New mount

[Allen Sutphin 705]

Well, new mount is made!  May have to modify right side a tad for the exhaust system.  1/2" X .058 wall 4130.

[Allen Sutphin 705]

Well, mounted the engine today and the big snowball showed up again. Have to modify both sides again. One side because the carbs hit and the other side because the exhaust pipe hits. But the engine is centered in the cowling now. Also will have to turn the air filters up instead of horizontal with the help of a 90 deg elbow. This has been a nightmare! This project will probably do me in. Anything else will be a two part kit, the airplane and the key.

[akflyer 1427]

I am not too crazy about putting 90s on the intake side.  shorten up the diagonals and work around the carbs.  Same on the exhaust.  From everything I have seen, these engine mounts are way over built.  There are less tubes holding on engines on cubs and cessnas that have a whole lot more weight and more ponies hanging off them.

 

[Allen Sutphin 705]

The reason for the 90 degree intake elbows is the air filters would stick through the cowling. And this mount is probably a little overbuilt for a 100 lb engine. A bad habit of mine. I talked tp Matt Dandar of recpower.com (Hirth supplier) and its common on several Hirth engines to turn the filters 90 degrees as long as the elbow is short, smooth and the same size as the carb intake. Evidently K&N does not make filters for the Delorto carbs. I was surprised to find that a Subaru fit in the cowl fine and I have issues fitting a inline two stroke in it.  I don't remember if NSI made the cowling for their engine package or not. Its been too long ago to remember.  If they did, then that's probably the initial start of the problems.

[1avidflyer 1983]

Allen, before you buy new air filters, I have some new ones still in the plastic from my buddy's plane.  If they will work for you, you can get a deal and save something and I can move some more stuff out from that plane.  Once you know for sure what you need, if you like, we can both do some measuring.  JImChuk

[Allen Sutphin 705]

Redone the mount today and the carbs fit, the exhaust fit, so on to getting the air filters to clear the cowling. Might take a little hillbilly engineering to accomplish but after everything else, this will be minor stuff. I'd bought new filters from Hirth,which look just like K&N with out the name. They are a tad long for my carb/cowling setup and the dia. is different than Bing's. No double is available for Delorto carbs since I guess, they are used on motocross bikes and street bikes. According to Matt Dandar at Hirth, my modification on the exhaust might give me a tad more performance from the engine. But hey, things are starting to look a lot more positive and the engine is mounted on the airframe where it will live. Now for all the little tabs and brackets that it will require.  As of now, the torches and tanks have paid for themselves. Two pair of socks have been sacrificed due to not keeping the feet out of the way of the torch. OUCH!

[TJay 1041]

Once your flying it will all be worth it and all the troubles will be forgotten. Looking good excited to see how the Hirth performs.

[Allen Sutphin 705]

I feel you are correct TJay. Made some custom intake runners to move the air filters a tad to clear the cowling. That problem solved. The exhaust will only need new hooks welded in place, child's play after all this. If it runs as smooth as Matt says, it ought to be sweet at 4250 RPM. It is a reed valve engine and that in itself makes a smoother running engine.

[Allen Sutphin 705]

Well, the dang thing fits! now on to other problems, like throttle linkage, etc.

[TJay 1041]

looks like a nice snug fit.

[Allen Sutphin 705]

I've got about 1" clearance around everything. Will probably install an alum sheet under the muffler or some fiberfax for a heat shield. I am curious about the elbows in the intake, might have to change the jetting to match the airflow. But its a clean smooth transition of airflow with no offsets in the elbows so the dia. is a smidge larger than the carb intake. Otherwise it does fit after a lot of re-engineering and anatomy scratching.

[Matthewtanner 44]

Looking good friend! Keep up the good fight!