One of the last decisions I need to make here is what I will hang my P-Ponk on when the engine does eventually arrive. There seem to be a couple schools of thought:
1. Remove, IRAN, and reuse the original mount with some new paint or powder coat
2. Replace with heavy duty alternative (SPW, Skyways)

I know that being a 1957 airframe, I have the lightest of all possible mounts in a 182. P-Ponk has also quite clearly told me they don't need a stronger mount. If you hear it from SPW, you need their mount/exhaust combo or you will regret it later, however it's $10k and requires moving some minor things around. The other end of this is to strip my mount down and inspect closely, and send to a repair shop as needed. Total cost probably somewhere between $1k-3k to get this done. Wag-Aero has an $850 rebuild job up to 4 tubes that seems quite reasonable, though I assume powder coating is extra after that.

I am looking for real user feedback here. Did those of you who kept the stock mounting really feel like you're missing some magical component worth another $10k? If you used a SPW or equivalent, do you feel like the wallet-emptying upgrade is worth the high cost?

For reference, this will be an (I)O-520 P-Ponk, probably mated to an MT 2 blade prop. Lighter weight and less vibration, but more power than Cessna envisioned 60+ years ago *if I go below Denver elevation*. Up here with a best case 20% decrease to start, I think I am still <230HP which is stock 470 rating. I also just tossed new LORD mounts at it, so I don't want to waste that expense without good reason.

We bit the bullet when installing our IO-520 based Pponk and did the SPW mount and Acorn exhaust. Needed the mount however since I was installing the seaplane kit at the time. Also needed new exhaust as our stock risers were pretty bad and the new exhaust has larger diameter tubes, better for the larger displacement anyways. I've been amazed at how smooth it is.

Over the years I can recall installing 3-4 SPW mounts on 185 factory seaplanes and all of those owners to a man raved about the level of smoothness afterwords. At least 2 of these were new engines as well but a couple were not. These examples are not perfectly germane to your airplane but I do believe much of that smoothness comes from those upsized Lord mounts on the SPW mount.

Also, how old is that mount of yours? It's often impossible to really know. I would be inclined to have the tubes ultrasounded if you go the overhaul route, be a bummer to have it crack out after all the work you're about to do...

Although Steve says you don't need to change the mount, it just doesn't make sense (to me) to keep the stock mount with the addition of the extra power. Like Sam, I wanted smoothness, so I too went with the SPW engine mount. I also chose to go with the STC'd SPW (Acorn) w/ no cones for that added bump in HP. Necessary? No... worth it? Yep.

I installed a SPW mount on my IO-520 powered 1976 185 that had 2 blade prop, I was VERY happy, I would do it again. Don't skimp on your mount, you will have to sit behind that engine for a long time, the extra weight and money will be forgotten in short order but an engine that is not as smooth as it could be will never be forgotten. Also, make sure you balance the prop after install.

CP:

I have owned a 55 180 with a stock 470 and, for the last 15 years, a 59 180 with a P-Ponk 520.

I sure don't think I really noticed any more vibration with the 520 nor do I believe the 520 is any less smooth than the 470 was.

The 520 is a big smooth running engine and I have never had any complaints about roughness, etc.

I have never flown behind a Skyways and maybe if I did I would be a big fan. But for 10K , knowing what I know, I would be hard pressed to pull that trigger. As I mentioned, I have had my bird for 15 years and no sign of cracking, stress, etc. on the mount.

Regardless of your decision with the engine mount, you will never regret the decision do the power upgrade. It feels like a whole new plane.

Good Luck! L

I just went throught the same decision making process- Colorado front range, early model airplane, old mount. I decided to keep the old one after making a few phone calls. Acorn told me that it would be a straight exchange for an overhauled mount regardless of the condition of my mount - about $2500. They also told me that I was the first person in 10 years that had even inquired about the early mounts and that it was a waste of my time (should buy a new one). Atlee Dodge told me it would cost between $300 and $1800 to inspect, fix, and powdercoat and that they work on them all the time. You can send them freight on Alaska airlines to them for cheap. I decided to blast mine, dye pen inspect it, and paint it in grey epoxy to make it easier to inspect in the future. There are more sophisticated ways to inspect and more qualified people inspecting but for a mount that worked just fine for 2500 hours, I am not changing it. Steve Knopp does not advocate for a new mount. $10,000 is a significant amount of cash to change something because someone says that it is smoother. Has anyone had a broken early mount with a pponk engine that was not related to poor/lack of maintenance?

silflexer wrote:... Steve Knopp does not advocate for a new mount. $10,000 is a significant amount of cash to change something because someone says that it is smoother. Has anyone had a broken early mount with a pponk engine that was not related to poor/lack of maintenance?

