Donuts every 500 miles, WTF???

[bigreis]

Anyone have ideas why I am blowing through donuts after 500 to 800 miles? I have tried OEM graphite as well as aftermarket copper and get similar results. On my third set of y-pipes after 8000 miles... love the sled but tired of the constant maintenance.

 

[kirkswim]

Check the rivets on your tunnel. On my rx1 after I did the exhaust gaskets my exhaust broke at the weld and I looked at those rivets and they were all loose and I can actually lift the back bumper and inch due to all the play in the rivets . I replace the rivets and now have 6000 K on it donuts are still good .

 

[Redbeard]

Anyone have ideas why I am blowing through donuts after 500 to 800 miles? I have tried OEM graphite as well as aftermarket copper and get similar results. On my third set of y-pipes after 8000 miles... love the sled but tired of the constant maintenance.

Are the front exhaust hanger rivets pulled through the tunnel by chance? Did you by chance grind away some of the spacer on the donut clamps so they'll tighten even more than intended? I'd say check your motor mounts, but bad mounts probably would cause the sled to eat drive belts?

 

[RTX]

Agree with the above statements.
You need to go over the sled and check for any worn or loose rivets.
On my sled all the tunnel to bulkhead rivets had be ome loose by 10000 miles.
Digging deeper and looking for potential long term problems will only benefit you in the long run.
Good luck

 

[Redbeard]

On my sled all the tunnel to bulkhead rivets had be ome loose by 10000 miles.

Absolutely! I didn't think of that! Every tunnel - bulkhead rivet on my 2004 Warrior had to be replaced last fall. That chassis flex alone would cause your issue.

 

[steiner]

Like all above posts. Check all the rivets in the mounts for the exhaust and grind a few thou off the clamps.
I added a mid hanger to my system. Takes away some of the load and strain from the front mounts and removes more of the bounce in the entire system.

 

[bigreis]

Thanks for the replies guys... finally got motivated to tear the sled apart today. I jacked the sled up as close to the tunnel to bulkhead junction as possible and then a buddy and I pushed up and down the front and rear bumpers at the same time to try to get it flex at that position. I heard a very small amount of creaking, but didn't notice anything significant in terms of flex . After removing the gas tank, I found 2 loose rivets in the bulkhead to tunnel attachment area, but I wouldn't think that would be enough to cause the issue I am having. Getting into the exhaust, I noticed that on each Y-pipe assembly only the right side donuts were worn to the point where they had slop after removing the flex pipe to Y-pipe clamps. To me, that would indicate I am getting some sort of fish tail flexing going on with the chassis that is causing the exhaust system to rock back and forth instead of up and down. But even if that is what is going on, I would have still expected to see more loose rivets. Any other ideas?

 

[bigreis]

So I drilled out the loose rivets and found the lower portion (the tunnel) to be very egged out. Drilled out a few more of the ones I thought were "good and tight" and found the tunnel portion to be egged out as well. So maybe we were able to exert enough force by pushing up and down on the sled over the pivot point to get it to slip. I am going to drill out the rest of the easily accessible ones and see what I find. As far as repair goes, the current rivets are clearly 100% steel, as a magnet picks up all of the shavings. The rivets I have are the multi-grip OEM style but are aluminum with a steel mandrel I purchased from a local race car shop. Do you guys think these rivets will be sufficient or should I get some steel multi-grips if I can find them? Also, instead of putting the new rivets in the old egged out holes, should I just drill new ones adjacent to the original ones?

 

[steiner]

What kind of replacement pipes are you using? Since I have gone to the stainless steel pipes I have not broken or cracked a pipe.
How close is the track to the exhaust? Even with the tunnel protectors in place I found the track can still slap the pipes.
I have welded my protectors with a spacer to eliminate the squish of the factory u shaped mount as well as an extra support in the rear of the exhaust system(pic in above post).
As others have mentioned, grinding off a few thou of the clamp spacer also keeps the flange tight with the flex pipes.
The front exhaust hanger on my sled also needed attention. I had to add fender washers to the rivets because the holes were badly worn.
The factory exhaust is heavy. Keeping it tight will help the donuts and the rest of the system healthy.

 

[steiner]

So I drilled out the loose rivets and found the lower portion (the tunnel) to be very egged out. Drilled out a few more of the ones I thought were "good and tight" and found the tunnel portion to be egged out as well. So maybe we were able to exert enough force by pushing up and down on the sled over the pivot point to get it to slip. I am going to drill out the rest of the easily accessible ones and see what I find. As far as repair goes, the current rivets are clearly 100% steel, as a magnet picks up all of the shavings. The rivets I have are the multi-grip OEM style but are aluminum with a steel mandrel I purchased from a local race car shop. Do you guys think these rivets will be sufficient or should I get some steel multi-grips if I can find them? Also, instead of putting the new rivets in the old egged out holes, should I just drill new ones adjacent to the original ones?

Structural rivets are all steel zinc coated multi grip. As far as the egged out holes I would install new rivets in them and then look were there is room to add a few new rivets nearby.
Don't go too crazy with the drill. Ya could make it worse instead of better.

 

[bigreis]

Structural rivets are all steel zinc coated multi grip. As far as the egged out holes I would install new rivets in them and then look were there is room to add a few new rivets nearby.
Don't go too crazy with the drill. Ya could make it worse instead of better.

Thanks for the advice, do you know of a source for cheap steel multi grip rivets?

 

[Viper_Dave]

Amazon is your friend . Search Avdel Stavex multi grip rivets 3/16ths inch. I purchased the standard size heads and larger sized heads and had them in 3 days with free shipping with my my Prime membership.

 

[RTX]

So I drilled out the loose rivets and found the lower portion (the tunnel) to be very egged out. Drilled out a few more of the ones I thought were "good and tight" and found the tunnel portion to be egged out as well. So maybe we were able to exert enough force by pushing up and down on the sled over the pivot point to get it to slip. I am going to drill out the rest of the easily accessible ones and see what I find. As far as repair goes, the current rivets are clearly 100% steel, as a magnet picks up all of the shavings. The rivets I have are the multi-grip OEM style but are aluminum with a steel mandrel I purchased from a local race car shop. Do you guys think these rivets will be sufficient or should I get some steel multi-grips if I can find them? Also, instead of putting the new rivets in the old egged out holes, should I just drill new ones adjacent to the original ones?

Dont use aluminum rivets.
I bought my steel multigrip rivets through MSC years ago but i am sure they still sell them.
Also theres guys on here selling them just do a search

 

[TBay Sledhead]

Try these guys. DO NOT USE ALUMINUM RIVETS!!!!!
https://www.mcmaster.com/#
Could drill the holes the next size larger.

 

[bigreis]

Like all above posts. Check all the rivets in the mounts for the exhaust and grind a few thou off the clamps.
I added a mid hanger to my system. Takes away some of the load and strain from the front mounts and removes more of the bounce in the entire system.
View attachment 123093

Why does it look like your stock rear tunnel reinforcement has been cut out and covered over with another plate?