Back in the Saddle Again

After a long period of low activity, driven by some personal issues and competing activities (a couple of bathroom remodels) I’m working on the Locost in earnest again.

I’ve re-built the build table, making it: 1) sturdy enough to support the car with the drivetrain installed, 2) level without the levelling feet, and 3) low enough so that I can more easily work on the chassis and, especially, weld on the top of the chassis. My excuse for burning holes in the top surfaces of the top tubes is now gone.

I had the engine and tranny mocked up in place and was about to fab and tack-weld the engine mounts when I decided that, although I knew the depth of the shallow(er) Race Craft oil sump I planned to use, I wanted to actually see it in place when I finalize the engine location. So, I ordered the sump. I’ve pulled the engine from the chassis, mounted it in the stand and, with the help of my friend Woodinville Dick and his brother, turned it upside down so I can access the sump.

Raceline Sump

New Raceline oil sump sitting on top of the stock one. You get an idea of the difference in depth. It provides about 1 7/8″ more clearance.

While I was tracking down some rubber lube that I need to use when I mount the sump, I’ve worked out the positioning of the front four suspension A-arm mount brackets. I have them C-clamped in place so that I can tack-weld them. Now I’m working on the lower rear mount brackets, which require mocking up the lower A-arms to get the angle right.

Front suspension brackets

The brackets are clamped into place in preparation for tack-welding. The string that you see dangling is for a plumb bob that is tucked (mostly) out of sight.

The jury’s out on the upper rear brackets. I have been planning on using removable brackets made from aluminum plate that I can remove and replace so I can play with anti-dive geometry. But something is whispering in my ear, I don’t know whether it’s the little angel on my left shoulder or the little devil on my right, that I should dispense with that complication and simply weld brackets where the book says to.

Suspension Brkt

Close up of one of the clamped-in-place brackets. The bent-up brackets are from Jack McCornick’s Kinetic Vehicles in Oregon. In the upper right corner you can see the holes drilled for the upper rear brackets. I haven’t installed the bushings yet.

When I get the suspension mounts at least tack-welded in place I ‘ll be able to fab my A-Arms. Then, with the wishbones in place on one side, I can work out my steering rack position.

But first I’m going to flip the chassis over and weld in the steel panel that goes in the bottom front bay, just behind the radiator, and the sheet steel floor panel in front of the driver to which the brake and clutch pedal assembly will be mounted.

And then I’ve got to determine whether I want to use aluminum or steel sheet for the rest of the cockpit floor panels. And if steel (cheaper but about 20 lbs. heavier), go ahead and cut them to shape and weld them in place.

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Slow Progress

Chassis on New Build Table Aug 3 2017

Hmmm. This looks a lot like a previous post, except that the build table is rebuilt and now strong enough to support the car. And the chassis and drivetrain are off the floor and on the table. Thanks to my friend Dave for help positioning the drivetrain and to my friends Ralph, Gary and Thomas for help positioning the chassis. Next step is to fine tune the engine and transmission locations and fabricate the engine mounts. Then on to the suspension mounts.

Mock-Up

IMG_1591

After a several month long hiatus I’m working on the car again. I’ve got the chassis perimeter largely welded, and the other day set it up at approximate ride height with the drive train mocked up into place so that I an work out final positioning and dimensions for the transmission/driveshaft tunnel.

First impression, that the engine and transmission unit looks so massive sitting there in the chassis, almost more like  street rod than a svelte sports car. It’s going to push the hood/bonnet higher than I’d planned.

Also that the Miata 6 speed transmission is both longer and wider than the 5 speed that I was going to use. Interference between the transmission and a chassis crossmember forced the engine several inches forward from where I wanted it. I cut a chunk out of the crossmember and pushed the engine back until the bell housing aproached the upper firewall crossmember. That gained me about an inch and a half. Then, after more consultation with Tom, who is building a Car9 in the area, I’ve decided to modify the firewall and move the power train back another two inches.

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The engine sits an inch to the right of the chassis centerline in order to line up with the differential input. And that just gets me enough clearance for the steering shaft so that I’l have a straight shot with just the two universal joints at its ends.

