hummer portals

[Ark]

What are the specs for the helical hummer portal boxes? I'm curious what gear sizes the hummers use eg. width, diameter, tooth # ect. It seems like they are pretty small gears to handle the 520 ft/lb and 37 inch tires on the 05 alpha. I've looked around for this information and haven't been able to turn anything up. Thanks everyone.

[crusty1007]

X2 any pics?

[hmcoleap]

I don't have the specs on hand, but I can tell you they are pretty bulletproof -- I have never heard of anyone exploding them. I have wheeled very hard for over 145k in my H1, and done nothing but change the gear oil in the portals periodically -- no problems. During that same time frame I have grenaded a t-case, toasted two transmissions, broken about a dozen half-shafts and CV joints, peeled the tubing on a rear prop shaft in half, broken two alloy wheels and bent a few steel ones. The geared hubs never flinched, though, beyond leaking a little at the seals.

In a couple of rare instances reported where a spindle broke loose due to a defect in materials, causing a lost wheel/tire on the highway. (read: very bad)

[hmcoleap]

Cut-away picture of portal hub that I took last summer in South Bend attached - this one has the straight cut gears rather than the helicals -- reportedly the helicals are "quieter" without a significant loss of strength:

[Ark]

Thanks, that's a pretty sweet pic. I guess I'm not so worried about breaking the portals. I've heard they're pretty bullet-proof and wanted to know why. The amount of stress that they can handle is impressive. I'm interested in doing a project that will have forces similar to what the portals experience and the specifications would give me a good baseline to work off of.

I did find an interesting website in the meantime that does have some specs on their portals. Here it is.


http://www.marks4wd.com/products/gearmaster/Nissan%20Portals/Nissan%20Portal%20History.htm

[hmcoleap]

Wow, very cool custom portals there...

Thanks, that's a pretty sweet pic. I guess I'm not so worried about breaking the portals. I've heard they're pretty bullet-proof and wanted to know why. The amount of stress that they can handle is impressive. I'm interested in doing a project that will have forces similar to what the portals experience and the specifications would give me a good baseline to work off of.

I did find an interesting website in the meantime that does have some specs on their portals. Here it is.


http://www.marks4wd.com/products/gearmaster/Nissan%20Portals/Nissan%20Portal%20History.htm

[Flint_Jeff]

HMMWV A2 Upper Gear Data Courtesy of FLIS

MATERIAL - STEEL COMP 8620 OVERALL
MATERIAL DOCUMENT AND CLASSIFICATION - ASTM A322 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
TEETH QUANTITY - 13
PRESSURE ANGLE - 25.0000 DEGREES
PRECISION CLASSIFICATION - QUALITY NUMBER 6
STYLE DESIGNATOR - 4 PROTRUDING HUBS
PITCH DIAMETER - 2.6000 INCHES NOMINAL
NOMINAL OUTSIDE DIAMETER - 3.095 INCHES
FACE NOMINAL WIDTH - 1.880 INCHES
NOMINAL DISTANCE BETWEEN BODY FACE AND PROTRUDING HUB END - 0.930 INCHES BOTH ENDS
BORE STYLE - 6 INVOLUTE SPLINE BOTH ENDS, 14 W/COUNTERBORE COUNTERBORE, FIRST END, 14 W/COUNTERBORE COUNTER BORE, SECOND END
BORE NOMINAL DIAMETER - 1.4010 INCHES BOTH ENDS
SPLINE QUANTITY - 32 BOTH ENDS
SPLINE PITCH DIAMETER - 1.3333 INCHES NOMINAL BOTH ENDS
COUNTERBORE NOMINAL DEPTH - 0.930 INCHES COUNTERBORE, FIRST END, 0.390 INCHES COUNTER BORE, SECOND END
COUNTERBORE NOMINAL DIAMETER - 1.487 INCHES BOTH ENDS
HUB STYLE DESIGNATOR - 4A 1 STEP BOTH ENDS
END NOMINAL LENGTH - 0.870 INCHES BOTH ENDS
END NOMINAL DIAMETER - 2.000 INCHES BOTH ENDS
FIRST STEP NOMINAL LENGTH - 0.060 INCHES BOTH ENDS
FIRST STEP NOMINAL DIAMETER - 2.500 INCHES BOTH ENDS
BODY STYLE - 1 PLAIN, SOLID
III END ITEM IDENTIFICATION - TRUCK, VEHICLE, SYSTEM, 1 1/4-TON (HMMWV)

