Exhaust clearance

[00Dan]

Couple questions about exhaust clearances. First thing first, the 1/2” nuts. I have tried all variations of swivel sockets and wrenches and cannot get any tool on some of the inside nuts. Open to ideas here.

Second, I found a spot on the corner of the sump where the 3/4 crossover just barely touches the sump. Is this okay or a recipe for problems?

 

[BillL]

I use a 1/4" drive 1/2" 6 point swivel socket. Then use an 18" extension.

I use MAC, but snap-on may have something similar.


#2 - recipe for problems, it will rub a hole and/or heat the sump. Get adjusted, re-bent, or welded.

 

[00Dan]

I use a 1/4" drive 1/2" 6 point swivel socket. Then use an 18" extension.

I use MAC, but snap-on may have something similar.


#2 - recipe for problems, it will rub a hole and/or heat the sump. Get adjusted, re-bent, or welded.

I was using a similar socket (1/4” drive flex socket on an extension) and still couldn’t get it to fit.

As for the sump, I’ll get the other crossover tube on and see if it holds itself off with the other side on. Otherwise I’ll have to get creative.

 

[skybolt31]

If memory serves, those exhaust studs are 5/16-18 threads, I used some ARP 301-8343 5/16"-18 12-Point Nuts, the 12 point are smaller so there is more clearance

https://www.amazon.com/ARP-301-8343-18-12-Point-Nut/dp/B009XUO5A4

 

[gasman]

The socket needs to be thin wall to easily fit..

 

[00Dan]

If memory serves, those exhaust studs are 5/16-18 threads, I used some ARP 301-8343 5/16"-18 12-Point Nuts, the 12 point are smaller so there is more clearance

https://www.amazon.com/ARP-301-8343-18-12-Point-Nut/dp/B009XUO5A4

You’re correct that the studs are 5/16-18. Normal sized nuts are 1/2”. Smaller nuts would definitely help.

Would any stainless or steel nut be an appropriate substitution? Since it’s course thread I can probably source it locally as long as it’s not something that will weld itself to the stud after a couple hundred hours.

 

[Jetmart]

Grind a socket down to make it thin wall.

 

[lr172]

what is wrong with an open end wrench?

 

[9GT]

I bought a cheap 12 point 1/4” drive swivel socket set off Amazon and the wall was thin enough to fit those close quarter 1/2” exhaust nuts. Money well spent and with the 18” extension was able to torque to spec using a torque wrench.
Tip: only finger tighten the front nut. There is enough play in the holes of the flange to pull the pipe/flange out enough to get the socket on the back nut.

 

[Reflex]

Tough nut/spot indeed. This worked for me (barely):

https://shop.snapon.com/product/AN85088B

 

[JDeanda]

Some Thots

I’ve had the most trouble on the manifolds on the little Continentals… O-200, C-85 etc. Lycomings are just a bit easier. I carefully thinned the wall on a Snap-On swivel (universal) socket and used a 1/4” drive, long extension like the poster above. When the universal joint wears a little, the socket gets floppy and hard to manipulate onto the nut, so just put a wrap or two of masking tape around the swively bit and it’s much easier. Once the nuts are out, I replace them with next size down brass nuts that I drill out and tap as required. Continental has sold brass exhaust nuts for decades, at their high price of course. I get the tall brass nuts at better hardware stores or online. Seems like any plain steel or stainless nuts weld themselves to the studs eventually. Brass nuts always come off easily. Regular ol’ AN washers are fine.

 

[hgerhardt]

.....Tip: only finger tighten the front nut. There is enough play in the holes of the flange to pull the pipe/flange out enough to get the socket on the back nut.

YES. This is important.

Also, if your 1/4" drive, 1/2" socket doesn't have a thin-enough wall for clearance, modify it so that it does.

And if all that ain't enough, get 12-point nuts which take a 3/8" socket: https://www.mcmaster.com/90759A200/