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Brotus7
Brotus7 Dork
5/14/22 9:16 p.m.

Almost 20 years ago I started building a Locost with my dad, but it was a 7 with a twist.  We liked the look and proportions of the orginal Lotus 7, and happened to find a guy nearby who had a jig used to build the DSK chassis.  DSK was a firm that strengthened the original 7 and I think was tied with Autodynamics somehow.  Anyways,  that project stalled out, maybe it'll return now that my old man's retired?

The bug bit me though, and after building a LeMons 280ZX, I was looking for a new project.  I knew it was going to be a 7, but couldn't just follow what others did because I tend to overcomplicate crap (ominous music....).  Before long, I found a really interesting chap in Massachusetts with a massive Lotus collection, and a wrecked Caterham SV chassis and a couple body parts.  With that, I'd forged a plan.

The plan:
Very briefly I considered straightening the Caterham chassis, but too many tubes were bent for it to be worthwhile.
Reverse engineer the Cat chassis
Build my own from scratch
NA Miata drivetrain
Original Caterham nosecone and scuttle
Caterham CSR style rear chassis mods

Simple enough, right?  

NOT MY GARAGE, but I happened to spend a weekend in London for work and found my way to the Caterham factory for research.

Datsun310Guy
Datsun310Guy MegaDork
5/14/22 9:23 p.m.

that green and yellow paint is awesome.........in the words of Garth - Schwing. 

Brotus7
Brotus7 Dork
5/14/22 9:23 p.m.

Bent chassis that got me started.  Each tube with blue tape is bent.  I don't remember the details, but I think the story was that the car was hit on the driver's side by a Jeep.  In any event, it turned out to be too far bent and out of square, but provided me what I needed and then some.  Especially for the price - free!

Here's the free bits vs the '94 Miata donor

ae86andkp61 (Forum Supporter)
ae86andkp61 (Forum Supporter) Dork
5/14/22 9:28 p.m.

Oooh; interesting project that is right up my alley! Definitely going to follow along for this one.

Brotus7
Brotus7 Dork
5/14/22 9:30 p.m.

As I mentioned, I started the project a while ago, worked on it almost every weekend before burning out due to a combination of issues.  I just didn't have the skill or patience to do work to the caliber that I wanted, finding myself getting impatient and taking bad shortcuts.  Rather than doing things poorly that I'd have to spend more time fixing, I parked it and embarked on an "easier" project. Well, that distraction was fun but it's time time send the Europa on it's way.

I had a build thread on LocostUSA, but I think a bunch of my older pictures got lost between Photoberkit and the forum domain.  In any event, I'm going to gloss over getting to hear, but will be happy to go into details of anything I've done if there's interest.

Igor  getting suited up for a trip.  Story To Be Continued.....

Brotus7
Brotus7 Dork
5/14/22 9:43 p.m.

After waking up the 7 and bringing it over to the Light Side, the first order of business is to sit in it and make racecar sounds!  

With that out of the way, let's start cleaning up my mess.  I needed to weld some mounts on my aluminum radiator, but didn't really (still don't...) know what I'm doing.  I didn't do a good job cleaning up the aluminum and ended up melting a hole in the fancy radiator.  Phone a friend and the hole is fixed, and a couple hours of aluminum welding 101 gets me here...  Zapped up the radiator and some adapters beceause I'm an idiot and didn't get one with the right fitting sizes (remember how I was getting impatient?)

While I'm at it, let's fix the intercooler.... This was a bit of a chore to deal with cleaning up contaminated welds, but it's all welded and air tight now!

Next up: Finish the IC and cooling systems.  Modify the water pump inlet flange to clear the turbo.  After that, I'd like to get the car off the build table so I can roll it out of the way as needed... Need to free up some room on the dark side first.


 

 

This is evidence of my stupidity.  Adapter at the radiator outlet.  Not thrilled, but I didn't want to cut the original fitting back farther and risk the cooling tubes.  It's less than ideal, but I suffer from enough analysis paralyisis as it is.  If it overheats, I'll revisit.

Brotus7
Brotus7 Dork
5/14/22 9:53 p.m.

Suspension... Please ignore the notched upper control arm mount.  I didn't realize the gussets I'd welded in would clash with the control arms.  Another thing I'll need to clean up.

The rear suspension is pretty neat, and if I'm honest... I'm proud of it.  I dun good.

I think this is the last time I had it off the build table?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
5/14/22 10:49 p.m.

Fun build!

I'd like to know more about your cooling system mods - it looks like you've deleted the mixing manifold. Do you have a thermostat in the car? If so, what's the water flow when it's closed?