Lower Gear Data

MATERIAL - STEEL COMP 4320 BODY
MATERIAL DOCUMENT AND CLASSIFICATION - ASTM A322 COMP 432 ASSN STD SINGLE MATERIAL RESPONSE BODY
TEETH QUANTITY - 25
PRESSURE ANGLE - 25.0000 DEGREES
STYLE DESIGNATOR - 6 FLUSH HUBS
PITCH DIAMETER - 5.0000 INCHES NOMINAL
NOMINAL OUTSIDE DIAMETER - 5.395 INCHES
FACE NOMINAL WIDTH - 1.736 INCHES
BORE STYLE - 6 INVOLUTE SPLINE BOTH ENDS
BORE NOMINAL DIAMETER - 1.984 INCHES BOTH ENDS
SPLINE QUANTITY - 46 BOTH ENDS
SPLINE PITCH DIAMETER - 1.9167 INCHES NOMINAL BOTH ENDS
HUB STYLE DESIGNATOR - 1 PLAIN BOTH ENDS
HUB NOMINAL DIAMETER - 2.500 INCHES BOTH ENDS

[Jeepocabra]

helical gears are stronger not weaker. The cut pattern creates more contact area on each gear. Thats why ring and pinion gears in solid axels are cut that way.

[hmcoleap]

Helicals providing more surface area in a Ring and Pinion is a no brainer, due to the perpendicular arrangement of the gears... more to mesh. Are you positive the same holds true in a configuration like this where the gears are side by side? I would have expected a simple straight cut gear to be stronger.

[Ark]

It's my understanding that the helical gears themselves are indeed stronger than the straight cut gears, even in a side by side arrangement. However, the problem with helical gears comes from the fact that they cause a side loading when under torque. This isn't much of a problem in normal gear boxes but in portals, there is also side loading created from the vehicle being off-camber. Depending on trail conditions and use of throttle, these two forces could potentially combine causing a huge amount of stress on the portal housing.

[Ark]

Hey hmcoleap, how do I post a pic? Do I have to put it up somewhere else on the internet and link to it or can I get pirate to host it on their server?

Here you go

[Bebe]

I sent you a PM with my e-mail. Send it to me and I will post it for you.

[Jeepocabra]

Side loading on the gears wont be a problem if your timkin bearings are in good shape. If you jack up one tire, grab it top and bottom and try to move it. It should not be loose if it is, you got problems

[Ark]

I wasn't really talking about a side loading on the gears. It's more of a problem with side loading on the portal housing itself. The gears transfer the loading that they create through the bearings and into the housing. This housing already has a loading just from the weight of the vehicle on side-hills since it is off-center from the axle. The portal box has to handle both of these loadings. Straight cut gears wouldn't add this secondary side loading to the box like helical gears do.

[DaveCheviot]

Hey guys I know this is an old thread but has anyone got ideas where I can get a set of dropboxes from, I'm not bothered where it is as I'll need to get them shipped to the UK anyway.

Cheers

[hmcoleap]

There aren't any cheap ones floating around anymore... Scot at http://www.sax-express.com can probably get you a set.

[GEN. DISASTER]

we may have a few left over scrap sets in our back pile. we used them for testing against our new boxes so they would probably need rebuilt. contact russ@portal-tek.com. he will know if they are still there

[uninformed]

in my opinion helical gears are not stronger.... yes each tooth is longer because its on an angle, but, by the nature of how they turn, the whole width of the tooth is not in contact, it rolls across the width...

straight cut roll but the whole width is in contact...

on top of that you have the side loading characteristics...

i looking at the 2 pics i would much prefer the straight cut gears... but both would probably be strong as f......

serg

[Guinness44]

The helical gears come with the Alpha. They definitely are less noisy. During braking less growling and rocking.

[ron b]

the rocking puts me to sleep at stop lights.

[JESSE_at_TLT]

I'm researching parts for this project (http://race-dezert.com/forum/showthread.php?t=33846) and I'm considering using Hummer portals. I got interested in the Hummer parts after talking to Brad Falin, who races a Hummer-based Class 1 vehicle (http://bradleysraceworks.com/gallery.htm). He also built and prepped a few of the stock-full desert racing Hummers back when they were racing those too. He told me that parts availability wasn't a problem and that there were a lot of used parts around. He said we should be able to get four portal boxes, CV's and both diffs for around $1000 (used). I didn't really look int it much further than that, but the other day I was talking to Tech-Tim about it and he told me that the used parts market was dying-up. He also said that the Miltiary was going to stop supplying the civilian market with complete surplus parts because the portal boxes had been deemed unsafe or something like that. I started wondering whether Brad's information might be a little outdated, or whether he might be finding better deals than the average bear.

So I spent a few hours this morning looking into the availability and pricing of these parts and it's not looking good. Kascar's prices were outrageous. Scott at www.sax-express.com told me that used portal boxes are hit-and-miss. He can get the helical-cut Alpha portals for about $700-800 each (new, complete), which seemed reasonable but he doesn't expect the supply to continue seeing as they only made those models for one year. He said the straight-cut portal hubs run about $1300 each (new, complete).