The stock (Focus) oil sump hangs down an inch and a half below the chassis, bringing it to about four inches above the roadway. Its too low. I could just run a skid plate but eventually that would catch up with me. Modifying the Focus sump is an option. The lowest part of the sump is actually a small rectangular-shaped area. I could simply cut that out and plug the cutout (trying the Alumiweld rod that my friend Brian gave me) and move the drain plug to a different location. That would gain me about a half an inch – in other words, not much. One alternative appears to be to buy and modify a Ranger sump. I could mill off the bottom, form a new one, then have it TIG welded. The more elegant solution would be to buy an aftermarket sump. They’re available in the UK. At today’s exchange rates the cost would work out to about $400 for one fabricated in steel, or about $550 for cast aluminium. Plus shipping. Plus VAT tax if I can’t figure out how to get it deleted.

There are interference issues at the rear as well. I’m using the rear axle from an 84 RX7  GSL-SE (4.1, LSD).  The nose of the differential doesn’t have enough clearance from the rear bottom crossmember at the back of the cockpit, and if I want to use the Watts Linkage bellcrank that came with the axle I have an interference issue with the rear cockpit bulkhead.  But I’ve also got an interference between the frame and the top of the coilovers, which I can address by fabricating different shock mount brackets from what I’d planned, which would mount the shocks an inch and a half or two towards the rear. To keep the springs vertical I’d have to move the axle back as well, so that is probably what I’ll do.

And on we go. Step by step.

WAS – Keep it Simple

People ask, well some people ask, why is that fuel rail there with the WEBER carburetors?

Duratec with Webers

Thinking one morning about how some of the decisions I’ve made have increased cost, complexity and probable build time, I started to rethink the EFI decision.

As it stood I had a set of motorcycle throttle bodies, with the linkage and throttle position sensor (TPS). I was going to need to fabricate an intake manifold, purchase and wire the MegaSquirt and Ford EDIS ignition module, purchase all the sensors and wire harnesses, procure a laptop computer then load the tuning software and tune it. And I would need a high pressure fuel system with expensive components and the complication of a return line.

Reading the ad copy  for MSD ignition controllers I’d seen that they could be operated with a crank trigger. A friend, Brian, who is relatively expert with Weber carburetors had pointed out a couple of times that, although difficult to set up, once dialed in a pair of DCOEs would be relatively trouble-free.

I started to visualize a solution using the carbs and a simple stand-alone ignition –  clean and simple. And I had spent so little on the EFI stull so far, less expensive, or so I thought.

Needing to educate myself on the carburetors, after a little research (mostly reading on-line product reviews), I bought and read through copies of  “How to Build & Power Tune WEBER & DELLORTO DCOE, DC/SP & DHLA Carburetors” by Des Hammil,  and “WEBER Carburetors” by Pat Braden. (each book covers stuff that the other doesn’t, I recommend getting both)

I determined that I would want a pair or 45mm DCOEs for a two-litre engine producing 140-165 maximum HP at around 7,000 RPM. A little more research and I ordered a set.

Then I debated about whether to build or buy an intake manifold. They looked simple enough. But warnings in the Hammil book about manifolds with poorly aligned carb mounts, and concerns about my ability to weld the carb mount flanges to the runners without warping them led to the decision to buy.

The carbs and manifold on their way, I started reading up on the MSD ignition.

Uh oh, it looked like I would need to buy a purpose made MSD crank trigger for what looked like a lot of money (Brian, who is running an MSD ignition off a crank trigger in his very nice 911 has contested this and is looking into it for me) . And it was a big, honking thing, more appropriate on the front of a big domestic V8 than my little four-banger.

Okay, what about Megajolt, the ignition-only counterpart to MegaSquirt? A quick read through the Autosport Labs web page indicated that they were relatively inexpensive, but that I’d also need the EDIS control unit and, uh oh, most of the same sensors needed for MegaSquirt.  Cost would work out to roughly $150 less than using a MicroSquirt EFI module (plus another two to three hundred bucks for the high pressure system).

I wonder.

A little more research and it wasn’t hard to find people running just the ignition side of MicroSquirt modules with carbs, and that would provide the option to upgrade to EFI down the road. Or, if I’m going to go to all the trouble to install the MicroSquirt up front, why not just go ahead with the EFI using the DCOEs as throttle bodies?  And I’ve gone full-circle.

The jury is still out.

