Copper donuts + Ultra copper gasket maker????

[sleddog66]

on my 4 stroke quad, 525 ktm, I used many sealants to try to seal up a leaky head pipe including ultra coppercoat sealant by permatex. It is a very tight clamp style seal, but leaks a small amount of air on decel. NOTHING has lasted more than 5-10 hrs. So I would assume that the head pipes get pretty hot on these 4 stokes as well. Probably well over 1000 degrees f on a long, hard pull

 

[DigitalFusion]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

 

[yamaha convert]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

Would I be correct in saying that the flange you had it on was machined or ground flat?

The more I think about it the problem with copper is it isnt really forgiving enough to make up for the inconsistencies in stamped flanges with the factory clamp. In an ideal world, if you had two perfectly machined or prefferably ground flat surfaces, you wouldn't need a gasket. Gaskets only make up for the inconsistencies in a machined surface.

The problem with the exhaust donut flanges is they are not machined. I believe it seals better on the cylinder head side due to the fact the flange that the donut seals to is welded to the pipe that the donut spigots off. Becuase of this the flange holds it shape better and even more so the donut is using the pipe as a spigot on this side. Being so tight on pipe - its spigot, it makes is more difficult for the gases to get past and go back out the cylinder head flange side, kind of like a double seal. The other side doesnt have anywhere to locate and relies totally on the clamp pulling the flange towards the donut. This is why I think people see a benefit in modifiying the clamp stop so that it pulls down a little tighter, but Im not sure if this enough when using a rigid copper donut.

It would be good to see a copper donut from a member that modified his clamps.

 

[ranger1]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

Would I be correct in saying that the flange you had it on was machined or ground flat?

The more I think about it the problem with copper is it isnt really forgiving enough to make up for the inconsistencies in stamped flanges with the factory clamp. In an ideal world, if you had two perfectly machined or prefferably ground flat surfaces, you wouldn't need a gasket. Gaskets only make up for the inconsistencies in a machined surface.

The problem with the exhaust donut flanges is they are not machined. I believe it seals better on the cylinder head side due to the fact the flange that the donut seals to is welded to the pipe that the donut spigots off. Becuase of this the flange holds it shape better and even more so the donut is using the pipe as a spigot on this side. Being so tight on pipe - its spigot, it makes is more difficult for the gases to get past and go back out the cylinder head flange side, kind of like a double seal. The other side doesnt have anywhere to locate and relies totally on the clamp pulling the flange towards the donut. This is why I think people see a benefit in modifiying the clamp stop so that it pulls down a little tighter, but Im not sure if this enough when using a rigid copper donut.

It would be good to see a copper donut from a member that modified his clamps.

Yamaha convert, very well put, I agree with you %100 & that is why I was looking into using the copper gasket stuff to make up for the inconsistencies in the flanges. Unfortunately, however, it seems like not many are having good luck using the high temp silicone on the exhaust, appears that it is burning off.
For this reason, I opted to abort installing the copper donuts this weekend & must try to find a better way to make a good seal between the donuts/flanges.

 

[yamaha convert]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

Would I be correct in saying that the flange you had it on was machined or ground flat?

The more I think about it the problem with copper is it isnt really forgiving enough to make up for the inconsistencies in stamped flanges with the factory clamp. In an ideal world, if you had two perfectly machined or prefferably ground flat surfaces, you wouldn't need a gasket. Gaskets only make up for the inconsistencies in a machined surface.

The problem with the exhaust donut flanges is they are not machined. I believe it seals better on the cylinder head side due to the fact the flange that the donut seals to is welded to the pipe that the donut spigots off. Becuase of this the flange holds it shape better and even more so the donut is using the pipe as a spigot on this side. Being so tight on pipe - its spigot, it makes is more difficult for the gases to get past and go back out the cylinder head flange side, kind of like a double seal. The other side doesnt have anywhere to locate and relies totally on the clamp pulling the flange towards the donut. This is why I think people see a benefit in modifiying the clamp stop so that it pulls down a little tighter, but Im not sure if this enough when using a rigid copper donut.

It would be good to see a copper donut from a member that modified his clamps.

Yamaha convert, very well put, I agree with you %100 & that is why I was looking into using the copper gasket stuff to make up for the inconsistencies in the flanges. Unfortunately, however, it seems like not many are having good luck using the high temp silicone on the exhaust, appears that it is burning off.
For this reason, I opted to abort installing the copper donuts this weekend & must try to find a better way to make a good seal between the donuts/flanges.

The sealant is only burning of as the gap its trying to seal is excessive. Those sealants work fine with small tolorances. I think they would have a chance of working on the cylinder head side if the donut flange and may work on the other side also. Someone will have to try it and see.

