A new thread on the rearend in my lakester.....

[1FATGMC]

Since the other post was about the bandsaw, buy migrated towards the lakester I've move discussion on it to a new post.

I appreciate all of the input and ideas you guys have presented and I'd like to go over a couple of them here.

unklian

On the spider gears,I think just greasing them should be fine.

I tend to agree, since in a week on the salt the car probably wouldn't go a total of 50 miles if I'm lucky and most of those miles would be towed at 25 mph and in a straight line.

unklian

You can split your driven sprockets in half,like to Karting guys do,
so it will be ALOT faster to change gears.

I looked into that, but a tech guy at a large motorcycle sprocket place said he wouldn't recommend that with the HP I'll be putting out.  I'm starting with a 36 tooth rear sprocket and can run 14 teeth to 18 teeth front sprockets.  With a 14 in the front 12,500 rpm in 6th gives 167 mph.  With the 18 tooth sprocket 12,500 gives 217 mph.  The 15, 16 and 17 tooth sprockets all up the mph in about 15 mph increments at 12,500.  The stock bike (Suzuki GSX-R 750 runs about 175 mph at 12,500).  

GPster this also applies to your comments.  thanks.

unklian

Don't forget,you will need some method of adjusting chain tension.
A idler sprocket would work,but reliability is a concern.Adjustable motor mounts would be my choice.Build them with more adjustment,
front to back,than you think you will need.

   

I mostly will use an idler sprocket like Rick Yacoucci  uses on his 330 mph motorcyle powered streamliner.  I considered moving the motor, but later with the turbo, intercooler and all of that along with control lines I think that would be more complicated.  I'm going to look into maybe moving the center section of the rear.  I need to see where it would sit, front to back, with the large countershaft sprocket and  where it would sit with the small countershaft sprocket.  If this distance isn't too much and doesn't put the 1/2 shafts at too much of an angle in these two locations this might work.  Here is a picture of what they did with the Rice Vigeant lakester.

 

Quote from them:
 

The rear suspension was made from a design we "borrowed" from another team in our club.  Our old car had to be adjusted by prying back the axle, a stuffing shims under the bearings.  We knew it was something we had to change.  After looking at several of the small, chain driven cars that race at Bonneville and El Mirage, we thought we knew what we wanted.  The we saw Brant & Wright.  The design of their rear axle was far superior to anything else we had seen, so we adapted the idea for our car.

Leon

To lock the rear you may want to drill and tap a holes behind the two idler spider gears and screw a bolt into each so the end of the bolt that has been turned down to a round post screws into a hole in the gear. That way to go back to an open rear you would just remove the two bolts.

Interesting idea.  I'll look into it.  I've looked at some tabs that would be forced into the gear teeth, that I could also remove.

C9

Are you running a late diff?
If so, mini-spools don't cost much.

I looked for full spools and mini-spools for the Datsun Z rearend with no luck.  I would still consider a mini-spool if I could find one.

purplepickup

I think welding would distort the gear bores enough that you might not be able to assemble or disassemble the shaft/gear assemblies.

I worry about that also.  I'm not messing with the one good set of spider gears I do have.  I would love to find another set, but so far no luck on e-bay or elsewhere.  If I could find another set I think I would try just welding up a couple teeth on them like Ian said.

slocrow

Sum; If I remember correctly, those two tooth locking spiders were available years ago and were made of bronze or brass. Maybe you can still find them through e-bay or google.....Frank

If I try to make some they would be out of billet aluminum.  Hope that will work for what I'm trying to accomplish.

unklian

I understand there are guys now running modified automotive differentials like you show,open with no cover.

I'd like to see pictures of those.  Legend and dwarft and some others use a narrowed Toyota rear in their cars, but drive it with a driveshaft coming off off the motorcycle motor's countershaft that is sideways in the car.

Well anyway thanks for all the great input guys.   I'm trying to add another page to the construction today if I get time.  It is on the outer hubs for the IRS.

c ya, Sum

[unklian]

If the bores distorted after welding the spiders,
they could be honed to get the size back.

