Several questions..but I'm getting better

[mally002]

Alright,

I just got the new carbs and intake bolted up. Since I've moved from the 1973 version to the 1971 hear are my questions:

1. Can I replace the metal or copper tube that would not mate up with a piece of hose? The original was metal or copper and ran around to the other side of the engine and into another fitting, does it have to be replaced with metal or copper or will hose or line work. When I removed it alot of antifreeze drained out. Please see picture's with Yellow circle's.

2. Since there are soooo many extra pieces left over I am assuming I can just remove all this crap. There is a pulley and various hoses. Please see picture with Red circle.

I'm using my 71 as a refrence, and it does not have all these extra "parts" but wanted to make sure it wouldn't affect anything.

Thanks for any help,

Randy

[tibZ]

My 73 has a 72 carb setup on it. It has a fitting similar to yours coming off the manifold except it is longer and has a hose connected to it.The other end has a short hose connected to a bent pipe that comes around the back and connects to the front hose, so you need to have something there. My smog pump is gone.

If you look in my photobucket pics under "engine before pulling" you can see the pass. side of the setup

Edited September 28, 2008 by tibZ

[xray]

The tubing and piping to the carbs is for manifold warming, felt to help with cold start and (IIRC) may improve emissions by shortening the amount of time the engine has to run richened by the choke. The "pulley" and its hoses are emissions equipment that can be removed, but should be blocked off at the manifold/balance tube to prevent vacuum leaks.

The second pic shows a branchpoint where water is diverted behind the block to warm the intake manifold via the tube in the first pic. You can disconnect it from running to the intake, but don't plug it completely or it'll cause problems running water to your heater.

[mally002]

So do you think it's ok to connect the two with a piece of hose? It had metal tubing before, does that matter....Wait here's what I took off because it would not work with the new setup. I was just going to go with a piece of hose if it doesn't matter.

Thanks guys,

[xray]

Randy,

Sorry, I'm away from home so this is mostly from memory....If you re-plumb the pipes to/through the intake, IIRC you also have to reconnect it to the thermostat housing, so confirm you have the correct housing first. I would suggest not connecting it, and just keep the heater hoses connected as you have it currently. I have a similar setup (N36 intake) on my L28 which is not warmed, and I have no cold start issues.

[beandip]

The coolant was meant to go through the intake manifold for BOTH heating and cooling . The Z club I belong to recently held a car show. And had a Dyno available to us to run our cars. I found it interesting that the Zs that had the water disconnected to the intake manifold had predetonation problem under power. I have the lines hooked up and had no trouble. I realize that driving on the road and on a dyno are two different things , but with the exhaust manifold only inches away , think about it before you re-engineer a proven method. Believe me after 35 years you are not the first one contemplating this change. I suppose if you live in a cool climate you could get away with it. But having the coolant going through the intake does NOT effect the performance. Save your old air pump. In the event that you have to test for emissions , Just the core charge is $200.00 for one of these.

Edited September 29, 2008 by beandip
More info.

[bobc]

Rnady,

How you doing? Long time since we've said hello. I'd go with reconnecting it. I don't see any problem with using heater hose to connect it, but I'd fabricate some pipe to go from around the fitting on the passenger side of the engine to come around to the fitting and then put only a short piece between the pipe and the fitting on the intake manifold. That's the way, it was orginally done. I'd send you a picture, but my Z is in storage right now:disappoin

As far as the pump, we need to see what else you've left on the manifold in the way of pollution gear. Yes, you can take it off (I'd recommend it), but be sure to block off the air gallery pipe at the check valve. I noticed you left the fresh air gallery pipe attached to your exhaust manifold. If you haven't tightened everything up, I'd get rid of that too. If not, just leave it, but be sure not to just leave the check valve sitting there with no positive pressure. It will corrode and start leaking eventually. PM me if you need further help.

Bob

[xray]

The coolant was meant to go through the intake manifold for BOTH heating and cooling . The Z club I belong to recently held a car show. And had a Dyno available to us to run our cars. I found it interesting that the Zs that had the water disconnected to the intake manifold had predetonation problem under power. I have the lines hooked up and had no trouble. I realize that driving on the road and on a dyno are two different things , but with the exhaust manifold only inches away , think about it before you re-engineer a proven method. Believe me after 35 years you are not the first one contemplating this change. I suppose if you live in a cool climate you could get away with it. But having the coolant going through the intake does NOT effect the performance. Save your old air pump. In the event that you have to test for emissions , Just the core charge is $200.00 for one of these.

That's some faulty logic there, similar to saying "All the green cars predeontated, therefore green paint causes predetonation." Were they running hot? Too many other factors (ignition, ignition timing, fuel supply, compression ratio/head mods) can contribute to predetonation. IIRC, triple Webers' intake manifold are not plumbed for coolant, so there's that aspect as well.

I've run my car on a dyno without issue. I've driven it in 90+ degree heat, also without issue. I think it's fine to reconnect it, but not an absolute necessity. I would make sure though, regardless, that the coolant connection at the back of the head remain in the circuit.

Would you show me where it's stated that the purpose of those pipes is to COOL the fuel/air mix? Every other setup I'm aware of that pumps water into the intake is to help with cold starts and improved atomization of fuel/air mix. My position was confirmed when I spoke about it with ZTherapy, but I could've misinterpreted what they said. Thanks.

Edited September 30, 2008 by xray

[Sailor Bob]

Randy - you're still asking all the good questions and I'm still several steps behind you on the engine. Just removed my carbs last night and I am replacing four screws (which replaced the flattops) with three screws from ZTherapy.

I intend to get the old (coolant) setup functional. The same thing happened to me last night but slightly different - had to clean the spacers (they had the holes blocked with sealant) when they came off, a couple of litres of coolant dumped on the floor of the shed through the carb cooling lines. It was all hooked up with the lines blanked at the spacer.

It's a learning experience.

I'm going with Beandip on this one - I get what he's saying - the manufactured purpose is to warm the carbs at startup and whether intented or not it would make sense that it keeps them a little cooler when the engine (and exhaust manifold) is heated up.

Edited September 30, 2008 by Sailor Bob

[Diseazd]

Z Therapy recommends not running water through intake manifolds unless you're in an extremely cold area of the world.......they say it warms the mixture and that's what I've always heard.

[doradox]

The main reason for manifold heat is to keep the vaporized fuel from condensing on the carb and intake walls. It will condense out of the air just like water does on a cold glass on a hot summer day. This will lean the mixture and cause cold running problems. The change of the fuel from liquid to vapor draws heat out of the air and intake, and will cool a manifold well below freezing on a cool day. You folks that live in the southwest know what an evaporative cooler is, the process is exactly the same in your carb and intake manifold. Ever seen an intake manifold with frost on it or even IN it? Look up carburetor icing.

It's unlikely that your intake charge would be warmer than your coolant so since heat flows from hot to cold you'll never cool the air/fuel mixture. Well, except if you've got a big turbo compressing and heating the intake charge.

Steve

[d240zx2]

Yep, Steve, we know all about "swamp coolers.";)

Those of us that fly are also familiar with the carb icing phenomenon in piston engined aircraft. In a car, you'll likely not even notice it, but it makes airplanes quit flying.:mad:

Frank