Oh, and how much money have I saved? By the time I got the carbs and found an intake manifold actually available, from the UK, with exchange rate, the VAT tax that I didn’t think that I’d have to pay, and shipping; I spent just about what it would have cost to get a set of purpose-made set of throttle bodies for the Duratec from Raceline.

Footnote – I keep looking at that oil filler cap projecting from the top of the cam cover. Getting rid of that would help with car’s lines. Even cutting off the tab would help ( I bought an aftermarket (Stant) cap that didn’t have the tab but it fit so loosely that I tossed it into the trash). There’s an aftermarket cam cover that moves the filler to a lower location, but it’s prohibitively expensive. The cover is a relatively simple design. I’ve got access to a friend’s vertical mill (conveniently set up in my shop) and could try milling one myself. But it would be a lot of work for not much actual benefit. Or, and this just occurred to me while staring at this paragraph, I could modify the stock, plastic cover, then sheath it on the outside with a layer of carbon fiber. The hardest part of doing that would have been the strengthening webs on the side, except that with the CFRP adding rigidity I could remove the webs. And I’m planning to do some vacuum-bagging on this thing before I’m done anyway.

Slow Progress, and still the three step

Three steps forward and one step back, three steps….

looking forward

Looking forward as I cut and fit the chassis members.

The perimeter frame is tacked and I’ve been welding the joints. It’s been another exercise in frustration. I have a medical condition which interferes with my vision, so it is very slow going. My welds look like crap. A few look good. Some are ugly but adequate. A few are getting ground out and redone. I burned through in three places. Those will get reinforcement plates to insure integrity.
I’m not happy with the workmanship at all.
Generally the frame is straight enough to use (i.e. all the suspension pick-up points can be correctly located), except for one bad warp. The rear rectangle, at the back of the cockpit, is warped because I overheated the inside weld at the upper side member.  Theoretically I know how to fix it. Heat the opposite side of the member and it will contract when it cools, but I’ve been afraid to do it for fear of making it worse.
I’ve set the chassis on the floor and dropped the transmission roughly into place in order to get a rough idea about how it will fit. The engine in an NC (3rd generation) Miata tilts ten degrees toward the passenger side. To use it in an upright position the transmission will tilt the ten degrees toward the driver. The drive train will also be located about an inch to the right because of the pinion offset. I’ll need to modify the shift lever to get it to stand up straight but it looks like it will work. And it’s going to be really tight on the passenger side.
transmission in chassis
Next step will be to mock things up with the engine, transmission and rear end positioned in the chassis. Then I can work out the exact dimensions for the transmission and drive shaft tunnel and see if, with very careful fitting, I can squeeze out another inch for the passenger seat.
I may throw a party. Get it all mocked up with drive-train and steering wheel in place, mock up a cardboard seat, cook a pot of my generally well received chili (the secret is in the chiltepin peppers), then invite anyone who wants to look and/or offer input to come for a Saturday lunch.
In the mean time, parts keep arriving. And money keeps departing.
My oil filter bypass plate, needed to clear the chassis, arrived; as did the remote filter mount, oil thermostat and oil cooler. So I’ve got all that stuff except for the lines.
An RX7 driveshaft followed me home from Covey auto wrecker/recycler and is standing next to the Miata driveshaft that the rear yoke will be mated to. A Miata steering column found its way from Treasure Coast Miata in Florida, for about half what one cost locally. I found an acceptable (to my eyes) steering wheel on Amazon.com for less than half what a MOMO or Sparco one cost. Late night web searches turned up a  fuel pump inertal cut-off switch on eBay for about a third what one would cost new (or about a fifth of what one street rod wiring supplier gets for them), and an electronic self-canceling turn signal controller – a motorcycle retrofit unit that cost way less than the street rod stuff.
After much hemming and hawing, and several decision reversals, I ordered a pair of Weber DCOE side draft carburetors. They look good, in keeping with the spirit of the car. but they  can be difficult to set up. But a fuel/air ratio gauge so that I could tune them properly would add another two or three hundred bucks. Now I’m wrestling with whether to make or buy my intake manifold. I can make one for less than fifty bucks. But I’m worried about warping the flanges while welding or brazing it and ending up with an unusable part. I can buy one for about two-hundred and fifty bucks. Another quandary.
