Indeed Peter! ~ and I can highly recommend the Den Braven sealant.

 

I'm right at 14 days before I start heading south from Chicago to the gulf coast for the South Alabama British Car Festival. One thing that I wanted to take care of was the vacuum actuated fresh air vent at the base of the windshield. I've used a piece of plastic to prop it open this summer, but I wanted the ability to open and close it from inside the car.

The vacuum actuator for the air vent was extremely rusted and would not work when vacuum was applied. I disassembled it for a post-mortem.


The rubber diaphragm inside had a tear. I might have been able to patch it with a bicycle repair kit, but I didn't feel like that was going to be a long-lasting solution with all the flexing it does.


If you've ever tried to buy a BD25328 scuttle vent diaphragm, you know they haven't been made in a long time and there is no easily available replacement. I didn't think it would be too hard to find something that would work.

I started with the turbo wastegate vacuum actuator for a 6BT Cummins turbo, part 3592766. The problem was this was a pressure actuator, not a vacuum actuator. I didn't feel bad sending this one back to Amazon.


On the left we have a turbo wastegate vacuum actuator for a 1998-2004 VW Beetle. This one was a vacuum actuator and fit well against the firewall if you removed the extraneous bracket. Being meant for a turbo I thought it would hold up well to the heat under the hood. The only problem was this only had about 1/2" of travel which was not enough to open/close the vent properly.
Next to that is a Dorman 604-922 HVAC Blend Door Actuator for select Chevrolet/GMC models. This one has about 1" of travel so it's plenty to open and close the vent. The arm had to be filed down to fit through the hole in the firewall, and I am worried about how well it's going to hold up to the heat. But for $11.42 delivered to my door I am willing to take the chance.


I welded a piece of coat hanger to the end of the arm to connect to the vent door.


Not the greatest picture but here's a view through the vent showing how the diaphragm attaches to the door.


And here's a video showing it in action. I still need to adjust the vent door.

Now that I had that working, I needed to get the dash switch working. If I hooked up my vacuum pump to the switch, it would not hold any vacuum whatsoever. I thought maybe the rubber pads inside had dried out so I soaked it for a day in some interior protectant as a "what do I have to lose?" play. It surprisingly didn't make a difference.
I took the switch apart and found a good bit of corrosion. My guess is there was a problem with the heater valve and coolant got sucked into the switch.


Here's a picture showing the rust where the rubber pads slide and either allow vacuum to pass or seal it off. This was double trouble because the rust meant the pads did not seal, then the rust started to abrade the rubber pads.


The metal part actually cleaned up well, but the damage was done to the rubber pads. After 55 years the rubber had lost a lot of it's softness, and the rust had sanded down part of them.


I have a Plan A and a Plan B in the works, but we have to wait a few days for a UPS delivery...

 

Hi Thorsen,
Don't worry about the heat on the actuator, it will work for a long time. GM used them in the engine compartment and in the interior. The location is not super hot, its not over the exhaust manifold.

 

My Plan A mentioned above was purchasing a NOS vacuum switch. Even though it was new it wouldn't hold vacuum. I'm guessing the rubber lost its pliability but I have not opened it up yet.


Plan B was to use a 3 port 2 position pneumatic switch. I used but this is only going to be a temporary solution to get me through the next few weeks. I'm not going to permanently mount it.


In the picture above, engine vacuum comes into the port on the lower right. The port on the top connects to the scuttle vent. Flipping the switch up connects the vacuum to the vent and opens it. Flipping the stich down connects the scuttle vent to the open port on the bottom left which allows air to flow back into the scuttle vent so it can open. It simultaneously blocks off the engine vacuum port so the engine isn't pulling in extra air. It works pretty well.

Plan C and D are on hold until I take the car off for the winter season. Plan C is making new rubber sealing blocks for the factory switch. If that doesn't work, plan D is to figure out a way to retrofit the pneumatic switches into the factory switch.

 

I have both parts, just ask.

 

I was able to finish up the radio install and I'm pretty happy with how it turned out. It looks like an old AM radio but has a USB drive, bluetooth, and adjustable color so it will match the gauges.
With the radio off, it just looks like an old AM radio...


When you turn it on the display lights up and you have a radio with modern features.


I spent the rest of the day with my buffer and polishing compound in an effort to bring a little clarity to the paint. I followed it up with two coats of carnuba wax and while it looks better I still think I have some room to work with it.

 

I'm less than a handful of days away from an epic road trip so I spent today changing the oil, lubing the chassis, and cleaning and waxing the wheels.
It's been pretty chilly in Chicago the last few days but the factory heater seems to do an fair job of keeping the cabin warm. If I try to run the fan it sounds like it's out of balance but I'll live without it until I can restore the heater box.

 

Today is the 2nd day of a pretty epic road trip. Day 1 was Chicago IL to my parent's house in downstate Illinois near St. Louis. Not much to see on that trip except miles of cornfields.
Today our first stop was Chester IL to check out the Mississippi river.


We got stuck by a train hauling box cars and coal.


I believe this tow boat was waiting for upstream traffic to pass before he continued going down stream. The water level is pretty low in the river right now.


It's been a really long time since I've used a gas pump without a credit card reader.


Cairo Illinois has a floodwall that drops down to prevent the town from flooding when the river is high. We didn't have that problem today.


Kentucky Hillbilly BBQ. I always time my travels so it's meal time whenever I pass by here.
To say it another way, it's always meal time when I pass by here.


After lunch Dad had fun blasting through the twisty country roads in Kentucky.


