73 240Z VQ37VHR Swap Build Log

[Sanchez 2]

Took a small break from the frame work to deal with some small areas that were bothering me like plugging holes from the factory and PO that I wasn’t going to need.

 

[Racer X 69 0]

On 8/17/2020 at 9:58 AM, Sanchez said:

 

I was hoping maybe some of you could suggest a relatively good primer to use to keep the car from rusting while I do the body work. Something that I can body fill over before using a a highbuild primer primer before paint?

 

 

 

 

I've been using Variprime 615S self etching primer since the late 1970's. Excellent stuff, it kills any surface corrosion that happens between the stripping of the old finishes and when you get the car to your shop. It also is a good base for high build primer just be sure and go over it with some scotchbrite first to promote good adhesion.

 

 

http://products.axaltacs.com/dcat/us/en/dr/product/615S.html

 

[Sanchez 2]

@Racer X 69

Thanks for the suggestion I’ll look into it. I’m gonna be grabbing some POR15 for the insides of frame rails, and have some weld through primer I put on these pieces for metal to metal and lap welds.

[AydinZ71 15]

1 hour ago, Sanchez said:

@Racer X 69

Thanks for the suggestion I’ll look into it. I’m gonna be grabbing some POR15 for the insides of frame rails, and have some weld through primer I put on these pieces for metal to metal and lap welds.

eastwood sells a coating you can spray inside frame rails with a wand. It’s expensive, but the long tube is convenient and their products are very high quality IMO. 

 

im doing tons of panel replacement and rust repair myself. Feel free to scroll though the videos on IG @240z_restomod. You might see something that jogs your mind  

[Chico260Z 0]

Hye,

If you want some informations, i have a VQ37VHR swap in my 260Z 2+2 😉

 

See my FB or Insta:  Chico260Z

 

[Sanchez 2]

Firewall/kick panel coming together. Anybody else attempting to work this area I would definitely suggest breaking it into sections and not trying to make this as one piece. There’s just too many bends, folds, flanges required unless you have some industrial metal working tools.

[Gumiho3 0]

I just took off my factory sound deadening and found a big hole in that area that the previous owner patched with fiberglass....

What guage you using? I have lots of 16Ga but figured it was overkill. Also juat got my wiring from hexagarage and the wiring seemed like it was done good lol. Will need to hook it all up to test 'er out.

[Sanchez 2]

@Gumiho3

Good to hear about Hexa Garage, I’ve been speaking with the owner and will probably get my harnes done in 1-2 months. You can use 16ga if you want, the stock is 18ga though for floor pan and firewall metal. If you’re good at welding and lap the patch it shouldn’t be difficult. I’m sticking to stock metal thickness throughout my repairs and doing the strengthening at specific stress points on the body later.

[Sanchez 2]

Not really a progress update on the car, but I did just adopt a new helper who may eventually learn to fetch me tools.

You can see a bit of the Z in the background. She’s settled in nicely at home so I can start bringing her to the garage and get back to the body work after this 2-3 week break.

Edited March 16 by Sanchez

[Sanchez 2]

This Sunday I finished up all the welding of my passenger floor pan, ton of work having a buddy hold a flash light from the under the car to see all of the small holes here and there but it is fully in place (minus a frame rail, ordering those soon). Waiting on a sheet metal punch to finish up the firewall now that I have all the metal cut and then I have to figure something out for that little fan blower intake chimney in the cowl area that’s rusted through. I may just weld it smooth and make the system pull cabin air or modify it to take fresh air from the passenger side fresh air duct. 

[AydinZ71 15]

9 hours ago, Sanchez said:

This Sunday I finished up all the welding of my passenger floor pan, ton of work having a buddy hold a flash light from the under the car to see all of the small holes here and there but it is fully in place (minus a frame rail, ordering those soon). Waiting on a sheet metal punch to finish up the firewall now that I have all the metal cut and then I have to figure something out for that little fan blower intake chimney in the cowl area that’s rusted through. I may just weld it smooth and make the system pull cabin air or modify it to take fresh air from the passenger side fresh air duct. 