Sometimes the rabbit trails lead in circles. It was an internal dialog about how I was unnecessarily complicating the project that got me to the decision to go with the Webers. I planned to pair them with an MSD ignition, which I had read could be actuated by a crank trigger. A little research indicated that it would need to be a purpose-made MSD crank trigger, for what looked like a lot of money. And it’s big and ugly, something that belongs on the snout of a big V8.
Well, what about Megajolt? I’d have to pair it with a Ford EDIS unit, still cheaper than the MSD controller and crank trigger combination. Oops, wait a minute, and I’ll need some of the same sensors that I’d need with the EFI controller. Following a thread got me to a discussion board, and information about using just the ignition side of a Megasquirt or Microsquirt ECU with the carbs. Then I’d have the option to use the DCOEs as throttle bodies and run a Microsquirt ECU. I wouldn’t need the fuel/air gauge, which would more than make up the cost difference between the Megajolt and Microsquirt units – but I’d still need those other sensors and the high pressure fuel system. And around we go.
My radiator arrived. It’s an aluminum unit that is intended for drag racing. I did a lot of searching on this one. It’s the largest radiator that I could find, for the lowest cost, that will fit the confined space (ignoring the very cheap ones on eBay [but look at that shipping cost]). It just barely fits and will take some creativity to mount.
And I’ve been doing a lot of late night reading. Books and catalogs on automotive wiring (the Tony Candela books have been particularly useful). Staring at the darkened ceiling, thinking about how I want to do my wiring. I’m not an “electrical” guy but I spent thirty-five years in electrical design and manufacture in the aerospace industry and have some strong ideas about how I want to do it. I considered getting one of the street rod wiring kits from Painless, Ron Francis, or some other source; primarily for the labeled wires (remembering frustrating hours of troubleshooting British auto wiring (the most smudged-up page in my MGB workshop manual was the wiring diagram). But I don’t think I need it, and they don’t really match my needs.
Shades of overconfidence? I’m reminded of  a T shirt I once had with a quote from an old fisherman. “Those what’s afraid of the sea gets drownded. Those what’s not afraid of the sea only sometimes gets drownded.”
But I picked up a six circuit switch and breaker panel from DIY Autotune that looks remarkably like a Moroso unit. It was on sale for about half price. That should get me all the circuits I need in the dash. I want the fuses for the rest of the chassis wiring to be accessible under the hood so I’m thinking that a small marine type fuse block will get me what I need. I’ll need to construct a relay panel for the relays for the lights, fan, fuel pump, etc. I’m picturing very carefully routed, color-coded wire with labels at the ends. Signals separated from current. Something that will look good, like it belongs –  not something that I’d feel the need to hide.
I may go a little higher tech for wiring associated with the ignition/EFI controller and its sensors. I have a friend who used to have a small aerospace wire shop as a sideline business. He has aerospace quality wire and connectors available. It would be a kick, if for no other reason than to see the mil spec stuff in the car. And it would emphasis the point – this is signal wire. That other stuff over there generating those electrical fields is for current to operate equipment.
Sometimes just picking up a catalog or pulling up a website and following a thread. It’s pretty common for me to find something that I missed before. This morning for example the Speedway Motors catalog fell open to the section with accelerator cables and linkages. I’d been wondering about how to do the linkage. How to get a secure but bind-free mechanism from my Offenhauser knock-off (Speedway Motors again) gas pedal to the Weber linkage. Dealing with adjust-ability, different ranges of motion at each end. Something that will stand up to the heat, won’t bind, and won’t come loose. The Speedway cable that looks like it’s supposed to go with the pedal uses a simple loop in the cable to go around a bolt, possibly riding against the threads. It looks like it would quickly wear out.  The catalog led to a web search, which led to an off-the-shelf assembly at Jegs that looks like it will work.
“And the beat goes onnnn…”
Slowly
Step step back, step step back, step step….

 

 

Seattle Three Step

Chassis members clamped into place in preparation for tack welding.

Chassis members clamped into place in preparation for tack welding.

You’ve heard of the Texas Two Step? I’ve been doing the Seattle Three Step: Two steps forward and one step back. Two steps forward and one step back… as I cut, grind, file and fit; then occasionally toss a part in the scrap bin and cut, grind, file and fit again. Then tack-weld the part into place. Then another. Then occasionally cut out the tacks and re-position a part as I discover one that is crooked when I flip up my welding mask to admire my handiwork. Getting the chassis pieces fitted and tacked into place before final welding is taking forever. But it is still a lot faster and easier than working with the round tubing from my first chassis attempt.

