You lot can skookum all you want.
Off to Summit to buy some more stuff.
You lot can skookum all you want.
Off to Summit to buy some more stuff.
Summit didn't have what I was looking for in stock, but they did have a big bag of 1/2" washers for cheap, and they also had a $130 TPS setup for Holleys marked down to $50, with 25% off on top of that, and I'd like to redo the utter bodge of a TPS that I have right now.
Why was I interested in washers? This is why:
That don't look right. Turns out that the bearings are supposed to sit out from the bearing housing because that is what locates the drum brakes' backing plate. And since I am not using drum brakes, I have no backing plate to take up the distance. Well, duh. I grabbed some washers that are roughly backing plate thickness and put them in there.
Still not 100% ideal but I'll just make a note to check the torque on these fasteners on a regular basis until I am confident that nothing is moving around. (So, why didn't I buck up for the full floater setup I wanted originally?)
I also used a pair of 1/2-20 bolts (the wrong-length ones I bought for the bearing retainers) and a couple nuts to make a spreader tool. Because I welded the link brackets on BEFORE verifying that they weren't squooshed in shipping or something. You can't fit a 2.5" wide link pivot in a 2.4" wide mount. This spreader method worked incredibly well.
Yes, that's the side that I cut off and installed the new bracket on to fix some hearty mismeasurement.
Popped the axle links into the rearend after verifying that the rod-end end will in fact fit the chassis mounts, found the new brake rotors (they are for an '00-04 Volvo S40, weigh nothing and cost even less), slipped them onto the hubs and held them on with some open-end lug nuts (spline drive, because $10 for a bag of 'em at Summit), and... stop point. Because I want to WEIGH this thing to see how much more unsprung weight I have added to the car.
Moar.
Moar is imminent. Battery on the tablet died so I can't upload the pics just yet.
I acquired a scale, amongst other things. No pictures because it's a digital one that displays the result for about thee seconds then shuts off. Old and busted, complete with lower links and brake rotors but without calipers, weighed 140lb. New hotness, complete with lower links and brake rotors but without calipers, weighed 181lb.
Now, mind you, old and busted had large IRON calipers, that were big to cover over a vented disk. New hotness has tiny little aluminum calipers that have pads maybe half the size, and only have to clear a solid disk, so they weigh a lot less. How much do the old calipers and new calipers weigh? Don't know yet. Maybe 10lb difference in total? That would mean the new assembly is 30lb heavier.
5.43 gears are HEAVY because of how thick the ring gear is. Detroit Lockers, even the NASCAR unit I have in there, also have a lot of mass. I could probably make up the 30lb by going to a spool and a lightweight, taller R&P! I really don't want a spool, but I have been thinking that the 5.43 may be a little excessive, and takeout lightweight 4.56s are cheap cheap cheap. We'll see.
I'm eating tonkatsu ramen with eggs poached in it. Mmm, zero effort food...
Epiphany at the BMV today. Why was I at the BMV? Birthday is next week and I have been putting off my annual tithe. (This year's bill was $210.36) Since I had a bunch of time, and a clipboard and pen because I had to fill out a new personalized plate form (OKTAVIA is no more, car's gone off to a farm with a lot of other Volvos to play with) and so I combined pen, paper (back of E-Check paper was dandy) and clipboard... to do some trig.
And now I realize that the registrar kept the paper. ARG. Oh well, I was doing square roots by the old "multiply two numbers and see how close you are" method. We're not looking for exact figures, just useful approximations, after all.
The sticking point I'm having is that, when articulating the rearend, the Watts bellcrank smashes into the pumpkin and/or the exhaust pipe. Part of the problem is my exhaust system is a bodge and the Racing Beat muffler is kind of in the wrong angle, and i'm not sure if a genuine RB header would make things fit because the *engine* is kind of in at a different angle because of the FC subframe and the engine mounting arrangement I had to invent. What I worked out is that, assuming the suspension has 8 inches of travel (3 down/5 up, generally) and my new lower link is about 290mm long, the mobile end is going to move (very) approximately 20mm to the side. 20mm of motion on the end of a 80 or even 100mm bellcrank is going to cause a lot of angle change.
