Exhaust Stud Removal

[Sonex374]

Anyone else experienced issues removing the threaded studs from the exhaust ports? Mine seems to have had all available Loctite used. I have twisted one off and now trying to decide how to best remedy this.

I cannot understand why they are even in a new head which Sonex knows is going to need bolts rather then studs.

[wlarson861]

I got most of them out with a pair of channel locks, one I had to use a small pipe wrench to get it to yield.

[rizzz]

Anyone else experienced issues removing the threaded studs from the exhaust ports? Mine seems to have had all available Loctite used. I have twisted one off and now trying to decide how to best remedy this.

I cannot understand why they are even in a new head which Sonex knows is going to need bolts rather then studs.

They are in there because that's how Sonex buys them from their supplier (I believe that's Mofoco now, it used to be CB Performance).
Sonex just machines (or outsources machining) the heads for dual ignition and sells them on to you, they don't bother removing the studs, possibly because depending on your application you might want to keep them in place. (remember the AeroVee is not only sold to Sonex customers, other airplanes might require different exhaust systems and perhaps prefer the studs instead)

I have a (non AeroVee) VW engine also with the same Mofoco heads (mine were machined by Hummel) and I have an old set of 4 separate exhausts rather than the 2-in-1 system, thus I was able to leave my studs in place and use the standard VW copper nuts to install the exhausts.
My problem is opposite to yours though as I was removing one of the exhausts recently the stud came out with the nut, not enough locktite perhaps? Anyway, not a drama to fix that issue :).

[jjbardell]

I removed all my studs with double nuts. It popped everyone of them off with ease.

[Sonex374]

Well out of the 4 three need to be drilled used double nut method soaked numerous times with pb blaster thru talked with some heat and use candle wax. Did not work two twisted off one nuts stripped threads, then used vise grips to no avail. These puppies must have been epoxyed in. Now drilling out one down and saved 2nd in process.

I'm a not a happy camper with this. For something new never run this should not occur. The opposite head was easy.

[SNX1508]

Anyone know the torque value for installing the exhaust pipe bolts in the cylinder head? For whatever reason this is missing from the torque values in the AeroVee assembly.

Thanks,

Terry

[wlarson861]

I had one stud that would not budge, double nut, channel locks, nor large vice grips would turn it. Finally tried a small pipe wrench, it would cut into the stud and not slip and it turned right out

[Sonex374]

Terry the torque values are in manual in a chart near the last section they are based on size not .specific to location I think

[SNX1508]

Torque chart in AeroVee manual does not list the exhaust pipe to cylinder head bolts.
Terry

[Sonerai13]

There is no specific torque value for the exhaust bolts. This is because there are several different gaskets that may be used, and some people put high temp RTV on the gaskets and some don't. In other words, too many variables. Most people over-tighen the exhaust, which will bend the ears on the flanges and cause leaks. Just bring them up until you see a little compression of the gasket and let it go at that. They don't seem to have a tendency to come loose, so you should be fine.