My 6-71 Blower rebuild, Part 14: Final assembly.
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- Опубликовано: 27 авг 2024
- ***Added detail that was not captured on Video***: I lightly lubricated the Neoprene seal surfaces with Silicone based grease. When I checked one of the standard Chemical Compatibility charts, www.coleparmer..., I saw that Grease has a "Poor" rating which means that it is absolutely NOT compatible with Neoprene. I played it safe and used Silicone to lube the seal areas.
Final assembly actually goes pretty quickly if all of the work leading up to assembly is done correctly. The only clearancing step left for final assembly is rotor timing. Rotor timing as shown in the Detroit Diesel manual can be confusing with the “C” and “CC” clearance designations, and the two sets of diagrams, depending on which model engine and blower is being checked. I cut right to the chase and only showed the step where I checked for interference between the rotors as if they were being driven while they were in operation.
Machining off the back of the blower gears is typically described as a “race blower only” clearancing step, but I disagree with that. My passenger side gear shim that was on the blower when it was being run on a diesel, was in relatively rough shape, so this tells me that these shims have a tough life even in normal operation. It takes very little work to do it the right way, and select machine the gear shoulders to get the final clearance that I wanted, so there was little reason not to do it. In the end, the rotor timing exercise is pretty straightforward: If you want to decrease the clearance between the rotors, machine material off the drivers side gear. Machining .003 off the rear shoulder of the gear will tighten clearance between the two rotors by .001 of an inch.
There will be at least one more video remaining in this series, with the next one being the video of how (and why) I designed and machined the carb adapter plate out of a piece of Magnesium plate. I have an idea for a really cool sight glass to put into the triangle opening in the front cover, but haven’t decided for sure if I will do it. Stay tuned to see where I go with that.
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Disclaimer: This video series is not intended to be an exhaustive “How to do it” tutorial on how to rebuild a 6-71 blower for Gasoline use. Rather, it is meant to be a “How I did it” journal of one of many projects that I undertake in my home workshop, using hobbyist equipment and methods. If you attempt to duplicate any of these methods, you do so at your own risk. Therefore, I will not be held liable for any incidental or consequential damages as a result of trying to duplicate these methods.
Sources for clearances and tear down/assembly details referenced the Detroit Diesel assembly manual, with additional details referenced from the SA Design book “A Do-it-yourself guide to: Street Supercharging” by Pat Ganahl, ISBN 0-931472-17-2. If you are not an experienced mechanic/machinist, do not attempt to replicate this work. Take your Blower to a professional Blower builder.
On my aluminum carb adapter I cut it out on my table saw with a carbide blade. For the square openings for the carbs I used a hole saw for the round corners, then I cut the center out with my hand held Jig saw. On the side of the carb adapter for linkage clearance first I drill holes for round corners then I finished cutting out the indentations on my band saw. To smooth out all the saw cuts I used my table router and carefully guiding the adapter by hand then I cleaned it up with a file. I polished it to a brilliant shine with 2500 wet sandpaper and counter sunk the bolt holes. I needed a 1/2" adapter to keep this 8-71 and carbs under the hood of my 56 Caddy with a 500 cid. I have a 1 1/2" clearance under the hood for affixing side mounted air cleaners. I'm so happy.
After assembling a few of these I learned that if you bevel the leading edge of the seal surface with a fine lathe file then polish it theres no need for seal protectors and the bearings can be pressed in on a surface with support rather than tapping them in after with only the case supporting it. Sometimes they go in really tight especially on some of the after market plates I have purchased. Your able to check and make sure bearings are still smooth before pressed on rotor as well. Cheers love these videos
Very Nice Job On Your Videos,I’ve Watched Them All On The 6-71 Build !!!
Nice job. I may have missed installing dowel,pins and relocating them to adjust top and bottom clearances . A number of ways to do this and repairing over size or wallowed out holes was done in the early days. At times it was a tricky operation.as you might only have to move holes a few thousandths of an inch. I made a separate end plate with hard bushings fo guiding drills or readers. Occasionally a hole could get deformed and it became very difficult to over size or drill and ream for a repair bushing. Having a milling machine and boring head made life much easier. It still took precision work to do correctly. A bad backfire or motor explosion could distort the cas so that meant a new unit. These used to be available for 50-100 bucks in good shape an sometime you could find a near new one that’s had many hours on it but very clean air cleaners so they might be near perfect inside. I had several streetrods I drove for years an I built several more for other guys. We ran these on top fuel dragsters and top gas cars then top alsohol funny cars. Noe most of these are billet construction so perfect when new. They usually have nylatron strips in the seal areas and depend on the fuel for a bit of cooling and lubrication. No fees are very good but better than none.
