1973 Grande Build

[Steve McMahan]

Well, tomorrow is here and I am closer to finding my vacuum leak. I pulled the vacuum feed from that plastic manifold attached to the firewall, maybe a vacuum distribution terminal? In addition, I pulled the PVC valve from its hard-to-get-at rear location, behind the intake. My plan was, start it up, see if blocking the PVC valve improved the vac reading. Bar that, restrict the PVC, block the grommet the PVC plugs into, and see if I had any vacuum at the vent hose from the throttle body. It was a recommended these from the 5.0 guys as a test for a leaky intake.

So I start it up, look at the vacuum gauge and to my surprise, this:

View attachment IMG_2669.mov

As I say, I’m not sure what I did, but consistent and steady 18” sounds like a win. Now, to be clear, as Aces has said before, this is the engine running in Open Loop, as the O2 sensors haven’t warmed up yet. But still, I feel a sense of victory. So, I’m gonna get my vacuum pump and one by one, test everything I disconnected to discover the leak the smokers didn’t show. To be fair to the smoker, it did find three leaks which I’m sure will contribute to better running in closed loop.

 

[Steve McMahan]

Well, it just goes to show you, a part can test fine in mock-up and then, installed, it fails. The EGR Solenoid valve that regulates the opening and closing of the EGR valve failed. Specifically, the diaphragm leaks. I doubled checked my spreadsheet, and I have a record of testing it, and it passed, about one year ago.

All of the other stuff passed with flying colors. What a difference in idle quality and snapping the throttle didn’t produce any pop or hesitation. I get my new one on Wednesday. I still want to get it out and run it for like 30 minutes to get a full feel of the engine and how the EFI system is acting.

Thank you again for the encouragement and support.

 

[AcesArneson]

Thanks guys for the great advice. Tomorrow, I’m going to try and remove one of the last potential source for a vacuum leak, the PVC valve. I’ve already isolated every other connected source with no change. I didn’t see anything in the compression check that would lead me to think the motor cannot create at least 17” of vacuum. After several discussion with others on other forums, I’m beginning to believe my problem with low vacuum is mechanical in nature. If it turns out to be the PVC, and it’s a new one with a new rubber insert, what would you do next?

If isolating the PVC doesn’t improve the idle vacuum, the only other known vacuum leak source is the idle air control valve. There is no easy way to isolate that, as far as I know. The other sources of leak are the manifold. I’m trying so hard not to do that, for now.

Well, it just goes to show you, a part can test fine in mock-up and then, installed, it fails. The EGR Solenoid valve that regulates the opening and closing of the EGR valve failed. Specifically, the diaphragm leaks. I doubled checked my spreadsheet, and I have a record of testing it, and it passed, about one year ago.

All of the other stuff passed with flying colors. What a difference in idle quality and snapping the throttle didn’t produce any pop or hesitation. I get my new one on Wednesday. I still want to get it out and run it for like 30 minutes to get a full feel of the engine and how the EFI system is acting.

Thank you again for the encouragement and support.

Hooray! Way to stick with it and troubleshoot systematically. You are teaching the rest of us with your learnings!

Fixing this will surely set you up for open loop. It is usually idle that causes the most problems. Since you are running the system exactly as it was in the Tbird I think you will be fine. Check out EFIDynotuning to see what can be changed and how.

 

[Steve McMahan]

Ty for the advice.

 

[Steve McMahan]

Well, glad to get, for now, the vacuum/idle issue resolved. Now, it’s time to turn to fixing the leaking PS box. The leak is coming from the top of the unit (more like an ooze). While I understand it makes sense to “rebuild” the unit since I don’t know the internal condition or the history, I’m trying to avoid my tendency to “just one more thing” it to death. plus, it’s working great otherwise. My history is too much working on and not enough enjoying driving. So, while pulling the box and doing a complete rebuild make sense, I just want to fix the leak. And sure, this could blowup in my face and I could end up doing it anyway. But, I’ve got the kit to do what I want and next month (Nov) when I’m back in Az, I’ll be pulling the box out.

So, all that to ask, beside the pitman arm puller, are there any special tools I will need to replace the seal at the top of the unit? I’ve also got a new rag joint, not that the existing one looks bad, but I’ve got to remove it anyway, so.

Thank you the continued encouragement.

