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Air Filter Damage

Champ

Well Known Member
I had a dirty injector, cleaned it and did another GAMI Lean test using Savvy's procedure. The lean test came out good with .4 GPH spread. However at the end of the 3rd run I also did an in-flight mag check. I was aggressively leaned at this point and heard what I thought was a cylinder missing on both the Left & Right mags (a little worse on the Right).

On my walk around today I saw this on my intake filter.
Air Filter Damage.jpg

It looks more like a backfire than a cylinder miss. Is it possible to get a backfire in a situation like this?

I'll be ordering a new filter K&N 33-2060.
 
I had a dirty injector, cleaned it and did another GAMI Lean test using Savvy's procedure. The lean test came out good with .4 GPH spread. However at the end of the 3rd run I also did an in-flight mag check. I was aggressively leaned at this point and heard what I thought was a cylinder missing on both the Left & Right mags (a little worse on the Right).

On my walk around today I saw this on my intake filter.
View attachment 8967

It looks more like a backfire than a cylinder miss. Is it possible to get a backfire in a situation like this?

I'll be ordering a new filter K&N 33-2060.
Is it electronic Mag or slick? I am not sure if .4 GPH spread is all that good. The aim is for .2G or less. but to I think it is possible to have back fire in those condition depending on power setting, advance timing.
 
Ive had a couple hot start backfires that did that. Now I never have the throttle full open on a hot start. I hot start with throttle closed and butterfly in servo keeps it from backfiring in the airbox blowing out the filter. Haven't had to replace one since. Basically my hot start is throttle closed and mixture idle cutoff and then slowly add mixture as it catches.
 
A start up backfire makes sense. It could have happened on a less careful recent start where I let off cranking before I got a clean start. I start with the throttle cracked and mixture at ICO and advance on firing. I'll have to try a throttle closed start and make sure I keep the starter engaged.

Bavafa - I have had .2 GPH spread on previous GAMI tests. I have dual P-Mags.

Thanks everyone.
 
I thought K&N filters were free-flow........

Shouldn't a blast just flow right thru it ?
 
Just a thought...

You may want to take a look at your snorkel and assess it's condition. I had a startup fart once (which at the tome didn't think it was too bad) but later found the snorkel had about an 8" split from the back pressure.

No big deal to fix it but you gotta find it first!
 
Backfire

Had the same thing happen to a customers airplane, RV14, when an Emag went 180 degrees out of time. Not only did it require replacement of the air filter it blew a 3 inch section out of the tailpipe. Very expensive to repair. No answer as to why this occurred.
 
Yes, as stated, this was most likely caused from an earlier backfire. We see a few of these very year. Somehow it gets missed on the preflight. I seriously doubt it could happen in flight without a lot of damage elsewhere.

Vic
 
I had a dirty injector, cleaned it and did another GAMI Lean test using Savvy's procedure. The lean test came out good with .4 GPH spread. However at the end of the 3rd run I also did an in-flight mag check. I was aggressively leaned at this point and heard what I thought was a cylinder missing on both the Left & Right mags (a little worse on the Right).

On my walk around today I saw this on my intake filter.
View attachment 8967

It looks more like a backfire than a cylinder miss. Is it possible to get a backfire in a situation like this?

I'll be ordering a new filter K&N 33-2060.

Mine looked similar after about 500 hours. The metal mesh deteriorates over time and changes into the shape/position that the filter is oh slightly loaded to.
 
Took the cowl off - no damage or evidence of backfire in the snorkel. Pulled the air filter - damage to the pleats and breaks in the wire mesh. No bulge like Scott's picture. So, could be either backfire or weakened filter stressed mechanically like Kevin suggested.

New filter is on order from ACS.
 

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