That led to the first Aha! moment.
Now that this song is stuck in your head too, we'll continue. The aha! moment is that, even if I hadn't lowered the rearend's droop maximum about 30mm relative to stock, I also relocated the bellcrank 40mm LOWER relative to RX-7, which would throw everything all akilter. The lower link would not be starting from level at ride height, it would be starting at a steep down angle... And then I want to put the 100mm end of the bellcrank down instead of up, which makes it even MORE bad.
Image from previous page for reference. Also note that the upper link is not supposed to be parallel, it has a whole lot of up angle and is only parallel to the ground if you remove the pumpkin so the rearend can travel that high without smashing the pinion into the floor. (Another reason I wanted a 9" - can get the car lower)
So, what I need to do is relocate the chassis side lower Watts mounting about 40mm. While I am in there, I may as well move it outboard as well so the link can be longer. Good thing I only tack welded the adjuster sleeve threaded thingies in place.
The other Aha! moment was when I was considering the upper link, which is still kind of ignored. I realized that the exhaust is fixed in place, and I have to extend the bellcrank anyway, so all I really need to do is make sure the upper link is going to clear the exhaust. Everything else will follow. The aha! is me remembering a comment made by a racer on the old Mazspeed forum about twenty years ago. The Watts as done by Mazda does not move the axle up and down, its vertical motion describes an S curve. (Panhards are actually better because of this, their motion is more linear and predictable) So of course I am going to have problems if I just floorjack the rearend up and down, that isn't the motion that is going to happen!
With those Aha! moments, I know now what I have to do in order to make the Watts work. Move the chassis lide lower mount, put in the upper link, find the worst articulation clearance problem for that damned upper (it's generally right side drooped and left side compressed), use that to define how long the bellcrank upper has to be... and it WILL work. Maybe.
Here's the left side at max compression.
How do I know this is how much travel I can expect to normally see? My rally tires are about 12.5-13" in radius. 12.5-13" above the axle centerline is this in the wheelwell:
Here's the right side at full droop. No, the axle is NOT properly centered, we're still trying to figure out how the hell we're gonna do that.
So left side at full stuff, right side at full droop, let's see where the upper Watts sits in relation to the bellcrank and such.
170mm away from the pivot. The standard locations are 80mm (upper) and 100mm (lower). Making the upper link longer will get me a little bit closer, but I won't for reasons I'll talk about later. I can maybe gain 10mm or so by cutting the webbing off of the top of the pumpkin, which I WILL do, but not to make this easier. It's because of what I saw when I kept the left side at full stuff and tried jacking the right side up to full stuff.
I'm an inch or two away from full stuff on the right side and it can't go any higher because the pumpkin is cramming the link end into the edge of the angle iron I used to brace the floor to the 3rd link mount. There isn't much more up that than available anyway. Yay, I get to cut out even more floor! But the kicker, since at this point the upper Watts link is being levered up by the pumpkin, the pivot-pivot distance is now 180mm. So if I only extend one end of the bracket to 170mm, I will still need that 10mm-ish of extra clearance.
It was at this point that the battery in my light died, so I didn't bother taking any more pictures, and measuring/seeing stuff was difficult besides. But the gist is, when at full DROOP, the upper Watts is hitting the 3rd link to where it can only go 160mm from the main pivot. And now that I think back to '06ish when I did my first 3 link, I think the Watts hits the 3rd link at right side compression and left side droop, so I need to double check all this again. I have been expecting to alter my 3 link geometry which is why its bracket is so rudimentary at this point.
On the lower Watts link front, I set the axle in at ride height and eyeballed level to require the chassis side pivot to be 60mm lower. I'm going to reforge the link bracket that I cut off into a Watts mount extender thingy. I took measurements, and since I cannot remember numbers, I took a photo of my notes!