I was gonna suggest that they ask Knopp about his mount recommendations. You beat me to it.
I don't think the idea behind a new more better mount isn't so much the worry about the original one failing,
it's the smoothness that you will (hopefully) get with the beefier new mount.
I've seen some mounts that were referred to as a "three-blade mount"--
besides the extra vertical members, they incorporate another mod or two which are intended to keep vibration to a minimum.

As a side note, my 53 C180 was upgraded to a 470K many years ago.
Probably to save money, they changed the mount attachments on the K engine case & stuck with the original A/J engine mount.
I wish they hadn't-- IMHO the newer mount uses a superior configuration of Lord rubber mounts.
The old style like mine break down a lot sooner than the newer style.
They're a PITA to change out, and plenty spendy too..

I would send my mount to AWI for IRAN, and never look back. I don't think they'll leave one original tube in it. It WILL be new for all intents and purposes. I'd have them build it up as a K or L mount. And find the right legs for your motor. You'll save to yourself enough cash to do a new interior, or most of a vfr radio stack.
How often do you hear of any of the multitude of other airplanes running IO520's shedding engines because they didn't have a $10,000 mount?

And yes, you are correct. Ditch the A/J legs. A K engine can have late legs with a half breed mount on an early airframe....way better having your engine sitting on rubber as opposed to having the rubber upright with the lugs running through it.

I like Robs suggestion. One thing no one else mentioned is to be careful with powder coating. Personally, I would stay away from it in a critical spot like an engine mount. It will hide cracks. Just paint it primer grey or white.

Sent from my SM-G870W using Tapatalk

Seaplanes West was bought by the owner of Acorn Welding. Within the last year, I believe. This is a good development. They have always manufactured the mounts for SPW anyway!

I put an IO-550 in my 185. I reused the Cessna three blade seaplane engine mount that had been installed as a service kit when the three blade was first offered for the 185. I used the money I saved over a SPW mount to cover the up-tick for an MT prop over the eligible McCauley and Hartzell offerings. Acorn overhauled it, and it's better than new. They know the weak spots, and know how to prevent future failures. I'm very happy with how smooth it feels. I may not get to TBO with one set of lord mounts like the SPW probably will, but without all the extra weight of a metal three blade cantilevered out the front, I may be pleasantly surprised.

I should add that the main reason I went with the new engine mount wasn't just because of smoothness, its the build quality. A quick side by side glance is all you have to do to see which one will serve you better over the years. Yes the orig mount did just fine, but technology has improved a bit in the past 70 years and it's hard not to admit that the more robust design and exacting fabrication techniques wont be the better choice.

The fact is that the STC does not "require" you to make any changes, so "technically" you don't have to do anything... but the price consideration is surly one that cant be avoided. When the conversation becomes about $$$, its hard to criticize anyone's choice one way or another as the most important thing is access to the air. For me, I am fortunate not to have to pay for labor, so these choices are often much easier to make.

For the sake of argument, lets take the fact that someone has or doesn't have the cash out of the equation for a second:

First, the cost of the Acorn (SPW) mount is not $10k, it is $3995.

Second, if you are pulling a motor, (and lots of guys don't do this) you are required to do NDT on the engine mount. Done right, this is going to cost somewhere around $1k if nothing is wrong (more if there is an issue to fix.) Since you have to take the mount off regardless, you really can't add the labor cost into the equation. So the delta now drops to $3k.

Third, with the motor off the mount, (in most circumstances) one would be foolish not to change the mounts. Remember, the mounts may "look" ok, but they do wear out, and worn out mounts do transfer unwanted vibration. Yes the larger lord mounts are a bit more expensive, but not dramatically... Also, the prices SPW sells their "kit" for (mounts & associated hardware) is insane. All the constituent parts can be sourced for about $600-$700 less elsewhere. Also, with the engine mount off, you really should be replacing all the hardware, so we are really only concerned with the additional cost of the larger Lord mounts.

