LQ4 into a 3rd Gen/1972 Nova by frojoe

5 minute(s) of a 891 minute read

Then I wrapped up the motor mount pedestals. I triangulated the drive side since it's under tension, but I didn't want to eat up too much room on the inboard side so I just added some 1/8" flat bar strapping to strengthen the rectangular tube weld to the flat plate, as well as give the flat plate some rigidity...

I also added a simple rectangular tube gusset to the passenger side (under compression) just to help the welds and spread the load on the plate a bit better...

Lastly, I face milled the T3 turbo flanges on the hot piping, since they experienced some warpage. I normally try to weld things on a jig or with some type of reinforcement, but with the flanges being 3/8" thick, and in the interest of time, I gave it a go. Lesson learned...

The 1/2" thick SS304 flanges for the manifolds came out nice and flat...

The 3/8" T3 SS304 flanges from Precision didn't come out as flat...

On the passenger side I ended up removing about 0.030" to flatten the gasket area..

The driver side only needed about 0.010" removed...

The face-mill pics aren't playing tricks.. I left the couple areas unmilled as I didn't want to keep removing material.. the key areas for the gaskets are flat now so it's all good. There's also the possibility that those areas could add some spring/preload to the bolts going thru those holes, and maybe act kinda like spring washers... who knows.

Good notes about the mild steel vs. stainless steel. SS is for sure harder to work with.. but what would you recommend for a coating if I went with mild steel? I guess surface rust on the outside of the tube isn't a huge deal.. but would be nice to just not have to worry about that. Some high-temp VHT spray paint?

I'm happy with the motor mounts.. I was a little on the fence about the space (between gusset and bolt holes) on the outboard side of the driver side (yellow circle below), but I wanted to keep that area open for downpipe clearance and possible turbo drain line routing. After thinking about it a bit, I figured the engine torque is going to be pinned about the passenger side mount, so the torque will be pulling directly up, which will try to "open up" the inboard side (red arrows) more harshly than it will try to rip open the yellow circle area.. so I left the yellow area untouched and added the 1/8" strap for rigidity to the red area.