Tom’s Car9 – LS3 Build

[horchoha]

. If #2 becomes a problem, than a more serious heat transfer barrier can be added to both coil packs. As you pointed out, it does bear monitoring.

Exactly what I was thinking. Fab up a heat shield from some .062" steel and have it mount with the coil mount and stand off 1/2" from the coils (on the exhaust side).

[seattletom]

Following Bent’s observation, I’m going to add heat shields to protect the coils. The 1" engine offset puts the right-hand side coils too close to the exhaust manifold. Perry, I like your approach, but think I’ll use aluminum panels covered in DEI heat shield instead of steel. The standoffs will be a PIA to make because of the odd shapes required, so that qualifies as making eight more br@ck^ts. I’ll add this to my to-do list and come back to it a little later.

Scuttle floor install was completed and ECM and associated fuse box mounted. The third box shown is the Coach chassis relay/fuse box and hasn’t been mounted yet. Excess engine harness length lives in the snake pit in the center area and has been lashed down to avoid abrasion.

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The driver’s side of the scuttle area is consumed by the inlet ducting.

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Still lots of wires to add to the scuttle area: Chassis front and rear harnesses, switches and instruments along with several small control boxes and relays. But the basic scuttle footprint is locked down.

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Next is final mounting and hook up of the intake manifold and ducting.

[Kartracer47]

Gorgeous!!!!!!

[cheapracer]

Building it up in layers as there's not much room for big hands.

I don't think there's many if any ladies reading the comments, so no need to show off.

[seattletom]

I don't think there's many if any ladies reading the comments, so no need to show off.

CheapR, you caught me trolling again. Great to hear from you.

Kartracer, thanks for the kind words. Wycked7 still inspires me!

Finished trimming the scuttle firewall pieces to fit the final chassis welds.

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Installed the intake manifold. Firewall needs more fettling for throttle body clearance, but close.

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Still deciding whether to use the scuttle volume as a cold air box, move the air filter outboard or something in between. Need to final fit the intake plumbing and decide.

[seattletom]

Finished the cold air intake. Decided to leave it per my original concept, keeping the under-scuttle air filter, but had to modify the duct bend angle a bit with a cut and weld to make it fit right. Mounting br@ck^ts for the intake tubes had to be tweaked/re-made as well.

Added a baffle beside the air filter to keep the larger birds out of the scuttle. Will probably add some closed cell foam filler pieces to further reduce scuttle air flow aft of the filter. I’ll still get rain drips on my toes, but that will be the price of eventually getting this thing running.

Fuel injectors, MAP, MAF and electronic throttle control connections hooked up, which completes the engine-side ECU harness connections. Filtered-air side of the PCV system now plumbed.

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Scuttle firewall mounted. Had to extend the hammer-formed relief on the driver’s side piece to give more clearance for the throttle body.

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Still have the chassis electricals to mount/wire in the space over the passenger’s feet and the dashboard to wire, but all the under-scuttle mechanical work is done.

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And eventually it all gets covered up by the (now dusty) scuttle skin.

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Just passed the 12-year mark on this Build Log. How the time flies.

[horchoha]

Getting closer to being a 10%er Tom!

[B85]

Looks great ! Think you will have enough power ? LOL
Been thinking about getting my American 7, 5.0 off the lift and running ?
Kinda burned out on the 15. Think I need a brake.

Randy

[seattletom]

Looks great ! Think you will have enough power ? LOL
Been thinking about getting my American 7, 5.0 off the lift and running ?

Thanks, Randy. I think the operating phrase will be "Traction Limited."
Glad you're keeping the V8 in the American 7.

Getting closer to being a 10%er Tom!

Thanks, Perry. Half-steps to infinity...

Last fall, I thought I had “final mounted” the LS3 coil packs in the engine compartments (an aesthetic choice.) However, an astute observation from Bent Wrench and others pointed out the potential of cooking the coils with heat from the headers.

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A mental block about do-overs postponed addressing this, but the garage got chilly this week and I needed to find an indoor project. So off came the coil packs.

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First, aluminum heat shields were added, standing ½” off the coils. This requiring some mods to the packs’ mounts and related fiddling. The engine is offset 1” to the right, so the passenger side coils are most at risk and got a big shield.

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And then a reflective insulation layer was added to increase radiant heat protection. (Bubba likes the shiny stuff. ) The LS7 sourced headers have a double wall which should help, but the insulation’s adhesive will still get a good test.

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On the driver’s side, the steering column and brake reservoir tubes limit space available, so a smaller heat shield was fitted. But engine offset and the steering column’s shadow should help reduce the coils’ radiant heat exposure.

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Time to final mount the coils again. The heat shields are not a perfect solution but should help the coils live.

Then off to “final mount” something else. Maybe aft of the dashboard for a change.

[KB58]

About insulating the units, while it slows heat transfer, it doesn't prevent it, so during a long drive, they'll still get warm. Also, that same insulation will prevent internally generated heat from leaving the units, so a small air duct can solve that if necessary.

[seattletom]

About insulating the units, while it slows heat transfer, it doesn't prevent it, so during a long drive, they'll still get warm. Also, that same insulation will prevent internally generated heat from leaving the units, so a small air duct can solve that if necessary.

Good points, Kurt. While the heat shields and standoffs allow for some chimney-effect convection, ducting would definitely improve airflow. As the "outside" of the coil packs face the side panels, adding small scoops or louvers would be relatively straight forward.

Not sure what the coils' temperature tolerance level is, so will be monitoring the situation once up and running.

[horchoha]

Not sure what the coils' temperature tolerance level is, so will be monitoring the situation once up and running.

That's what I would do, most likely won't be an issue.

[SamY]

One other minor suggestion. Using a heat insulation washer such as Mica/PEEK/Fiberglass between the heat shield mounts and the coil bracket would eliminate some of the conductive heat transfer. Not sure how much conductive transfer they'll get vs the radiant/convection heat coming thru/around the heat shield, but every little bit helps.

[seattletom]

One other minor suggestion. Using a heat insulation washer such as Mica/PEEK/Fiberglass between the heat shield mounts and the coil bracket would eliminate some of the conductive heat transfer. Not sure how much conductive transfer they'll get vs the radiant/convection heat coming thru/around the heat shield, but every little bit helps.

Thanks, Sam, that's an interesting heat path I hadn't considered. The coil mounts had been attached to the chassis using nuts/bolts, but when adding the heat shield I had to put nutserts into the coil mounts in order to bolt the assembly to the chassis. The nutserts I had on hand were not flush-mount types so their lips act like the washers you described. Just not insulating. But a mica washer layer could be added if need be. The heat shield bracket does lay flush to the chassis, however, so that side of things might warm up a bit. It bears watching.

On the flip side of the temperature topic, it's been durn cold in the garage the last few days. So took some time to desk-check my chassis circuit drawings and trying to remember why I was going to wire the car that way. Then laid up the rear chassis harness in the indoor shop. The harness is now strung loosely along its mounting points from the scuttle thru the tunnel to the fuel tank. After staring at the tunnel and with my warm coat still on I rummaged around in the garage and finally found my driveshaft and safety hoops. It's supposed to warm up and snow tomorrow, so maybe I'll have something picture worthy to post soon.

[seattletom]

Got the driveshaft and safety hoops in place. Just need to torque down a bunch of bolts. Interesting exercise juggling that assembly into place while leaning over the roll hoop forward braces.
It all fits into the tunnel, but only one way--from the driver's side.

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