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5 minuets ok or just long enough to load it on trailer?
CK5
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Running motor with nothing for exaust on 1 side
- Thread starter sponsoredbydad
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Done it many times. Just not long.
Without an exhaust manifold there is NO WAY i'd start the engine.
Like I said. Done it many times just to move a vehicle. Did not run it long enough to cook anything. Barely off of idle.
If it is a high performance high dollar engine, I wouldn't. But a stocker, yes.
If it is a high performance high dollar engine, I wouldn't. But a stocker, yes.
Myth.
You don't ruin engines from no exhaust. You ruin engines from running lean. There are still people who don't understand how that myth got started, now we know why problems may happen with no exhaust. This is that whole "you need some backpressure but too much is bad" pseudo-science belief.
Might it run lean with no exhaust? Likely, since Chevy exhaust is restrictive (stock) but if you have the induction setup for high flow exhaust already, your AFR is probably fine.
If you aren't putting a lot of load on the engine, it will be fine. I'm sure we can find all sorts of applications that use exhaust solely to direct the exhaust flow, and nothing more.
You don't ruin engines from no exhaust. You ruin engines from running lean. There are still people who don't understand how that myth got started, now we know why problems may happen with no exhaust. This is that whole "you need some backpressure but too much is bad" pseudo-science belief.
Might it run lean with no exhaust? Likely, since Chevy exhaust is restrictive (stock) but if you have the induction setup for high flow exhaust already, your AFR is probably fine.
If you aren't putting a lot of load on the engine, it will be fine. I'm sure we can find all sorts of applications that use exhaust solely to direct the exhaust flow, and nothing more.
Series 60 Detroits make a lot of noise when you do that.
Martin
Martin
vandelay industries
1/2 ton status
i'd like to, hopefully, clear up another possible myth that is also related to exhaust:
i noticed some heavy duty trucks and farm tractors have a metal flap on top of the exhaust pipe(s).
What is this for?
i noticed some heavy duty trucks and farm tractors have a metal flap on top of the exhaust pipe(s).
What is this for?
It's a rain cap--to keep water from building up inside the pipe,and eventually,into the engine's cylinders...
Flap is to keep water from running down into vertical exhaust pipes. Water pooling inside exhaust = bad things for engines. It will leak into the cylinders and rust them to the engine block. This is referred to as a "frozen" or "seized" engine.
Some folks use cans or buckets to cover the pipes when not in operation. But letting something sit with an exposed vertical pipe is asking for trouble...
I've never heard of this pseudo-science "backpressure" claim. But my understanding is that after shutting down a manifold-less engine, cold air can circulate in the exhaust ports and cause thermal stress in the hot components. Warped valves, seats, ports, etc. So damage can result after shutdown, and the damage will be proportional to the temperature difference between the components and the air temp. So, a few seconds in the summertime should not be a problem. Running for 1/2 hour at 8*F (today's temperature in my region) may very well be a problem, as the heat-soaked parts will not enjoy their encounter with the frigid air after shutdown. How long you decide to run your particular engine on any given day will depend on how much risk you want to take with your valves. As Wade said:
I've never heard of bending a piston (
), but I tend to agree with the rest of Zim's post.
Your answer wasn't posted when I started typing!...but the first one that appears wins,right?...
Your answer wasn't posted when I started typing!...but the first one that appears wins,right?...
Same here...but I ended up winning last place. I must type more slowly than other folks do. Or maybe I just type more...
Either that,or you have the slowest internet provider server?..
As for running without exhaust manifolds,heck,we had demo derbies at the junkyard with a lot of vehicles with nothing but bare ports!...the biggest risk was setting something on fire under the hood in my experience...
We loaded dozens of vehicles onto trailers with no exhaust manifolds..the engines didn't seem to care...they were only run just long enough to get them on the trailer..
I have heard of the exhaust valves being liable to warping during the cooling process though--that's why the dragsters mechanics put tennis balls over the zoomies,so cold air wont get at the valves and cool them off too rapidly and let them warp..but I've had many air cooled small engines with no muffler run so hot you can see the exhaust valve turning red,and I haven't had any warp a valve yet..maybe I'm just lucky..
