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prkaye

Well Known Member
I'm trying to puzzle-out how to connect the Dynon MAP sensor using the IE VMP INSTALL kit I got from Vans.

1) It looks like the SS hose I got is supposed to connect to cylinder #3? Problem is, I have routed my primer line to cylinder #3. Can I use Cylinder #4 instead for MP? (what would you do for MP if you wanted primer lines in every cylinder?)

2) The Dynon documentation recommends a restrictor fitting. THe fitting I got from vans that goes into the cylinder is just a plain old AN816-4D fitting. Is there a restrictor version of this available? Part number?

Thanks!!

Phil
 
Phil

You need a few small hole in the restrictor otherwise you'll get flucations. In the end I used a cigarette filter in the line to dampen out the flucations plus a metal filter screen to ensure the cigarette filter couldn't move.

Do a quick search as this topic comes up often.

Peter
 
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You need a few small hole in the restrictor otherwise you'll get flucations. ..I used a cigarette filter
Click to expand...

If this is really a problem, surely the aviation industry has come up with a proper fitting to solve the problem?
 
Phil
It is very easy to modify the AN fitting at the cylinder. And yes, #4 cylinder will work just as well. On the flared end of the fitting drill the hole using a #30 drill. Drill it out deep enough for a #4 universal rivet to fit. A -3 length will be long enough. Put a dab of red lockite on the rivet and tap it into the hole. Now take the smallest drill you can find, 1/16th will work, but smaller would be better, and drill through the rivet. Now grind off the head of the rivet until it mimics the flare of the fitting. Thats it. I have used this technic on numerous airplanes, it works and can be done faster then the time it takes to order a fitting.
 
Good timing on this thread.

The Mooney my engine came from tapped the #2 cyl for MAP. Is there any reason I can't Tee it into the 1/8 NPT port on the bottom of the intake, right behind the fuel servo, tapping the horizontal tee port making sure the sensor box is higher than the intake ?
 
Phil-
If you bought Van's firewall forward kit and an engine from Aerosport, you may already have an extra fitting. Check your firewall forward kit for an extra black 45-degree VA-128 fitting. You need one for your fuel pump pressure outlet and one for your oil pressure outlet on the engine. Van's provides 2 in the kit, but my Aerosport already had one in the oil pressure outlet.
Hope this helps.
 
I tried to use a spare on my engine and it would not fit because it would not turn due to hitting the cylinder fins.
 
What about the fittings for the oil and fuel pressure?

Tom Martin said:
Phil
It is very easy to modify the AN fitting at the cylinder. And yes, #4 cylinder will work just as well. On the flared end of the fitting drill the hole using a #30 drill. Drill it out deep enough for a #4 universal rivet to fit. A -3 length will be long enough. Put a dab of red lockite on the rivet and tap it into the hole. Now take the smallest drill you can find, 1/16th will work, but smaller would be better, and drill through the rivet. Now grind off the head of the rivet until it mimics the flare of the fitting. Thats it. I have used this technic on numerous airplanes, it works and can be done faster then the time it takes to order a fitting.
Click to expand...

Do you follow the same procedure for your oil an fuel pressure restrictors? I like the approach and need to modify my fitting so I can mount the engine. I'd rather not wait the 5 day turnaround for parts from Vans.

I would expect you drill the tapered end to 3/16" and push in (+loctite) a drilled #6 universal rivet. Please confirm.

Doug
 
Just a note to those using cigarette filters - some have found that the material eventually gets sucked into the engine. It probably won't hurt anything, but it won't help, either.

Probably best to go with a restriction fitting.
 
After watching a cigarette filter begin to disassemble itself and eventually disappear, I tried a variation of the drilled-rivet technique. Unfortunately, my drill chuck wouldn't snug down small enough to use the tiny bit I had intended to use. Harrumph.

So, while checking out the aviation aisle at Lowe's, I found a Briggs & Stratton fuel filter for a few bucks. Small, plastic and has a fine screen inside. I cut up some cotton gauze that I had and stuffed it into the side of the filter away from the cylinder until I had to work to blow air through it.

It was the perfect size to fit my tubing, and damped the fluctuations perfectly. And I don't have to worry about another cigarette filter disappearing. :)
 
Doug
Yes I use the same proceedure for oil and fuel pressure. I use a -4 rivet in those locations as well. If that is too small for the fittings that you are using then try a larger rivet. The drilled hole in the centre of the rivet is still about as small as you can get it with a drill.
 
don't use the sniffle-valve port

RV8RIVETER said:
Good timing on this thread.

The Mooney my engine came from tapped the #2 cyl for MAP. Is there any reason I can't Tee it into the 1/8 NPT port on the bottom of the intake, right behind the fuel servo, tapping the horizontal tee port making sure the sensor box is higher than the intake ?
Click to expand...

Wade - it sounds like you are referring to the sniffle valve port in the bottom of the intake plenum. Don't tee into that for your MAP, because the sniffle valve needs to drain and it will be open to atmosphere.
Note older angle-valve engines IO-360-A1A didn't come with a sniffle valve, but its a pretty good idea to retrofit them. Anyway - don't tie into that port for your manifold pressure.
 
I am debating the valves usefulness in this location in a taildragger. At the current aircraft angle the rear of the sump would have to pool up quite a bit to reach the valve.

Then there is the issue of air leakage. I hope to slightly pressurize my induction system and therefore it would be a source for leaks.

A local Lancair guy discarded his valve and plumbed his manifold pressure there, is an IO-320. I have decided on #3 cylinder, as gives better idea of pressure at the cylinder. Still thinking about valve though. Thanks for the input.
 
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Tom Martin said:
Doug
Yes I use the same proceedure for oil and fuel pressure. I use a -4 rivet in those locations as well. If that is too small for the fittings that you are using then try a larger rivet. The drilled hole in the centre of the rivet is still about as small as you can get it with a drill.
Click to expand...

Tom,

OK I have figuered out why I have been confused - I now see that the AN823-4, -3 and -2 are all 1/8" BSP so are equally suitable for the sensor connections but each have different tube sizes.

I have blindly followed the Vans catalog and used an AN823-4 but you are using either the -3 or -2 size (requiring the smaller -4 rivet) and running smaller diameter tubes to your transducers. That makes good sense and something I will keep in mind for the future.

Thanks,
Doug
 
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