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Engine mount confusion

N

niblettda

Well Known Member
I probably know enough about Lycoming engines to make wild accusations and speculations. :) So I'm looking for some clarity.

I've got an IO-320-B1A engine, it's a Dynafocal 2 mount. Another on the forum said that Van's didn't want to sell a mount for their project, which surprised me. So I dropped off an email to Van's. The answer was, they'll sell a Dyna 2 mount, but it's special order. All well and fine by me, but then they said they were more concerned about the forward facing induction sump. ?!?!

The mount is not a problem - it is a D2 engine I believe which is special order though.

You will have other issues with a forward facing sump - we do not have an
exhaust that will work for it on a 320, and the FAB will be hard to modify and
fit. A vertical induction sump would be easier: I'd use that if you don't yet
have the horizontal sump.

Vans
Click to expand...

The B1A was off a Comanche twin, and has a rear facing induction sump. My belief is that with a 9A, there is no way I'm getting the rear induction to work since I think the nose gear weldment is right there. So I was planning on going with a cold air induction kit that makes the sump forward facing induction.

1) Are there no RV-9's with a forward facing sump? I'd really like to avoid the snorkel if possible.

2) What's the exhaust got to do with where the air intake on the sump is? I'm planning on using a Vetterman exhaust, but still this confuses me greatly.

Anyone out there that can share some tips. Even better if any of you out there are flying a B1A engine?

Thanks as always, Happy New Year!
 
David,


Change your plane to an RV-9 and it greatly simplifies things. ;)

You will be fine with the forward facing sump, FwF the -9A is the same as a -6A or -7A.

Larry Vettermans does make an exhaust that works with the forward facing sump, just not the standard crossover exhaust. The reason the standard crossover exhaust will not work is it would cross right in front of the fuel servo, causing some other interference issues. Check with Larry to see what he recommends.
 
I just got finished (yesterday, as a matter of fact) talking with Larry about this very issue for my bird. I'm planning on running a 360 in my 9A, with the forward cold air induction. If you use the Superior cold air sump, it won't be a problem and you can use either the 4-pipe or the crossover exhaust he makes. AERO has them on sale right now, I ordered mine yesterday.
 
Thanks Greg. I figured someone out there had to have trod this path before. I've been told that Divco can machine the case to be a Dynafocal 1 mount which I might do, but I've awhile to worry about all these options.

Knowing all I know now during the build process I'd probably have tried for a different engine, but I got this one for a **** of a deal. That's the way it always works, save a bunch here, spend a bunch over there.
 
It depends

niblettda said:
snipped
The B1A was off a Comanche twin, and has a rear facing induction sump. My belief is that with a 9A, there is no way I'm getting the rear induction to work since I think the nose gear weldment is right there. So I was planning on going with a cold air induction kit that makes the sump forward facing induction.

Anyone out there that can share some tips. Even better if any of you out there are flying a B1A engine?

Thanks as always, Happy New Year!
Click to expand...

The B1A engine requires 4 special [ie $$$$] "spacers" for use with the Dynafocal II motor mount. They were on the original Comanche twin. Did you get those spacers with your engine? Will you be overhauling the engine, or simply installing it as is?
Your induction choices are to either convert to forward facing horizontal induction [with proper sump] or vertical induction. Vertical induction sumps are easier to find and less expensive. Note that there are differing model sumps for vertical induction. They vary by intake tube diameter and location of the carb/servo on the sump. These variations were required by the airframe manufacturer, to get the engine to fit in a particular airframe.
If you decide on vertical induction, ask your exhaust vendor to recommend what engine model(s) to obtain a sump from. He will probably recommend a sump off of a more popular [mass produced] engine. That will make finding a sump easier on you.
Charlie Kuss
 
Charlie,

Yup I got the spacers when I bought the engine. Several reminded me to get those, but many have said these items are very expensive. I once found the part number for them and they are only like $125 for a set. If you had a lathe and some experience you could most likely make them yourself since they are nothing more than a turned hunk of aluminum.
 
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