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   All Posts (Dodgeman)


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Re: A15 turbo manifold build
No life (a.k.a. DattoMaster)
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Some would say that backwards mounting of the turbo is bizarre. I say, If it fits & works properly, it's perfect.
Looking pretty good from here.

Posted on: 2017/8/1 22:47
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Re: FS Cherry E10 model head - very similar to the A12GX head (I believe)
No life (a.k.a. DattoMaster)
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The four holes under the inlet ports transfered hot coolant into the water jacket under the inlet manifold.
The GX was a street model in a country where it snows, so it is necessary to ensure complete vaporisation of the liquid fuel by the simple expedient of manifold heating.

Regular models do it by using the exhaust manifolad hot spot under the carb.

Posted on: 2017/7/31 10:43
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Re: BMX
No life (a.k.a. DattoMaster)
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Things have changed. New abode in a regional city. The daily driver 1200 coupe is being retired & will be looking for a new home soon & my new home will allow me to get the guns out & do a little target shooting & perhaps some pig & goat hunting also. I still have the KB10GL too.

Posted on: 2017/7/24 3:12
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Re: BMX
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For those that have ever wondered, yes, I am still alive.

In relation to my last posts in this thread, the last "survivor" unrestored Quicksilver Team Helium model that changed hands went for $5000. [yep, five thousand dollars] That was about a month ago.The only real thing of value on it was the frame as even the fork was a second level down model. It had been in a garage only a relatively short distance from me [three villages away] for the last 33 years & I didn't know. I must be slipping.
Even at that price, I'm not offering any of mine up for sale.

Posted on: 2017/7/23 23:44
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Re: Car Running Too Cold?
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Quote:

unfamilia wrote:

im no mechanic but in cold eropean and even alpine regions in australin winters, they do restrict airflow to the radiator by blocking off the airflow- cardboard is just a rudimentary way of doing it.

ive had extractors on every datsun i have ever owend, never had this issue related to extractors, just issues with radiators.

personally try the cartdboard, if it works your onto something. if it doesnt,move on through process of elimination.

Actually, old chap, you are right in some respects for reasons you probably haven't thought of yet.

In really cold weather, particularly sub zero, the coolant circulation through the radiator is VERY low & since the coolant that is flowing into the engine is also VERY cold, it has the ability to soak up a LOT of heat before it becomes hot enough to open the thermostat, or to keep it open.
The amount that it opens in an efficient engine can be quite small & the flow is likewise very small.

This means that the coolant in the radiator is exposed to the icy airflow for often a surprisingly long time so if we restrict the airflow through, lets say, half of the core, then we have much less of the core now exchanging heat from the coolant into the air. [The radiator is nothing but a water to air heat exchanger remember]
The result?
Since the radiator is now a less efficient heat exchanger the coolant that reaches the block is a little warmer & absorbes less heat, resulting in an increased coolant flow which puts more hot water into the radiator core which in turn heats the [now restricted] air flowing into the engine bay & this air is being drawn into the carb.

The cylinder head/thermostat will not really see any effective change but the overall temp in the engine bay will be warmer & the engine will thank you for it.
This assumes of course that the engine does not already use a heated air induction system.

Oh yeah, the covering of a portion of the radiator will also reduce the risk of the coolant in the radiator freezing solid in extreme cold, particularly if the coolant is untreated water.

Back in the 1980's & early 90's I was the district Fleet manager for Telecom [as it was known back then] based in Goulburn. My teritory covered a fair bit of south west NSW including Cooma, Berridale, Bombala & the snowfields.
In winter I noted with interest the number of private cars at the various repairers that we used that suffered from this exact condition.

Stock engines with extractors that ran fine in the summer but were absolute dogs in the bitter depths of winter. My own Valiant fleet car was also a victim of this when I had the cracked manifold replaced with extractors in the summer of 1980. [I was the manager, I could get away with this sort of thing]

Refiting a stock manifold rectified the situation overnight & this is how several of the local yokels cars were fixed also. Additionally, I blocked off a portion of the radiator in that Valiant & in my 1200 Ute when in sub zero temperatures & reaped the benefit.

Posted on: 2011/5/23 14:19
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Re: Car Running Too Cold?
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Well, my 1932 Dodge 6 cylinder sedan uses an updraught manifold with a hot spot & my 1933 Coupe used a downdraught manifold with a hot spot.
From memory, so did my FJ Holden & every single carb Datsun I ever saw
This was all well before emmisions regulations came in.

One must ask the famous Julius Sumner Miller question, .... "Why is it so?"
Why did hundreds of auto makers, over a period spanning 80 years or more, include inlet manifold heating when they could have left it off, still [as you claim] provided perfectly normal engine operation, & saved a few sheckles on every engine that they produced.

Would it be the same reason that the thermostat was never eliminated either?

I speculated that the overcooling & the unsatisfactory running of the engine that is the subject of this thread were in fact separate problems.

The overcooling is, I believe, a thermostat problem that it easily fixed, but unsatisfactory stock engine performance, during a wet winter, when operated at low speeds in an urban environment may well be caused by the lack of fuel vaporisation resulting from the removal of the inlet manifold heating function.

I then went on to describe the two main refrigritaion principals that take place at the throttle plate & the resultant loss of fuel vaporisation.
These are
1. Latent heat of evaporation &
2. Temperature drop at the point of pressure drop.

