Intake mani

[Kulper620]

Putting a new gasket on for my intake/exhaust mani and the person gooped up the water ports for the intake completely closed, was wondering if anyone had an idea to why this was done or if it even matters, thanks for any and all input, my build is almost complete and should be back on the road in a day or two will post pics soon

[Kulper620]

Oh my bad, this is on a l20b for my 620 build

[dr.feltersnatch]

some different intake setups dont use the water ports. if i remember correct the side drafts dont. you do not NEED them to be open but it is preferred if possible. it will keep everything at a constant temp and help prevent things like vapor lock. 

[jvb5577]

Yup.  Most side drafts don't as seen here.

If you are putting the same intake on that doesn't have these water passages then keep them closed.

 

On the other hand if your intake looks like this. See water passages on bottom if intake ports..

Then open the holes up!

[Stoffregen Motorsports]

The water jacket in the intake manifold is actually a good thing. It's not so much a preheater as it is a cooling device, keeping the intake manifold (and air, and fuel) cooler than the exhaust manifold that sits directly below it.

 

Unplug those holes and get the right gasket, and you're good to go. I use a little high temp RTV around the water holes in the gasket just to help seal them otherwise they can leak.

[datzenmike]

 

Take note that these coolant ports do have an outlet at the front base of the carb (near the front carb mounting stud above) on the intake. To cool or warm the manifold coolant must move through the intake runners. The outlet should have a small hose connecting it to a metal pipe running forward and joined to another pipe from the thermostat housing. From there across the front of the motor and down to the lower rad hose inlet pipe to complete the circuit.

 

The only stock inlet I know of without this manifold pipe are the L20Bs (car and truck) for the '75-'77. These '75-'77 used hot exhaust to warm the intake but did no cooling whatever. '78 saw this system done away with and coolant used.

[Kulper620]

Thanks guys, yea I was really suprised when I took it off and saw that the holes were completely filled with gasket sealant, if she lives today I will be posting pics and maybe a lil video, have a good day and enjoy some football today

[datzenmike]

So did you check the outlet piping on the intake? It may have been plugged because he doesn't have anywhere for the water to go.

[Kulper620]

Got it all taken care of, still not sure why it was done, maybe they thought it was something ok to do I don't really know, now I have everything put together and she runs like a champ, all that's left is finding a drive shaft that will be long enough to fit, mine is the two piece and now that I have the four speed manual, which was in a 510 I believe I need one that is about 4-5 inches longer, I still have to measure for a more accurate number, not gonna lie I'm super excited to get back on the road

[Kulper620]

http://i968.photobucket.com/albums/ae170/kulperj/8A2D7BFD-4776-4CA4-B2E2-168F0F0CD548-1773-000004EBF55B558A_zps13d41b23.mp4

[datzenmike]

Got it all taken care of, still not sure why it was done, maybe they thought it was something ok to do I don't really know, now I have everything put together and she runs like a champ, all that's left is finding a drive shaft that will be long enough to fit, mine is the two piece and now that I have the four speed manual, which was in a 510 I believe I need one that is about 4-5 inches longer, I still have to measure for a more accurate number, not gonna lie I'm super excited to get back on the road

.

Yes, the 620 uses a two piece driveshaft. Findt a front one from a '72/'73 that had the same transmission you have and you're good.

 

Alternatively, a '74 and up 4 or 5 speed froom a 620 or 280z or zx or Maxima will also work without changing the driveshaft.