So, after hearing that nasty high pitched metal on metal sound again...for the 3rd or 4th time; i can't keep track anymore. I decided to strip down my head unit and figure out what is going on.

I found the phenolic cage on the high speed impeller side was broken. Not melted broken right in the middle of where a bearing sits.



well after some investigation on similar bearings I have come across this information...Vortech uses NACHI Single Row Angular Contact precision bearings.

http://www.nachi-fujikoshi.co.jp/eng...l_t/index.html

Click the link for the PDF with specifications. The bearings are 7003C P4. This bearing has a 15 deg angle, phenolic cage and now for the drum roll TAKE A LOOK AT THE OIL SPEED RATING...hmm 42,000 RPM

I think we have been http://images.ibsrv.net/ibsrv/res/sr...lies/owned.gif


Let me see what vortech's site says my stock V2 SCI trim blower is rated for. 53,000 RPM hmm if my math is correct that is an "11,000" RPM difference!!!

stock 350z kit runs 34T jackshaft and 32T SC pulley based on the impeller calculator I am over spinning those bearings (50,200 impeller calc) - 42,000 rating...8,200 RPM over the bearing manufacturers specifications...duh no wonder they keep failing http://images.ibsrv.net/ibsrv/res/sr...ies/icon18.gif


It's probably less of an issue for the mustangs since they are probably hitting redline around 6k, which is probably more in spec with the bearings.

so not only is the Z spinning the bearings past their specifications. At around 5900 RPM you are at the limits of the bearing. Pretty easy to get to 5900 RPM often, isn't it?

My solution...unfortunately it's expensive ~305 just for the set of bearings, but in this case I guess you get what you pay for!

I am going to put a set of SKF 7003CD/P4ADGA in there. According to their product specifications these bearings can handle 70,000 RPM

I'm just tired of this...I usually only get about 3k miles before she BLOWS

Could someone who knows better than I verify that the bearings needed are low preload - thanks

 

wow good info...Did you call vortech to see what they had to say about that..Already know its gonna be b.s but worth a try...Good job on the research

 

Good info there. $305 seems like a steal if it keeps your car on the road. I hope this proves to be a long term fix that many of the SC guys will be VERY thankful for.

 

great info!!

I have the input and output shaft seals.. but HOW IN GODS name did you take apart the blower??... I wish I knew this so I could do the seals my self.

Make a DIY on how to take it apart and this thread will be MONEY!!!

I was going to go with the ceramic thrust for $550. I think you and me are on the same boat..

shoot me a PM if you can

 

I'm about to call Vortech and Nachi and see what they say. DO NOT GO CERAMIC!! I have had a couple engineers say that a bearing failure would be catastrophic to the SC...although so could metal, but basically they said it's not worth the expense for them.

550? you must be lookin at superchargerrebuild.com - I have a call into them to see what manufacturer they use.

Do a google search for for Vortech rebuild. there is a great PDF on it. Make sure you find the one with the appendix for the V2, since it will have the info for the different part numbers.

 

what a joke it was pointless to call vortech. They wouldn't even let me talk to one of their engineers. LOL!!! he said I was more than welcome to rebuild the S/C myself - thanks vortech - oh and they hardly see any bearing failures...less than 1% of all S/C...and he has never seen a rev-up 350z blown bearing...well they have seen mine 3 TIMES!!! he said all the bearing failures they have seen are due to overspinning the S/C haha I said that is because they use 42k bearings

vortech if you are on here please speak up as to why you use 42k rpm bearings for a 53k rpm supercharger...my guess is COST

 

Its because they are a bunch of dur da durs.

 

Good info!!!!

 

called Nachi tech services got vmail...waiting for a call back

 

without looking to closely, bearings are rated based on L10 life at a certain RPM.

The bearing in the vortec you are looking at is rated at that RPM which does not mean the bearing is incapable of handling higher RPM. It just means that as RPM increases, expected bearing life decreases.

here is the equation:

L10=((60*Lr*Nr)/(60*Nd))*(C10/Fe)^a
a for ball bearings is 3
Fe is the equivalent load based on axial and radial loads
C10 is a specific load for a bearing based on bore diameter.

60*Lr*Nr is usually 10^6 and based on how a manufacture tests their bearings. SKF bearings are generally 10^6. Nd is the operating RPM. L10 life means this: 90% of bearings show no signs of wear during this period.

So, you operate the bearing at more than rated operating RPM, L10 life goes down. Obviously, with a supercharger, you are operating all over the place. So the brief periods when you do operate higher than rated operating RPM hardly make an impact on the bearing life.


I dunno. I am probably wrong. I am not saying you are wrong but just saying that the bearings are not failing because they are being forced to spin too fast. I think they are failing because load is being put on the bearings that they are not rated to handle. If you look in the formula, if you decrease Fe which is the equivalent load, the bearing life goes up drastically. Conversely, if you increase equivalent load, the bearing life goes down ^1/3!