 

[Steve McMahan]

Well, another month and progress. I ended up readdressing the vacuum issue because I discovered most of the vacuum valves from the 5.0 are directional. In that, while all but one is on or off, what connection to the vacuum source makes a difference in the performance of the solenoid. On the purge, EGR regulator, and both TAB/TAD solenoids, where the source is connected to affects the performance of the system. In three of the four valves, they leaked vacuum by when they were in the closed position. The purge valve was the worse, with the EGR regulator second. Rearranging those connections solve the vacuum and idle surge issues completely. It now idles great, no surge, no off throttle hesitation, nothing but very consistent 650 RPM idle.

So, now the power steering leak issue. That sucker is heavy. I do not recommend removing the steering gear by yourself. I did, and it wasn’t pretty. I got it out by gravity. On the bench, try as I may, I couldn’t loosen the top ring (the part at the top of the steering shaft with the four holes) with the correct tool. I soaked it in various chemicals to no avail. I only have a small plumbers soldering torch, and that didn’t help.

I finally gave up and bought a new steering box. Again, I would not recommend to install this beast by yourself. But with my floor jack, a positioning jig in the jacks lifting cut to align the box, a rope at the top to guide it into the steering shaft, I got it in, and all four attaching fasteners torqued to specs. I got the pump tank filled, started it, and no leaks. Now my problem.

Because this is my “keep’s me busy and out of the house” project, and I like to thrift shop, I found a power steering oil cooler for a Porsche that I couldn’t resist installing as part of this project. While I was at it, I also installed an in line filter, just to be safe, all .375 power steering hose on the return side. What’s happening is the cooler’s top is about 3 inches above the top of the fluid reserve cap. When I first started it, I needed to add quite a bit of PS fluid. I finally got it when I was happy with the “running” level in the reserve. So, I put the cap on, turn it off, and watched the fluid come out of the vent in the top of the cap, and run down the side; it was quite a lot.

So, my idea to solve this is to install in the return hose, after the cooler, a .375” check valve, to keep the oil in the cooler, and from running back and overflowing the PS fluid reserve. Problem is, and this maybe my internet skills, I cannot find one that will fit on a .375” hose. I’m hoping one of you guys know where to get one.

I‘m very happy with the way the car is running, I’ve got no codes that indicate any issues with the factory EFI system, and now with the new steering gear box, I’m ready to have it aligned so I can drive it here in Az over the winter to gain confidence in the mechanical aspect of the car.

Thanks again for reading and for solutions. Steve

 

[Steve McMahan]

So, as I mentioned in the previous post, I’m having an issue with too much PS fluid running into the PS reserve after I turn the engine off. My problem is related to the oil cooler being higher up that the height of the reserve and the cooler routing being return line top of cooler, bottom of cooler line to reserve.

So, I asked for help finding a valve to restrict the flow of the return to keep the PS fluid in the cooler, not the reserve when I turn the engine off. I didn’t stop looking for a solution and I found this at Summit:

https://www.summitracing.com/parts/rus-650613
This is a 5 PSI seat pressure check valve. I’m wondering if this is the right direction to go in creating a stop that will hold the cooler’s fluid in the cooler. Here is my lines and cooler configuration:


In the first photo, the return line has a filter and is routed to the cooler, second pic, through the core support. My plan was to mount the check valve in place of the filter and move the filter to the return line from the steering box to the cooler.

Any thoughts? Also, and just as an aside, I was surprised I couldn’t find something like this for trans cooler lines. I remember having one long time ago on an RV. Any help is appreciated.

 

[Steve McMahan]

Ok, more info. I rerouted the cooler lines, reversed them, so the return to the pump reserve is coming from the top of the cooler. It helped a bit: while running, the PS fluid is about 1/2” covering the pump top. Once the engine is off, the fluid is about 1 1/2” from the top of the reserve. Not sure where that level will be once the fluid is hot.

I still would like to find a solution that would “freeze” the fluid level mid reserve.

 

[Steve McMahan]

Anywho, can’t find a solution to the PS reservoir level issue. I do have a question for other 73 coupe owners, is my front end up too high?

I ask because my original car was a 351C with AC. I’ve rebuilt the complete front end, and kept the original stock springs. I now have a 302/AOD from an 87 TBird and it looks jacked up to me. The 5.0 has AC compressor, in case that matters.

From my searching, I estimate the front of the car is about 105 pounds lighter. That’s 90 for the two engines and 15 for the compressors.

Is that enough that I should be modifying the coils and if do, by how much to get a more stock height?

Thanks, Steve

 

[Sheriff41]

She's riding pretty tall and proud!

