Cleaning heat riser - ? solvent?

[Komissar]

Hello,

I am starting to suspect a clogged heat riser in my car, (since winter came on, and when driving in cold weather the car sputters and "coughs" , and the intake manifold below the carb, is only just warm, even after driving for 20km, or so ) .
Anyway, today I took my time with a spare manifold, the heat riser was clogged as well... after a challenging hour trying to get an old speedo wire through , i have finally managed to get the wire on the other side. I have started to spin the wire with a power drill, and I have done that repeatedly, however, anything bigger than a speedo wire ( clutch cable, for example ) won't go in , so THERE ARE STILL some clogging remains in there.

The question is: can I SOAK the heat riser in some solvent for a couple of days to dissolve the deposits inside the heat riser ? If so WHAT should i use?
_________________
1965 Sunroof Beetle
1972 Type 3 Squareback
1978 Skoda 105S

[83_WabbitGTI]

Elemental carbon will not dissolve in solvents, however, it will react with oxygen and other oxidating agents to forms carbonates and carbonites. Carbon doesn't "dissolve" in a classic sense in molten iron, it melts and forms a mixture with molten iron.

As for why elemental carbon is insoluable.... carbon needs other atoms attached to it to become polar enough to be soluable in water. For example.. carbon (C) is insoluable, but carbon dioxide (CO2) dissolves in water. Other small molecule "forms" of carbon that dissolve in water are formaldehyde (CHO) and acetone (C2H5CO)

So basically there isn't a solvent that will remove the carbon. High heat is really the only way to remove it. Like an oxyacetylene torch. You may even try some "Oxy-Clean" worth a shot.
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[Komissar]

Ok... so chemistry is working against me. - anyway, the big problem is that i have no easy acces to an oxy-acetilene setup (or someone that has it ) ... so that;s why i need OTHER methods of cleaning the heat riser .

Regarding the "heating-up" method with the oxy-acetilene lamp - if heated up to glow-red condition, won't that melt the soft aluminium casting that surrounds the heat riser and manifold ? ...
Also, how does this work? - will the carbon deposits melt ? or just come-off ?
_________________
1965 Sunroof Beetle
1972 Type 3 Squareback
1978 Skoda 105S

[79SuperVert]

Many threads on this, but the method that worked for me was drilling a hole in the bend on each side and then reaming out the riser and welding up the hole again afterwards. Doing it at the bend makes it easier because you don't have the tight constriction of the bend to deal with. I didn't do this myself, my old-school mechanic did it for me but you can't even tell that it was done when the engine is in the car.
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Central Jersey VW Society

Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt.

[Dangermouse]

Do yourself a favour; life's too short.

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC%2D113%2D129%2D701%2DK

Only other semi-reliable method I've ever heard of is to hack off the risers, drill straight through and weld 'em on again. I don't believe there exists an easy or reliable way of clearing these if they're good and blocked. With the solid rocket booster method (with the oxygen), the carbon burns off (apparently)...
_________________
Do not follow me, for I may not lead. Do not lead me, for I may not follow. Do not walk beside me either; actually just bugger off and stand over there will you.

[61Ragster]

Komissar, seems that if your heat riser was clogged then you wouldn't have anything close to "warm" immediately below the carb. It would be icing up like crazy. If you feel the left side and right side heat riser tubes close to the muffler and find a noticeable difference in temperature, then it's not clogged and your sputtering if from some other cause (careful not to burn your fingers though...).
(BTW, did you solve last August's chatter/shaking during take off from a stand-still? Was it Bowden tube problems?)
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[Komissar]

Yes, it was Bowden tube related - i don't remember if I mentioned in that topic at the time, but I have found out that the whole clutch cable metal conduit was lose inside the tunnel. I had to open the tunnel up, with some incisions, and weld it back on .
Since then i have replaced the 1200 engine with an 1500cc beefed up to 1600 single port.


Regarding the manifold from CIP1 - that would be nice, but, considering my location ( Romania, European Union ) the shipping plus customs would more than double the price for it - also, there is the waiting time.


In relation to my manifold problem - although the area below the carb is warm, the right and left arms of the heat riser are warm as well, but I CAN TOUCH THEM with my bare finger. This makes me think that they might not work as supposed to.


Later edit, as I mentioned above in my post, I have managed TO PASS an speedo cable from one end to another. However, anything larger than a speedo cable won't go through, and when passing the speedo cable i can fell it hitting solid deposits inside the heat riser. So, this makes me think that although I have a connection (free passage) from one side to another, there is still a lot of clogging, and the heat risers will not work properly.
_________________
1965 Sunroof Beetle
1972 Type 3 Squareback
1978 Skoda 105S

[79SuperVert]

When the engine is warmed up, I can't touch one side of the riser, it's so hot, and the other side is very close to being untouchable. But that's when the air temperature is reasonably warm, not when it's very cold outside. It may be that you need to let the engine really get warm before trying the risers with your hand.
_________________
Central Jersey VW Society

Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt.

[Komissar]

Yeah, ... i want at least to get to the point where one side is almost untouchable Winter is on right now, and in the last week temperatures are a tad bellow zero even during daytime, so the heat riser is damn important.
_________________
1965 Sunroof Beetle
1972 Type 3 Squareback
1978 Skoda 105S

[Michael Fischer]

I heat them with a propane torch and beat on them with a metal hammer. Takes awhile but eventually it clears up. Once I get it to where I can blow through it with compressed air and feel it coming out the other side I throw it in my cabinet and shoot glass beads through it.

[Ronny Bailey]

About how long does it usually take, once you get to the beadblasting?

[notsnarb]

I did this job back in January. I tried every method I found in the threads on Samba without success, soaking, heat and hit, etc. I considered drilling holes in the ends as a last resort.

