03-01-2010, 12:02 PM #1
Exhaust bell again ... input? pics
Last spring I put a new 08 exhaust manifold on my ski, drilled it for AFR, cleaned up the bell carefully and sent it off to Jet Hot to high temp coat the bell, hoping it would help it last. Pics are attached ... it did not last. I had issues with the ski (cam was advanced 1 tooth), I did not run it much and almost never at WOT for more than a few seconds. Even so, part of the bell is gone, and the bits of aluminum were scattered all over the bell and into the exhaust manifold ... it looks to me like it was running rich (lots of carbon) yet there are still bits of aluminum up into the manifold ... a little reversion, or?
Just a bit stumped on this one ... setup is in my sig. I ran a SS bell for two years, but that got loose due to aluminum melting where the bell fit into the manifold. What to do to keep the manifold bell from melting??
03-01-2010, 12:58 PM #2
i dont think theres any way to stop it. Even when tuned correctly the hot exhaust from a modified ski will melt it. mine has done i some and I know for sure it was never lean. But I was running 15 PSI on the stock ECU
03-01-2010, 01:42 PM #3
- Join Date
- May 2005
I would get an adapter for the bung where the afr O2 sensor mounts and install an EGT sensor--they are set up for 1/8" npt. You need to see where you are at on the exhaust gas temp even if your afr's look good. I run over 300 hp and run up around 820 degrees C, or 1508 degrees F at the bung on the J-pipe. Never had any problems with deterioration on the exhaust manifold bell.
03-01-2010, 02:01 PM #4
03-01-2010, 04:30 PM #5
- Join Date
- May 2007
your must external cooling line from pump to external intercooler to outside fron the hull and external cooling line to mainfould.when riding in the river with hot water must the pump spacer mounting from x modell.
sorry my englisch is not good
03-01-2010, 04:35 PM #6
Just put the 08 mid pipe and waterbox on and forget about the bell.
03-01-2010, 05:49 PM #7
All good input, thank you. I know that good AFR does not necessarily correlate to exhaust temperature ... that was one of the things that Louis914 was getting, and that he increases timing to lower temps, then adjusts AFR.
Nico, do you mean split the cooling line off the pump and run one line right to the manifold, and the other to the intercooler, then dump overboard, so that the manifold gets the coldest water?
Good point on the '08 up setup ... has anyone with the '08 up setup melted the bell? Maybe the J pipe is just too restrictive and traps heat ...
03-01-2010, 07:27 PM #8
Vern what temp coating did you get? I haven't had any problems with mine and I was running a little lean with my set up and believe me I was running WOT for a long time, just ask mrbtd, I needed to to keep up with him at MB
03-01-2010, 08:08 PM #9
03-01-2010, 08:32 PM #10
The problem is air entering the exh at the flange.
O2 is re-heating the gas in my opinion.
Everyone I have seen has a leak at the flange, or hair-line leak in the flex joint.
The mating surface has to be flush, but not tight. Overtigtening the clamp distorts the seal.
The gasses are hot, but the effect here is like that of an oxy torch, add more O2, and usually you can work out where the leak is from where it is on the bell. Excessive engine movement can open the almost indiscerable gap too.
I have some real hot engines without the problem, and yet I got one in this week, and you can see where it leaked, and why.
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