Why no exhaust rain cap on some older dozers, specifically D7's?

[LCA078]

I saw something peculiar in the online pics of older Cat dozers like D7's. I notice a decent number of them had straight up exhaust stacks but no rain caps. Sure there were the obligatory coffee cans on a couple but some didn't appear worried about rain getting into the exhaust when parked. Is there a drain port or something to keep water out? What am I missing?

 

[56wrench]

no drain port that i know of otherwise it would blow exhaust back at the operator if the fan is sucking and blow exhaust into the rad if it is blowing. and yes, a heavy downpour will let water into the engine and too much will hydraulic a cylinder on start-up or seize it with rust from sitting too long. any expansion joint between the turbo and the elbow may allow a small bit of rainwater to drip out but a covered exhaust is the best. even flapper style rain caps will let some water in during a windy pounding rain or worse, a heavy wind from the wrong direction will blow them open and could let in water. i've even seen small dead birds blow out of the exhaust on start-up on an engine with a 3", 45 degree angled exhaust, so a coffee can is still the best for any prolonged storage in my opinion as long as the can doesn't rust out

 

[Welder Dave]

If the exhaust is similar to my 931B, the pipe coming out of the hood is a larger diameter than the pipe coming off the muffler and is not a solid connection. Water will run down the side of the larger pipe and not into the muffler. Additionally there is a drain hole should any water get in the muffler. The drain hole can get blocked though. I think it is a good idea to put a can over the exhaust if the machine will be sitting for awhile. I put a rain cap on the pipe out of the hood just for piece of mind. I get some black smoke under the hood and on the top of the rad because the pipe/flange out the hood is larger than the pipe out of the muffler. It's not even a slip fit, the pipe off the muffler fits inside but I'd guess it's a 1/4" or more smaller dia. than the pipe out the hood. Cat isn't going to put an open pipe on a machine to direct water into the engine.

My skid steer is a different story. Pipe off manifold goes straight up and had a Supertrapp style muffler on the end. A guy was renting my machine and I went to change the oil in it in his garage before I took it home. The junk factory muffler rusted out so he just removed it. Good thing it was winter and had just happened. He was too stupid to realize it was a straight pipe to let rain directly into the engine. I put a baffled silencer on that wasn't straight through and a rain cap. I was very limited for room so needed something that was a smaller diameter. Works good and seems to be just as quiet as the original muffler.

 

[lantraxco]

A lot of guys hated those damn flappy bird rain covers, the typical accessory was a coffee can or five gallon bucket, metal in those days.

 

[old-iron-habit]

A lot of guys hated those damn flappy bird rain covers, the typical accessory was a coffee can or five gallon bucket, metal in those days.

Them damn flabby bird rain covers stood up every time the wind blew during a hard rain and directed the water down the stack. Even with them in place after a couple of water episodes I install a bucket or can over them. There only use is one might sneal by if you forget to install a bucket on the stack.

 

[LCA078]

Okay- agree the flappers aren't the best... but to have nothing to block rain on a straight up pipe seems pretty ridiculous (which is why I'm wondering if there is a drain or other way for water to no infiltrate the engine.) And a small hole to let water out wouldn't cause much exhaust to hit the cabin. I bet most engine's breather tubes put out more exhaust fumes than a drain hole would.

So here's another D7F on machinerytrader.

https://www.machinerytrader.com/listings/construction-equipment/for-sale/197517753/1974-cat-d7f

I'm not interested in it but only point out the lack of a rain guard. I'll post some pics so future readers of this thread can still see it after it sold or what not.

I do see what folks are talking about regarding the loose fitting muffler to turbo. Seems like there is soot (point A) coming out so maybe it's a loose fit on purpose? Also what is the hose (point B) that's going into the bottom of the muffler? Not sure but it also looks like water can flow out around that area too.

 

[lantraxco]

Somebody made a real rain cap, looked a lot like the usual kind, but it had a spring and a thermal device, it would open under exhaust pressure and then when it got hot enough it opened and stayed open, then closed when it cooled back off. Never actually saw any in use, LOL!

 

[hosspuller]

I had a flappy thing on my BH exhaust. I hated it, rattled and made twice the noise of the exhaust. The painted soup can works so much better. If I forget it on start-up, there's an audio /visual signal when it lands on the hood.