I’ve gotten to the point where I need to take some measurements from the engine and transmission before fitting some of the frame members so I went ahead and got them (with the very generous help from my friend Gary and his truck). I’ve read of others using the “book” dimensions, then finding that their chosen power train won’t fit and having to cut out and replace some of the parts.

The 2.0 Ford Duratec engine, from a 2008 Focus. And a six-speed gearbox from a 2007 Mazda MX5/Miata.

The 2.0 Ford Duratec engine, and six-speed Miata gearbox.

The two litre Ford Duratec is from a 2008 Ford Focus. The all aluminum engine puts out 140 hp in stock form. It was developed jointly by Ford and Mazda and the basic engine is used in, among other things, the third generation (NC) Miata.

The transmission is a six speed from a 2007 MX5/Miata. It’s massive. I’d originally planned to use the much more compact five speed, but I couldn’t find one with a shifter. Mazda doesn’t sell the shifter as a unit, but would happily sell me all the parts to build up my own, for significantly more than the difference in cost between a five speed and a six speed from a  wrecker/recycler.

Why not use a Miata engine instead of the Ford? Low mileage Focus engines are plentiful and relatively inexpensive. This one has six thousand miles on it and cost less than a third of what a Miata engine with sixty or seventy thousand miles would cost. The Miata engine puts out about fifteen more horsepower than the Ford, but it has variable valve timing, which I wanted to avoid.

The next big decision is going to be what kind of induction system, Carburetors or EFI.

Webers DCOEs – The appeal is the relative simplicity, lower cost; and I also like the idea of a low pressure fuel system. Can be difficult to set up, although I have access to at least one knowledgeable expert – who says that once I get them set up they should be relatively trouble free. (my own past experiences with carbs, by the way, revolved around SU’s and down-draft Rochesters and Carters)

The other option (within my price range) is a set of ITBs and Megasquirt EFI. The up-side, well people keep asking me why on earth would I consider carburetors in this day and age. The down side, besides the extra expense is that I’m worried about getting in over my head. Some people have great luck with Megasquirt and some people really struggle with them. And I’m a little afraid of having a high pressure fuel system in the car.

I’m wavering. A good strong gust could blow me either way.

 

Skin in the game – the chassis build table / jig

It is said that you don’t truly own a project until you’ve bled on it. I passed that milestone the other morning. I didn’t actually bleed on the car, but the chassis construction table should suffice. I didn’t notice at the time, just later when I was leaving a small trail of blood as I worked.

Both the Champion and Gibbs books show the chassis structure being fitted and welded on a flat table. The lower members being held in place by wood blocks and clamps, and the upper members held in place using clamps and welding magnets. I’m going to augment that with some vertical members to hold the upper longitudinal frame members and the cross-piece behind the occupants’ shoulders in place.

But first comes the table. It needs to be large enough for the basic frame to fit, flat and level. I once read that straight, level and plumb were the fundamental aspects of carpentry, everything else was secondary. Pretty much the same thing applies here. How accurately the frame is constructed will affect how well other parts and assemblies fit, how the car drives and how it looks.

A four by eight foot sheet of 3/4″ thick plywood is just large enough to fit, with roughly two inches all to spare at all four sides. To keep it flat I’ve attached the plywood to a rectangular framework of straight 2×8 lumber. There’s a 4×4 leg attached to each corner and I have I have a lag bolt screwed into the bottom of each leg. Then with one long level down the middle of the table and one across each end I turned the bolts until the bubbles in all three levels were centered.

IMG_1859

Lag bolt screwed into table leg. It’s not very robust looking but it works. I’ll need to check it periodically as I go.

I’ll be leaning on the table as I fit and weld the chassis parts, perhaps even climbing onto it on occasion, so I’ll need to check periodically to and readjust as I go.

Once I had the table level I drew a centerline. Then I measured out and drew the outlines of all the frame longitudinal and cross members on the bottom of the chassis. Next step was to attach small wooden blocks to hold the frame members securely in place. After that I can start cutting and tack welding steel.

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Finally it feels like I’ve actually started.