Very cool stories from the golden days of drag racing. Yes, the dowel pin part of the project is outlined in the part 13 video, here: ruclips.net/video/Ke2DrtZA4g0/видео.html
here's a shortcut to c and cc clearance adjustment. no need to push the gears on several times. even with new parts. start both gears on the shaft. tap them sufficiently to prevent them falling off. measure the c and cc, tap one gear or the other until proper clearance is achieved. now take the depth mic or calipers, measure the difference in height from one gear to the other gear. that's how much shim to add. do not ask how i figured this out. (hanging head in shame it took so long).
Thanks for this tip! It’s so simple and makes perfect sense! Why didn’t I think of it?! I’m in the process of converting my first 6-71 and will definitely do this.
Hopefully I can get mine to work. Appreciate all the videos
Great job I used to rebuild blowers injectors all the gm diesel years ago
So did I but I advise not using handle to stop it turning and to use a rag as Detroit recommend as you can cause deformation to rotor with localized pressure, also rotor clearance is an issue if not running fuel thru it as temperature of rotor alters dimension as can be verified by different spec for turbo application FWIW
Detroit Diesel sells over size shaft sleeves and Teflon seals, plus the tools to install both. Blowers are simple to rebuild just pay close attention to clearances and shims behind drive gears. Never seen anyone cut the backside of the gears always used shims. good luck sir
I was fascinated by this video :)
Great information thank you ever so much
I called Dyers several times with no answer, emailed them stating that I intended to buy an 8-71 kit from them and never got any response. Called BDS and got a far superior blower for just a little more money and it arrived in a week. Dyers can pound sand.
What a shame that Dyers appears to have gone downhill in recent years. They used to be the go-to guys in the Midwest, but I guess any business can decline over time. Hope that you get great results with your kit from Blower Drive Service.
Bob the builder. Good job!!
what an amazing job!
Thank your video
Where can I find blower specifications like the ones I see you have? Is there a website to find them? Thanks
Am watching your video to help with my project. It's my first time dealing with a blower. Put oil in the tank and it leaked out right away. Pulled it apart and when pulling the gears, a bunch of the shims dropped out. Don't know which side they go on. How can I fix that? Thanks in advance, Bill
Bill: Choose a side at random and re-install all of the shims on that side behind the drive gear. Then start watching the video at this spot: ruclips.net/video/T-lCAhEyZdU/видео.html and go through the rotor timing step. If you have the shims on the wrong side the measurements will be WAY off, and you will know to switch the shims to the other side. You may have to get a shim pack and slightly change what you already have, but usually the stock Detroit Diesel shims at least get you close. Good luck with your build!
Your vid has been a great help for me rebuilding my 671! Thank you! One thing I noticed on the positioning of rotors you are showing blank spline at 3:00! My gears have two dots on one gear and one dot on the other! I'm presuming those dots should be lined up rather then the 3:00 position you showed? It's the same thing I think just 1/3 trun off gets my dots lined up! Hope it's right!
What is the size of the shaft seals without the shaft sleeves? Thanks :)
Q: why can we not use the shims on a petrol application? Will they burn out? Changing rotor timing? Also I don't have a lathe and am miles from civilization. I am thinking of using a sheet metal plate 0.8-1.2mm thick to space the rotor ends from the end plate for grow room. Kina like a thick gasket but between the housing and endplate.
If it is not a racing application, I would not hesitate to use the shims to time the rotors. I only machined the back of my gears to time the rotors because I have all of the proper equipment to do so, and then next time I tear the blower down, I don't have to worry about juggling shims. You do not need to put any shim stock or gaskets between the end plates and the blower case. The two existing flat surfaces seal fine as they are with only a light coat of sealer. As long as the end clearance is correct, that provides all the room for heat growth that you need. Good luck getting your blower together!
Great video.
How can I know the clearance required for a Busch pump WP500 D?
Hello, recently discovered this video while trying to rebuild my own whipple supercharger. Do you have any suggestions on how to determine how much rotor timing/clearance I should have? Factory won't get back to me with this information. My whipple S/C has a ring gear on the one rotor with 6 bolts that can be loosened so you can adjust the clearance without removing the entire hub. My current thought process was with a dial indicator mounted to the hub to just put it in the middle of the clearance, is it this simple or are there specific tolerances? Any suggestions would be appreciated.