Fourth, with respect to the argument that the orig mounts "did just fine," have a conversation with Paul at Acorn. He will tell you that aprox 80-90% of the mounts that they take in as exchanges have a deficit of one manner or another.

And fifth, the smoothness. There is no doubt that the larger mounts make for a smoother ride.

Of course there are substantive arguments against buying the SPW mount, but they are fewer. The $3500 delta is a big pill to swallow, especially on the heels of the new engine etc... Also, the SPW mount indeed does weigh more. I dont have the figure, but I am just about to pull my stock mount on my 180H, so I will weigh both.

In the end, the Pponk STC is a nice option for Skywagon owners because it offers a great power upgrade for the same cost as rebuilding a stock motor with zero modifications to the airplane. This is a good thing. That said, there are upgrades that can be done to make the Pponk STC even better.

In the end, its up to the owner which way to go, and there no wrong choices...

I’ve had a Pponk O-520 on my airplane(1962 180E) for 15 years; on the original mount. (Removed, inspected at the time)

About 5 years with a 2-blade C66, 10 with a 3-blade 401; both very smooth, the 401 slightly more so.

One other thing to consider is the weight of the new mount, especially if you’re replacing an early mount without vertical members.

Thumbs up on the muffler without cones. We took our cones out per a Cessna SB. Every little bit helps.

Bigrenna wrote:I should add that the main reason I went with the new engine mount wasn't just because of smoothness, its the build quality. A quick side by side glance is all you have to do to see which one will serve you better over the years. Yes the orig mount did just fine, but technology has improved a bit in the past 70 years and it's hard not to admit that the more robust design and exacting fabrication techniques wont be the better choice.

The fact is that the STC does not "require" you to make any changes, so "technically" you don't have to do anything... but the price consideration is surly one that cant be avoided. When the conversation becomes about $$$, its hard to criticize anyone's choice one way or another as the most important thing is access to the air. For me, I am fortunate not to have to pay for labor, so these choices are often much easier to make.

For the sake of argument, lets take the fact that someone has or doesn't have the cash out of the equation for a second:

First, the cost of the Acorn (SPW) mount is not $10k, it is $3995.

Second, if you are pulling a motor, (and lots of guys don't do this) you are required to do NDT on the engine mount. Done right, this is going to cost somewhere around $1k if nothing is wrong (more if there is an issue to fix.) Since you have to take the mount off regardless, you really can't add the labor cost into the equation. So the delta now drops to $3k.

Third, with the motor off the mount, (in most circumstances) one would be foolish not to change the mounts. Remember, the mounts may "look" ok, but they do wear out, and worn out mounts do transfer unwanted vibration. Yes the larger lord mounts are a bit more expensive, but not dramatically... Also, the prices SPW sells their "kit" for (mounts & associated hardware) is insane. All the constituent parts can be sourced for about $600-$700 less elsewhere. Also, with the engine mount off, you really should be replacing all the hardware, so we are really only concerned with the additional cost of the larger Lord mounts.

Fourth, with respect to the argument that the orig mounts "did just fine," have a conversation with Paul at Acorn. He will tell you that aprox 80-90% of the mounts that they take in as exchanges have a deficit of one manner or another.

And fifth, the smoothness. There is no doubt that the larger mounts make for a smoother ride.

Of course there are substantive arguments against buying the SPW mount, but they are fewer. The $3500 delta is a big pill to swallow, especially on the heels of the new engine etc... Also, the SPW mount indeed does weigh more. I dont have the figure, but I am just about to pull my stock mount on my 180H, so I will weigh both.

In the end, the Pponk STC is a nice option for Skywagon owners because it offers a great power upgrade for the same cost as rebuilding a stock motor with zero modifications to the airplane. This is a good thing. That said, there are upgrades that can be done to make the Pponk STC even better.

In the end, its up to the owner which way to go, and there no wrong choices...

Excellent summary!

hotrod180 wrote:I was gonna suggest that they ask Knopp about his mount recommendations. You beat me to it.

I have, and I know his suggestion that the stock mount is fine. That doesn’t mean a new mount isn’t better though.

As a side note, my 53 C180 was upgraded to a 470K many years ago.
Probably to save money, they changed the mount attachments on the K engine case & stuck with the original A/J engine mount.

Rob wrote:And yes, you are correct. Ditch the A/J legs. A K engine can have late legs with a half breed mount on an early airframe....way better having your engine sitting on rubber as opposed to having the rubber upright with the lugs running through it.