 

You and I seem to be working in the same area. I am eliminating the "cowl box" altogether. Previous owner already cut into the firewall to vent the engine bay through the cowl. Since its rusted quite bad (previous owner did not pay much attention to drainage), im going to rebuilt it with drainage in mind. Where the cowl vents are present, I'm going to build a ramp for air in the engine bay to continue escaping. Where the cowl is flush, I'm eliminating the cavity and placing 20-gauge sheet metal directly under the cowl.

 

Rain water will now drip towards the engine bay and through the fire wall.  Il be sure to seal the seams real well. I already eliminated the drain that passes from the cowl box, through the cab, and into the fender cavity. 

 

Since its race car, I no longer have a dash, and have no reason for the OEM mounting points. 

[Sanchez 2]

@AydinZ71 Yeah the blower intake seems like an area pretty prone to rust and causing issues in the cowl. I’m surprised that I haven’t seen more impressive engineering solutions to the stock part other than just recreating it.

My thoughts are, with the Civic or Kia blower motor a lot of people upgrade too, is how necessary is keeping the chimney the stock volume? Could I find a way to weld a plate in to flatten the area, cut a hole and weld some 2-3” diameter flared exhaust tube and not cause any bottleneck to the air flow? I plan on trying to figure out a way to make water drain better around this piece and have more access (more room between the chimney and firewall) to weld the piece in and seal it so this never happens again. I think even just tilting the stock chimney 45deg away from the firewall would be an improvement so debris doesn’t get trapped as easily and sealer can be applied better than what they tried 50 years ago at the factory.

[AydinZ71 15]

57 minutes ago, Sanchez said:

@AydinZ71 Yeah the blower intake seems like an area pretty prone to rust and causing issues in the cowl. I’m surprised that I haven’t seen more impressive engineering solutions to the stock part other than just recreating it.

My thoughts are, with the Civic or Kia blower motor a lot of people upgrade too, is how necessary is keeping the chimney the stock volume? Could I find a way to weld a plate in to flatten the area, cut a hole and weld some 2-3” diameter flared exhaust tube and not cause any bottleneck to the air flow? I plan on trying to figure out a way to make water drain better around this piece and have more access (more room between the chimney and firewall) to weld the piece in and seal it so this never happens again. I think even just tilting the stock chimney 45deg away from the firewall would be an improvement so debris doesn’t get trapped as easily and sealer can be applied better than what they tried 50 years ago at the factory.

 

So the rule of thumb on blowers (and pumps/fans really) is if the distance from the intake/exhaust of the unit is very short to the cab/outside, the duct only needs to be as large as size of the openings on the blower. If the ducting needs to be long (more than a few inches), then you should upsize depending on the distance the air needs to move. The assumption is that the engineers designed the fan with the appropriate apertures to maintain velocity and minimize pressure drop. If the ducting is long, the extra length contributes to more pressure drop so an upsize will compensate. Centrifugal fans/blowers operating near ambient pressure are very sensitive to restriction (think central air in your house), so its good that you had this in mind. When the pressure the fan is generating measures in inches of water (less than 1psi), there isn't much room for pressure drop.

 

Since you are keeping the stock chimney/cowl-box for your HVAC, i would consider angling the surface to drain to one specific location, then consider draining into the engine bay somewhere visible. You can use lightweight filler to achieve this, and seal it up real good with epoxy (either por-15 style single component, or dual component) I think a common rust point is where the cowl drains through the cab and into the fender cavity. Since you rarely look there without the fender off, its a common place for surface rust to proceed to full-blown pitting. 

 

This being a race car, I thankfully did not need to worry about a blower at all. I am however adapting to the passenger size fresh air intake into the cabin, for the driver. Funny note, it seems a literal rats nest was made right where it meets the cab down by the passengers feet. Previous owner had the car outside for years. That was fun to clean-up.