Starting Carb Conversion: Flat Tops to Paltechs

[w3wilkes]

34 minutes ago, siteunseen said:

I know the ZX dizzy requires an adapter sort of part to work on the older Zs.

Do you know what the "adapter sort of part" is?

[Dadsun]

I've got an issue with the exhaust manifold gasket. It's leaking noticeably up between the intake manifold sections. I may have put the gasket on backwards. 

You can see in the 2nd pic that I mounted it with the side with larger metal plates facing out.

The third pic is the gasket still in the wrapper, showing the side with the smaller trim metal around the exhaust openings... Should that side be facing out?

Sigh.

[siteunseen]

52 minutes ago, w3wilkes said:

Do you know what the "adapter sort of part" is?

The one on the right.

Here's what I went by to the T. 240 wiring diagram is at the bottom of the page. https://www.atlanticz.ca/zclub/techtips/distributor/index.html

Thank you @240260280

 

 

Edited January 24, 2021 by siteunseen

[siteunseen]

The shiny metal goes outward to the manifold or header for Nissan's and that looks like what you have.

Okay I read your post and you did right. I would tighten a little more working from the middle out. Or that's what I did and it worked.

Do you have square exhaust on the head and the manifold?

Edited January 24, 2021 by siteunseen

[siteunseen]

You can get an inch/pounds torque wrench at harbor freight pretty cheap for those specs.

[siteunseen]

What do you have? That's kinda crazy looking to me but I don't know one thing about a '73. 

 

[siteunseen]

[Dadsun]

That may look like a split but it's there on the gasket out of the box. See Zcardepot part here.

Yes, square exhaust holes on both.

[siteunseen]

Okay I see now. I guess my suggestion would be go a little tighter, maybe it will go away?

[siteunseen]

Could be the same holes?

[w3wilkes]

3 hours ago, siteunseen said:

The one on the right.

Here's what I went by to the T. 240 wiring diagram is at the bottom of the page. https://www.atlanticz.ca/zclub/techtips/distributor/index.html

Thank you @240260280

 

Thanks! I have the ZX dizzy, but it was installed by my Z mechanic almost 20 years ago. I checked and they did use the correct adapter thingy. Just FYI- The E12-92 matchbox works exactly like the E12-80 when only the top connector is used and the lower connector is left open. I've been running the E12-92 matchbox on the dizzy for almost 20 years and it works just great.

[Racer X]

4 hours ago, Dadsun said:

I've got an issue with the exhaust manifold gasket. It's leaking noticeably up between the intake manifold sections. I may have put the gasket on backwards. 

You can see in the 2nd pic that I mounted it with the side with larger metal plates facing out.

The third pic is the gasket still in the wrapper, showing the side with the smaller trim metal around the exhaust openings... Should that side be facing out?

Sigh.

A couple of things that I see.

The flange on the header is too thin. A good quality header will have a flange the same thickness as the intake manifold flange.

The other thing I see is hardware. The nuts, bolts, studs, washers are all wrong. The OEM washers are the best option, especially for the studs that share the intake manifold and the header. Some of the ones I can see aren’t even clamping the header, and are doing a poor job of clamping the intake manifold. The stackup of flat washers isn't transferring enough clamping force through both parts to the head.

One area where I diverge from stock hardware is I use brass nuts, made for exhaust assemblies. And I use high temp antisieze on all the threads so it will come apart when it is time to do so.

 

As for the gasket orientation, I don't know if there is a right or a wrong way. I would think the side with the widest bit of steel around the openings would be better next to the head, as that is the first stop for the hot exhaust on its way out of the engine.

I don't know if a copper gasket is available for the L series engines, or if it would work to seal the intake manifold side. But I had a Chevy 454 in a pickup that I used to tow the race car with that kept eating exhaust manifold (and header, I tried both) gaskets. I finally fixed it permanently with copper gaskets.  

Here is a picture of the setup I use. I use studs for all the fasteners except the six along the top that are only common to the intake manifold, which are Allen head with a lock washer. The OEM washers are for all the studs that share the clamping loads between the intake manifold and the header. The three studs that are only common to the header get a grade 8 flatwasher (get a high quality washer for this, that has a close fit to the stud, and is thick - a business that sells fastening hardware as their primary product is a great place to get all this stuff, not Lowes or Home Depot, even the chain auto parts stores suck). 
 

Get good hardware and a better quality header and you should be able to get the leaks fixed.

Also, it takes me several different wrenches and an Allen socket to tighten all the nuts and bolts for the intake and exhaust.

 

 

Edited January 25, 2021 by Racer X