Currently waiting for many of the materials for the stuff I need to make to arrive so I’ve just been practicing every chance I have with the TIG.
And then I bought another welder yesterday! Stoked for this, believe it or not all the MIG welding I’ve done in-house so far has been with my cheap harbor freight welder (albeit with high quality everything else). There’s a lot of tricks I came up with to maximize that little welder’s capability but I still had to go borrow time on a better machine when I had anything thicker to weld.
Scored this Hobart 210 off Craigslist, new and never used. It plugs into 115 or 230 and auto-adjusts accordingly, can do any thickness I’ll run into in automotive applications with ease, and these things are dead nuts reliable.
When fabricating, inspiration can be drawn from everywhere…
Really, the tube was just fitted to ensure the front of the radiator was placed low enough that the intake can clear over it. Although as goofy as it looks right now, it’s not that far off what I plan to do – going to curve over the top of the radiator, then do a small bend towards the passenger side so the intake is placed in that cool, positive-pressure area ahead of the radiator.
Parts on order for cooling and power steering. Was able to get just about everything I needed with just a couple items 1-2 weeks out… except for one thing – just about every 1.25″ silicone hose manufacturer is on backorder right now, Samco was 6-10 weeks and has to come from the UK for the specific hoses I need so looks like I’m going with HPS which is 2-3 weeks. Sigh.
In the mean time… I bought a TIG welder! For my previous V-mount setup each time I needed to weld aluminum I had to transport all the parts down to another location and borrow time on a TIG. This will be coming in handy very soon for the coolant and intake pipes. Finally got it set up with gas and started playing with it, spending time before work each day practicing:
So far very impressed with it. I haven’t run into anything to make me say “oh thaaaat’s why it’s inexpensive”. Does everything well. I didn’t bother trying the on/off trigger on the torch, went straight to the pedal which is how I learned TIG should be done, but perhaps the torch has its times it can be useful. So far I’ve been testing it on steel, going to start playing with AC on aluminum this weekend. I ordered a gas lens kit and TIG finger and have been waiting on that.
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Quiet for a few days but the work continues! Much Tetris-ing of various parts while I work on layout for radiator/cooling, power steering, and oil cooling all at once because they all need to interrelate to make the best use of space. Looking at lots of options among universal parts for reservoirs, lines, fittings, coolers, etc. and checking measurements to see what can fit where, ordering materials for what needs to be made custom, etc.
At the center of it all, I’m adapting our Goodwin Racing triple-pass NC radiator to this project, with custom mounts of course. More details once I’ve got things together more:
Alternator on the LFX had a bit of a clearance issue – the stud on the back contacts the subframe.
Solution we came up with was to clock the alternator. Four M4 bolts holding the front and rear together (remember to mark the studs position before clocking), then remove the plastic cover on the rear and finally remove the small plastic cover over the brushes in the center on the back:
Pull the two halves apart, rotate the assembly 180° and drop them back together. You have to push the brushes in for the center shaft to slide all the way back in.
With the alternator clocked, the stud is nice and far away from the subframe:
Location found for the SMI water temp gauge’s sensor. This port is plugged with an allen head bolt, confirmed it goes to a water jacket because I got a face full of coolant when I pulled the plug despite having the motor upside-down a dozen times..
With the engine in place I could finalize placement of the rest of the drivetrain downstream.
Transmission bolted up without issues. The trans has a mount in the rear that bolts to a crossmember which ties in with the framerails, so leave the framerails unmounted until you have the transmission bolted up to dictate their placement.
V8R uses an energy suspension poly bushing in the rear diff mount. Here’s the mount bolted up without the crossmember in place: **Note the ratcheting strap: the chassis is strapped to the lift front and rear, with everything down to the subframes going in/out multiple times you don’t want to need to keep track of how much weight is on each end of the car so it doesn’t fall off the lift.
Here’s the crossmember added. The crossmember interfered with the passenger side corner of the transmission tunnel and floor, which you can see in this pic:
Taking this notch out of the crossmember fixed the interference and then everything could square up:
With the crossmember bolted up, the framerails could be bolted in their final resting place. Lots of drilling and then torquing bolts (2 person job – one person in the car with a wrench on top):
Checking the transmission angle. It’s sitting at 1.7° nose-up here. With the rear trans mount torqued down it cinches down to 1.6°:
Moving on to the diff!
V8R’s diff mount kit includes a bracket that bolts to the two ears on the back of the Getrag diff which then slide up on to the same two long studs in the rear subframe that the Miata diff bolts to. The kit also includes two bare steel tabs that get welded to the subframe for the Getrag’s front mount.
V8R’s instructions are to weld the front mount in so that the pinion angle is 1.5° nose-up, which looks perfect now that we know the transmission’s angle.