I never even considered that the original engine (K or J I think) would have had different mounts than the L in there now. The L engine is certainly sitting on the rubber mounts directly, not hung sideways. Sounds like I may have a newer mount than original anyway? I'll have to try and find a part number.

Bigrenna wrote:First, the cost of the Acorn (SPW) mount is not $10k, it is $3995.

Second, if you are pulling a motor, (and lots of guys don't do this) you are required to do NDT on the engine mount. Done right, this is going to cost somewhere around $1k if nothing is wrong (more if there is an issue to fix.) Since you have to take the mount off regardless, you really can't add the labor cost into the equation. So the delta now drops to $3k.

Third, with the motor off the mount, (in most circumstances) one would be foolish not to change the mounts. Remember, the mounts may "look" ok, but they do wear out, and worn out mounts do transfer unwanted vibration.

The *mount* is $3995. However SPW (which Acorn is now) states that a different exhaust is required with their mount due to fitment, and my earlier airframe requires additional bits to move heating components, so the total bill from them is about $10k. If it was just a $4k mount that would be an easy decision.

Regarding the Lord mounts, I already replaced those earlier this year so they’re basically new. I could resell them as barely-used if I change the engine mount though, so I won’t eat too much on that other than the labor I spent to replace them.

colopilot wrote:....I never even considered that the original engine (K or J I think) would have had different mounts than the L in there now. The L engine is certainly sitting on the rubber mounts directly, not hung sideways. Sounds like I may have a newer mount than original anyway? I'll have to try and find a part number.....

The rubber mounts may have been revised somewhat through the years for the later engines,
but the old-style vertical rubbers were only used for the A&J engines
The C180 got the 470-K engine and the improved rubber mount arrangement in 1956.

I believe the C182 started right off in 1956 with the 470-L --
Basically the same as the K but with a slightly different intake arrangement,
required due to the nosewheel set-up interfering with the K style intake.

FWIW the O-470 TCDS says "O-470-L is same as O-470-K except for relocated carburetor and revised intake manifold oil sump".

.

An old but relevant post ;

Rob
03-19-2012, 01:04 AM
What year is the 180. You can use either an early mount or later mount. With an early mount you will need to change the legs because the pads (lords) are on a different plane. But you can still use the rest of the engine mount. With the early set up the engine is essentially hanging on rubber, with the later style it is resting on top of rubber.
The more critical piece will be which intake / airbox you have, as this will dictate which mount exactly you need. The latest mounts have the fwd cross member on the opposite side of the intake. Fwd instead of aft.
If you have one of the earliest 180s '53-'55 and want to take advantage of the later style mount, you will want to look for a 'K' mount. It has the late style pads / legs, but the fwd cross member is on the correct side of the intake. This is a single year engine mount, but I believe AWI has the jig to build one from any reasonable core. This mount also works with the dual mufflers (even the large after market set up). If you want pics of this arrangement send me a PM.

Take care, Rob

Big, your numbers are good, and in your case your choice is solid. I have used AWI and Acorn both, and have been very satisfied with both. I had a good understanding of where the $10K figure came from, because I have been down this path, I just didn't relate it well. I also suggested AWI, because I know firsthand that they have a pretty good handle on the issues associated with mix and matching early and late model airframe, mounts, and engines. In Retrospect Acorn probably does as well.

Take care, Rob

I've been running the original A/J legs on my original 54 with the K engine since 1995. Have been through several sets when they sag out but have noticed since getting rid of the original really heavy Hartzell, then 88 inch Mac, the 2 blade MT is lighter and they don't seem to be sagging after quite a few years. I think I remember seeing the older Helio Couriers had a similar style mount leg for the GO 480 engine install. If I were to change, I would go all out and get SPW mount with the monster Lord Mounts. Probably get a new composite cowl from Selkirk and get the latest airbox design and Acorn exhaust.

Bigrenna please site the FAR, AC and paragraph, or Cessna maintenance manual paragraph which requires the engine mount to be NDT tested any time an engine is removed from the mount. Otherwise it is just your opinion or that of someone who told you. As for most 180/185/182 mounts needing tubes replaced it is most often due to corrosion related to the close location of the tubes to the exhaust and the associated high temperatures the tubes are exposed to. Heat shields and corrosion control (touch up painting) will help with that problem.

Tim