I provided easily demonstrated examples of these principals. [Perspiring is an example of No. 1]

Some symptoms of this can be
1. Reduced power. [Due to the resultant lean mixture as seen by the combustion chamber]
2. Increased fuel consumption. [Due to the higher power settings required to maintain performance]
3. Backfiring through the carb. [again, due to lean mixture]
4. Possible carb icing, resulting in the blockage of some small air passages within the carb. [Fuel jets never block with ice, every mechanic should know that]This results in a rich mixture as a result of the emulsion jet no longer receiving sufficient air, or indeed, any air at all.
A byproduct of this is the reduced atomisation of fuel as it is passed into the airstream from the discharge nozzle because it is not being 'premixed' with air. This in turn makes the problem of overfueling with liquid fuel even worse as the hot spot is no longer hot.

These problems will be greatest in winter, particularly in high humidity conditions such as fog or mist.
They will also be induced at high vacuum settings such as at modest cruise speeds with very low throttle opening.

In warmer temperatures, particularly a hot summer, all of these symptoms may well be non existant as the ambient temperature can easily be high enough to negate the effects completely but right now it's winter in Australia [or soon will be] & it's been wet & bloody cold, just the right conditions for the problems being experienced.

Higher speed engine operation & sub zero temperatures will often overcome some these problems due to higher gas velocity in the inlet manifold, lower vacuum figures & a low humidity due to the sub zero temperatures.

That's my reasoning, but am looking forward to a properly researched counterview instead of a lot of running off at the mouth.

Posted on: 2011/5/23 12:55
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Re: Car Running Too Cold?
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Quote:

old-tin wrote:
well as a seasoned mechanic you would now that there is a big difference between an aircrarft doing 200mph in -20deg c and a motor car at sealevel(never hered of iced up jets in australia not even full on race boats), and the fact that you try to use that as verification is hilarious. im by no means trying to offend you but compleatly disagree with your interpretation on fuel atomization(not vaporization) and when i get time i will send you an email

have a nice day
Quote:

Dodgeman wrote:
Try page 24, the article is called "A Chill in the Air" & it deals principally with carburettor ice & its causes. It also describes the conditions that I described in my post. The aviation solution to this problem is "carburettor heat" where hot air is fed to the inlet of the carb while the automotive industry went for "hot spot" manifold heat, which was replaced by water heating of the inlet manifold, then hot air induction was added to make a near perfect package.


Been a while since I saw a jet engine with a carburettor, oh wait, nobody mentioned jets at 200mph & at high altitude [where it's really cold] except you.
Not a relevant comment & it is therefore ignored.

Aircraft have been using internal combustion, reciprocating piston engines with carburettors since December 1903 & you can still buy them in this basic configuration brand new.

Still waiting for that forum link.

Posted on: 2011/5/23 10:33
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Re: 11.5 sec electric 1200
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I know that I am drifting off topic so will not continue past this post but I suspect that I could get better mileage if...........
1. I was closer to sea level instead of 2,500 ft [carb runs richer due to less dense air]
2. My trans was a manual instead of auto [I love my auto]
3. I operated the engine at its most efficient speeds instead of trying to keep up with modern cars on the highway. [110kph + or 70mph +]
4. Did not drive into a fairly constant headwind every morning.

If I kept it down to about 50 to 55 mph [80 to 88kph] I would probably get better mileage but the big rigs would just use me as a speed bump.

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Posted on: 2011/5/23 10:21
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Re: does anyone else get excited when they see really old people driving 1200s?
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Well between BazDat & Ivan1 I guess I am in good company.
I'm 61.

Posted on: 2011/5/23 9:50
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Re: Car Running Too Cold?
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Quote:

old-tin wrote:
there is a discussion about your post on the morris forum feel free to check it out.
it's not so much your idea's on cooling thay are valid, but your interpretation of fuel and air behaviour is #OOPS#.

i could do a 1/2 page on your errors but i would hate to offended you with all my spelling mistakes. best you investegate how fuel vaporizes(-atomizes:)as it enters the engine and can infact do a 90deg turn without a heated manifold, as thay are for EMISSIONS

Well don't be shy, send me your half page of corrections as an e-mail & feel free to leave a link to the Morris website as I would dearly love to see what is being written behind my back.

I guess that in 45 years as a motor mechanic & 31 years as a small Datsun owner/maintainer/modifier I have obviously learned nothing but am ever willing to learn from those better versed than I.

I learned my trade in the '60's when many of our cars were years away from being manufactured & EFI was but a dream, yet problems with fuel vaporisation were well known & had been for at least six decades before that.

Even now this very subject is being discussed in the current edition of "Flight Safety Australia" [May-June 2011, issue 80] the aviation industry publication on air safety & aircraft maintainance.

Try page 24, the article is called "A Chill in the Air" & it deals principally with carburettor ice & its causes. It also describes the conditions that I described in my post. The aviation solution to this problem is "carburettor heat" where hot air is fed to the inlet of the carb while the automotive industry went for "hot spot" manifold heat, which was replaced by water heating of the inlet manifold, then hot air induction was added to make a near perfect package.

Perhaps you & your fellow forumites should do a little research before dumping on me or anyone else who has a better understanding of physics than you do.

Remember, if you're talking about me behind my back, you are close enough to kiss my [censored]

Posted on: 2011/5/23 9:41
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