Until I get a whiteboard, I'll just continue to Sharpie my notes on the workbench.
Incidentally, as it sits, the driveshaft has maybe 1/2-1/4" of plunge remaining at all axle gyrations I could muster. The pinion angle is way down, so I will correct the angle by lengthening the upper link, which will also give me more driveshaft room.
If the engine is TU internally, I have enough FC parts to put together an FC engine around the internals. When I mounted the subframe, I installed it an inch or so forward of stock. This made using unmodified FC mounts impossible. Now, if I needed to use FC engine parts, I could just shift the engine forward (or stock location on the subframe), then move the axle forward to compensate slightly to get the plunge better.
Just another reference photo - this is normal ride height, as recorded by some random dude on Facebook.
All six tires on the trailer are 185/65-15s. For some reason they look gigantic. Street tires on the rear are 205/70-15s to cut the revs down with the 4.78s. And I'm taking those out for 5.43s! I didn't think my cunning plan all the way through.
Eight days since last update. I feel ashamed.
I have been massively beat up after work, which is a lame excuse. I have NO berking clue how to make either a Watts or a Panhard work without dauntingly potentially fragile hackery, which is the honest truth. And any time I'd go out to the Batcave, I'd be in there for about fifteen minutes of staring at the problem before my fingers would go numb and I'd say "berk it, go home and stew about your situation" while watching the calendar ticking off valuable days.
Then prereg for Rallycross PE1 was opened. There's the kick in the ass I need. The time to hesitate is through! No time to wallow in the mire!
Now that song is also stuck in your head, we'll continue. I remembered to bring my gigantic parrot-beak pliers home from work so I could unstick my stuck upper link, my collection of cutoff wheels that have been sitting on my work cart since I fabricated an exhaust for a Torino last FALL (and the engine we're building for the Torino is worthy of that exhaust.... mega-inch 385 series motor, with a solid roller cam spec'ed out like the Himalayas, Kaase heads, huge intake manifold, Dominator carb... *homer drool noises* Should idle like a bowling ball in an industrial clothes dryer and make 900hp-ish) and went to Home Depot to pick up some stuff I've been meaning to get for my ignition coil mountings. And a 9" Sawzall blade, singular, because wow they have gone up in price for some reason.
About an hour of annoying the neighbors with grinding, cutting, hammering, etc, I get the center bushing and sleeve removed from a half-a-bellcrank that I've had kicking around for a while. That,plus my old bellcrank, is mocked up here to make a 168ish mm c-c bellcrank. Why the old bellcrank? I don't want to berk up the new one if I make a huge error somewhere. Plus it isn't actually bad like I thought it was. The new bellcrank can go on the '81. Anyway, sidetrack. I heard you like bellcranks, so I put a bellcrank on your bellcrank:
Now, let's shave a pig!
One (1) Yukon through bolt 9" case:
11 minutes of application of a coarse toothed 9" Sawzall blade:
Three minutes later:
Now that we've removed some extraneous ribbing, let's throw the MegaCrank on the rearend and articulate it and see where we're at:
Huge clearance! I could probably make the bellcrank 15mm shorter and still have acres of room. Note that the link is not fully seated on the bellcrank because I raised some burrs on the stud while trying to remove the old center bushing.
Very nice. I think I have a Way Forward now. If I can get the bellcrank below 160 then I won't have to extend the third link bracket. I can close it in and call that done. And the shorter I can make the bellcrank, the less likely I will need to hack up the floor.
Heaps big progress. More on the way. It's going to get ugly though.
Knurled. said:Heaps big progress. More on the way. It's going to get ugly though.
Ready by April 14?
I'd love to but it would take a miracle.
They are still salting the roads, and the stuff they use nowadays isn't quite "rock salt" but some stuff that seems to seep in to the roads. It takes a rainy month to wash it all away. I don't want this car to dissolve.
Had some place to be tonight and I have to go to work tomorrow...
