Why does hot air rise? because cooler, more dense air moves in below it. I.E a difference in pressure.


One last question I will throw out: the flapper obviously diverts exhaust flow either to, or away from the intake. Diverted to the intake, the intake gets "hot". Diverted away, the intake is somewhat cooler (I'll use "cold" as a descriptor). Without the flapper, I would think the intake would be somewhere between the extreme 'hot' or extreme 'cold', since the hot exhaust is no longer being directed to the intake, nor directed away. Instead there is a large pocket where the exhaust would be turbulent, but it is not necessarily being forced to pass by the bottom of the intake. That is just the impression I get from 5 years of finite element analysis with fluids, obviously that does not make it a correct assumption. thoughts here?

The easiest way to test this whole fiasco would be with one of those hand held infra-red temp gauges, which i think was mentioned back on page 1

That is the way I always thought it worked, based on personal experiance.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Eric, I don't think anybody refered to you or anyone else as "stupid"... Just that taking the flap out is a stupid thing, which it is! Doesn't mean you're stupid. Based on what you typically post at this site, I'd gather that you're far from stupid. We all do stupid or ill advised things on occasion, however. Can't we have discourse here without people getting their feelings hurt or taking every little thing personally? I'm still interested to know what advantage you realize to taking out the flap. Maybe there is a really good case to be made for it and I'm stupid!


D/W

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If it ain't broke, fix it!

Dennis, I never in this thread said there was an advantage to removing the flapper valve. I removed mine because the valve shaft was frozen, and the spot welds holding the valve in place on the shaft where not holding (probably due to rust eating away at it). The original manifold was cracked, and I had this spare, un-cracked and better (from the '73 engine I currently have) one laying around. So instead of fixing it properly (are kits even available to replace them?), I removed the works and tapped and pluged the holes. I run a slightly recurved distributer, a Holley 1920 with a #61 jet, 8BTDC timing, 2" exhaust w/turbo muffler and the stock air cleaner with the heat stove and tube going to the air cleaner in place. Nothing fancy or special.

Fair enough.

D/W

P. S. - you looked!

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If it ain't broke, fix it!

don't need to. I know what you posted on that thread. You're becoming like the Jaques Lacan of slant six

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

No, that would be density, not pressure. Heating air does not create a vacuum. It causes air molecules to expand, which makes it less dense than the air around it, hence making it rise. And by the way, the example kevin gave was to jam a water hose into an open manifold and observe gravity pulling it through towards the ground. The flow and convection patterns may approach similarity if this test was done blasting very hot water through a manifold completely immersed in cold water. Gravity plays no role other than perhaps the force acting upon the heat riser and counterweight against spring tension and airflow in the manifold. This argument is degenerating into a pissing contest over semantics that is far removed from the core argument. I will concede that a missing heat riser will not result in full manifold heat but will certainly elevate it to a point where efficiency becomes a problem. Will your car run without it? Yes. Slants are very forgiving as we can all attest. I have been running for three months or more with a worn throttle shaft and improper jetting as I continue to fight for a replacement, and I am surprised my head hasnt been ruined. So there you go.

Yes, a heat riser kit is still available from the dealer, you can even get a new manifold from Motormite.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

I don't know who Jaques Lacan is, nor could I find that thread searching your responses, but Im going to bite anyway.

The secondary circuit of an ignition system can be compared to an athlete in the high jump. If the bar is only set to two feet, there is no need for the jumper to jump eight feet, nor is he likely to. The reliability of the points style ignition system is inferior to that of the electronic and aftermarket pereformance systems, but in a stock engine, little to no improvement in power or economy is going to be noticed simply by upgrading the ignition system. You might have a little bit better stability in the timing, longer plug life, less maintenance, but upping the voltage potential of the secondary circuit will have no effect if the ionization demands are the same as stock.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

hey steponmebooom

jaques lacan was a french shrik that used to made spectacular controversial statements that ended up being bluff or better called bullshít.

I buy your explanation, but I add that in a mild modified engine, considering mild modification even a change in the spark plugs gaping, electronic ignition provides more stability and reliability than points, not to mention the huge time cutoff in tuneups. So, add to that a mild cam, some miscarburetion, raised comp ratio, crappy gas, you name it, and EI is better way to go. Now add to that multispark capabilities (that produces more even, better combustion last time I cheched) like MSD and then look me in the eye and tell me that points=MSD, would you? neither do I. I'm not against the simple, real explanation you provided. I'm telling you that SSD first post was "points=MSD" then when I jumped on his back he posts "the amount of voltage needed to jump a given gap is.... blah". That's what I call Lacanism.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Aha! I recall that that particular discussion started when I posted that MSD or capacitive discharge units burns out "hot" spark plugs, wich I experienced and SSD posted that "it ain't true". I think that's one of the reasons why this kind of pissing contests starts, when someone that experienced something posts it here and SSD tells him that it can't be true, no matter what.
that's the last thing I'm going to say about this "sparky-flame thrower" threads that are draining away the joy and pride of being a member of this comunity.

juan

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

NOOOOOOO!!!!!!!! I DON'T WANNA GROW UP AN' YOU CAN'T MAKE ME! NOOOOOOOO!!!!! NO! NO! NO! NO! NO! *kick* *scream* I WANNA COOKIE!
Uh...not really, guy, no. It don't make no nevermind to me how well or poorly your car runs.
Promises, promises...

I respectfully submit, Juan, that you misunderstood my initial remark, which caused you to raise an eyebrow at it, which caused me to clarify it.

I have no doubt that you have an MSD ignition. And I have no doubt that you experienced premature physical burnout of your spark plugs. If I doubted that, I'd be calling you a liar, and I don't think you're a liar.

What I doubted was that the cause of your premature spark plug failure was what you thought it was.

Likewise, I've no reason to doubt that Eric's slant-6 without the heat riser flap runs as well as he wants it to. That's never been the issue, from where I sit.

As my dad once said, "all cars are different, you're next tank off gas could totally change the way your carburated car runs".

Are they going to lock this thread like they did the last one

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

He was right.

But, the next tank of gas isn't going to change your four-cycle engine into a 3-cycle engine, or rewrite the way the ignition system functions, or anything like that.

not contesting that,
that isn't my argument. My argument is that overkill in an ignition system is useless and has no benefit.
Id like to see that post. Seems there is a witch hunt afoot and Im not so sure its warranted. I do not go for his attitude at times but I havent seen anything so far that is absolutely false here. I think we all need to stop reacting and start reading. Everybody.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.