J

Joe

Well Known Member
RV-8A with IO360-M1B from Van's with horizontal induction and Vetterman's crossover exhaust purchased from Van's. How does one install the Van's-supplied sniffle valve? As many have discovered, the exhaust interferes with the port location on the sump.

If a remote-mount using a tube or an elbow of some sort worked for you on an RV-8A, I'd appreciate seeing a picture of how you did it.

Thanks,
Joe
 
SmilingJack said:
There is a thread on this issue.

I used the Piper sniffle valve as in this thread.

http://www.vansairforce.com/community/showthread.php?t=86090
Click to expand...

Thanks -- I searched only the RV-8/8A forum and didn't see that thread.

I hadn't considered buying yet another (expensive) sniffle valve and maybe that's a solution. But I would like to make this Van's-supplied sniffle valve work with this Van's-supplied engine and Van's-supplied exhaust.

I could ask Van's but I'll probably be told I'm the only one with this problem :-(

So my question remains: How does one install the Van's-supplied sniffle valve? If a remote-mount using a tube or an elbow of some sort worked for you on an RV-8A, I'd appreciate seeing a picture of how you did it.
 
Sniffle valve

Joe,

I have a Piper sniffle valve you can have. Don from AFP also makes a sniffle valve that works quite well and clears the exhaust, that is what I ended up using. Give me a call and come over to the hangar and see it in person

Kai
 
I see you have a solution that has landed in your lap. Luck is a good thing. :D

Here are some images for others just to confirm you are not the only one with M1B sniffle valve clearance issues.

My first try at it and the realization that it was no good.
4702795615186bae51e52a.jpg


I learned of the Piper valve but struck out on the first attempt to get one.
While continuing to search, somebody on VAF recommended a brass 45 so thats what I used. I'm satisfied with the function of the valve after 120 hrs.
4747045635186bb96b5b06.jpg


I decided to cover the short section of rubber hose with fire sleeve just to keep it from an early heat demise.
8612512835186bbfd4a450.jpg


FYI on different subject. See that rubber bit on the throttle? It needs a piece of firesleeve. Mine suffered heat abuse from the exhaust during the first year. It's probably old news to many. It was new to me on first annual.
 
I removed mine and so far have not missed it. Good idea? I don't know.

Random thoughts...comments please.

I suppose a pilot could run enough fuel into a horizontal intake sump to liquid lock a cylinder during start. Anybody ever heard of it happening?

The above may be only a taildragger issue, as I suspect fuel would run out the intake on an A-model before it got very deep in the sump plenum. Of course if the the airplane had a Vans snorkel from the left cowl intake and no drain hole....

It would seem like you should have a sniffle on a high wing airplane that can gravity feed fuel through a bad fuel valve/fuel servo/etc. That's not pilot error.

FWIW, the Lyc angle valve parts manual only lists a sniffle on two models with the common 74384 horizontal intake sump, A1B6 and A1D6. It lists four 1/8NPT plugs for the A2B, with a note "Assemble in fuel drain bosses in sump". Other models don't specify anything.

A good pressure recovery intake might open the check valve in flight. Sump plenum pressure should be higher than ambient, for sure if the sniffle drain line is plumbed to a static pressure point outside the cowl. Result would be a small manifold pressure loss and mixture tending rich. Both would be minor, but....
 
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Another without

For another data point, do not have a sniffle valve either. Plugged the hole. No issues or regrets so far.
 
Kudos to Kai, who flew over yesterday and delivered a Piper-style sniffle valve right to me in my hangar!

But it's still not a "drop in" fit and I'm wrestling with the idea of trying a 45-degree adapter from an auto parts store like BruceEicher mentioned and as shown in rzbill's picture.
 
Rv8a sniffle valve

I too had the same problem ( among others from Vans) I used a 90 then extension about 4 " with a 45 then the valve with a rubber hose which exited thru the metal plate that covers the nose gear hole.
Brand new engine not running well at idle but good at top end. Looking for leaks
Turns out the sniffle valve failed, I was going to throw it out today but decided I might send it back to Vans. It was not the problem with the engine.
I Live in Harmon rocket country and none of the rocket guys use them.
When I queried Vans about the valve being too close to the exhaust they put it off on Vetterman. I'm probably going to leave it out.
I also had similar problem with the throttle cable bracket, all Vans FWF, engine etc. no room between exhaust and throttle cable not enough room to put heat shield, had to make my own bracket then purchased better throttle cables (cheaper than Vans) and added a heat shield.
 
Options

What if you did not need to put the valve in at the sump? It may be OK to just put a fitting in at the sump port, run stainless tube from there to a point were you mite like to set the valve on a bracket on the down streem end of things. This would put the valve away from the heat and you could use hi-heat clamps to run the tubing and mount it all to the engine for vibration sake...... Just a thought....
Yours as always R.E.A. III # 80888
 
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