I bought 3 pieces of wire rope from Lowes about 3 feet of each. Something like 3/16, 1/4 and 5/16 dia. I put the smallest in my Battery drill and cut the wire length so it would reach just past the half way point of the heat riser. Wearing a good leather glove I started it into the heat riser tube. BE WARNED if you rotate it the the wrong way the wire rope comes unraveled and gets stuck. Use a variable speed drill so you have more control over the wire or it will whip about and bite you and guide the wire with your gloved hand.

Gradually I forced the wire rope into the heat riser. It found it's way along the heat riser pipe snagging on the carbon deposits. When I got it in as far as possible and past the half way point, I started it from the other end. At first I lubricated the wire, but It's better to do it dry, then the debris can be shook out at a bit at a time.. The wire wears into a point eventually. When you get through with the small wire try the next size and so on.

I really didn't think it would work. Took me all evening but the heat riser is now completely clear.

[83_WabbitGTI]

^^ That's the best method right there.... Other then buying a new one.
_________________
2013-2014 Vice President of SOVW www.sovw.org

"No matter how a VW breaks down.... You can always make it home on Zipties, Ducktape, and JB Weld...."
-Doug Christen, VW Owner

83 Rabbit GTI - 83 Rabbit LS Custom - 63 Westy - 65 Bug - 64 Baja (Herbie's Studly Cousin) - 91 Audi 90 Quattro 20v - 85 Vw Cabby - 84 VW Scirocco - 69 Beetle (Phantasm Bug) - 78 Cabriolet

Need a VW website built? PM me.

[Komissar]

Ok ...
The situation has changed - FOR THE WORSE ....

I have cleaned the above mentioned manifold the best I could. I let it soak for more than 24hr with water and detergent, after that, I have tryed the drill+wire approach some more and I said - THAT'S IT ! - is going on the car!

Today, i took my time to install it.
Taking advantage of my time with the car, I have ALSO installed a working thermostat assembly and a "Mexico Header" new exhaust.

During install, the carb and distributor were left untouched ... i have not messed up with the settings on those.
The carb is a Brosol H30/31 virtually new ( no more than 2000km on it, milage done by me ) , and the distributor is the stock 1500 dizzy.

Ok... I have put everything back together, and took it for a spin ! HORRIBLE ! - the car sputters and dies when pushing down the throttle, sometimes when taking-off from a standstill it dies, .... it has a HERRATIC throtle response, .... (example: if gradually pushing down the throttle the car does not pick up speed and dies, even though you push down some more, almost to 60% throttle , it still dies and doeas not pick up speed ) . Sometimes, when pushing the throttle down hard and SUDDEN the car comes to life and the it gets very nimble, but sometimes no. Also, a couple of times, as I was in 3rd gear, and going CONSTANT, the car started to lose speed, .... and slow down.
And of course, the heratic sputtering (sometimes it does, sometimes no) - it's a very loud sputtering and the car shakes like hell - it even unlocked a door when moving.
However, it holds idle... , and when reving it up with the gearbo in neutral the engine revs up nicely, and at sudden throttle changes there are no sputters ... in load things start to go wrong.

Anyway, scared like hell by this result, I have installed an used Solex 32-PICT carb , - by this moment, the distributor was still left in the " before" position, no messing with it. - anyway... with the SOLEX, at idle, without touching anyting at the car it went from FAST idle to SLOW idle, by ITSELF ! ...

I got scared with this result and reinstalled the Brosol H30/31.
By this time I have started messing with the timming ( by ear, + trial and error ) and i have turned the mixture screw for a rich(er) mixture ( about 1 turn ) - however, the benefits were AT BEST minimals.

Overall, the weather was about 5 degree Celsius, and the engine was warmed up a lot in the garage, and, even though the therkostat din not opened , the overall condition of the engine, was warm...

Before today's work on the car, the engine ran resonably good, when above zero temperatures (like today, ) and in NO WAY so bad as after today ....


Anyway... any advices ?
Thanks in advance.
_________________
1965 Sunroof Beetle
1972 Type 3 Squareback
1978 Skoda 105S

[Jody '71]

Question:

You got the old crush washers out ok???? The ones that fit into the head opening. You can't put new ones on top of old ones. If there's any residual leftover old copper crush washer the new ones you install won't seat right and you'll have vacuum leaks. The mainfold needs to be tourqed back down evenly onto the heads so the new washers seat
properly. Sounds like that may be your problem.
_________________
'66 Beetle
2011 Hyundai Elantra Touring

[tim925]

[[email protected]]

Besides the cable method, consider the compressor method.

If you have a compressor, blowing back and forth thru the tubes also helps. You can also build full pressure on one side, then the other. Having 125psi against the debris is a lot of pressure. Be warned, WHEN it clears it will come out the other tube like a shotgun, and you DO NOT want to have skin (or anything nice) in front of that shotgun, so be careful where you are aiming.

Work back and forth with a lot of pressure, even a little movement in there will eventually break up and work out.
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[Hammarlund]

Did you check to see if you have condensation/icing on the carb/manifold? If so, the car's not going to run well no matter what you do with the timing and the carb. Check for condensation/icing now before you disturb any other settings!

Most headers don't do near as good a job as the stock exhaust when it comes to circulating heat through the risers.

In addition, many headers have the heat riser flanges blocked, that is, set up for dual carbs. To use them in a single carb set-up with the risers, you must drill out the blocking plate!

If you do not have condensation/icing on the carb, 2x on what Jody said about the crush washers.
_________________
Trying to diagnose electrical problems without paying attention to what the red light is telling you is like trying to play the piano without using your hands.

[Michael Fischer]

[Komissar]