 

[midlife]

Have you driven a mile or two with the suspension (rear leafs, front lower arms) lightly tightened? The suspension will change to its true height with minimal drive-time and that is when you should tighten the suspension bolts to spec.

 

[Steve McMahan]

Yea, that picture is after 5 miles, over bumps, etc, not more than 35mph. Any advice how to get it closer to stock height? I see lots of folks cut their coils, I just want to do it once .

 

[midlife]

Cutting a coil won't do anything for the rear end height...
Loosen your suspension a tad, drive around, and see if the height drops down.

 

[Steve McMahan]

Yea, the rear has those jacked-up shackles on the rear shackle. I’ve got to replace them with stock. But, what do folks do if the front is too high? I followed the guidelines of installing the replacement front suspension not tight, drove it around, and then tightened the UCA and LCA Completely. That’s where I am now.

 

[Steve McMahan]

Ok, so new issue/problem to solve.

As some of you know, I’ve swapped a 87 TBird 5.0 drivetrain in my 73. The design of the water for the heater core is shown on the following photo:


It may be difficult to see, but there is a rubber heater hose at the rear of the valve covers that is connecting two heater tubes. That setup provides the warm water to heat the throttle body, so I would like to keep that. What I’m trying to noddle through, is how I can install the vacuum operated valve, to keep the water out of the heater core while the AC system is running while still having water circulate through the system.

If I just connect that top fitting to the vacuum valve, then route it to the heater core, then back to that lower pipe, while I’m using the AC, it will cut off that flow. I need likely, a more complicated valve that will bypass the heater but still allow for return circulation. And, it all has to fit in that very limited space, unless someone has a better idea (that’s what I hoping for). As you can see in the next photo, from that hose to the heater core inlets, there isn’t much room or distance:


I’m not working on it today, and I don’t have the AC connected. I would like to plan for this since this is an Az car and I will be enabling the AC as soon as I can in the first quarter next year. All ideas are welcomed and thanks for taking the time to help me, Steve.

 

[Sheriff41]

The water in the metal tube will heat up regardless of flow. It may just heat up slower if the flow is blocked, but since it'll be in AZ summer heat it probably won't make a difference.

 

[Steve McMahan]

What I’m trying to avoid is not enough heat to the throttle body as needed. And how much is needed, not sure. It definitely heats it up at startup. Would be great to find a valve mechanism that would do what I want.

 

[Steve McMahan]

What do you think of something like this! I wish I could clock the end piece. The function of this 4 line valve is what I need, but packaging and fitting this in the space allowed seems hopeless.


It might be better to try and locate this when the vapor canister and TAD/TAD valves live. I know I can do without the TAB/TAD valves, but would want to keep the vapor can. I think I’m on the right track, but with the space issues, I need a paradigm shift to reimagine the solution.

 

[Steve McMahan]

While I wait to remove the HVAC box in the spring, I started on my next crazy project idea, a custom air box. For reference, here’s what I currently have for an air cleaner:



We’ll, spent the day building the first cardboard segments, and here’s what I have do far:



I don’t have the filter to fit this, am not sure how to proceed. I thought it might be more difficult to make a filter fit without knowing the available space to start. So I’m kind of doing a circular interpolation approach. This is close to the available area, so I’m going to look for a 3.5” inlet filter that still fits the box.

I’ve left the bottom open, not sure what’s best. Should the front bottom be enclosed to deflect water or?

Any other ideas from those of you who have already made the mistakes I can learn from?

Thanks in advance for the help, Steve

 

[Steve McMahan]

While I contemplate my air intake situation, I’ve been playing around with ideas on how to modify my existing shock tower braces )with tje get-40 intake, tje existing brace will not work). For the last month or so, I’ve been making cardboard mock-ups, primarily of the passenger side, where the throttle body intake hose 90 degrees to the front of the engine compartment, interferes with the stock brace.

So, last week, I took my template and cut up my stock brace. This is what it looked like after I cut and did a little forming:



That cut was made to facilitate the air inlet 90 degree section (shown). I kinda rolled the edge of the cutout to strengthen it, but holding it in a vice and doing the same to the drivers side brace left me thinking it had loss enough stiffness that I needed to address it.

So, I took some 1/2” cold steel stock and added these braces:



I went back and added more weld attachments to the braces, and cleaned it up a bit. While not factory or even aftermarket, it’s better than no brace for now. Gonna clean it up, make it pretty and then try and figure a way to do something on the drivers side. That is significantly more difficult to modify the existing brace, but it’s fun to see what can be done. Steve