The cars we used to race were callled "Formula 4",so you might be able to search for something like that.Formula 440 is different.Our car was chain drive,with a locked axle.The axle center section was a piece of precision ground shaft with keyways cut in it for the U-joints,disc brake hub,and drive sprocket hub.The axle ran on a couple flange bearings,chain tension was adjusted by moving the flange bearings.

One inovation we did,remember this was 20 years ago,was using an aircraft push-pull cable to operate the shifter.All the other cars in the class ran a solid linkage on the left side,because all the bike shifters are on the left.Awkward,and ugly.We ran a push-pull cable from the shifter on the left,forward under the gas tank where it snaked over to the right.The shifter lever was to the right of the steering wheel.
EVERYONE said it would not work,never had a problem with it.

[sirstude]

Sum,

Ican't remember, but you are using some kind of Datsun rear aren't you?  What spider's fit?

Doug

[1FATGMC]

Sum,

Ican't remember, but you are using some kind of Datsun rear aren't you?  What spider's fit?

Doug

It is out of a Datsun 240Z, but as far as I can tell they used the same rear in the 260 and 280 from 1969 through 1978.  If you find any let me know. Thanks


Ian the following is a picture of another rearend I got from the same guy I got the Datsun rear from ($100 for both setups plus front hubs, and disc brake rotors and calipers).  He used it in some kind of motorcyle powered sports car that he raced.  There were some elements of it that I was suspisious of, the middle coupling, the sprocket mounting, the biscut u-joints on the inside of the 1/2 shafts and the small u-joints on the outside of the 1/2 shafts.  It was also going to be harder for me to get wheels made for the salt with the 6 on 5 inch bolt pattern and the studs were only 7/16 and the way I read the rule book I think I need 1/2 studs min.  I think the datsun rear and 1/2 shafts are much stonger.  Also the carrier on the datsun only weighs about 10 lb.

c ya, Sum

[GPster]

I sometimes work with just images of my memory of things but, on the locking of the differential: If you took a spare spider gear and filled the groove between the teeth at 90 degree intervels could you not put it in place in the axel and spiders and lock it from turning? That way you would not be welding on a stressed piece but on a plug fixture. You could do it to two and put them in from both sidesand hold them in with a cover over the differential casting. GPster

[unklian]

Here is the bike chassis I mentioned earlier,from Kosman.net





More here:
http://www.kosman.net/gucci3_gallery.htm

[1FATGMC]

I sometimes work with just images of my memory of things but, on the locking of the differential: If you took a spare spider gear and filled the groove between the teeth at 90 degree intervels could you not put it in place in the axel and spiders and lock it from turning? That way you would not be welding on a stressed piece but on a plug fixture. You could do it to two and put them in from both sidesand hold them in with a cover over the differential casting. GPster

First thanks Ian for the bike picture.  That looks like a nice set-up.

GPster here is a closeup of the carrier.  I think you and I are thinking along parallel lines, scary, but with a different approach.  First if I can get another pair of spiders I think welding between a couple of their teeth on each side of where they engage the side gears (don't know what they are called) would be the easiest.  I could then quickly change back and forth if needed to the non-welded gears to either have an "open" or "locked" rear.

 

I think what you are saying is put another set of welded spiders in at 90 degrees to the ones that are already there.

What I can envision is a set of fork like pieces that would press down on the teeth of either the side gears or spider gears at points on the gears oposite each other (see arrows in picture).  In the picture the gears are not rotated to the best location to do this.  The fork like pieces would come out of the open center and be held in with a piece of strap that would wrap around the whole center. This could all be removed at any time to return the rear to normal.  They would also be on the opposite side of the carrier.  I guess I don't know how much pressure there would be on these areas while cornering.  Going striaght there is none.

Just a note: this is a pretty small rear carrier, only about 5 inches in dia. for the center of it.

Like I said I just need to find a spare set of spider gears.  I should be able to do that given time.  

c ya, Sum

[sirstude]

Sum,

I know the yard out here has several Zcars.  I will check with them next time I get out there.  I have dinner with the owner every Wednesday (Cruise Night) and if I don't get there before then I will put the bug in his ear.

