48Chief just start whistleing

[hdhikaru]

Hi experts,

she was running ok today but suddenly start to whistleing like this...

any advice where its from..??

tks!!
Shin

[ChiefTwoKicks]

Sounds like you have an air leak somewhere... maybe a head gasket. I also have found a leaking sparkplug at the threads or where the insert threads leak at the aluminum head.
Many years ago, on my '47 Chief I found the front head had a crack (undetectible, until the head heated up). This one had the crack right in the middle of the combustion chamber, about a half inch long. I found that one by putting some gun bluing in the sparkplug hole before I started the engine. After a few minutes the crack showed up across the outside of the top of the head, between two fins. Usually a crack at the sparkplug hole is pretty easy to see (not always).
If you dont want to tear apart both heads... open the valve covers, rotate the engine watching the valves as both are closed on each cylinder, respectively. You will be looking for which cylinder is on the compression stroke. It may help isolate which cylinder is leaking. Sounds like a pretty big leak... so, hopefully it will be fairly easy to find it... Good Luck. C2K

[otis71]

Was the choke completely closed? Sometimes the restriction makes the small manifold leaks more apparent.

[PRG]

Howdy sir,

Very melodic there. The tone doesn’t seem to change on draw or compression and is present for both cylinders, I’d pull your breather off and check to make sure the disc and gasket are in place. That sound is reminiscent of the Krank Vent once marketed for Chiefs which partially sealed off returning air to the sump on the compression stroke. Most of us concluded fitting valve stem seals and good gaskets were more elegant solution.

[T. Cotten]

I don't identify as an 'expert', Shin,..

But when sounds are confusing (always for me), it helps to make them visible.

With a little soapy water around the spark plugs, valve covers, and head gaskets, etc., leaks should make bubbles when the motor is turned.

(This is how I learned copper gaskets ain't worth it.)

,,,,Cotten
PS: Always rinse detergents thoroughly!

[slamiste]

I agree with PRG that the breather is suspect. I had a buddy that had one of those Krank Vents on his 1947. I started calling it the Goose Valve because that's what the sound reminded me off. He hated the good natured fun we had at his expense enough that he replaced it with the OEM style breather and the noise and the fun were gone.

[hdhikaru]

thank you guys for the useful advices!! on the first video, I took off the spark plugs so no compression on top. so... it comes somewhere from crank case.. so,,,, must be breather.. .. will check! tks!! Shin

[T. Cotten]

,,I agree with PRG that the breather is suspect. I had a buddy that had one of those Krank Vents on his 1947. I started calling it the Goose Valve because that's what the sound reminded me off. He hated the good natured fun we had at his expense enough that he replaced it with the OEM style breather and the noise and the fun were gone.

Filtered vents for milwaukee machines made me money in my glory days, Folks!

They were oil traps, and people paid me to take them off after paying other shops put them on.

A 'win-win' it wasn't, as the demise of the aftermarket service industry is proof.

I'm all for better ideas, but it's always hard to beat OEM design, (or reproduced exactly.. )

....Cotten

[ChiefTwoKicks]

After re-visiting Shin's video, I realize I kind of jumped the gun, thinking about a head gasket leak. For me, finding a head gasket leak between the fins, was an issue I struggled with,
for some time. I forgot about the Krank Vent, which was also a problem I dealt with. I too, removed it.

As for the breather/disc... what is the best solution ? plain disc, disc with a hole ? Again, questions about the baffle plates... and more. std. cams and compression, or stroker and high compression ? Crankcase breather has been a hot topic for a very long time... especially for Indians.

A long time ago, one of my many mentors, Pop Standley, told me to attach a 3/8" rubber hose to the breather casting, mounted upside down, and running the hose up between the tanks,long enough to extend past the frame center post, almost to the back axel. Open ended, the rubber tubing is long enough and high enough (above the cylinders) so any fluid will fall back through the tube and back into the crankcase, and not on the ground. I've tried this, both with and without the disc. I have a disc with a hole. The rubber tube length is about 48" long. I use an "O-Ring" drive chain, lubricated with spray-on lube.No need for crank vapor to lubricate the drive chain.

Not here to hi-jack Shin's thread, but... if the breather is the issue... what IS the better idea ?

[T. Cotten]

..Not here to hi-jack Shin's thread, but... if the breather is the issue... what IS the better idea ?

Twenty years ago, C2K's,..

It was the Moto-Valve: http://virtualindian.org/5techmotovalve.htm

Duff, the inventor, is still active upon the VI Mailing List: VirtualIndian-subscribe@egroups.com

And I think I have one on the wall.

...Cotten

[PRG]

Howdy Chief,

Most Chiefs are tuned overly rich making any leak from a gasket, cracked head or loose plug insert readily sourced as a tar/oily sludge of unburnt gas (and sometimes oil) leeches out.