 

um yeah that went over my head. you must be an engineer

I received a call back from Nachi and he said the 7003c bearings they supply to vortech are 61k RPM and what I see on their site isn't right. He said the cage probably broke from heat. I never saw the oil temp go over 260 and that was peak for only for a couple mins. Oil temp is normally around 230. The tech at SKF said 260 was fine...

Anyway I already planned on putting an oil cooler in. I'm still going to go with the SKF bearings and see what happens.

 

Well that of that was just to say, we might not be seeing the whole picture on their website. I just happened to do a little studying on ball bearings recently.

Try the SKF bearing. Obviously, something isn't working with the Nachi bearings.

 

Looks like you jumped the gun and got owned.

Vortech is on this site and I am sure that they will post if they feel that your thread is worth responding to.

Your first fault was calling up a company and expecting them to give you information on parts and services that they sell so you can bypass them.

Either way I hope that you get a better bearing and stop blowing your blower. I would consider checking the quality of your case and shafts in order to see if there is any reason for them to create additional heat and wear to the bearings.

 

I've been doing some more research about the cage material used in these bearings based on the fact that I may not be over spinning the bearings and heat may be the problem. I haven't been able to find exact peak operating temperatures for Phenolic resin, but I did find this from the SKF site:

Polyetheretherketone (PEEK)
The use of the glass fibre reinforced PEEK for cages has become common within SKF for demanding conditions regarding high speeds, chemical attack or high temperatures. The exceptional properties of PEEK are superior combination of strength and flexibility, high operating temperature range, high chemical and wear resistance and good processability. Due to these outstanding features, PEEK cages are available as standard for some ball and cylindrical roller bearings, like hybrid and/or high-precision bearings. The material does not show signs of ageing by temperature and oil additives up to +200 °C. However, the maximum temperature for high-speed use is limited to +150 °C as this is the softening temperature of the polymer.

The SKF engineer I was talking to suggested I look into PEEK, but they currently don't make a PEEK cage for the 7003 series. According to the documentation above if the max temp for high-speed use is 302 degrees Fahrenheit and it's use is for high temp applications I could assume the Phenolic is not standing up to the current temperature it's seeing. If my oil temp reading is 260 after spirited driving, the bearing temp is probably much higher than that.

BTW quamen thanks for the useless contribution

 

you know I wouldn't have "jumped the gun" if Vortech would have let me speak to one of their engineers. Anyway, I'm still not convinced the Nachi bearings are rated for more than 42k RPM. I will go with what I see written in documentation before what someone tells me over the phone. Ever heard of CYA?

 

ya but you are running a 34/28t combo as per your sig (not the stock as you are using for your calcs). even with a 3.12 pulley you are WAYY over the limits if you have kept the stock redline. the extra amount of heat and the high rpms could easily cook those bearings.

just get some hi speed skf's like you mentioned and dont worry about it again

 

Well seeing as how I am an engineer and I also design supercharger kits and rebuild superchargers part time I can fully understand why they wouldn't waste their engineers time.

Your comment in red is exact proof of why sales men are not allowed to connect people to engineers for the most part. Even though Nachi specifically told you the bearing can handle 61,000rpm's you still don't believe them.

You wanted hard data and the manufacturer of the bearing gave it to. The information they gave you even proved that Vortech was in fact being conservative on their bearing limit. Yet you still won't believe they can handle above 42,000 rpm's.

There are a number of reasons beyond what you have mentioned that could be the cause. Is the impeller out of balance for whatever reason? Is the shaft have axial play in it? Is the case where the bearings sit worn out? Are the alignment dowel pins between the two halves of the case in good condition? Do the dowel pin holes on the back side of the case have run-out?

Any of these reason could easily increase vibration and destroy a bearing. Not to say that Vortech shouldn't be checking all of this stuff when they do a rebuild but I don't see how you can be the exception for repeated bearing failure unless there is something else being overlooked.

The reason that Vortech advertises 53,000rpm's for their blowers is related to the fact that the tips of the impellers want to break off shortly there after, the impellers are not balanced to a much higher rpm, and as a margin of safety. Ever heard of CYA?

 

you are correct. I was comparing stock ratings. When I redline I am at 58k RPM. BTW My previous failures where with the stock setup.

question...does anybody know why the S/C is only rated for 53K RPM if the high-speed bearings are rated for 61K (if what the Nachi guy said is correct). Would it be be due to the impeller?

never mind...quamen answered my question above

 

hey man don't take it personal see this is informative!!! thank you very much.

Last time the S/C was sent to vortech they replaced all of the internals - impeller, gears, bearings and seals.

 

do you have a suggestion for my situation?

1. Do I try different manufacturer's bearings possibly with a peek cage and risk another failure?

2. Do I talk to vortech and see if they have another head unit that would be better suited for my setup?

3. In either case should I add an oil cooler?

thoughts? thanks for your help