On my shaft seals (front bearing plate) one side is flat and the other has a recessed lip. What direction does the seal go? Your video appears to show the flat side faces the rotor. ??
Can you tell me what the case numbers are on that large bore case
Eaton has no manuals for this, guess they viewed it as a throw away after bearings and or seals wear out
I don’t see any adjusting washer or spring to adjust the distance between side plate and rotor? Pretty sure the side plate and rotor might rubbing each other because of the axial movement of the rotor when spinning.
Yes, your right, it does look like that at first glance. Go to the 10:00 minute mark in the video. Do you see those round plates with the three screws in them? They trap the bearing firmly in the bearing plate so the bearing cannot move axially at all. The front rotor stub shaft has a shoulder on it which is pulled up tight against the back of the bearing when the gears are tightened down. You can see that at 15:00 in the video. The gears keep the rotor from being able to walk backwards in relation to the bearing plate. This locks the rotor axially into the bearing, so everything stays positively located, and the axial clearance (end clearance) between the front face of the rotor, and the inside face of the bearing plate is maintained. Yes, everything grows a little bit as the case heats up while running, but the rear bearings CAN slip on the rear rotor stub shafts, so that allows things to move just a tiny bit with heat, instead of binding. Hope this explanation makes sense. Thanks for watching!
Awesome work! I really like all the tools you made for this job. would you be interested in doing a blower for me if I shipped it to you? It is actually a 471 that I am putting on a flathead ford in a 32 roadster
Unfortunately, the demands of my Corporate job don't allow me to take in outside work. However, the guys at Dyers Blowers in Chicago IL have been very helpful to me in the past. They are one of the best professional blower builders out there and you could send your unit into them for rebuild. You can call them at 708-496-8100. Their website is www.dyersblowers.com. Thanks for watching!
@@MakerCave Thanks, And your right about Dyers. I know Bill Dyer, He has Done some 671s for me in the past and I have bought a few units from him and sold him some cores before they started casting there own complete units. The thing that impressed me about your video was your attention to perfection. I have not messed with blowers in about 9 years, As Going Fast just isn't what it once was for me anymore. I have been playing with flathead fords and am looking to get 275HP out of one. Not gonna beat any mustangs on the street, But it will be cool as hell...I picked this 471 up on craigslist off a dozer for $100 and will probably just send it to Bill and have him convert it for me. Thanks for the reply and again good job on the build and tools you made to do it.
@@sophiagoucher3087 Thanks! I absolutely love the look of a flattie with an old ScOT or Jimmy 4-71 on them, especially the ones that use the multi V-belt drives, like they did in the early 50's. I bet that yours turns out awesome!
Have Ben searching for a month now, the shops that do it, are holding the knowledge, to fill their wallets.
Sir please tell me detail 2 lops timings sittings please
on using detroit blowers , do the gears need be upgraded or just reclearanced? does the rear housing have to be after market? before i even start attempting a rebuild is there a parts list i need to start out with? love your videos, keep up the good work.
Stock gears are just fine for a street blower. It is best to use an aftermarket rear bearing plate. If you are going to go through the time to set clearances, best to do it with a good plate. You can purchase rebuild parts from www.dyersblowers.com. Thanks for watching!
I have blower Gordon Denver ti408 can u rebuilt for me and how much. What’s your Location .?
Hello, how are you, very good and well explained videos, I ask you a question, what code do the bearings on the front and back plates have?
Thank you!!
Great series, I watched them all!
My (6-71) blower front cover came with a manual pressure relief valve and a sight glass (not installed and no instructions). Is there a specific location for those?
Thanks for posting.
It's hard to describe in text, "keep the oil level a little above the bottom screw in the triangle cover" so just look at this very nice video from The Blower Shop. They show it visually which is easier to understand. The vent can go high up on the front cover, well above the oil level. You can also see that in their video. Thanks!
ruclips.net/video/p-wMTv6XwRg/видео.html
@@MakerCave ok I'll check it out. Thanks for the reply!
I missed the end of this video before apparently... Will that carb adapter allow 2 Holley double pumpers to fit without turning them sideways? It sure as hell looks like it would.
