I was joking around with the techs who are doing my install in my supercharger retro fit. We were joking about: once we get the supercharger installed what if the supercharger is broken or is bad.

So my question is.. Who could you tell if you had a bad SC before you install it? The clutch spins and you can hear and feel the twin screws moving inside. So thats a plus. just wondering if there is anyway to tell if a SC is bad before you install it.

 

The only one that I saw that was bad wasn't able to turn...

gearing was toast

 

Thats what I thought, It moves freely so i'm thinking it must be ok. It was one of those "imagine if I got this whole project done and the SC didnt work" things.

 

god that would suck.....kinda like when a real good friend of mine got a used sc so he could get it ported and polished. The port and polish turned out great, its just the used sc didnt turn!

Now that sucks.....

 

 

You need to consider many questions before you decide to install ANY used piece of hardware that involves moving parts.
Obviously, some parts require more scrutiny vis-a-vis their condition than others.

Others may disagree with my take on this, but I'm coming from a background that requires extreme **** retentiveness.

So.... your USED supercharger spins 'freely'. What does that mean?

Since you've had one in your hands, you know how many moving parts, gears, bearings, rotors, etc. are involved. You are probably also aware of the tiny tolerances between the rotors themselves and between the rotors and casing.
I strongly recommend (if you haven't already) that you read up on Finny's wonderful account (with great photographs) of the M113K supercharger workings (see his 'Project Stock to Awe' thread and specifically his 'Supercharger Anatomy' on the W211 AMG forum).


What you probably DON'T know is what condition the supercharger is in:

Where did the supercharger come from?

Why was the supercharger pulled off the motor in the first place?
(and I mean the 'real' reason!)

What was the mileage on the supercharger?

Was the supercharger overdriven? (i.e. larger crank pulley)

Was the clutch ever replaced?

You have two equally likely scenarios:

A. The supercharger is perfect / like new.
We sincerely hope this is the case for you.

B. The supercharger is NOT perfect:

(i) During the removal, can you be sure no particulate matter of significant size made its way into the casing via the ports? You better hope it was sealed up and that there isn't anything in there! When that 2.3L blower is engaged for the first time, it'll spin and churn up anything that's in there.

(ii) Can you be sure that the rotors are in good shape? I direct you to read up on how Jakpro1's supercharger was found to have serious damage done to it and it spun freely (a chunk was broken off from one of the rotors). It was only when his motor was not producing the expected power that Vadim looked at the supercharger itself. Nobody would have found it otherwise.


[Photo by Vadim: taken from the above thread]

(iii) Related to the above - can you be sure that the supercharger is flowing properly? Although unlikely, are there any chances of leaks / bad seals?

Why take the chance?
Why would you assume that something you purchased (with so many unknowns) is going to be just fine on your motor?
I would contend that if it is worthy to be placed on an AMG engine (because of the cost of replacement), then all measures should be exhausted to ensure it is working properly.

You've spent a pile of cash thus far on this awesome project. What's another $700-$1200 to get it rebuilt? You already know what a M113K supercharger costs new!!
At the very least, have a professional thoroughly inspect the supercharger. There are a handful of W211 AMG members who appear to have such expertise.

Again, perhaps I'm just a funny-duddy, but I have many parts from the M112K motor that I would like to get rid of. The fact is; however, I could not (in good faith) sell those parts to somebody without first testing them.
For example: I have M112K superchargers lying around that spin freely.
Am I certain as to their functionality?
NO.

The bottom line is this:
Used parts are exactly that: USED.
If you purchased a used pump or alternator, you'd want it tested.
If you purchased a used crank pulley, you'd certainly want to get it rebalanced.

I could ramble on and on, but I don't think I can better articulate my thoughts on the matter!

 

....superchargers....an in, plural?

boohoo, you're hoarding.

 

boohoohorder

 

"Boohoo-Pedia"

 

Wiki-Boo

good stuff boohoo, you are dead on. Ive asked myself the same questions. If the blower is bad, (I doubt it is) getting its not the end of the world and a rebuild is not to much money when thinking of the scope of this project $$$.

 

Wow boohoo. Good stuff. Are you by any chance an aerospace QC inspector/repair shop manager?

 

That's just awesome. Boohoo you're one of my MB idols. All we need is splinter to chime in, post some diagrams, and this thread is GOLD.

 

LOL! - I know it may seem that way!
I'm not really though - I promise I'm not trying to corner the market!
I usually keep backups for everything I have as 'insurance' (again, **** retentiveness and a healthy dose of OCD!). However, when it comes to my C32 brethren, I would never sit on a part that I know is in perfect condition if I knew somebody really needed it.

Haha - I've been up all night and I had to think about this one for a sec - it sounds lewd!

That's the spirit!

No - I'm a scientist (or at least that's what I call myself!).

^^
Now that I agree with! Splinter is a tremendous resource to have around here.

 

I kid with you, of course. I have a spare S/C stored in my garage also. It was such cheap insurance against for the up-and-coming clutch failure that I couldn't resist.

I just kept my stock to a single unit though.



Your write up about the the reliability of used parts, such as this, is quite disturbing to me. It makes me think twice about installing this part, when the time comes. I guess my safest choice would be to just swap the clutch instead of the entire S/C.