 

[wkp774]

Any cat i have ran has a small hole in the exhaust manifold to drain water, you notice exhaust out of it on startup but disappears once it warms up, so no need for a storm cap.

 

[Welder Dave]

Yep, I was told most Cats have a drain for water but they are small and can plug up. The pipe on the hood usually fits loose and is just so the exhaust doesn't get blown in your face. I have a rain cap on my skid steer but it generally runs full throttle so doesn't rattle at all. Even with a curved exhaust end, if the wind is right will still blow rain in the pipe.

 

[LCA078]

The painted soup can works so much better. If I forget it on start-up, there's an audio /visual signal when it lands on the hood.

That reminds me of my early days working the farm in the summer with my grandfather. One of games we used to play was me trying to catch the soup can off the JD ag tractor when he started it. It was a guessing game to see if I should be on the left or right side when he hit the starter.

Still remember the sweet sulphur smell of burning that old, oily, yellow diesel. Today's diesel just doesn't have it...

Good memories- thanks for bringing those back to me.

 

[John C.]

All the mufflers than I have cut open to repair or remove baffles have a partition in the middle. It would take gallons of liquid to get over that partition. I have not seen any drains on the mufflers used in the vintage of dozers shown in the photos. The can is the best way to keep rain out of the muffler but the easiest is to put an elbow on the top of the stack. We used the cans all the time in the mountains as you can get snowed out for a month or more in the winter and snow does pile up. The noise the flappers make, in my experience, only happened when the machine was parked and idling. Complaints of that noise were usually handled as a notch on the operator's cost benefit ratio and a check on how much work was actually getting done with the machine.

 

[Welder Dave]

Snow can be worse than rain but I doubt Cat or any other manufacturer would deliberately put an exhaust on a machine that directed water into the engine. A can is a very good idea if the machine is sitting for long periods or in inclement weather but how often do you drive by a dealer or equipment yard and see soup cans on the exhaust pipes coming out of the hood? Kind of similar to claims the wind will spin the turbo hauling a machine. Don't want to get into a subject that's been debated a thousand times, just saying.

 

[colson04]

We had a Case 9250 articulating tractor with an M11 Cummins with an angled stack. Never really worried about it until it sat most of one summer facing due south. We had several bad storms from the south that year and it did flood the turbo and suspect some got in the cylinder too. It started up and blew the exhaust apart. I don't remember if it cost us the turbo or not. After that, we always put a 5 gallon bucket over the stack when it was parked, especially if it was done for a season or heavy rains expected.

 

[hosspuller]

I read the back and forth about spinning the turbo without lube pressure during transport. I figured a couple of minutes, a plastic grocery bag and some tape on the stack was cheap insurance when I trailered my new tractor. And I am cheap

 

[John C.]

Most people use duct tape.

 

[Coaldust]

In 2010, My little town bought a ice-breaking, fast-ferry landing craft to use between PT. Mac and the Port of Anchorage as part of the Knik Arm Ferry Project. The M/V Susitna cost 80 million.

Great idea, Except, there was no dock facilities at PT. Mac. And no place to park it. So, it was sent to Ward Cove in Ketchikan for safe keeping. My little town was paying moorage fees and some dude to babysit. That cost $100,000 a month.

Then, the February wind & rains came, the plastic buckets covering the exhaust stax blew away. The Dude that was babysitting her didn't take notice, until three of four engines were filled with water. Then, it got towed to Seattle for 3.5 million engine overhauls.

Then, The City of Wasilla sold it to the Philippine Red Cross for 1.75 million.

good times. That's when Alaska was flush with money and our leaders couldn't spend it fast enough.

 

[John C.]

I like the post but don't like the story. It is pretty typical of government people in positions they are not qualified to handle spending other people's money.

 

[colson04]

I like the post but don't like the story. It is pretty typical of government people in positions they are not qualified to handle spending other people's money.

I was thinking the same thing

 

[JD955SC]

I like the post but don't like the story. It is pretty typical of government people in positions they are not qualified to handle spending other people's money.

Your typical higher level government administrator is in their position not because of competence but because they are not employable anywhere else and they get promoted by the Peter principle. F*** Up Move Up is a very real thing.