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Matthew Abate

1973 Rebuild

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Matt - here's a pic of the flow guide valve, slightly diferent versions on each year but essentially the same.

It mounts to the inner fender wall beneath the ballast resistor.

Valve01.jpg

Check this diagram for the hose routing - one line from the small tube on the crankcase breather pipe, one short hose from the tank vapor line in your pic, one line to the back of the air filter to feed the vapors into the carbs. The valve is #57.

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/emission-control-device

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Okay, thanks. I’ll find this and mount it and see if this vapor pipe mates up to it.

However, I was planning to delete my emissions control devices, so not sure what to do now.

Edited by Matthew Abate

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12 hours ago, Matthew Abate said:

Okay, thanks. I’ll find this and mount it and see if this vapor pipe mates up to it.

However, I was planning to delete my emissions control devices, so not sure what to do now.

I understand - I have that equpiment off my car as well. This bit of plumbing is entirely passive and uses the air flow thru the air filter box to pull excess fuel tank and crankcase vapors so they can be burnt. The connection between the valve and the pipe is a 3-4" piece of hose usually secured with a couple of spring clamps.

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On 7/20/2020 at 8:49 AM, jfa.series1 said:

I understand - I have that equpiment off my car as well. This bit of plumbing is entirely passive and uses the air flow thru the air filter box to pull excess fuel tank and crankcase vapors so they can be burnt. The connection between the valve and the pipe is a 3-4" piece of hose usually secured with a couple of spring clamps.

Any chance you can post a few photos of how this vapor line is secured to the engine bay? I’m trying to figure out how to rout it through all of the insulator clamps that hold it onto the car.

I found this build log that has some usable photos, but the vapor return line is significantly different from mine. I’m thinking these Classic Tube lines have some incorrect bends, or they are at least twisted.

Edited by Matthew Abate

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Matt,

I think this should meet your need. The vapor line gets connected to the vapor valve with a short length of hose, not yet installed in this pic. The vapor valve is just below the ballast resistor. FYI - the not-stock item below the vapor valve is a compressor for air horns. Let me know if any questions.

Jim

03.jpg

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Thanks, Jim. Yeah. My vapor line is substantially different. I bought the one for the ‘73 and didn’t realize I wouldn’t be able to figure it out.
 

6DF1CB01-DFEA-4E42-86F3-1C4F5ACCCDCA.jpeg

There are some hard to see but usable photos here that will help. I think I need to get the brake lines in before I continue with the fuel lines, plus it looks like I have a few things wrong with how it’s mounted right now.

Edited by Matthew Abate

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Okay. Got the four main lines in The tunnel tonight. I had to mess with these Classic Tube lines quite a bit to get them in, and I’m a little unsure about how they are in the back, but I’ll leave the Dif out for now in case I need to mess with them more.

the main issue is the vapor and main fuel lines are a bit long and the fuel line was missing a few bends in the middle for the trans mount support and had an extra two bends in the back, at least as compared to my old lines.

whatever. They’re in. Now on to the rear brake lines.

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I woke up this morning and had a flash of a realization that I am wasting my time cleaning up my proportioning valve because I am putting discs on the back, so I need to put an adjustable proportioning valve on the car. Naturally I have a bunch of questions as a result.

First, is there a Nissan adjustable proportioning valve out there? It seems that everyone is using the small Willwood one.

Second, is this larger Willwood valve actually meant to replace the distribution block (middle in the photo below)? I have read here that this should be kept factory original.

Third, I have a '73 made in July, which has the proportioning valve in the engine bay (bottom in the photo below), 280z style, and the small t-block (top in the photo below) that will be left alone.
 

These are my parts:

image.jpg
 

I’m thinking of going with a valve from Tilton because it has 10mm ports and I won’t need adapters. Anyone have any comments? It’s not super pretty but I’m concerned about failure at unnecessary connections.

Edited by Matthew Abate
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I encountered the same issue when I changed to a big brake kit from Arizona Z car including the change to discs on the rear.  In my opinion the Wilwood prop valve is big and clunky and I wanted something more compact that ideally could be installed in the same position as the OEM fixed prop valve.

So I ended up using this:

https://www.speedwaymotors.com/Speedway-Compact-Adjustable-Brake-Proportioning-Valve,1979.html

It's really small and adjustable but does require conversion fittings to adapt to metric lines.  Alternatively you could change the fittings on the lines themselves to match the threads on the prop valve.  I ended up having to make a new line from the splitter to the prop valve as the original one was a little short and I had to devise a way to mount it to the firewall in the same OEM location, but it all worked out.