Bolt the rear mount to the diff and then bolt that to the subframe. I forgot to specify I wanted the diff’s factory mounting bolts when I got the diff from the yard so I had to source some – they’re M14x2.0, two 45mm long for the rear and one 90mm for the front plus lock washers for all three and a nut for the front.
The rear mount has roughly the correct angle preloaded into it, so with the diff mounted to the subframe you just shim the nose as necessary to dial in the exact angle. I needed to shim the nose down a bit, you can see the shim stack in the background of this pic:
Also pictured is the fun discovery that the front factory bushing was completely shot – it just popped out in my hand. Obviously this had to be replaced. Despite most of the bushing already being out, the tough part of the bushing removal was still to be done. You have to remove the steel sleeve that the bushing was once connected to. It does not come out gently:
The factory design is prone to fast wear under hard use because it’s soft and has a lot of air gap around the center sleeve. On a street car you’ll want the factory bushing (Moog PN K200641), but for track use I chose a poly replacement. There are a couple on the market, I settled on one from Creative Steel – this is the “street” durometer which is 75A. We air-hammered this in which was nice and easy. I don’t envy someone trying to press this in considering the proximity to the housing:
With that lovely side-track behind us, back to the front mount…
The two steel tabs are identical, but I found they both needed some grinding to clear the housing better. The front just got a bit of clearancing on the outer radius by the hole. The rear tab needed to be notched:
More than one way to tackle setting the pinion angle prior to welding, my method to eliminate variables as much as possible was to set the whole assembly on the bench and shim the subframe to dead level and then shim the diff to the 1.5°:
Then tack-weld the tabs in place:
Rear tab tack welded in, you can see why I notched that tab:
These are tack welded ONLY at this point. Always test fit in the car and measure before finalizing. The car might not be dead level on the rack or jack stands, and that transmission angle that was measured is relative to actual horizontal, not to the car. Measure many, many times and weld once.
Turns out, the car is level on the rack ! Diff sits at 1.5° nose-up, matching the transmission’s angle within 0.1°:
Subframe comes BACK out again, and final welding can happen. Diff is removed from the subframe for this of course. I cut a length of steel tube to match the length of the diff’s front mount and bolted that between the tabs while welding to prevent warping. Don’t leave the diff in there to serve that purpose, you’ll melt the bushing.
That’s it! Subframe will get cleaned and painted now along with some other parts.
Notes… Remove the alternator and oil filter housing before it goes in, it makes navigating the engine between the frame rails much easier. Once engine is in you can bolt those back on.
I hammered more on the firewall by the heater hose holes than it turns out I needed to, but it’s nice to have room to work back there. Once the engine is back out I’ll probably cut that section out and weld in a new recessed wall there.
Final work on the engine bay after much stripping of seam sealer goo and paint removal – stitch welded the shock towers, frame rails and firewall.
Some might also remember that I had triangular shock tower gussets, those were something I made almost a decade ago, with my first welder when I had very little idea what I was doing… It was time for those to go, but for primarily nostalgic reasons I made new versions of those gussets, this time with dimpled holes for more strength and some much improved welding.
Sprayed all the welds with primer for the moment, will be painting the whole bay once all the test fits of the engine and other parts is done.
The existing cross-brace between the frame rails in the front was another area that I originally did many years ago and needed an update. That brace also had brackets for the now gone V-mounted intercooler, so a new version will be needed. Once the stitch welds had cooled I cut the old cross brace out, which has the added benefit of making ingress/egress for the engine test fitting nice and easy:
Rocky (Resident Miata Yoda and shop owner) wants the car to be running already:
Engine bay is ready to rock and roll for test-fitting the engine!
Note: in this photo, one thing was left to do before the engine could fit; the firewall area around the holes for the heater hoses needs to be massaged with a mallet to clear the high pressure fuel pump protrusion on the back of the LFX’s left head. I did that after taking this pic, and it’s not a very pretty sight for now, but once test fitting is done I’ll come up with a clean way to finish that area.
Thermostat housing. After looking at the coolant flow layout, we’re pretty sure the heater line in/out (lower two holes) are not critical to coolant flow when thermostat is closed like on the BP motor. Used freeze plugs to seal those up, part number 555-007 (~0.47″) and 555-016 (~0.38″).
New thermostat (PN 73580) and gasket (PN 35781) installed as well.
New V8R pan is on the engine, Picked a location for the SMI gauge’s oil temp sensor, just above the drain plug in the pan:
Excited for the progress! So far I’m about 65 hours in, 40 of which are must-do’s for the swap, the other 25 hours on “while I’m in there” stuff. First test-fit of the engine will be soon so I can start looking at logistics for cooling and exhaust as well as mock up the transmission which will allow me to do final placement of the frame rails and the differential pinion angle.