So last time, at the Batcave...
I took my bellcrank of ill repute, cut the tack welds, cut some off of the extension, and re-tacked it at a hair under 150mm c-c. Put it on teh car.
Left side, axle hitting chassis rail.
SUCCESS!! Just enough room!
Now let's jack the rearend all the way up and not just left side articulated:
More success! The rearend isn't "all" the way up but the bellcrank is clearing the floor with no issue.
Why is it not "all" the way up?
Hard contact with the exhaust system. Now, the exhaust has no rub marks on it, so even with my soft-rate springs the old rear NEVER got up THIS high, so it is safe to say that I have those clearance problems nailed.
New issue. Went to jack up the RIGHT side to check for clearance against the 3rd link, and broke the bellcrank. Frustrated, I went home for the night. Then borked my good knee at work on Friday and missed out on the weekend. But all was not lost, because I spent time Pondering.
Tonight, I applied step one as making the bellcrank permanently 150mm c-c.
Lots of welding:
I didn't get pics of this process, but what I did was use some of the tube/sleeve that I bought to make my 5/8 rod end to 14mm bolt adaptors to make a sleeve for this. The inner sleeve just locates the outer on the stud, while the outer is what the nut will tighten against. I cut it to 40mm long (same as the sleeve in a Watts link) and then cut a big notch in it to shoulder over the bellcrank extension. Then I welded the snot out of it.
Then, I cut a strip off of an old broken trans mount to get a piece of filler material for that big gap off to the side.
My initial plan was to weld the "ring" to the fill-in, then seam weld the fill-in to the main bellcrank, but there was so much slag/spatter because flux-core that I ended up just blowing in a bunch of weld out of disgust.
Should be okay. This is only part one of the bellcrank after all.
Now, the part that I really had to ponder. How do I raise the 3rd link pivot? I generally make the bracket by clamping two pieces of stock together and cutting/drilling as an assembly, so everything is symmetrical and on center and such. Hard to do that with the rearend in the car, and iterating will be difficult. So, here's what I did:
Just tack a 16mm bolt to the TOP and see where that gets us as a first cut. Now, let's jack up the right side and check it for clearance...
30mm of clearance at the tightest point! So, working backwards from there, I think I want to put my new pivot point here-ish:
Incidentally, the gaping hole in the floor is that wide on purpose.
I don't know how the Escort guys get away with 2" wide link boxes. Maybe it's because their 4 links are mounted at only a 3" radius from axle centerline? I guess i do know....
To do: Remember to bring my center punch home from work so I can drill the new mounting points. Now that the geometry alterations are figured out, I can drop the rearend back out and finish making the 3rd link, make the Watts outer linkage pivot support, add the brake lines. Seeing the light at the end of the tunnel here.
Just for S&Gs.
My third RX-7, on the Diamonds and RE71Rs that I used for track days on my previous RX-7.
Old meets new. Yes, the '84 (officially my fourth RX-7) was purchased on Koseis. It has never had 13" tires on it for the entire time I've owned it. Date on the image is October 9, 2007. Huh, I thought I bought the '84 in '08. I guess I got it in January of '07. This is the longest I have had any car ever.
Trivia: The first time I rallycrossed the car, it was in PR. Mainly so I could get a trophy with my initials on it. It was, in fact, PR legal (catalysts were not required in Prepared back then), although the 12A that came in the car was tired to say the least. It died not very long after I got the car on the road. The apex slots in the rotors were so worn out that you could fit an apex seal spring in next to the apex seal. That was the main reason I went Megasquirt, as I had a GSL-SE engine that I swapped in and didn't feel like running the OE wiring. Then that engine died a month later, so I put the EFI on my peripheral port 12A.
That sucked (largely, in hindsight, because of the tiny 2x40mm throttle body I used) so I assembled an engine out of a core S4 13B and a set of Turbo II engine housings.
That engine went like stink and I eventually bridge ported it because MORE.
Best decision ever.