It would be rad to use Hummer portals, but don't want to design the whole front-end of a vehicle around parts that might be hard for people to find, or too expensive to purchase in the future.

Would appreciate any input that will help me make a decision about whether or not to go this route.

[Guinness44]

Are you building a racer or a crawler?

[JESSE_at_TLT]

Something about as in-between the two as possible. Still early in the design phase, but you can read about the project here (http://race-dezert.com/forum/showthread.php?t=33846).

[Tech Tim]

Yeah, it's old, but since it's been drug back up I'll jump on. :D

in my opinion helical gears are not stronger.... yes each tooth is longer because its on an angle, but, by the nature of how they turn, the whole width of the tooth is not in contact, it rolls across the width...

straight cut roll but the whole width is in contact...
serg

I've heard the strength argument both way. Some will say that with a helical gear, it is true that the whole of any one tooth is not in contact, however due to the helix, there there is tooth contact at all times with a helical cut gear than with a straight cut gear. Hmmm we need a gear engineer to chime in on this.... where 's Bongard when we need him?

Of course we need to ask that if this was only offered 1 year, was it due to a strength issue or a cost cutting issue?

[ron b]

the links you posted are interesting -- very cool build. As far as the geared hubs -- I don't imagine you'll need to be replacing them (maybe some components?) so if you had 6 that should last you. They are tough as shiite (cast steel) and I've never (though I haven't done a search on the hml yet) heard of a well maintained one having issues. Just gotta find out how long AMG's humvee contract is and that's at least how long they'll be making them.

[Guinness44]

Cool project. At 4000 lbs, the geared hubs are desinged for at least 2 1/2 that much. To keep them reliable, peek under there a LOT to check for leaks. We RnR the oil every 12K miles (using Lucas 80/90), and check level and fluidcolour every 3K miles.
The helical hubs were designed for the Alpha, to make it more quiet, less rocky.

[JESSE_at_TLT]

Thanks. I'm not really concerned about finding one set of parts. I'm pretty good at sniffinf out deals. I'm more interested in ensuring that oter people will be able to find these parts at reasonable prices. That's the whole point of this project; to distribute the blueprints (for free) and encourage other people to build these things. So I want to make an effort to design the vehicle around parts that are 1) available, and 2) somewhat reasonably priced.

I've read that portal boxes have failed in some cases because of the side-loading effect of the helical gears. Scott at Sax-Express confirmed that. Either way, doesn't really matter to me because the dimensions are the same between them so they're interchangable. I'd probably just go with whatever I could find the best deal on, as I'm only planning on putting a turbocharged Toyota 4-cylinder in my truggy (the drivetrain shoud hold-up to a healthy V8 though).

Can anybody tell me what type of prices you're paying for used parts?

[Tech Tim]

Hmmm we need a gear engineer to chime in on this.... where 's Bongard when we need him?

Got a Skype messange from Mr. gear engineer:


Straight cut or Helical, Which is stronger and why?
TL says: Obviously it is a loaded question that needs better detail to answer correctly, but in general which would be stronger.

DB says: Go helical.
Technically straight cut are stronger during part of the rotation and weaker during the other, where as helical are generally even throughout the rotation. If you had to qualify it as an average you would actually say that the straight cut are stronger...but that still doesn't eliminate the weak spot. But if straight is all you can get I don't think there it would matter much. Unless you need quiet...then go helical all the way. Oh, and if you go helical you need axial support as they impose small side loads on each other.

[JESSE_at_TLT]

Tim, please thank him for his input. I've already decided that if we end up using Hummer portals, I'm going to buy the helical ones. Half the price and less backlash.

[bartonman]

I have three of the 10,300 pound GVW portals or geared hubs (whatever you would like to call them) along with the halfshafts. I upgraded mine to the 12,000 pounds units that are the helical ones. If anyone is interested in buying these from me email me. These DO need to be rebuilt but it is not hard to do yourself. All the bearings can be bought from KASCAR for pretty cheap or Bluehummer.com.

Email: kennyj@ittbarton.com

[600dollarXJ]

helical gears are stronger not weaker. The cut pattern creates more contact area on each gear. Thats why ring and pinion gears in solid axels are cut that way.

helical gears turn the line loading on the gear into a point loading and are weaker. Think about applying 500 lbs to a square foot, to a line a foot long, or to the end of a pencil.

ring and pinion axle gears are cut like this to change the axis in which the power is being transmitted, and most conventional rinion and pinions geometries are much more complex than just helical, its called a hypoid gear. The pinion is offset so that it can be larger and have more contact area.

http://en.wikipedia.org/wiki/Gear