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Mon Jan 19, 2009 1:42 pm

my 1700 type4 i just rebuilt seems to run tight.i am experienceing a problem now where it hesitates a little so i adjusted the points.this helped a little but not much.then now it is running poorley at any rpm above idle.the carb bottom keeps condensing so much it freezes when this starts to happen is this normal?

Mon Jan 19, 2009 2:02 pm

What kind of carb? Is it a two barrel webber? if so, thats probably your problem.

Mon Jan 19, 2009 2:13 pm

I've got a '72 also. The PO put a webber dual progressive( progressive is the key word ) and a 009 dizzy. I experience the same problem. I am living with it for now. It seems to be related to both. I've asked here a while ago and got many helpful answers from using a SVDA dizzy to rejetting the carb. However its not my daily driver and I have other prioritys right now so I have not come to a conclusion yet. Hope this sets you on the right track.

Mon Jan 19, 2009 3:32 pm

well i think it was mostly points,i went and ran a bill between them and took the distributor out to get a good look at it.it seems to be running ok now.i have always had a little hesitation at low rpm with my weber.and yes an 009.i also have another question i recently put another trans in from a old donner bus.it seems tight but whines when driving.well it even does at when idleing and in neutral with the clutch out.is this worn bearings.i replaced it because my old one seemed to be so sloppy and grinded gears.this one seems so tight.i hope its not a problem.

Mon Jan 19, 2009 4:59 pm

Regarding the condensation I had the same problem, some tiny drops of water began to condensate in the base of the progressive in the mornings, I put a air filter box from a dart K 2.2, it just to have the same carburator undre the brand holley, then this box has a preheat intake that you connect to the stock snorkel from piston 1 front, and a manifold vacuum "T" from the brake booster hose. if you click in my gallery there are some pictures. I will try to build an enclosure to keep warm the progressive carburator base with the crankase heat, I think it should be like a chimeney leaving some cold air getting inside, then the hot air elevates and surounds the aluminum base.

Mon Jan 19, 2009 5:52 pm

Good idea on using the K 2.2L air box. Looks like a good place to start.

Here are some pics on my prototype manifold heating system. It works the way it is but needs a larger heat collection fin on the bottom and more crossectional area to move the heat upwards. At present it will get and keep the manifold above the dew point, but not get it up to 120°F or so where I would like it. Ignore that I have it set up for use with a single runner manifold, the same idea should work with the more common dual runner manifold.

Tue Jan 20, 2009 8:25 am

hey joe73 that looks like a very good rig you have.where did you run the pre heat tube to into what..?i get the rest of it but coulnt seee where you got the warm air from.i saw the tube you had the white arrow ahowing where does it go.heater box.

Tue Jan 20, 2009 1:53 pm

hesitation is one of these normally

Dwell and inital timing are off

Timing advance is not advancing normally - weights can be sticky or vacuum can bad

Your power enrichment circuits are too lean - or sometimes the butterfly doesn't line up properly with the enrichment holes

You have too much carb and what you are really feeling is low speed gasp. If it is a progressive, then sometimes people have tweaked the secondary so that it opens too soon.

Tue Jan 20, 2009 3:53 pm

sounds like a good possibilty i will look at that next

Wed Jan 21, 2009 10:09 am

Brandon: the picture with the arrow shows the hole where the preheated air is connected, it comes from the front of cylinder #1 in the stock type 4 engine, through a square section tube called the snorkel, but I have see sombody taken preheat air from the heat exchanger, then the dart K airbox has the intake preheat tube at the bottom, the progressive intake runners have a piece of metal strip reinforcement that has to be sawn to leave room for the tube, then the tube goes between the runners, the vacuum for the preheat valve is from a "T" from the booster hose.

Wildthings: Nice heat riser, if that metal is aluminum then should work perfect, the problem maybe that the alluminum is dissipating the heat on its way, maybe if you put an enclosure with some isolation, or a sleeve, I was thinking of making a chimeney with a tapered angle, kind of pyramid to conduct the air from the bottom to the manifold but maybe a combination of thick metal base as you have it and a sleeve to keep warm.

Wed Jan 21, 2009 10:42 am

joe73camper wrote: Wildthings: Nice heat riser, if that metal is aluminum then should work perfect, the problem maybe that the alluminum is dissipating the heat on its way, maybe if you put an enclosure with some isolation, or a sleeve, I was thinking of making a chimeney with a tapered angle, kind of pyramid to conduct the air from the bottom to the manifold but maybe a combination of thick metal base as you have it and a sleeve to keep warm.

My one idea is to make a tapered and sealed enclosure similar in shape to that which you speak and fill about 5% of its volume with a liquid with a boiling point around 60°F. The evaporation of the liquid would move a lot of heat upward as soon as the block had warmed a bit. Insulating the structure would certainly help as well.

As I said the one in my pictures is a prototype and for a first shot I am happy with it. Just getting rid of the bolted joint in the middle of the fin would probably get me 10°F higher temps.

I have several different ideas I may try with time. Need to come up several more center manifold pieces that I can chop and weld on.

Thu Jan 22, 2009 7:10 am

hey wildthings is that carb base plate in ur picture modified for a type 1 single port?

Thu Jan 22, 2009 11:23 am

brandon chidester wrote: hey wildthings is that carb base plate in ur picture modified for a type 1 single port?

Early in my ownership of a progressive fueled T4 I decided that I might get better atomization by copying the 1600 dual port system, so when I built my first exhaust heated manifold I converted the whole system over to a single runner system. The system worked quite well, but after 15 years I worried about rust and clogging of the preheat passages and wanted to come up with something simpler as I had given that bus to my kids for use while away at school. I just kept with the single runner system because that is what was now on the bus. Can't really say if the single runner system by itself is an improvement or not.

Here is my earlier system with an exhaust heated manifold.

Mon Oct 26, 2009 5:24 pm

I have been working on this manifold heat box

This is a modification to prevent carb icing on type 4 engines equipped with weber progressive carbs, initially the box conducts heated air from the No. 1 cylinder snorkel, and when the engine gets hot, the box conducts heat from the crankcase, the system turns on and off automatically via the stock 73 temperature switch that grounds its terminal below 12 celsius, and manually with a toggle switch, all this keeps smooth riding at any temperature.
The cork isolations prevents heat dissipation.

Thu Oct 29, 2009 5:56 pm

i also found that if you zip tie cardboard over your vents when its really cold it wont ice up either.low tech