Exhaust and Intake Risers Touching?

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shoffert
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Re: Exhaust and Intake Risers Touching?

Post by shoffert »

As it turns out...Rich is correct. No noticeable wiggle.

Next attempt is ordering new intake and exhaust risers...try to see which one isn't quite the right size.
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Steve
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Re: Exhaust and Intake Risers Touching?

Post by Steve »

Ordering all new intake tubes and exhaust risers will be expen$ive. It would be better if you can determine what the fault is before throwing a lot of parts at it. For all we know now, your muffler could be out of spec. Speaking of the muffler, does it have the brace installed (MSB40-044/1)?
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shoffert
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Re: Exhaust and Intake Risers Touching?

Post by shoffert »

It's just the intake and exhaust on #1, not a full set. So hopefully it won't be that bad. I'll try to make sure I can return the parts if this isn't the error.

Neither the intake or exhaust have any play in them...the "top end" of each is bolted to the cylinder...they would touch even if the rest of the muffler was totally removed below the clamp...makes me (and my IA) think either the intake or exhaust riser must have been constructed in error.

With the tolerances being really small in this case (less than 1/4"), and me not having another IO-360 M1A on the field to compare little measurements with, I don't know of another way to tell which of the two pipes is just a little out of whack?

If the top bit of the intake was just a little shorter I'd have space, and if the top bit of the exhaust was just a little longer I'd have space.

With the motor only being 50 hours outside of rebuild and no signs of wear on either pipe, at the moment I'm guessing a part swap happened there?
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Steve
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Re: Exhaust and Intake Risers Touching?

Post by Steve »

That sounds like a plan. It will be interesting to find out what the issue is; wrong part, badly manufactured part, damaged part...

As much as these things cost, one would expect perfection.
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Rich
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Re: Exhaust and Intake Risers Touching?

Post by Rich »

Steve wrote: Tue May 19, 2020 2:03 pm That sounds like a plan. It will be interesting to find out what the issue is; wrong part, badly manufactured part, damaged part...

As much as these things cost, one would expect perfection.
My money (well, to be accurate, it's Stephen's money) is on the intake pipe These things are not chrome-plated from the factory. It may well be a part for a different IO360 variant. It still fits the engine, but not with the original exhaust system. The latter is not provided by Lycoming, it's Diamond's design.

Aircraft Spruce shows the intake pipe as $161.75, but not in stock.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Exhaust and Intake Risers Touching?

Post by shoffert »

An update...

After having a lot of eyes on the exhaust, and the exhaust of other DA-40s, it looks like a repair done just before the engine overhaul just shifted things a bit out of place where the tolerance was already pretty tight. There are new welds on 3 of the 4 risers as well as down around the muffler, too. Documented in the logs, just as it should be.

The thought is that if we just replace the one riser, even though all the couplings in there can tolerate a little shift, that the exhaust won't fit back together properly.

Since this is important to get right she's going to go down for a while and have a pro get her all squared up.

Kicking around the idea of going for the Powerflow (my prop already meets the STC) rather than putting more cash into this exhaust...which sadly is in really, really, nice shape besides being a bit out of rig.

Thoughts? New Powerflow vs good sized welding job?

As a nice, light, 2002 she's already fast getting 140KTAS at 8k, ROP.
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Re: Exhaust and Intake Risers Touching?

Post by blsewardjr »

Powerflow will add a couple of knots and a 100+ FPM climb. Downside is increased maintenance each annual.
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Re: Exhaust and Intake Risers Touching?

Post by Rich »

Having converted to Powerflow from the original, here's what I wound up with:

-Several knots additional cruise over book. This differential is higher at altitude. My 11,000 ft DA cruise (with MT prop) is reliably 141 knots. It used to be about 130 or so. (I also have the magic nosewheel fin which makes this consistent.
- I saw a 300 FPM improvement in sea-level climb rate. This jives with current measured performance vs. book and matches theoretically calculations.

Installing the PF isn't particularly challenging. But there is the problem of arranging for patching/painting over the hole in the lower cowling now left vacant.

My PF now has about 13 years on it. Minor periodic maintenance required.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Exhaust and Intake Risers Touching?

Post by blsewardjr »

The continuing airworthiness requirements are at

https://drive.google.com/file/d/1ftdK5E ... g1KI3/view

It takes my mechanic 2.5 hours at each annual.
Bernie Seward, IR, AGI
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Re: Exhaust and Intake Risers Touching?

Post by Rich »

blsewardjr wrote: Wed May 27, 2020 11:57 pm The continuing airworthiness requirements are at

https://drive.google.com/file/d/1ftdK5E ... g1KI3/view

It takes my mechanic 2.5 hours at each annual.
We get it done in about 45 minutes. The only routine time-consuming part is the lubing of the joints. Many shops familiar with the system find that it's a function of hours and will often just do this lube every other annual. This is what we're doing, given the modest number of hours between annuals. The joints have never seized. The only thing that has ever failed is that rubber muffler hangar occasionally will wear. I check it every oil change and replace it if necessary. The actual parts are like $10.00 ea from PF. I've replaced 3 in 13 years.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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