Summer/Winter Switch

[Disposition]

Ok, first off this isn't that big of a deal, more of a curiosity. I searched the forums first and didn't turn anything up.

I know the older Z's are notorious cold starters. But now that the temp has dropped here in sunny Florida (31 last night), it took 25 minutes to get the engine warmed up enough to drive her. She lives in a garage and I left my shoplight on in the engine bay overnight for added warmth. (Yes I am a little obsessive).

I have just recently purchased the SU Videos but haven't had time to tackle the adjustment yet. It runs good when warm, just a little afterfiring.

I remembered the Summer/Winter setting on the air filter enclosure. I set it to winter and then noticed that the hose was missing that connected it to the manifold. I bought a flexible hose from Autozone 1 9/16" x 21" for six bucks. Perfect fit. However, there didn't seem to be a noticeable difference.

As I have stated before, I do not claim to be a mechanic. The only knowledge I possess is from tinkering with my Z and reading this site. Little help please.

Mainly I wanted to know, should the replacement of that missing hose make a difference? And does the opening and closing of the mouth using the winter/summer switch really correspond to the outside air temp? Does it really matter?

Thanks in advance,

Darren

[Bambikiller240]

Yes, that hose does help to warm the engine as it feeds semi-warm air into the carbs from near the exhaust manifold, but if it takes 25 minutes for your engine to warm up, I believe that you need to replace the themostat on your car. It should not take more that 5-10 minutes at the most to warm the car at the tempertures you are describing.

PS, I leave the summer / winter switch closed all winter long from November through March. I live in the S.F. Bay area of CA

[Disposition]

Thanks for the quick reply Carl...

However, I don't think that the problem is within my thermostat.

I probably didn't describe my situation clearly enough.

The engine runs best when the temp gauge reads in the center position. This takes about 20-25 minutes of sitting at a little above idle with the choke on during a cold morning.

In the first 5-8 minutes the engine warms to about 10 degrees below the center mark. At this temp it sputters badly in first gear when taking off, and will do so until the temp moves up to the center. Once it's there, she sails.

But I almost got smacked pulling out of work Monday on a cool evening.

It had been warming for 10-15 minutes, and I thought it was fine. I pulled out and expected to go and it just sputtered around, I floored it and it was just putting, and then it kicked in and flew. Did the same thing at the next stop sign. Until the needle reaches the center spot, it runs like crap.

So I guess it could be the thermostat but it doesn't seem likely. Anyway, maybe this better describes the situation. I have the new hose on and the switch set to winter, but to little avail so far.

Any thoughts would be appreciated.

Thanks Darren

[Victor Laury]

Darren, It's VERY likely that your thermostat IS stuck open or missing. It should only take 5 minutes to come up to temp.

Ok, that being that, you still want to know why your car runs crappy while cold - I don't know. Mine does too. I always left that question to the "Nature of the Beast" category, as All my Z's have operated that way.

I run with the choke on for the first mile or so, to keep from stumbling in the middle of the intersections.

[Disposition]

Thanks Victor,

I guess I will look into replacing that thermostat.

It is very cosistent in it's behavior so I assumed that it wasn't a problem. But who knows. I'll start there.

I'm happy to hear others have this same problem. No offense. But at least I know that it is common to the make of the car. I thought that there must be something wrong when I was driving with the choke on for the first 1-2 miles.

If that's normal I'll let this rest.

Thanks Darren

[Bambikiller240]

Hi Darren:

The thermo *should* let the engine warm up fully to normal operating temp, if it's operating correctly. It's possible that the themo in your car is a 160 degree unit, whereas for *most * cars in your climate a 180 degree unit would be more suitable. To be honest, since it only costs about $10 for a thermostat and gasket, unless you have replaced it yourself recently, I'd start with replacing it.

Are the Spark Plugs and Plug Wires in good order? If so, it could be that the carburetors need some adjusting.

[Disposition]

I will replace the thermostat a.s.a.p.

I didn't realize it was that inexpensive or I would have already done it.

The plugs and wires are all new.

The carbs are probably slightly out of adjustment. I still get some afterfiring. I haven't had the time to tackle watching the videos and making the adjustments just yet.

Luckily in Florida, even up in the N/W where I am, it doesn't get overly cold too often.

I don't know how anyone manages to get 240's to start in Colorado and up North in the winter. I've seen photos on this site where the Z's are covered in...what's that white stuff called?

Anyway,

Thanks Darren

[Dtsnlvrs]

That white stuff is snow, and it is real fun to do donuts, err i mean drive in. The summer/winter flapper's sole purpose in life was to reduce carburetor icing in frigid environments, like colorado, I would not even waste the time and energy to flip it...shhot i dont even have one.

[240ZMan]

FWIW, I live in Colorado and until last week, we were having days where the high was in the 20's and the lows in single digits (which is colder than normal for us). Anyway, I had no issues with driving my 240 with 72 carbs (at least related to the cold ) After starting I let it idle around 2k for about a minute, and simply began to drive. I did make sure to keep the revs up when starting from a stop, but I had no bucking or other issues. Not sure what to recommend to you, but it is possible to get the SUs to run just fine in cold weather. I'd start with a rebuild as the ZTherapy video shows. If I had to guess, that will likely make things much better.

Good luck!