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-   -   Need Help With A Slimline Pitts Muffler (https://www.rcuniverse.com/forum/beginners-85/6217625-need-help-slimline-pitts-muffler.html)

Ferocious Frankie 08-09-2007 05:22 PM
Need Help With A Slimline Pitts Muffler
 
Hi guys,

I have a slimline pitts style muffler for a Saito 180. There are two tapped holes. One which is protruding out, I assume is the for the tank vent nipple. The other one is on the side of the muffler intake.

My first question is what size fuel line nipple do I need as the muffler didn't come with it?

My second question is, what is the second tapped hole for? Is it for the breather nipple?

Thanks

JohnBuckner 08-09-2007 05:54 PM
RE: Need Help With A Slimline Pitts Muffler
 
One of the ports may be intended for a smoke oil injection point as to which is which or what size nipple that question may best be answered by Slimline.

John

Ferocious Frankie 08-09-2007 06:16 PM
RE: Need Help With A Slimline Pitts Muffler
 
Hi John,

This is just a regular one. I didn't get the one with smoke.

horace315 08-09-2007 07:35 PM
RE: Need Help With A Slimline Pitts Muffler
 
did you buy this muffler new?most of them will come with a nipple for pressure and the smoke tap plugged.

Ferocious Frankie 08-09-2007 07:37 PM
RE: Need Help With A Slimline Pitts Muffler
 
Yah, I got this new from Tower, but I don't think the second hole is a smoke tap because the picture of the smoke muffler shows the smoke tap on the flat end side of the muffler.

broke_n_bummin 08-10-2007 10:15 AM
RE: Need Help With A Slimline Pitts Muffler
 
Does one of the nipples have a smaller hole than the other? I've never seen one on a Pitts, but some aftermarket 4 stroke mufflers have a PCV nipple (crankcase vent). The hole in the nipple is smaller than the nipple for the exhaust. If so, run a piece of tubing from your crankcase vent to the nipple with the smaller hole.

broke_n_bummin 08-10-2007 10:27 AM
RE: Need Help With A Slimline Pitts Muffler
 
My bad .... Guess I oughta read the whole thing. It didn't come with any nipples .... Ok then , the hole on the side would be the PCV tap. I don't know the exact size, but I know the PCV nipple has a smaller hole than the tank pressure nipple. I don't know if I helped you out any or just confused you more. You might get a better answer in the Glow Engines forum .. or at least a better explanation.

Ferocious Frankie 08-10-2007 02:44 PM
RE: Need Help With A Slimline Pitts Muffler
 
I think you're right. It probabl is for the crankcase vent. The hole does look a little smaller.

JohnBuckner 08-10-2007 03:38 PM
RE: Need Help With A Slimline Pitts Muffler
 
There is no such thing as a Polution control valve or PCV tap on any model aircraft four stroke engine.

The majority of model four stroke engines do have a crankcase vent and most have a nipple to plumb the vent outside a cowling venting to atmosphere. This vent is not plumbed to the fuel tank or muffler! Agine do not plumb this crankcase vent to the fuel tank or muffler.

YS engines are an exception here as they never have vented crankcases and case pressure is used for different purposes with that engine.

If your engine used a pressure tap on the stock muffler then do plumb a pressure tap line to the tank breather from the new muffler. If your stock muffler did not employ a muffer tap the it may not be needed at all.

No matter who or how they got there if your new muffler has two taps or holes you can bet they were intended for !. fuel tank pressure tap 2. smoke oil injection port.

If you don't have smoke then plug the extra hole. If you want to use a muffler pressure to tank pressure then pick one and use it. Usually the best pressure is obtained where the tank first opens up in area. However on those box mufflers thats always a crap shoot but not a big deal.


John

skeeter_ca 08-10-2007 04:22 PM
RE: Need Help With A Slimline Pitts Muffler
 
There is no such thing as a Polution control valve or PCV tap on any model aircraft four stroke engine.
Never heard it called that before. As a professional automotive technician for over 27 years I always called a PCV valve a Positive crankcase ventilation valve.