Double Pumpers (4150 style) with rear metering blocks will not fit on this custom plate. I spaced the centerlines of the carbs so that only a 4160 series carb with NO rear metering block will just fit, in only an inline configuration. I think that there is enough real estate to spread the spacing a little bit to fit a 4150 on this type of plate, and really all I would have to do is move things around in my 3D model which would only take about 5 minutes, and re-generate the G-code, to make a new variant of the plate. Thanks!
great video and explanation but i noticed you didn't remove the bearing seals. they looked like the metal shields
I did this project about two years ago, but I do recall the front bearings being open enough to be able to get gear lube from the gear case. On the rear bearings, some builders strip one seal and pack with additional grease, but I asked one of the guys at Dyers Blowers many years ago, and he said that they leave the seals intact and stay with the grease that is packed into the bearing from the factory. I did another blower like that 25 years ago, and it is still running fine on an old street rod all these years later, so the grease has held up for a long time now. Thanks for watching!
@@MakerCave cheers for the reply, i have 2 671 superchargers i will be setting up for chev engines do you know what the difference is between the housing with the 3 flush bars on the inlet side and the housing with the center bar flush and the two other bars about 3/16" below the surface
@@raymorrison919 Excellent projects you got going, Ray. The rounded inlet ribs are usually on Small Bore 6-71's and the flat machined ribs are on Large Bore 6-71's built up until the early 70's. I have heard that there are some blowers around the changeover time that are exceptions, but every 6-71 that I have handled over the years has been like this. I found this listing of bore diameters and displacements over on Offshoreonly.com and they seem to line up with what I recall from measurements I have taken in the past:
6:71 small diameter
Rotor dia=5.505", length=14.975", displacement per full turn of rotor=339CI.
6:71 big diameter
Rotor dia=5.778", length=14.975", displacement per full turn of rotor=411CI.
Good luck with your rebuilds!
@@MakerCave once again cheers for the reply. i think i will use the big diameter on the boat and the small diameter on the show car
Wow that’s a fantastic video. Any chance you want to rebuild a 6-71 Bowers Blower that’s similar to yours?
Thanks for watching, Chuck. Unfortunately I do have a full time corporate job that keeps me too busy to do hobby work for hire. However, check with Dyers Blowers out of Chicago. They do excellent work, and can get you taken care of.
the blower is pretty clean, how do you clean those gunk built up inside the housing and the lobe?
The diesel fuel/oil residue actually washes off very easy in an automotive parts washer. You could probably also use simple green, but I used regular petroleum based parts washer fluid in my parts washer.
thank you sir.
Would love to see what engine you’ve placed this on?
How did you go about fitting the belts etc?
Sorry about the letdown on not carrying this all the way through to implementation. Had some substantial interruptions that put this project on the back burner for a couple more years. Although the scope of the rebuild video series was just to show the conversion process, I did intend to wrap up the project showing it installed on the running large journal 327 chevy that is waiting for it. Hoping to still get to that once the other demands are clear.
Are the deep scratches I see inside the blower case anything to get worried about Or ?????
The scratches in my blower case look a lot worse on camera than they really are. However, if this was a race blower, as opposed to a low boost street blower, then a brand new case with no scratches would be best.
I’m going to try and rebuild one of my blowers that the shaft broke on I’ve tried finding new lobes online but I’m having trouble finding a place that sells them would you have website that you know of where I can look thanks and great video
Excellent. If your case is very good, then save it. Call Dyers Blowers in Chicago (Summit) Illinois at 708-496-8100. www.dyersblowers.com They should be able to fix you up with a new rotor, or rotors if both of your rotors were damaged when the stub shaft broke. They will want to know if you have a "Large Bore" 6-71 or a "Small Bore" blower. Tape measure the diameter of one rotor cavity in the case, from top to bottom. If I remember right, a small bore case is 5 1/2" and a large bore is 5 3/4" when checked with a tape measure. Good luck getting your blower together, and post back here if you can, to let everyone know how it works out!
@@MakerCave awesome thank you and I will definitely let you know it should be interesting and a challenge to do and yes I believe the case is good I’m sure I’ll have to do some rust removal on it it’s been sitting for a couple of years will know more once I dismantle it still worth a shot lol especially when a new one is over 4,000 👍
For the average guy like myself machining a blower rebuild kit isnt an option.
Why can’t someone do a video just like this for a TRD 3.4 Litre Suprcharger, or rather just an Eaton M62 supercharger rotor pack FRONT baring /seal change and assemble
would this fit in a miata :))))))))))))
Need to scrap that ole Indian head sch lack and use a nice anaerobic sealer for case's,, just my 2 cent's ;-)