Thinking about it even more this afternoon, grinding the clamp spacer isnt the answer either. The clamp spacer is designed in such a way that when it bottoms out the clamp has even pressure aroung the circumference of the exhaust joint. Allowing one side to compress further by grinding down the spacer without doing the other, will pull the clamp out of round. Unfortunately you cant change the other side as it has a pin holding the two halves together.

I do have an idea but I want to try it myself first before I go mentioning it. I still think the copper donuts are the better solution, but not with the factory clamp the way it is. Luckily the factory clamp when tightened in position has its openings facing east and west as if they were north and south and the leak was bad enough we could see some possible problems. Inadvertantly the clamp acts to push any leaks out the side which is a good thing considering we have fuel tanks just above them.

I have sent a PM to Crewchief to make him aware of this thread in case he hasn't seen it, and have asked him for feedback. Hopefully we will have some suggestions soon.

 

[Crewchief47]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

Would I be correct in saying that the flange you had it on was machined or ground flat?

The more I think about it the problem with copper is it isnt really forgiving enough to make up for the inconsistencies in stamped flanges with the factory clamp. In an ideal world, if you had two perfectly machined or prefferably ground flat surfaces, you wouldn't need a gasket. Gaskets only make up for the inconsistencies in a machined surface.

The problem with the exhaust donut flanges is they are not machined. I believe it seals better on the cylinder head side due to the fact the flange that the donut seals to is welded to the pipe that the donut spigots off. Becuase of this the flange holds it shape better and even more so the donut is using the pipe as a spigot on this side. Being so tight on pipe - its spigot, it makes is more difficult for the gases to get past and go back out the cylinder head flange side, kind of like a double seal. The other side doesnt have anywhere to locate and relies totally on the clamp pulling the flange towards the donut. This is why I think people see a benefit in modifying the clamp stop so that it pulls down a little tighter, but Im not sure if this enough when using a rigid copper donut.

It would be good to see a copper donut from a member that modified his clamps.

Can't argue with any of your points. I do believe there may be more concern than required regarding the level of sealing of the copper donuts. We can all agree that any 'leaks' you have with the copper are miles smaller than the ones you likely had with the OEM. In the sleds I have access to, one will stall, the other will come very close to stalling and the third has enough of a leak at the muffler joint to only dip the RPM. We've changed the muffler joint gasket but it remains leaky so something is out of tolerance with one of the pipes. It's not enough of a concern for me to solve on that sled. Two of those sleds actually have bronze donuts on them. The current donut alloy is softer than the bronze and as soft as I've been able to source and still have some machinability.

On the tight fit, I really haven't considered doing anything about it because I haven't had enough feedback to suggest it is a widespread problem. I envision most people installing donuts and then forgetting about them for the rest of the life of the machine. Even when removal of the exhaust is required, re-assembly normally doesn't require the donuts to have been removed from the bellows pipes. Obviously if a bellows is being replaced we may run into a problem but I've only ever had one request for the sale of a single donut due to damage from a removal attempt, the rest came off to my knowledge. Does that mean I should open the ID up a little?

All of these little question areas are the main reason I was focused on getting a donut made that I could price near the OEM donut (over here anyway). That way if they don't work for a customer in some fashion, they are out the same cost as the stock donuts ( which they'll likely be replacing again in two seasons).

 

[yamaha convert]

held up great on my car. I dunno, maybe it was because there was a lot of airflow over where it was used, and a lot less vibration than an ATV/snowmobile environment?

Would I be correct in saying that the flange you had it on was machined or ground flat?

The more I think about it the problem with copper is it isnt really forgiving enough to make up for the inconsistencies in stamped flanges with the factory clamp. In an ideal world, if you had two perfectly machined or prefferably ground flat surfaces, you wouldn't need a gasket. Gaskets only make up for the inconsistencies in a machined surface.

The problem with the exhaust donut flanges is they are not machined. I believe it seals better on the cylinder head side due to the fact the flange that the donut seals to is welded to the pipe that the donut spigots off. Becuase of this the flange holds it shape better and even more so the donut is using the pipe as a spigot on this side. Being so tight on pipe - its spigot, it makes is more difficult for the gases to get past and go back out the cylinder head flange side, kind of like a double seal. The other side doesnt have anywhere to locate and relies totally on the clamp pulling the flange towards the donut. This is why I think people see a benefit in modifying the clamp stop so that it pulls down a little tighter, but Im not sure if this enough when using a rigid copper donut.

It would be good to see a copper donut from a member that modified his clamps.