Here's a few pictures of my install.  The valve works great and I have it adjusted so I get an optimal bias between the fronts and rears.

Hope this helps.

 

DSC_2047.JPG

DSC_2048.JPG

DSC_2045.JPG

DSC_2119.JPG

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I might just have to send my willwood valve back and pick that up. Question about the adapters: are they IFF or concave usually? I was going to call classic tube to find out but was on hold forever.

and how did you mount it?

Edited by Matthew Abate

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The threads on the valve itself are 1/8 NPT.  You would either need to get an adapter that converts that to the metric fittings on the Z lines or remake the lines with the appropriate fittings.  They actually sell a version with SAE adapters included.  You can find it here:

https://www.speedwaymotors.com/Speedway-Motors-Brake-Proportioning-Valve-Kit-With-Fittings,387281.html

As far as mounting it, I attached a 1/8 inch aluminum "plate" to the side of the valve and drilled and tapped a hole in that plate.  I then used a small right angle bracket that attaches to the valve in the new tapped hole and the other side of the right angle bracket goes into the original tapped hole on the firewall that used to hold the OEM valve.  You can see the "plate" that I added in the last picture that I posted above.

Hope that helps.

Mike.

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Okay, so even though I greatly prefer the look of that little brass one, I’ve decided to go with the Willwood valve I have for two reasons: 1) I have it on hand, and 2) I suck at fabricating brackets and the Willwood looks like I can use the factory mounting hardware after some persuading.

I also would rather not have to use the adapters. If it came in m10 I might have changed my mind. Plus, the Willwood won’t ever go to complete shut off, so I can’t accidentally turn off my rear brakes under any circumstance, as you could theoretically with the brass one.

Edited by Matthew Abate

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Anyone have any idea what the torque for the two m21 plugs on the sides of the distribution block might be? I want to make sure those new copper washers seal completely, but not ruin them.

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No idea.

Would be surprised if its published anywhere. I dont think they really expected the part to be serviced. Maybe you could interpolate a value based on the bolt size and threads

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Okay, it’s been a while because I was stuck on how to mount the proportioning valve, but I think I have figured it out.

Home Depot has chrome spacers that are close to the same outside diameter as the Nissan spacers, but in a variety of lengths from 1/4” to 1”. The problem is the inside diameter is 3/8ths and the bolt that needs to go through them is m6. To solve that problem I found some nylon tubing in the plumbing section that is just over 6mm ID and 3/8ths OD that I cut to the length of the spacers to act as a bushing.

 

2D0CF294-AC30-419F-8CB8-404F0885819F.jpeg

BCCF920B-CE03-483E-B2FD-DD693F9E6988.jpeg

95EBB4C1-DC0D-4A3C-9F46-ACFC425EB222.jpeg

66F8492B-7E8E-4B94-B4D6-59010C3789DC.jpeg

6989B333-C92D-46F5-BD5C-149A31599468.jpeg

1A644A5A-232A-4F6D-8258-D9A395918E6A.jpeg

145D0245-2533-41CA-B8E3-475B3A63A96D.jpeg

2D516674-F008-45FE-AEDC-E6D9D53E15AA.jpeg
 

Sorry that some of those are blurry, but I think you get the idea. That last one shows the m6 stainless bolts I bought to replace the original 50mm hex bolts. Unfortunately, they are threaded the entire length and don’t have a grip, but they match what I am using on the engine and I think the nylon mitigates the need for the grip enough to use them. It’s not like they are holding the engine together. I selected lengths that give me as close to the same number of threads to the original configuration as possible.

Trial fitting happens this weekend.

Edited by Matthew Abate
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Nice adaptation! I would probably have spent hours turning a spacer out of titanium or something.

And then slapped myself in the forehead when I saw what you did.  :facepalm:

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3 hours ago, grannyknot said:

And one more version,

 

DSCN1513.JPG

DSCN1514.JPG

Did you fab the bracket from scratch GK?

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11 hours ago, wheee! said:

I just bolted mine over the stock safety valve.

Why did you keep the original valve, too? What am I missing?

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The original prop valve is very close to where my brakes are proportioned. I have the AZC trak pak of huge Wilwood’s front and rear. Paired with the 15/16” Master, the Wilwood prop valve is only for fine tuning. Most people have told me it isn’t necessary and I have it set wide open for the moment. I’ll adjust as needed.

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