Gratuitous shot of the dash.


Kentucky back roads.


The right fuel pump started working intermittently somewhere in Tennessee. We ran on the left tank for the remainder of the day, then picked up a universal pump and changed it out after dinner tonight.

 

My experience of NOS vacuum switches is that they just need some use & suddenly start working as designed. Otherwise some new rubbers do the trick.
I had the faith. I knew I was installing a NOS switch that leaked off vacuum and let air in. With use it works perfectly. David Manners found me a new Bezel & I re-chromed the backing plate with all my other chromework. Man there is a lot of internal chromework on an S Type & 420. I rechromed the armrest hinges the lot.

 

Replacing the right-hand fuel pump with a universal pump.
Hoo bloody hooray!! Another SU fuel pump bites the dust!
Honestly, I would not have an SU pump in any Jag I have resurrected in the last 20 years. (and that is quite a number).
There are numbers of aftermarket pumps which are a fraction of the price for a new SU pump and are far more reliable.
If concourse is your thing, then by all means retain SU. But for the everyday "club runner" or driver dump the SU and go for a modern pump

Only some of the discarded SU fuel pumps but not all of them

 

They are junk & the oil companies know it.

 

Day 3 of Epic Road Trip - Tupelo, Starkville, Hattiesburg, Biloxi.

I stopped at the Tupelo Hardware store where Elvis Pressley's mom bought his first guitar.


Stopped at Mississippi State University to take my niece and nephew out to lunch. Crawfish poboy for lunch!


My nephew joined the trip and enjoyed driving the Jaguar.


Eastern Mississippi is full of trees.


Stopped in Hattiesburg to see my Alma Mater and my old dorm.


Hwy 49 from Hattiesburg to Biloxi is one of my favorite drives.


Finally made it to the Gulf Coast.


View of the sunset from our dinner.


Aunt Jenny's restaurant where we had dinner.

 

Day 4 of Epic Road Trip and we come to the top reasons for this trip.

First, in 1997 while living in Hattiesburg MS my best friend and I drove our MGB's to the Mobile British Car Show at Bellingrath Gardens. Here we are prepping our MGB's for the trip.


And again in 1997, me sitting on my red MGB and my friend sitting in his orange MGB.


Back to 2022, we made a stop at the Biloxi Lighthouse on our way to the South Alabama British Car Festival.


My friend Jim and I back at the British Car Festival.


My nephew earned his keep by cleaning all the road grit off my car before the show.


My Dad and I


View of part of the Festival.


We left the car show early to go eat lunch at my friend's restaurant. The backroads of Fairhope AL are really charming.


BBQ shrimp and Fried Green Tomatoes


Shrimp and Grits

 

Days 5 and 6 covered the return trip home. I ended up covering 2,104 miles and only suffered loosing one of the fuel pumps - which was not a major issue since I simply switched tanks. Today I had a 20-25mph tailwind and my best tank of gas was 26mpg @ 77 mph.
Was a great trip and I'm glad to be home - but I'm also ready to start my winter upgrades.

 

Tonight marks the end of the 2022 driving season for my 420. Since I bought the car back in July I have put on about 4,500 miles which is pretty impressive - but it's time to start knocking out items on my winter to-do list.

Before I pulled it into the garage one last time, I put some UV dye in the power steering tank and made a drive around the block to see if I could find where the steering box is leaking. The box was rebuilt in the last 12 months or so but you can see the leak from the steering shaft. I'll have to decide if I want to address that or leave it alone. I'll probably see what I can do to make it stop leaking.


As of now my winter to-do list consists of the following:
- Add air conditioning
- In concert with above, either rebuild the factory heater box or replace it as part of adding AC
- Have the exhaust manifolds ceramic coated (the porcelain has chipped off and looks pretty unsightly)
- Upgrade/improve electric radiator fan and add a PWM fan controller
- I will likely upgrade the alternator to account for the needs of the AC and electric radiator fan
- I think the rear diff is leaking from the input shaft. Major goal here is to resist the urge to drop the whole cage and completely rebuild it like I did on my XJS last winter
- The horn needs to be replaced with something more in line with the character of the car
- Think long and hard about the gauges. The speedometer is off by about 10 mph at speed, I don't have much confidence in the accuracy of the tach, I'm pretty sure the temp gauge is lazy, and the oil pressure gauge doesn't move much. The fuel gauge seems to work ok and I replaced the ammeter with a new volt gauge that reads about 1 volt higher than my DVM.
- The covers on my interior lights are long gone. I'm thinking about either 3d printing new ones or vacuum forming some.

 

I just had mine sand-blasted off, the guy used something from off continent to eat through the old porcelain _ I'll find out later.

I bought this high temp black paint, followed the instructions and the mat black is still black and looks great.
I just found it more practical than having the porcelain reapplied.

I'll post a photo too.

 

In another thread, someone mentioned Zircotec Ceramic coating. It's used in motor sport, looks good, said to be very robust, and provides some heat shielding. I don't know if it's available in North America or if anyone here has more experience with it. Almost anything is better than the original enamel.

 

I'm probably going to use Jet Hot Coatings as their chrome finish offers up to about 50% heat containment. They sent me a picture of a set of Jaguar manifolds they did a few weeks ago in their chrome finish and while I would prefer something black, their black finishes are only cosmetic and don't do help to reduce under hood temperatures.

 

Cost if you dont mind me asking

 

$280 to sand blast and coat both manifolds
$10 insurance
$61 return shipping
I assume about $60 to ship the manifolds there.