There's a turbo Miata powered SV in the Denver area. If you're ever over there, I could put you in touch.

Brotus7
Brotus7 Dork
5/15/22 7:07 a.m.

In reply to Keith Tanner :

Hey Keith, I'd love to find my way to CO some time, I'll keep you in mind if I do. Was that's Skip's blue one? I remember looking at some build pictures forever ago and it looked pretty clean.

Re: mixing manifold. I'm going to weld a bung to it for the turbo water outlet, with the line that originally fed the mixing manifold feeding the turbo water inlet.

What's the purpose of the small 1/4" hose that runs into the mixing manifold, I think from the thermostat?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
5/15/22 1:14 p.m.

The car is indeed Skip's. Has he sold it? I don't have my hands on it, but I can put you in touch with him.

I'm not the coolant specialist at FM, but it's my understanding that the entire output of the water pump goes through the heater core and into the mixing manifold when the thermostat is closed. If you try to feed it through the turbo instead, you're going to have awfully high pressure or very low water flow. You're trying to move a lot of water through a very small restriction.

The small hose is there to ensure there is water flow up to the thermostat when it's closed, IIRC. That's the line that is traditionally used to feed the turbo water line. Keep in mind that the turbo is a significant contributor to coolant temperature, and if you use that line the turbo water is not cooled before it goes back into the engine. I'm pretty sure that's a big reason turbo Miatas have such a bad reputation for running hot, and why we replumbed the turbo plumbing in our reroute kit to ensure that water goes through the radiator. You don't need massive flow through the turbo, it gets most of its post-shutdown cooling via thermal siphoning and that's what the water is for. 

I would recommend you grab a mixing manifold from a Mazdaspeed Miata, which is clocked down a bit and may give you the turbo clearance you need.

Woody (Forum Supportum)
Woody (Forum Supportum) GRM+ Memberand MegaDork
5/15/22 2:05 p.m.
Brotus7 said:

Bent chassis that got me started.  Each tube with blue tape is bent.  I don't remember the details, but I think the story was that the car was hit on the driver's side by a Jeep.  In any event, it turned out to be too far bent and out of square, but provided me what I needed and then some.  Especially for the price - free!

 

I love the approach that you're taking here!

I'm curious...did that chassis come from the guy in Scituate?

Brotus7
Brotus7 Dork
5/15/22 2:26 p.m.

Thanks Keith, running the small hose into the turbo inlet should be easy enough.  I'm not doing the reroute yet, but I can plumb the turbo water outlet into the radiator inlet line pretty easily.   Similarly, I'll weld a bung on the mixing manifold for the hose that'd typically come out of the heater core.  I won't actually be running a heater core, so I assume I'll want some sort of restriction in the line that'd mimic the heater core.

While noodling about the cooling system and taking inventory of my hose and fitting assortment, I whittled out a throttle cable pin out of a 3/8" bolt.  The pedals are from Birkin - they weren't cheap, but they're really tidy.

Brotus7
Brotus7 Dork
5/15/22 2:32 p.m.
Woody (Forum Supportum) said:
Brotus7 said:

Bent chassis that got me started.  Each tube with blue tape is bent.  I don't remember the details, but I think the story was that the car was hit on the driver's side by a Jeep.  In any event, it turned out to be too far bent and out of square, but provided me what I needed and then some.  Especially for the price - free!

 

I love the approach that you're taking here!

I'm curious...did that chassis come from the guy in Scituate?

It sure did! Have you met him?  I've never seen so many Elans in one place before, and that was before we even went into his house where there were more hidden.

Woody (Forum Supportum)
Woody (Forum Supportum) GRM+ Memberand MegaDork
5/15/22 9:34 p.m.

I've never met him, but I remember him from when I used to hang out on the Lotus forums. I was thinking about buying an Elan Coupe from him.  When you said Lotus collector from MA and I saw the cattails, I figured that it was the same guy. 

sanyarcosean
sanyarcosean HalfDork
5/16/22 8:50 a.m.

Following Intently

Brotus7
Brotus7 Dork
7/22/22 11:13 a.m.

Been a quiet couple months as I messed around and fussed over my turbo.

I designed the turbo system around a WRX TD04 because I had two, they're dirt cheap, and we'll matched to a Miata engine for 200hp.  Problem being: I can't clock out compressor, turbine and center section in a way that just works. The wastegate actuator mounting boss is cast into the compressor housing, and it's 180 degrees off from what I need.  So enter another bout of analysis paralysis.

First thought: weld bosses where I need. But I'm not great at welding aluminum and now I can't just swap the turbo out if one dies.

