side questions with a Ztherapy swap

[bounce]

so I'm gonna go with a ztherapy SU carb swap on my 71. this poses some removal options with the smog and balance tube, I think. I'm still confused as to what is smog and what is water circ....

my air galley pipe looks like a long stretched out turd.... (read rust) I'd like to make it go away if possible.

1> I had thoughts of getting the MSA header with exhaust upgrade... so will this help in the desmogging process? as far as fittings for the oem header and rust..etc?

2> I haven't found a desmogging for dummies tutorial out there yet... is there one or something close to it?

3> I would prefer to remove the air pump, and other associated smog stuff....I can follow the manuals for this without killing my Z? (it runs now)

4> so i live in Flagstaff, AZ...7300 feet elevation.... COLD starts.......this smog stuff doesn't have anything to do with the 3 screw water passages and the heating aspect for cold starts does it? I think I need to keep this system intact and replace the old lines.

5> is it possible to order some new hose/lines and jump on replacement without causing problems? and what type of hose is recomended?

thanks...

[DaveBonds]

I am doing a similar modification on my car, but I'm taking it a step further and rerouting fuel lines, eliminating emissions and fuel feedback vent lines (making a new gas tank) as I have no mechanical pump in the front of the engine, as well as completely dumping my entire emissions setup on my '72.

The water lines have absolutely nothing to do with emissions equipment, such as your air pump.

You can also modify your exhaust manifold to eliminate the air pump fittings and rail by heating it up with a torch and taking the fittings out to replace them with plugs, or at the very least, trimming the tubing from the inside of the manifold and do some port work. The manifolds on these cars are actually designed very well for exhaust flow.

The only thing you need is a way for your crankcase to vent. You can ditch everything that the air pump hoses are attached to (red), all the way to the exhaust manifold and air cleaner assembly and replace any lines with plugs on the balance tube of the intake, with the exception of the power brake booster line on the back, if you are keeping power brakes (as most of us do).

Your intake and carburetors have a water passage in them, so if you do anything to them, be sure to drop antifreeze from the radiator first.

Here is a really crude hose ID that I slapped together-

The others not tagged are either breather lines for the float bowls of each carburetor to the air cleaner, a brake line, choke cable or something else that is irrelivant to this modification.

Hope this helps

[Zs-ondabrain]

George,

1> Definately Purchase the MSA header, I would suggest you spend the extra $$ and get the Ceramic coated header. They look great, allow better flow and eliminate the old smog lines and crap.

2> There's no Definative "How To" on desmogging the 240Z's.

3> Remove the old Air Pump. Typically dead weight anyways. Keep the stock air cleaner assembly. Leave the Block breather line that goes from the block (under the #1 cylinder) to the PCV valve on the center of the Ballance tube. Leave the Valve cover hose to the air cleaner there. Remove the Vacuum pots on the ballance tube and use a small zip ties to hold the bracket that the vacuum pot was attached to, to the front SU linkage. (You'll see what I mean when you remove the pot and the steel post connected to it and the center linkage)

Use the Gallery of Pictures or the Garage Feature to look at others motors for a better idea of what a smog free engine looks like.

When it comes to the water passages in and thru the carbs, they are typically clogged anyways. This happens because the heat from the exhaust crystalizes the coolant that is in the passages after the engine is shut down each time. Over time, the deposits all collect there and eventually clog the passages. Most people use a large bolt or plug to plug off the hose, at the "Y" pipe above the starter. Then remove the hose that goes around the back side and into the rear SU. Then plug the Thermostat off after removing the front SU hose.

Most find that the car runs better without the extra Lag on the front pulleys, the air pump out of the way, and the emissions gone.

4> The Water lines don't have anything to do with cold starts. Just use your chokes to start it but don't leave them on too long. I have a new set of ZT SU's and they barely need any choke to start. But when they do need it, it only takes a little, and then I shut them off after 20 or 30 seconds of running. And just feather the gas with my foot or ease the chokes way down.

You can order new hoses but if your eliminating all this stuff, you won't need them. Hope this helps.

Dave

[tlorber]

I just went through a header/exhaust upgrade-partly to improve the flow and partly to clean up the engine bay. I cut portions of my balance tube off and ground down the excess bosses to remove unnecessary clutter. The only vacuum ports now used are for the crankcase vent and the power steering.

Being in Los Angeles I don't need the intake heating so I removed the water lines-as stated above, these are independent of the smog equipment.

[beandip]

One thing you should consider when removing the water flowing through the intake manifold. And in some cases the 3 screws. Last year NorthWest Z had our Car Show-N-Shine at Forged Performance. They gave all cars entered in the show a killer deal on there Dyno. I ran my Z and had no problems , I have retained the water flow. Two of the other 240s that followed me both had detonation problems after the first pull and had to abort. I did all three pulls no problem. The coolant flowing through the intake is a cooling agent not just a heating agent for cold weather. Just think about the heat coming off the headers right under the intake manifold.

My 2cts Gary

[bounce]

wow...solid GOLD information fellas....thanks.

confused some more now on the water...but if MSA headers eliminate the manifold then that's that huh?

I was leaning towards re-lining the water and hopefully confirming it is not clogged.....temps here in the morning are 10-30 degrees for months....but if water doesn't do anything for cold start then it's not an issue except for the Dyno resluts as mentioned...hmmm....

say, do the MSA headers eliminate the manifold or does the oem manifold stay? those rusty pipes are an eye sore....I want to either replace or remove.

Also I'm thinking the vent tank and assorted fuel lines running all over the place can go away.....I saw a thread on re-routing the fuel lines to eliminate the tank.

Edited August 26, 2010 by bounce

[Zs-ondabrain]

Look at the picture above, you can see the header. It replaces the manifold from the Head to the collector (where the exhaust pipe connects to the header)

So yes, That's That.

You can take Garys info as solid. Just remove the carbs, clean the whole cooling system thru the manifolds, pipes, hoses, etc. Basically renew the system.

[DaveBonds]

I agree. Keep the water jackets free through the intake manifolds, MSA header is good, but not entirely necessary. You won't see much performance gain in one on a stock engine, especially in the lower rpm range. A header will require a bit of exhaust modification. In order for the header to bolt to your exhaust system, it needs a different flange that will be a completely different type, size and location on the exhaust. It will require an adapter from the header collector flange to neck it down to your stock exhaust size, or you can go with a new, bigger exhaust system.

[bounce]

It looks like I'll keep the existing header...and possibly get a little larger exhaust...

[72autoZ]

I've been reading a number of the posts about the intake manifold water line and the pros and cons about removing it. For information, the emission control section of my 72 FSM addresses it and also indicates that there is a manifold heat control thermostat in the line which is designed to close at about 175 degrees F. That would sort of put the kabash on the theory that the line helps during dyno testing or after the engine has heated up. The thermostat on my very stock 72 is just aft of the rear carb. The manual also states that if the thermostat fails to close in hot weather, carb percolation may occur.

[jwtaylor]

Hey Dave,

That second picture you posted is not exactly a common set up for our Z's. Do have a picture of the manifold side? It looks very interesting.

[jwtaylor]

Zs-ondabrain:

Dave, The second picture you posted above caught my eye. Do you happen to have a picture of the manifold side? Any other info for curious?

John

Sorry for the double post. JT

Edited December 3, 2010 by jwtaylor