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post #8 of Old 04-14-2006, 09:04 AM
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Originally Posted by Stang94GT
I'll edit the file and send it to Dedicated when I get a chance, probably in the next week or so. I've had about 4000 miles or so since the blower rebuild and so far no problems.

I used the "cone" to install the seal because it is spring loaded. Using only lube may cause the seal to bend or fold during installation. In fact, that's what I did when I put my blower back together the first time. After discovering that I had screwed the ID of the seal, I re-used the original seal with the installation sleeve.

If I recall correctly, the seals I used were identical (visually) to the seals that came out of the blower. Dedicated's seals may be better but I have no leakage issues to date. The leak I had was a misdiagnosed leak from my oil feed line.

I'm not in the bearing business so I don't know better. In what direction should the thrust bearings be situated? If anyone has some pics of these bearings and wouldn't mind emailing them to me I'll incorporate them into my writeup.

Curious, why would you use thrust bearings and then position them opposite of each other? I would think that you would experience thrust in only one direction and that the bearings would then be placed in the same direction. The only thrust loading that the high speed shaft sees is from the compressor wheel. On the low speed side, it would be from the belt. Does the low speed not use a thrust bearing as well?

The pics for the bearings are correctly labeled, text goes with the pics above them =P

If anyone's done a teardown of an SQ or of the 4.6l blower I'd appreciate some pics too. My email is [email protected].
I have the old high-speed bearings that I removed. I'll get some pics this weekend. They are clearly marked with part numbers that indicate an ABEC 7 precision angular contact bearing. They are also marked on one side with the word "thrust" This tells you which direction the bearing is designed to take thrust loads (note that all brands don’t bother to mark them because they assume that the installer knows what they are doing). These bearings are rated for 60,000 to 80,000 rpm (depending on the brand) with oil lubrication.

A single angular contact bearing cannot take any radial load at all. That is why they are mounted in pairs facing in opposite directions (sometimes facing each other, sometimes facing away from each other). When assembled in this fashion, together a pair will handle a significant amount of radial load plus the high thrust loads they are designed for. Regardless of what I say here, make sure you note the orientation of them on the shaft before they are removed so the new bearings can be installed correctly.

According to the SKF catalog the 6003JEM bearings that you used on the high-speed side are only rated for 18,000 max rpm with oil lubrication. It is designed to primarily take radial loads with only a small amount of thrust load allowed. That is why they are called “Radial” bearings. They are definitely not designed for a high-speed blower shaft spinning to 50,000 rpm!

The 6003JEM that you used might last a while on an occasional use car, or even a daily driver that never sees more that 3500-4000 rpm. However, they are on borrowed time regardless of how the car is driven. I would yank those bearings out of there quick!

The low-speed side of the blower will see much lower speeds and mostly radial loads from the belt pulling down on the pulley. The high-speed side will see a combination of thrust and radial loads. The radial load come from the gears trying to push apart from each other. The thrust loads come from the impeller trying to push it’s way out the side of the blower case.

I don’t like the seals you used for three reasons. First, they have an exposed metal case that can rust. The seals I used have a rubber-covered case that is sealed from the elements. Second, they put a green colored coating on the OD that is designed to scrape off when you install them to help seal against the housing. I wouldn’t want any of the crap to flake off during installation and get into the blower. Third, one of the seals you used has only a single lip for sealing against the shaft. I much prefer the double lip designs that seal much better.

I think you did a good job on your write-up. The pics are good and I love the drawings you did, they really look great. I just wanted to let everyone know that there were a few mistakes that needed to be corrected. Please don’t take any of this personally. I know folks who have been in the industry for years that still don’t get it.

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