Second thought: I've really wanted a GT2560R all along, but they're expensive.

Third thought: can I build a bracket to relocate the wastegate actuator and not have to weld on the compressor housing?

Let's try door #3... I welded up and machined a steel donut, with the intent of welding a circumferential rim around it for stiffness.

Yea, this sucks, I won't be able to fit the turbo feed/drain lines around the bracket and it's bolts.  More thinking needed..

 

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/22/22 11:20 a.m.

Corky Bell used to weld a 90 elbow on the compressor outlet for his kits. It's unlikely a turbo failure would take out the compressor housing so you don't really have to worry about having to do it again if the turbo dies, you just transfer the housing over.

Brotus7
Brotus7 Dork
7/22/22 11:23 a.m.

Alright, so the bracket didn't work, what now?

How about an eBay churbo. Enter wormhole of MaxPeeDingRods turbo research... Nah, the import turbos tended to be bigger than I want, after all this car should be 1300-1400 lbs all said and done, a laggy turbo or massive boost will make it extra hard to drive.

So, revisiting options.... How about this.... Things can't break if I never finish, right? So, using that rationalization, how about I try welding bosses on where I need them, I've got two compressor housings to try it on. If I'm successful, awesome, if I nuke the housings then I'll buy something that's easier to fit, and if i successfully weld it and it breaks in the future then that means I had a running turbo Locost, right? It'd be a badge of honor to break it, right? 

Wind in my sails, off to the 90F garage today.  Cleaned up the compressor housing. Turned some bosses. Fire up the spark machine and..

I'm chuffed! Alright, next hurdle is assembly.  I tried heating the exhaust housing with a propane torch before but couldn't get the bulk temperature high enough to overcome the tight fit to the center section.  Fire up the grill for the exhaust housing, throw the compressor and center in the freezer, clean up for an hour or so then magic happened.

Like a glove! Even had enough temperature differential to drop the center into the exhaust and align it up before tightening the center clamp. We'll let it cool down, then stick the actuator on and install. Time to move back to turbo service line routing.

 

Brotus7
Brotus7 Dork
7/22/22 11:42 a.m.

Damnit! Berkeley! E36 M3!

Actuator clashes with the steering shaft!

I may be able to use an actuator that doesn't have the Subaru big bracket one it.

Keith, I may end up trying an elbow next.

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/22/22 11:47 a.m.

That was meant more as an example of a modified compressor housing, not necessarily best practices :) But you do what you have to do, and it's unlikely to have any real effect on the system.

Brotus7
Brotus7 Dork
7/22/22 11:54 a.m.

In reply to Keith Tanner :

No worries, wasn't taking your comment as a FM industry recommendation, just an outside perspective of a possible solution.

I'll slap the spare turbo back together and see what my other options look like. I vaguely recall the compressor outlet pointing towards the engine now that I think about it.

Brotus7
Brotus7 Dork
7/22/22 2:45 p.m.

Scratch all that. We got this!

After a bit of staring, I realized I could redrill my spare actuator so it's farther away from the steering shaft and closer to it's original location. 

Original clocking on the right, my mess on the left. You can see how the actuator used to be at a slightly different angle.

And all said and done:

Brotus7
Brotus7 Dork
8/12/22 3:43 p.m.

Next order of business: turbo oil drain.  It's generally (foreshadowing...) not hard, with a lot of people doing it without removing the pan.  Drill a 23/32 hole towards the front of the pain, 1/2 NPT tap.  Take a little care so you don't drill into the oil pickup tube, JB weld and your fitting of choice and Bob's your uncle.  I figured the oil in the pan would help sweep away some of the debris, although sure - that's not ideal.

I did all of those steps, but I couldn't run the tap in deep enough for my 1/2 NPT- 10AN adapter to thread in.  So naturally, I stared at it.  Nope, staring at it didn't help it to thread.  Next step: remove oil pan, and weld in a bung.  The pan is only about 1/4" thick, so at best I'd have 2 threads.  Knowing that I needed to shorten the sump anyway, it isn't a big setback - just not something I felt like doing right now.  I was really hoping to get it running first before I tore into the engine.  

Now's a good time to do some more welding on the chassis while the drivetrain is out, then get it off the build table so it's more mobile.

Brotus7
Brotus7 Dork
8/12/22 3:47 p.m.

Here's an option for shortening the pan and adding back some volume.  That said, I'm not quite sure what to do with the baffles.  Probably should tack them into the bottom of the pan so they're less likely to break off.  Alternatively, some guys widen the sump and not lengthen.

 

Brotus7
Brotus7 Dork
8/12/22 7:40 p.m.

That escalated quickly 

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