for the blower pulley, harmonic balancer, cam drive gear and the oil pump is supported by the #1 main bearing that has 8" worth of cantilever load in front of it. That and the fact the crank snout is rather thin and was never designed to carry the load of a supercharger in the first place. The factory obviously felt it was important enough to equip our engines with a pulley support in the first place and this guy claims test bed engines under high boost and abuse have survived for 100K miles. Failing crank snouts are a problem with this car and will continue to be that way. If you run the engine on the street modestly you probably won't have a problem. Drag racing with massive shifts in RPM's is where you might run into problems.

 

[DSGWhippedSnake]

Take it from some with something to sell you

I'm sure there is some merit on what was said here bet he did not address the fact eliminating the pulley support means the only support for the blower pulley, harmonic balancer, cam drive gear and the oil pump is supported by the #1 main bearing that has 8" worth of cantilever load in front of it. That and the fact the crank snout is rather thin and was never designed to carry the load of a supercharger in the first place. The factory obviously felt it was important enough to equip our engines with a pulley support in the first place and this guy claims test bed engines under high boost and abuse have survived for 100K miles. Failing crank snouts are a problem with this car and will continue to be that way. If you run the engine on the street modestly you probably won't have a problem. Drag racing with massive shifts in RPM's is where you might run into problems.

+1 sticky tires+sticky track+tons of power is a recipe for disaster. If you really want to speed things up, an aftermarket non-caged lower, a manual tensioner cranked will do the trick. It seems like most failures have those key items in common. I'm hoping to be ok with a stock caged lower, stock or thump tensioner, and a not overly tight belt :shrug:

 

[DSGWhippedSnake]

Frank Yi, I am missing his screen name(had the black Cobra in Vegas running a 3.4L and than a YSI)

He had failures with a stock caged lower, pulling the entire crank forward and damaging the block. It was threading into the stock damper as it spun and pulling forward on everything I believe.

Seems from my memory of the failures all have been with aftermarket tensioners. some manual and some I think still spring loaded. I suspect the manual none spring loaded are going to be the most frequent failures as they have zero give.

Yikes. That'll do it


I'm trying to decide whether it would be smart to modify the stock lower or not. I also wonder if doing so will disturb the harmonics :shrug:

 

[04torchred]

Stock tensioner!

 

[testorossa1989]

Take it from some with something to sell you

I'm sure there is some merit on what was said here bet he did not address the fact eliminating the pulley support means the only support for the blower pulley, harmonic balancer, cam drive gear and the oil pump is supported by the #1 main bearing that has 8" worth of cantilever load in front of it. That and the fact the crank snout is rather thin and was never designed to carry the load of a supercharger in the first place. The factory obviously felt it was important enough to equip our engines with a pulley support in the first place and this guy claims test bed engines under high boost and abuse have survived for 100K miles. Failing crank snouts are a problem with this car and will continue to be that way. If you run the engine on the street modestly you probably won't have a problem. Drag racing with massive shifts in RPM's is where you might run into problems.

I work manufacturing as a quality inspector, i dont believe a word they say lmao im just putting it out there for you guys.

 

[SlowSVT]

I work manufacturing as a quality inspector, i dont believe a word they say lmao im just putting it out there for you guys.

It always a good thing to hear it from the horse's mouth.........even if you take it with a grain of salt.

As a quality Inspector it's in your nature to be skeptical (at least the good ones are :-D ).

 

[sabotage]

This is a scary topic ..lol.....I though it was more common with the metco units ...

 

[racebronco2]

My stock lower broke with a 2.3 at 19psi. It broke right where the outer pulley threads onto the allen head.