Exhaust/Heat Concerns

[jchiotti]

Hello,
I recently replaced the old two stroke kohler in my 1970's Argo with a 23 hp Vanguard. Conversion has gone fine and overall I am happy with the results. I wanted to get some advice/opinions on my exhaust system. I took it for a ride tonight and after shutting it down realized the hood was pretty warm. Warm enough that I was a bit concerned.

The muffler is standard from B&S. I wrapped it with heat wrap and then installed a heat shield over the top. Right now it has ventilation on each side and the hood was off when I was running it. I do not have an air intake running towards the engine. The heat shield is pretty close to the hood. Ranges from 1-4 inches.

I posted some pictures to let you know what I am talking about. Do the hoods heat up quite a bit on you machines? Almost hot to the touch when touching it for about 5 seconds? By the way it was 80 degrees out while I was driving it.

I am thinking my options are to add a heat shield to the bottom of the muffler as well to direct some more heat out the side. Possibly another shield on top of the existing, or making my hood a little bigger to allow for more room between the shield and hood. Just wanted to see what you were experiencing first.

Thanks

[ARGOJIM]

A secondary duct from the muffler to the perforated metal may help a lot, also we put a 12 volt fan on the right side blowing across the engine/exhaust on dad's 78 to help escape engine compartment heat ( similar to the one blowing on your school bus driver) which made quite an improvement on the Tecumseh compartment heat'

My early V2 with the side to side muffler with the separate manifold seems to escape more heat than the later front to back one piece muffler.

Nice job on the exhaust heat vent.

[jerseybigfoot]

The 4 stroke Agros have a duct to direct the heat from your muffler shield to the body exit, also a cold air duct on the engine inlet.

[ARGOJIM]

May have to be trimmed to fit in the tec/stroke bodies.

[Noel Woods]

The Briggs 23 hp is a fine engine in many ways, great power to weight in a fairly small package, etc., but on the downside: the cooling fan is on the small side, especially when its in a machine that has fairly restrictive air flow to the engine. The oil cooler is mounted on the backside of the motor where there really isn't any air flow to cool the oil. The factory starter is on the weak side, and you will have to adjust the valves occasionally, and this isn't very easy when the motor resides in a tight engine bay.

The motor isn't my favorite, probably perfect when mounted on the back of a zero turn mower. Not ideal for an amphib though.

[trevorakm1]

this is a question to you guys, how is this high heat affecting the performance of the engine? I see guys like Noel and Dan running with the hood off to help cool. Are you finding other than hot plastic but erratic idling of the engine, stalling at idle unless you keep the throttle up a bit.
Argo Jim, is the heat inside the duct on the muffler side too hot to run a 5" fan or two one each side of the tailpipe to exhaust the heat faster and more direct. I have been kicking this idea in my head for a while now and I hate to cut into the original plastic. I have seen some fans with an aluminum frame putting out 100-120 cfm, anyone seem fan issues caused by the heat? I figure wrap the tail pipe in heat wrap in between the fans to help protect the fan frame. Just thinking.

[ARGOJIM]

Trevor,I have no real world experience with those fans, the reason we put the fan on the right side was to aid in cooling complete engine compartment, by moving stagnant air and directing it towards existing vents. We had a vaporlock issue with the hood on.

The Tecumseh and 2 stroke machines have an internal heat shield with the muffler exposed in wheel arch.

[twinlakemike]

You can ad to the heat wrap with “refractory” material it is a white supper high temp insulation that is used in industrial applications. We wrap race car mufflers and headers with it and you can put your hand on them after an race.

[Tomo]

hi
OMG get rid of the across the cylinder head muffler as per pics . This will cause over heating of the engine compartment and the operators .
The pic muffler stores heat as the exhaust path is not in the one direction
There is a exhaust manifold [briggs or argo manifold ]that places the muffler inline with the air coming of the cylinder heads . The engine air then cools the hot dog size muffler also .
At this point manufacture a duct that goes from the cylinder heads connecting to the body out let . The muffler then fits inside of this .
Every thing is the way way cooler
Manufacture an inlet duct to the pull start side which comes from the bonnet . This may be available from argo
Many argo owners use bilge fans to cool engine bay /brake area
The engine will over heat if ducts are not around the engine
I operate in tropical heat and I found the system like u have does not work
Hope this helps ,not trying to be to serious just concerned. Even some of the late model argos have heat issues

tomo



h

[Mike]

There is a exhaust manifold [briggs or argo manifold ]that places the muffler inline with the air coming of the cylinder heads . The engine air then cools the hot dog size muffler also .

Do you have a link or photo of this exhaust. Will it fit in an Argo without hitting the lower tub? I'm trying to picture what you are talking about but nothing comes to mind.

[jchiotti]

Tomo,
Thanks for the advice. I have seen the more recent argo models with a duct running from the motor all the way to the outlet with the muffler inside of this. This is what you are suggesting right? Doesn't seem like it would be that hard to rivet one of those together. What do you think would be better.....an inlet duct to the pull start or a fan blowing air from the inlet vent towards the pull start? Seems like the fan would produce better results than just the inlet duct alone.

Right now, I am leaning towards constructing a new outlet duct which will fully surround my muffler and extend to the outlet vent and then adding a fan as well.

Thanks.

[twinlakemike]

If it was me I think I would make my own header/exhaust like the newer Argos and wrap it and run a cooling duck from the motor past the exhaust and make an cold air inlet from on top of the hood, like the newer ones, also adding an oil cooler and temp gauge will be very helpful for keeping your motor happy.

[Tomo]

hi
The engine pipe is a 2 into 1 y piece [factory item ] then fit a 3-5inch diameter up to 12 inch long straight thru muffler. Installs inline with the crank eg the exhaust gas flows from the right to the left without changing direction [this muffler will need a 1 1/2 inlet/ outlet either muffler shop or make one ]
2nd part create hot air duct from cylinder head to upper body duct . The y piece and muffler are inside the duct . The heads and the duct do not fit perfect together but far better than the original set up


The inlet side must have a duct .If u have a pull start cut part of the duct out and have a rubber flap .
THE ENGINE WILL DIE A SLOW DEATH WITHOUT A DUCT OVERHEATING BADLY
An auxillary fan may be needed for your brakes depending upon model and usage

tomo