Incidentally, I did the FC front suspension conversion, the 3 link rearend conversion, and pulled the engine out to bridge port it, in the same week at work. We were slow. I think the FC swap was two days, the 3 link one day, and the engine R&R/disassemble/port/reassemble/install was two days.
I am torn between Duratec 2.5, or Enclave (aluminum) 5.3l with a 58x-era 4.8l rotating assembly and the LS2 oil pan/pickup tube that I bought from Summit on a whim. A 58x crank allows one to use a newer PCM that controls the throttle directly, so one can play drivability/traction control tricks that can't be done with the 24x/TAC module setups.
Back to the world of non-make-believe. The '84 was bought after being sideswiped hard. The original rearend was actually cracked on the weld seam where the Watts pivot met it. So it should have been no surprise that the bellcrank was also massively borked:
Oh well. The new bellcrank can go in the '81, which will retain its originalness.
More importantly, the S60R needed attention. The steering shaft U-joint was binding so hard that it would take shoulder-effort to get the steering to turn in the morning,
See it way down there? That is where some previous berkhead replaced the 8mm bolt with a 1/4-20 nut and bolt. Which sucked to R&R because the TF80 trans is huge and precluded the use of two hands simultaneously in the same space. Also, the old rack input shaft rusted where the coupler wasn't in all the way. Which made it very difficult to properly install the new one.
And that's the wall that I beat my head up against last night....
I had to go pick up a racecar last night. I would say my night was better than yours...
Still gonna be ready for the April event so it can be cancelled the night before because there is way too much rain?
EvanB said:till gonna be ready for the April event so it can be cancelled the night before because there is way too much rain?
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Doesn't matter, I farked up my left forearm/wrist royally and I won't be driving anything with a manual trans anytime soon because of how painful it is to do anything with my left hand. (#insert obligatory_self_deprecating-joke here) For those keeping score at home, I borked my LEFT wrist and my RIGHT knee in the past couple weeks. But it is my RIGHT wrist and LEFT knee that have always given me problems. I can't even limp straight anymore, my head gets confused on what isn't working the most.
One of the calipers I bought for the new rearend is bad. Whatever magic happens inside the piston is NFG. Replacements are on the way, but ETA for them is April 11th.
I did find out that it is easy to widen the VW calipers to mate to the thick Mazda cables by heating the cable arm orange-hot with a MAPP torch and then first opening it up with a screwdriver, then clamping it over a drill bit with a set of pliers. This is way easier than my original plan of cutting the arm and re-welding it wider.
3rd link bracket is re-drilled, reinforced, and finished in with a backplate, which involved use of said MAPP torch and some clever hammering so that it could be contoured to clear the linkage. Watts right-side chassis mount extension is started. Shock mounts are fully welded.
Also discovered that the 10x1.5x40 flange bolts that I bought are completely useless because my calipers need 10x1.25 bolts. D'oh.
Much progress happened this weekend. Tablet battery is dead so I can't upload pics just yet.
While on my way to Summit, I noted salt trucks out and about. Does not bode well at all for rallycross. However, I did pick up a brand new, never-installed Dorman driveshaft for a Miata. 6" shorter than FB and replaceable U-joints! This will either facilitate that heavy engine setback I wanted to do or it will facilitate getting the RX-3 on the road. And it was only $60, which is way less than what I spent for the last used FB driveshaft I got from a junkyard.
So, part of my issue with how to brace the 70mm extension was that the extension was also quite a bit off plane relative to the original. In hindsight, I should have accounted for this when I made the sleeve, but oh well. The best I could do was this:
Yes, that is part of the suspension bracket that I'd installed improperly and cut off. This one was cut through that hole, so I just opened it up more to clear the sleeve. It's near-as-good-enough even with the spacer, so we can go ahead and do this:
It still needs a little trimming here and there but we'll call that part of the nightmare Sorted.