JohnBuckner 08-10-2007 04:36 PM
RE: Need Help With A Slimline Pitts Muffler
 
The point is there is no valve and that hole in the crankcase is a vent that is not plumbed to the muffler or the fuel tank.

skeeter_ca 08-10-2007 04:41 PM
RE: Need Help With A Slimline Pitts Muffler
 
I understood that. i was just joshin with you!

JohnBuckner 08-10-2007 06:17 PM
RE: Need Help With A Slimline Pitts Muffler
 
My apologies Skeeter and I did not intend to sound cranky [&o]

skeeter_ca 08-10-2007 09:32 PM
RE: Need Help With A Slimline Pitts Muffler
 
None necessary, i can take a joke better than i can give one. Uhh......wait i don't think that came out right. lol

RCKen 08-11-2007 11:24 AM
RE: Need Help With A Slimline Pitts Muffler
 
Frankie,
You may not have ordered it, but you did indeed get the muffler designed for smoke. A non-smoke muffler has only one tap on the side of it. My best advise is to find a bolt that will screw into the smaller smoke tap and put it in to close up the hole. Then just fly the plane. Under no circumstances should you hook up the crankcase vent line to the muffler tap.

Ken

broke_n_bummin 08-11-2007 03:27 PM
RE: Need Help With A Slimline Pitts Muffler
 

ORIGINAL: JohnBuckner

There is no such thing as a Polution control valve or PCV tap on any model aircraft four stroke engine.

The majority of model four stroke engines do have a crankcase vent and most have a nipple to plumb the vent outside a cowling venting to atmosphere. This vent is not plumbed to the fuel tank or muffler! Agine do not plumb this crankcase vent to the fuel tank or muffler.

YS engines are an exception here as they never have vented crankcases and case pressure is used for different purposes with that engine.

If your engine used a pressure tap on the stock muffler then do plumb a pressure tap line to the tank breather from the new muffler. If your stock muffler did not employ a muffer tap the it may not be needed at all.

No matter who or how they got there if your new muffler has two taps or holes you can bet they were intended for !. fuel tank pressure tap 2. smoke oil injection port.

If you don't have smoke then plug the extra hole. If you want to use a muffler pressure to tank pressure then pick one and use it. Usually the best pressure is obtained where the tank first opens up in area. However on those box mufflers thats always a crap shoot but not a big deal.


John
PCV = Positive Crankcase Ventilation ... Look at an FL -70, then tell me again there's no such thing. I've seen other mufflers that were intended for the same thing. I've even seen mufflers with 3 taps. I wonder what the third one is for ... colored smoke?

Ferocious Frankie 08-12-2007 04:01 PM
RE: Need Help With A Slimline Pitts Muffler
 
1 Attachment(s)
Hi guys,

Thanks for all the responds. Here are some pictures of what I was talking about. You can see both the protruding hole and the one on the side of the intake.

JohnBuckner 08-12-2007 06:17 PM
RE: Need Help With A Slimline Pitts Muffler
 
The smaller hole on the header portion is in a position for an effective muffler tap to provide pressure to the fuel tank if you choose to use it that is where I would locate such.

The larger hole is centered to the outlet pipes and likely an intended point for smoke oil injection to provide uniform smoke from both outlets. If you have no smoke then plug the hole.

Do not plumb the crankcase vent to the muffler, leave it open to atmosphere or just a length of fuel line to clear the cowling if you like.

John

rloeb 08-13-2007 08:10 PM
RE: Need Help With A Slimline Pitts Muffler
 
The larger hole is for mounting a bracket that holds the muffler to the motor.

Rog

Ferocious Frankie 08-16-2007 10:11 PM
RE: Need Help With A Slimline Pitts Muffler
 

ORIGINAL: rloeb

The larger hole is for mounting a bracket that holds the muffler to the motor.

Rog
Just wanted to give an update. It turned out that the protrudung hole is indeed for a mounting bracket, that does not apply to my application and the hole's size is 10-32. The smaller hole is for the muffler pressure nipple and its size is 8-32.

Thanks for everyone's help!


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