Breather situation: my 80 inch high compression Bonnie cammed hotrod Chief with no baffles and modern three ring pistons runs on a stock no hole breather with 3/8’s (I think) hose routed along the right side bottom frame rail exiting at the rear axle on a bracket slightly angled outward to project any oil laden vapor - of which there has been none in this healthy motor shown here in a previous post. This has been perfectly fine for 25 years since I built this motor so therefore one could be deemed adequate. Note, the longer the hose, the more resistance through flow restriction which will alter the effectiveness of your breather. Using very long hoses in conjunction with vertical routings is attempting to use the principle of surface tension to keep oil from blowing out one’s machine. Mist moving down these hoses collects on the hose walls into droplets which one hopes will then run back down the hose into the case rather that fog their machine. Overly oil laden mist exiting the breather is generally an indication of another problem needing addressing.

Now, as outlined in various threads here over the years, Chief V twins lubricated themselves predominantly by windage, not by oil pressure for which they generate little to none (pump output merely “sealed” to the timing side shaft by a felt ring) with the pump merely acting as a metering device for the oil tank above. Relative to engine displacement these motors have very little crankcase volume, meaning relative to that volume increase via piston rise to TDC in effect more than doubles the volume engaged by oil vapors and therefore creates huge windage. Besides controlling the amount of oil centrifuged off the flywheels up into the rear cylinder they used a system of ports in the baffles to break up oil droplets into mist which then circulates up the cylinder walls and through more ports in the timing side case directing it at the timing gears and valve train. As you can imagine this creates a lot of resistance and thus part of the reason these machines use four heavy tension based rings on their pistons. Especially with longer stroke 80 inchers the resistance you feel (along with the hissing through the breather) in the kicker is only partly attributable to compression ratio. It’s a combination of both trying to vent compressing air in the crankcase on piston drop to BDC along with the subsequent vacuum created in the rise to TDC all being routed through that small breather port. Efficient, no, necessary with this lubrication format, yes.

This format can exacerbate oil leaks from other sources so folks feel compelled to install various interpretations of PCV valves which essentially attempt to draw the engaged crankcase volume into a partial or complete vacuum. That’s fine on modern power plants using o-rings, valve stem seals, etc and positive pressure lubricated at all essential locations. Windage is the enemy of modern efficient clean running engines but, unfortunately a necessity for us. Vacuum in our crankcases can lead to possible “dry guide” wherein against this vacuum the motor trys to breath through the valve guides (ours run very loose clearances) pulling away oil and drawing in more exhaust gases leading to increased wear.

[T. Cotten]

...Most Chiefs are tuned overly rich...

Why is that, Peter?

Thanks in advance,..

....Cotten
PS: See you again at Davenport?

[ChiefTwoKicks]

Thank You Peter, for the detailed explanation regarding windage. I understand it OK, just not articulate enough to explain it well to others. And for Cotton, I also have a couple of those MotoValve's that Duff made years ago. retired them both. The Virtual Indian site, which doesn't get much attention these days is certainly worth a look. Lots of material there to study.

Thanks again. Roger (C2K)

[PRG]

Howdy sir,

Yessir, Davenport on the schedule. Against announced scaling back of Liberty at the time, bought a lifetime supply of floats and other trinkets from your table there. Because it’s easier and most are not looking for performance or efficiency, rather rideability and flexibility. And as our demographics age, easier starting when hot and the ability provide relaxed performance under varying loads while not adjusting the ignition advance from full while underway. Tune one fat and you’ll have all of that.

On the other hand, pursuing the best stocio for any given load/rpm via mixture and ignition optimization can reveal many things - possible shortcomings - about a power plant, ie, on my hotrod 348 merely changing from a restrictive foam air filter to a free flowing K&N caused it to to 8 stroke - so to speak - and surge at light part throttle load in 2nd, this likely a function of intake reversion, an aggressive cam with higher compression. Though it pained me to do so, merely softening it with a few richening clicks on the high side returned it to a pleasant plodder.

Roger, if that screed on windage wasn’t enough, here’s another even more lengthy at my Rapide site. It also extols the virtues of a lowly $5 PCV from Autozone that flies in the face of the elaborate, expensive and often unsightly solutions pursued by the effete Vincent crowd.

http://www.patwilliamsracing.com/vin...centengine.htm

[T. Cotten]

..I also have a couple of those MotoValve's that Duff made years ago. retired them both....

Did Duff send you the later stainless 'flappers', C2Ks?

The brass discs didn't last very long...

....Cotten
PS: Peter!
My philosophy for tuning a motor is merely to tickle it to where it likes it.

If it sounds strange, makes a mess, or merely protests,...

Something ain't right.