312-8 New exhaust!

[ChrisJordan 46]

Well the old girl has been getting noisier and smellier over the last few months, unsurprising seeing the state of the bottom of the silencer when I took it off!

 

 A quick search found it very hard (and expensive) to get a correct silencer, so I decided to make a new one up from stainless parts bought on eBay.

 

It's all welded up and fitted now, works a treat, nice and quiet and blows the exhaust well to one side so no fumes in your face.

 

I've still got to make the stead bracket to discourage it from  twisting on the exhaust stub.

 I think it looks pretty good and worked out at just under £100 for the parts and welding, which is less than anything WheelHorse/Toro can supply in the UK.

if anyone wants more info drop me a message. C

 

[ebinmaine 72,609]

Looks great. Very nice work.

[Maxwell-8 4,367]

Nicely done.

I noticed that mufflers rust from not being used. 

Are you going to paint yours?

[roadapples 6,983]

Is the muffler itself stainless steel. If so what did you use. Looks great 👍

[Snoopy11 5,718]

2 hours ago, ebinmaine said:

Looks great. Very nice work.

 

21 minutes ago, Maxwell-8 said:

Nicely done.

 

 We are not worthy 

 

 

Don

 

[ranger 1,798]

Very nice! My 312-8 (1989) rusted through exactly like yours. I cut it open and copied it in stainless, even down to the size of the holes in the baffles. Ever since, running under load the exhaust valve would seize in the open position, then close when it cooled. It seems the stainless system holds the heat in more. It happened again yesterday when mowing some really long grass in one of the horse paddocks. Pulling the silencer and running without I cut around a half acre or more of 12”/18” long grass which really loaded the engine, but it didn’t miss a beat! I think a change to a system like yours is now on the cards!

Doug.

[pfrederi 18,664]

12 minutes ago, ranger said:

Very nice! My 312-8 (1989) rusted through exactly like yours. I cut it open and copied it in stainless, even down to the size of the holes in the baffles. Ever since, running under load the exhaust valve would seize in the open position, then close when it cooled. It seems the stainless system holds the heat in more. It happened again yesterday when mowing some really long grass in one of the horse paddocks. Pulling the silencer and running without I cut around a half acre or more of 12”/18” long grass which really loaded the engine, but it didn’t miss a beat! I think a change to a system like yours is now on the cards!

Doug.

 

 

Stainless steel is not a good conductor of heat.  Hence good quality stainless cookware has aluminum  or copper plates on the bottom

[peter lena 9,261]

@ChrisJordan , nice job on that , made one years back , from stainless scrap in the salvage bins we kept for everything to recycle , glass pyrex , steel , iron , titanium , steel , etc , fortunate to have found a break down of a kohler muffler make up , duplicated it in stainless , last forever , pete 

[Pullstart 66,692]

Stainless stacks work as great as they look!  Your welds look amazing!

 

 

[tunahead72 2,543]

3 hours ago, peter lena said:

... fortunate to have found a break down of a kohler muffler make up...

 

@peter lena Do you have a copy of that diagram that you could share with us?

 

[peter lena 9,261]

@tunahead72 , not that I  have on hand , made that years ago , will start a hunt down , if I can find it , will get back to you , and group , pete 

[lynnmor 7,814]

22 hours ago, ChrisJordan said:

It's all welded up and fitted now, works a treat, nice and quiet and blows the exhaust well to one side so no fumes in your face.

 

 

I like the seamless design much better than cobbled up threaded water pipe fittings.

[ebinmaine 72,609]

1 hour ago, lynnmor said:

I like the seamless design much better than cobbled up threaded water pipe fittings.

Agreed. Neat and clean and looks sharp.

[ChrisJordan 46]

 

Many thanks for all the nice comments!!   I've got to admit I didn't do the welding... a guy at a local engineering works TIG welded it for me, if I had done it with my MIG welder it would not be so tidy...   I'll pass the compliments on when I next see him.

Roughly in the order in which people posted here are a few answers:

Maxwell-8  --  It's all stainless steel so hopefully won't rust.

Roadapples -- There's loads of sellers of exhaust parts on eBay.co.uk  the silencer I used was item no.(132426457365) and the pipes (233400861388) and (284237614638)

 

Ranger -- re. sticking exh valve,  that must have been really annoying! I think you are right the stainless doesn't carry the heat away so well so everything runs a bit hotter. My setup is 'straight through' so hopefully wont suffer the same problem. (Also I don't usually work it very hard).

 

Pfrederi -- agreed!

 

Pullstart -- Great to see your daughter learning to use tools, something that's sadly lacking in our schools nowdays. Great stacks on your tractor, what engine is in it?

 

Lynnmor -- Yes the guy that welded it up did a great job! Wish I was as tidy at it...   I could have bought a silencer with stubs on it and assembled it with clamps but it wouldn't have looked so nice, and by the time I had bought the extra clamps and the more expensive silencer there really wasn't anything in it cost wise.

A few tips (mostly found out the hard way)  for anyone thinking of making a similar setup:
1) There is lots of confusion with sizes when buying bits. A 38mm bore silencer does not fit over a 38mm o/d tube because of the internal perforated tube, the actual bore is about 36mm
2) 90deg mandrel bends are often not exact, both of mine were about 93deg, I had to grind the end of the bottom  tube at an angle to get the silencer vertical.
3) The exhaust stub on the Kohler engine is approx 36.5mm, too big to fit inside 38mm o/d tube. The suppliers could only expand the bend to fit over 38mm tube so it was then too loose...  I had to shim it out to get a decent fit.

 

Hope this is of help to someone!