Mark Maras

I believe you'd have to cut the lower end and weld in a piece to lengthen the shifter.

Old school method of checking the mixture is the color of the spark plugs. Simple and relatively accurate.

Pushing the car back and forth will frequently break them loose. You're fortunate the car has been garaged.

I'd do a compression check, just to put my mind at ease.

How much pressure are you going to use?

Way cool You realize, of course, that the orders for a kit are going to be rolling in. How long did you sit and watch it work. I would have cracked a cold one to fully enjoy the experience.

I once had a stock 621 PU that did the same thing.

Ditto on the blockage. Remove the inner panel carefully, especially if it's cold. They can crack when flexing them. (voice of experience) Heating the panel first with a hair dryer is a good idea. I would put the car on stands or a lift rack and inspect the fuel system front to rear for leaks BEFORE I dealt with the blockage. The blockage is a PITA but fuel leakage is hazardous to your health AND your Z's.

I don't think you're going to solve this with one fix. This is the type of problem that you'll have to chip away at. I think the blower is a good idea but it may take more than just that. Two pumps are recommended for a heat soak problem. Is your new exhaust close to the fuel lines in the tunnel?

I agree, I've noticed that as the muffler deteriorated over the years the popping would increase. IMO, If one wants a sweet sounding Z, one will have to put up with some popping on deceleration. Personally, I don't mind it as long as it's not excessive.

@jalexquijano, I'm still gathering heat soak puzzle pieces and trying to fit them together. Nissan says that fuel percolation occurs between the f. pump and the carbs and will cause an over rich condition. Vapor lock, on the other hand, occurs on the suction side of the pump. This got me to thinking about heat sources on the suction side of the pump. Taking into consideration all the work you've done under the hood to stop the problem, is it possible that the fuel is actually getting over-heated, in traffic, in the fuel lines under the car in the tunnel? My 240 tunnel used to get very, very hot, in traffic, in the summer. I can't imagine that a new exhaust with larger pipes would help either. BTW, I don't remember if you still have a mechanical pump along with your electric one (both are supposed to help the problem) To anyone, Was the fuel line location under the tunnel ever changed through the years? I'm still gathering puzzle pieces.

Yeah, it looks like a fan. Probably used to dissipate exhaust fumes. I wonder how well the modification sealed? On second thought, if that pic is from the 70's, the fumes could be from anything.

I didn't notice that. It does look "made to order" for twin hitachi's.

http://xenonzcar.com/s30/files/1973 240z 1974 260z fuel system modifications.pdf Submitted by ZedHead (and maybe others) a while back. Many thanks. The factory printed this in 75. It has some history of the problem on 240 and 260 Zs. While I find it very interesting, I also have to keep in mind that the problem seemingly got worse the more solutions they threw at it. They never did solve heat soak and it continued into the 280's. IMO, the answer lies in the past. The early 4 screw carbs, manifold, possible differences in the steel fuel rail (2line-3line), etc. The fact is, the early Z's rarely, if ever, had this problem using a lone mechanical pump. But, I guess heat soak must have been a problem somewhere, or else they wouldn't have tried to fix it. Even now, there seems to be more complaints of this problem with 3 screw carbs even with the water passage blocked.

Try the fan. You've got nothing to lose except the problem. BTW, If adding choke improves the performance, The engine is running too lean AT THAT POINT IN TIME.

Hmmm. I was hoping that it would have had some effect. Specifically, It would have taken longer for the issue to arise, or perhaps wouldn't have been as severe. Looking at your engine build and ambient temperature in Panama, an under hood fan may be the answer. I'd also consider a vented 280Z hood or louver the access panels on either side of the hood. Just for kicks, the next time you're in the conditions that cause the heat soak (traffic), try pulling the hood latch to allow the heat to escape, just to see if that will prevent the problem.

Curious if there was ANY improvement after bypassing the steel fuel rail? I'm of the opinion that wrapping fuel lines retains heat that comes from the fuel rail mounts, but that's just a theory and probably only part of the problem.

What color are the plugs at 2 turns?

@240znz, are you still with us? We haven't forgotten you. Jalex, As I recall your heat shield is two piece. (can't remember which thread the pic was in.) It's possible that the gap in the shields between the carbs is defeating the intended function. Just a theory. Instead of all this guesswork on everyone's part (don't get me wrong, treasure hunts are fun) have you, (or any other member with the gremlin), considered using an infrared thermometer to measure the temp of the the fuel system components under the hood? You are still connected to the fuel rail by the valve cover aren't you? I think this was suggested by another member a while back. I'm sure that everyone (including you) would love to have raw data to peruse. I'd start at the firewall and work my way forward to the float bowls. The findings would invaluable to you and others with the same problem.

Jai, That message was for Mike. He can wave his magic wand and move this discussion of RedBird's problem to your older "Something's Wrong". "RIP Deanna" didn't seem like the right heading for discussions about Redbird's problem.

@Mike maybe we should take this new discussion of Redbird's gremlin over to Jai's old "Something is wrong" thread. There's sure to be more discussion on this new problem.

Using a voltmeter, measure the battery voltage twice. Once with the engine off and again with the engine running.

Because updates didn't follow model years, I'd check the 73 wiring diagram. 7/72 could, and likely does, have had some 73 updates.

I didn't know they existed. Interesting idea but I have to question how they can afford to give them away at those prices.

I've seen them rust. There has to be some iron in them.