Doug

[Sean]

Back in the day (around here anyway), the trick for welding an open rearend and making it last awhile was to wedge pieces of keystock into the spiders, then Braze over them. This lasted a lot longer than stick welding them together.

Don't know that that helps you any, I just happened to remember doing it a few times...

[enjenjo]

You happen to know what the spline count on the axles is? I'm having a brain storm. Just for giggles, see if it's the same as the pinion yoke spline.

If the spline is the same on the pinion shaft, and often they are, you could make a mini spool by machining the yoke to fit in place of the side gear on one side, machining a second yoke for the other side. you would need to machine the Ujoint side of the yokes so the could be installed with little or no clearance. You would insert one into the carrier, turn it 90%, to give you enough room to insert the second one, then turn it to line up against the first one, with a rectangular hole in the middle. You would then have to make a block that would fit into that rectangular hole, with a hole bored through the center for the differential pinion shaft. Turn the two modified yokes and the block as an assembly 90%, ansd install the pinion shaft to hold everything in place.

If the yoke you have won't work, there probably is one that will.

[Beck]

Back in time I read an article in a magazine about making an econo posi out of an open 9" Ford. I tried it some time after that. It didn't work. The rear end locked up. The diff. refused to slip. This might be very simple. In the article it said to just add an extra shim to the inside of each of the spider gears, between the spider and the case. This puts more side load on the gears making them bind a bit. I called the author and he said the magazine article was written out of context. This was supposed to be a budget circle racing rear NOT for street use. It may be just what you need. Are there factory shims behind the gears now?

[unklian]

Now that you mention it,some of the Formula Ford 1600 guys were doing that 10 years ago.The rules called for an open diff,but that produces too much wheel spin,even with the mild motors they run.So they would put shims in the diff to create a bind,then it works more like a limited slip.

They later introduced rules specifying a maximum break away torque.

[Bruce Dorsi]

It looks like you've been busy, Sum!  

What retains the stub axles in the differential side gears?  .....Are C-clips used?

Also, what is your target weight for the Lakester?

[GPster]

Using your pictures and my mind I'll try again. Not that any of these other ideas don't have merit I'm just trying to see what  I need to do to understand my ideas. There was a time that someone was using this as a selling point. "Four spider gears rear end carriers" If you found two more spider gears and filled the teeth that weren't necessary mesh with the axel gears, I would think you would somewhat lock the opposite axel gears so that they wouldn't rotate. These two extra spider gears could be held in place from the outsideand would rotate with the carrier but because of the filled teeth would be held in-place by meshing with the axel gears so that the added spider gears wouldn't have to rotate like originally designed. I'm just thinking that these added pieces might be easier than having to take apart the differential to make the change. GPster

[1FATGMC]

Using your pictures and my mind I'll try again. Not that any of these other ideas don't have merit I'm just trying to see what  I need to do to understand my ideas. There was a time that someone was using this as a selling point. "Four spider gears rear end carriers" If you found two more spider gears and filled the teeth that weren't necessary mesh with the axel gears, I would think you would somewhat lock the opposite axel gears so that they wouldn't rotate. These two extra spider gears could be held in place from the outsideand would rotate with the carrier but because of the filled teeth would be held in-place by meshing with the axel gears so that the added spider gears wouldn't have to rotate like originally designed. I'm just thinking that these added pieces might be easier than having to take apart the differential to make the change. GPster

   

Joe I think I understood you on the last post.  You are saying to put the 3rd and 4th locking spider gears where I have the blue circle above.  Correct?

I think that would work also.  I'm going to take a closer look today at the carrier when I get off work or maybe bring it to work.  Don't tell the boss   .

I'm really not too interested in changing back and forth often between locked or unlocked.  Once I see what works it will just stay that way.  The main reason to want to run locked is that then the spider and side gears would never turn and there would be no lube on them.  This would eleminate one source of lub that could get onto my center mounted disc brake rotor.  I'll still have to deal with lub from the chain which is just a couple inches from it.  I'm hoping a couple simple guards will take care of that.  Also as we know most cars there hardly touch their brakes after a run as there is so much run out at the end of the last mile and over to the return road.  But I would like at least one working brake   .

c ya, Sum