Air Intake noise?

[xyzer]

I have 2 6/1 Listeroids. the Vidhata is very quiet as far as intake noise. My 6/1 PS has a very distinct intake noise that almost rivals the exhaust noise level. I have heard of some folks trying quiet down the intake but shrugged it off because I didn't have an issue with it at the time. Now I understand there concern! It must be valve timing or something ...... any remidies or known causes out there?
Dave

[carlb23]

Are you running the same air filter/cleaner on both engines?
Have you tried switching the air filters around?

Sorry but those are the only two thoughts I have at the moment.  I would check the Valve timing, I think intake starts to open about 7 degrees BTDC but I don't remember exactly off hand.

[xyzer]

Carlb,
I haven't tried the switch but have removed the loud one and it makes no difference. I will try a switch to see if it makes a difference. I doubt it but still need to try.
Dave

[phaedrus]

Intake noise engineering is the same as exhaust - same formula, different speed of sound because the temperatures are lower. It may be that a nice new clean car muffler on the intake between the filter and the valve will suit.

I am thinking along these lines myself, thanks to an alcoholic neighbor who gets to yelling at me on Sunday evenings, if I'm running the l'oid.

[lendusaquid]

There is a small hole 3/16" ish in my intake manifold which when i sealed made my intake noticeably louder. Maybe you could experiment with different size holes. Ok so that air going in the hole isnt filtered but will it matter that much?.Might be worth a try.

[listeroidsusa1]

I've been using mufflers on the intake for years. A muffler on both intake and exhaust makes the engines almost silent except for mechanical noise and the valves ticking. I'm building manifolds that allow using a muffler on both ports. It works.

Mike

[mobile_bob]

the only issue i would have with the use of a muffler on the intake is where it is placed in relation to the air cleaner
if it is between the air cleaner and the engine i would be very selective as to what type of muffler i would use
i probably would not use one that has a glasspack or fiber fill for fear of sucking bits and piece's thru the engine

however, if one used a filter housing such as is common on forklifts where you have an intake tube coming off a sealed
aircleaner unit i then would have no issues with useing any kind of muffler

basically then if anything came loose inside the muffler it would be caught in the aircleaner.

the pulsing nature of a single cylinder is such that over time i would be concerned that it would work loose
bits of crap and allow it to go thru the engine if it was mounted between the aircleaner and the engine.

better safe that "awe crap"

bob g

[listeroidsusa1]

Use a perforated metal baffle type muffler and you'll have no problems. I use an automotive paper element filter over the end of the muffler and in all the years I've done this I've never had a problem. Glasspack mufflers aren't a good solution for either intake or exhaust as they are considerably louder than the baffle type muffler and like Mobile Bob says, they can loose pieces of packing.

[skeeter]

xyzer - has this engine always had loud intake noise, or is this something that has recently develop.

[xyzer]

skeeter,
It has done it from the begining. I noticed fooling around it appears to have a slight puff of air out the intake manifold when running. I also noticed there is overlap between the intake and exhaust they are both slightly open at the same time. I'm not sure what the cause is. It runs great and other than the noise no other problems.
Dave

[Reno Speedster]

It sounds like there might be a slight timing problem with the cam.  The cam shaft is drilled and the lobes pinned on so if they made it on a monday morning the intake could be off enough so that the intake is opening too soon or staying open too long and you are getting some blow back.  Just a thought.

[xyzer]

Reno,
I did a visual on the overlap on the noisey 6/1 and did a visual comparison on my other quiet 6/1 and they both appear to have the overlap. I need to drag my dial indicator over and do a real comparison. I have heard mention of folks dealing with the same issue so it looks like there is a issue that only causes the noise but doesn't bother the performance. Love to get rid of the noise without buying a new camshaft.
Dave

[europachris]

Reno,
I did a visual on the overlap on the noisey 6/1 and did a visual comparison on my other quiet 6/1 and they both appear to have the overlap. I need to drag my dial indicator over and do a real comparison. I have heard mention of folks dealing with the same issue so it looks like there is a issue that only causes the noise but doesn't bother the performance. Love to get rid of the noise without buying a new camshaft.
Dave

Heh, you should hear my ChangFa R185 !!!!  It really honks when at speed.  I removed the stock oil bath filter and intake pipe and fabricated my own setup to which I mounted a Solberg filter assembly/silencer made for air compressors.  I think I used the 1-1/4 NPT size.  It has a replaceable wire mesh reinforced polyester element with foam pre filter, and silencer tubes built into the assembly.  It cut the intake noise significantly, eliminates the oil mess from the stock filter, and filters much better.  It's a very nice unit.

Since I installed a big round NAPA muffler on it, the only noise the intake (still loud) and the mechanical noise (sounds like a rock crusher).  But, she just chugs along hour after hour, sipping fuel, and keeping the lights on and the food cold when the power goes out.

I'd still love a Lister type,  but just don't have the space for one.

Chris

[skeeter]

xyzer - I wonder if this slight overlap could be negated by a very slight alteration of valve lash clearance or one or both valves. Probably a dumb idea, since your performance is already good, and you might wind up trading less intake noise for more mechanical noise, or worst yet wear. Maybe the solution is to just muffle it.

[xyzer]

skeeter,
I plan on trying some valve adjusment tweaking. I won't leave it out of spec but there might be a fine line there for curiosity sake. It looks like I'll have to fab up an intake silencer when I get time. Thanks all!
Dave