As for running without exhaust manifolds,heck,we had demo derbies at the junkyard with a lot of vehicles with nothing but bare ports!...the biggest risk was setting something on fire under the hood in my experience...
We loaded dozens of vehicles onto trailers with no exhaust manifolds..the engines didn't seem to care...they were only run just long enough to get them on the trailer..
I have heard of the exhaust valves being liable to warping during the cooling process though--that's why the dragsters mechanics put tennis balls over the zoomies,so cold air wont get at the valves and cool them off too rapidly and let them warp..but I've had many air cooled small engines with no muffler run so hot you can see the exhaust valve turning red,and I haven't had any warp a valve yet..maybe I'm just lucky..
I had that thought right after posting my comment. Throwing a blanket over the exhaust ports (or something to block the air) should allow it to cool at a slower rate. I have done such on at least one engine repeatedly, with no observed issues (after several months of running this way). I wouldn't worry at all if the cold air was kept out during cooldown...
Ambient temp on a HOT day is 120*? Exhaust temp is ~1200*
8* or 120* ambient, temperature difference is 9% given 1200* combustion. Either way, you are talking a 90 to 99% increase in temperature from ambient to valve.
Glowing exhaust manifolds we have all seen also reach ~1200*, while manifolds EVENTUALLY crack and fail, they are exposed to "open air" and don't fail spectacularly because of the heat cycles. If heat cycles were an issue, headers alone would cause valve failure, as they shed heat far faster than a cast manifold.
Valves are in contact with cast iron or aluminum, which is the sink. Somewhere around 75% of the shed heat from valves, is through the head.
One would think if the air was so hot that valves were melting, rubber tennis balls would as well, especially as hot as headers run. I'd suspect keeping debris out to be the concern if we are talking up swept headers.
Running lean drives combustion temps sky-high. Intake valves are cooled, exhaust is not. They are the first to fail due to temp. Removing an exhaust manifold (or installing headers) on the traditional small block, without correcting the AFR, WILL cause a lean condition because combustion efficiency has increased...more air in, but its up to a human to correct the fuel. Bad enough, that lean condition will lead to burned valves, pistons, etc.
Eventually, of course more extreme heat/cool cycles aren't going to help matters. Most racing applications that don't use much for exhaust probably aren't expected to run under high load for more than a few minutes in a season before parts are replaced, trying to run a daily driver with no exhaust would probably accelerate failure, but breaking an engine in without exhaust, or moving a car around for a few minutes isn't going to hurt them in any measurable way.
Again, without knowing AFR/combustion/exhaust temps, no valve failure can be blamed on lack of exhaust.
8* or 120* ambient, temperature difference is 9% given 1200* combustion. Either way, you are talking a 90 to 99% increase in temperature from ambient to valve.
Glowing exhaust manifolds we have all seen also reach ~1200*, while manifolds EVENTUALLY crack and fail, they are exposed to "open air" and don't fail spectacularly because of the heat cycles. If heat cycles were an issue, headers alone would cause valve failure, as they shed heat far faster than a cast manifold.
Valves are in contact with cast iron or aluminum, which is the sink. Somewhere around 75% of the shed heat from valves, is through the head.
One would think if the air was so hot that valves were melting, rubber tennis balls would as well, especially as hot as headers run. I'd suspect keeping debris out to be the concern if we are talking up swept headers.
Running lean drives combustion temps sky-high. Intake valves are cooled, exhaust is not. They are the first to fail due to temp. Removing an exhaust manifold (or installing headers) on the traditional small block, without correcting the AFR, WILL cause a lean condition because combustion efficiency has increased...more air in, but its up to a human to correct the fuel. Bad enough, that lean condition will lead to burned valves, pistons, etc.
Eventually, of course more extreme heat/cool cycles aren't going to help matters. Most racing applications that don't use much for exhaust probably aren't expected to run under high load for more than a few minutes in a season before parts are replaced, trying to run a daily driver with no exhaust would probably accelerate failure, but breaking an engine in without exhaust, or moving a car around for a few minutes isn't going to hurt them in any measurable way.
Again, without knowing AFR/combustion/exhaust temps, no valve failure can be blamed on lack of exhaust.
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I thought the flap was to keep rhythm at idle.
