Firewall Forward

In order to provide a better run for the hose bringing fuel to the fuel pump, and to make room for the control cables and exhaust hangers, I would like to replace the 90 degree fitting (center of picture) on the input side of a the fuel pump with a 45.

Rotation of the fitting is blocked by the constant speed oil pressure unit. This leaves me in something of a quandary as to which unit is easier to remove in order to replace the fitting.

If I take the fuel pump off by undoing the two Allen Key studs, will the unit in fact be removable? Remember on a -4 there is almost no room between the fuel overflow takeoff on the back of the pump and the firewall, as you can see in the picture. With the studs removed does it slide off backwards or could it rotate downwards?

The alternative is to remove the entire constant speed unit. Yes, only 4 nuts, but some are very hard to get to, at least with my fat spanners and the poor access behind the engine.

Postscript 1/12/07 - Today I took the constant speed unit off having been advised the fuel pump was not going to be easy. To get the c/s unit off I had to take both mags off. It was clearly the right way to do the job, I had the 90 degree fitting exchanged for a 45, and everything was back together in 80 minutes.

A very supportive phone call and email from Larry Vetterman.

"I have never seen the pipes this close to the tunnel. You can adjust the pipes however. They are new and very flexible. Take hold of the #1 and pull it towards the center. Give it a good push. No you cannot break it with just your amount of force applied. Then re align the #3 to it. Yes you can trim the extensions. We leave them long on purpose as some builder prefer them that way. My preference is to trim about 1.5 inches off the end. "

I spent a few minutes on it today and believe this will work. (Larry has other plans if not.) I will have some time tomorrow and when it is sorted will post some more pictures. It is great to have a supplier who is committed to having a happy customer. Larry clearly is.

Postscript 8th Dec - I wrestled with the pipes for a long morning and made a considerable improvement. Took some photographs and sent to Larry. His immediate response was that he would make me a new pipe for #1. How is that for good service. It was here in the UK 10 days later and fits a dream.

I seem to have a problem with the exhaust. I am wondering if it is just my set up, or if they are all like this.

If you look at the top picture you will see that the pipes are offset to the left (RHS of aircraft). This may well be because they do not allow for the fact that the engine is offset. The problem that arises is #3 is very close to the F-451 fairing. Perhaps 5/16". The #1 pipe, the inner one is about 1/16" from the sump if that.

As you can see pipes #2 and #4 do not have this problem.



Nothing to complain about here.

















But this seems really tight.











I wonder if I need the tails as long. If I took about 1.5" off the pipe, so the bent tail moved forward, the problem would reduce.
Hopefully other builders have been here, otherwise I will have to track down Vetterman.
I must say I would prefer more symetry,
but more importantly I am concerned they could hit the fuse when the engine stops/starts etc.