Next up, lowering the right side Watts chassis mount so that the link is more or less parallel at ride height, which it really wasn't after lowering the center pivot so far on the axle. Eyeball and by-guess-and-by-gosh estimations said I needed to lower it 60mm. The outboard mounting holes on those Allstar suspension brackets are roughly 65mm apart. Well, hell, we're piling estimate on estimate anyway, so let's go with that. First we slice the sides out and turn them around, tack washers to the inside to take up the clearance, and bolt everything up:
It's gonna get ugly fast.
Next, we weldify those suckers in:
Verify that the link can slip in and out BEFORE welding in the closing piece (ahem) and then use the opposite side of the "oops" bracket to make it:
And a whole lot more smoky spattery zap later, including a nice fat plug weld (rosette weld? something) and we get this:
Seriously, if you've never used it: flux core spatters a LOT. Summit's foam rubber garage work pad thingies are not exactly flammable but they aren't fireproof either.
I didn't like having that much extra overhang on the bracket, and there wasn't a good way of reinforcing it to the wheelhouse, so I settled for using the backside of that "oops" bracket to make a reinforcing plate to the chassis kickup. And somehow, in a 32 degree garage, the paint not only managed to spray, but it seemed to stick too!
Chassis mods: Sorted.
Next, dealing with the brakes. My initial plan was a pair of VW/Lucas calipers I bought from an eBay salvage yard, with some braided flex hoses I found at Summit. The flex hoses were for a GM truck and were massively long, needed a lot of grinding on the caliper end to slot into the Lucas calipers, and the holes drilled larger because VW uses a larger banjo.
After all that, I found that one of the calipers was seized. Ugh. So I used it as a testbed to see how about modifying the cable hook to fit the much wider Mazda cable. That went very easy, a little heat here and prying there and re-smooshing after a little more heat and all was well.
Found another pair of calipers on eBay, bought 'em. These ones didn't look like they were sat outside for five years. They were supposed to be delivered by the 11th, they actually came on Friday. And the seller included the VW flex hoses! Awesome! More awesome, somehow THESE calipers have a wider cable hook and they only needed a minor tweaking to fit the Mazda cables.
FINALLY. VW/Lucas caliper, Volvo brake rotor, Wilwood Dynalite caliper bracket, Ford 9" rear, Dutchman axle... and it all bolts up, the pad fits correctly on the rotor, and the rotor sits in the pad hanger without binding. That photo makes me very happy. It needed a washer to center up better (this was expected) so I tacked those in place and filed the welds flat.
Those bolts are caliper bolts from my ex-Quantum. I actually BOUGHT a set of four 10x1.25x30 flange bolts, but I accidentally threw them out. Long story. (That is to say, stupid story) I forgot I had these and found them while scrounging up fasteners for the Watts setup.
The VW flex hoses have quite a bit of hardline attached to them. I straightened them out and stuck them on the calipers to see how they'd sit. The left side is more than long enough that I can just cut it and reflare it. The right side will need to be extended a small amount. New problem: How do I secure the lines? VW used little plastic clips that I'm not even going to attempt to use.
At this point it was 8pm, I was dang tired, my light's battery needed to be charged, and I figured this was a good place to stop. Need to think on this problem for a little bit.
This thread is useless without pics.
Not sure if air in brake system or just squidgy new pads. Great brake pedal with flex hose clamped off, crap pedal otherwise. Decent pedal if hydraulic handbrake applied before foot pedal. Cable handbrake not connected yet but there is minimal takeup whe actuating the calipers by hand, so I don't *think* that it is a caliper retraction issue.
With the axle pushed up to nominal ride height and the axle squared up with the wheelwells (left link is 1/2 turn longer than right, not bad) and the Watts adjusted so that the axle is centered at ride height, the adjustable link is a scosh over 309mm center to center. In other words, it is 1.000 Lp long. Neeeeeat.
In reply to Knurled. :
I knew that unit of measurement would come in handy someday.
In reply to Knurled. :
That, sir, is an impressive bit of engineering.
Well done
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