Can't argue with any of your points. I do believe there may be more concern than required regarding the level of sealing of the copper donuts. We can all agree that any 'leaks' you have with the copper are miles smaller than the ones you likely had with the OEM. In the sleds I have access to, one will stall, the other will come very close to stalling and the third has enough of a leak at the muffler joint to only dip the RPM. We've changed the muffler joint gasket but it remains leaky so something is out of tolerance with one of the pipes. It's not enough of a concern for me to solve on that sled. Two of those sleds actually have bronze donuts on them. The current donut alloy is softer than the bronze and as soft as I've been able to source and still have some machinability.

On the tight fit, I really haven't considered doing anything about it because I haven't had enough feedback to suggest it is a widespread problem. I envision most people installing donuts and then forgetting about them for the rest of the life of the machine. Even when removal of the exhaust is required, re-assembly normally doesn't require the donuts to have been removed from the bellows pipes. Obviously if a bellows is being replaced we may run into a problem but I've only ever had one request for the sale of a single donut due to damage from a removal attempt, the rest came off to my knowledge. Does that mean I should open the ID up a little?

All of these little question areas are the main reason I was focused on getting a donut made that I could price near the OEM donut (over here anyway). That way if they don't work for a customer in some fashion, they are out the same cost as the stock donuts ( which they'll likely be replacing again in two seasons).

Thanks for the response.
I agree you wont get many complaints about them being tight as most wont check their sleds and I also agree that these cannot fail the same way the factory donut does which is great. I dont want this to sound like a complaint because it isnt. This is a conversation on how to maybe make the installation better. After all the purpose of these is to stop leaks not just most of the leak. Maybe high temp sealants will work in conjunction with the copper. Its just trial and error.

I know one thing with them being tight on their flange you have to be careful as when you grip the donut to remove it you distort the pipe its sitting on with out to much effort.

Maybe we should all gut our muflers and create less back pressure

 

[ranger1]

I concur, it is definitely not a complaint, we are simply trying to find the best way to install the copper donuts with as little leakage as possible. The OEM graphite donuts have next to nothing as far as leakage when new, however, after X amount of miles they start to leak then get progressively worse until they fail!
I for one, without a doubt, will use the copper donuts because they will out last the graphite ones by a large margin but would like to at least try to minimize the amount of exhaust leakage.
Still tossing the idea of filling the clamp with "lots" of the copper gasket stuff, so much so that when tightening the clamp it will compress it into every imperfection & fill every gap between the clamp itself , outer race of the donut & the flanges.
What do you think, worth trying or will it just burn out?

 

[Crewchief47]

I was hoping that any small leaks would carbon up in short order and effectively seal the joint. It would be interesting to try and run one with the tank off to see how much is actually leaking with no hand applied back pressure and with hand applied back pressure. I'm trying to think of a sled I have available to try that with but.......

I don't think the Ultra copper is a bad idea in any way. No idea how long it will last and since you are effectively trapping it between two sort of flat surfaces (flange and donut) it should stay put. I myself would only use it on the mating surfaces as the rest is likely a lost cause if any leakage occurs and it will add to any clean up if removal is necessary.

Now, on Automotive exhaust at work, we occasionally use muffler cement. The stuff is a large pain in the rear to clean up and it turns pretty hard. Someone could try that as an option but I won't be held responsible for any headaches that may result (cleaning up the donuts if the idea fails for example). A nice THIN layer on the mating surfaces would be enough I should think. I would be a small pain if you ever need to remove the pipes again though.

 

[ranger1]

So crewchief47 what your saying is that stuff is sort of like JB welding everything together? lol. Would be good if we knew we would never have to take it apart again but....manifolds do crack as well as the y-pipes, hahaha.
BTW, I am hoping that I will not have to clean up the copper gasket silicone at my regular maintenance check due to I am hoping it solely sticks to the inside of the clamp & by indexing them they should seat right back in their regular place
I do like your idea of testing without a tank. Actually being able to physically see if & how much exhaust is leaking & then determine if is it is worth trying to correct.

 

[Crewchief47]

So crewchief47 what your saying is that stuff is sort of like JB welding everything together? lol. Would be good if we knew we would never have to take it apart again but....manifolds do crack as well as the y-pipes, hahaha.
BTW, I am hoping that I will not have to clean up the copper gasket silicone at my regular maintenance check due to I am hoping it solely sticks to the inside of the clamp & by indexing them they should seat right back in their regular place
I do like your idea of testing without a tank. Actually being able to physically see if & how much exhaust is leaking & then determine if is it is worth trying to correct.

Oh, it won't be as hard to remove as JB Weld would be but I wouldn't want to be the guy that had to do it. Die grinder and wire wheel may get most of it.....