Engine shock mounts

[PTK]

I don't plan on an engine any time soon, knock on wood, but I was wondering. Is it ever necessary to change the engine shock mounts (before engine) much like we change the gear pucks? 

[Cris]

The short answer is yes. It depends on age and condition but they can sometimes be shimmed to bring them back into specs. Check around your cowl prop hub to see if the distance is the same. Typically the engine sags and begins to come close to the bottom of the cowl. It can effect the performance. 

[PTK]

Thanks Cris! I don't have any sagging but was looking for an excuse to swap them and finish and paint the mount like Byron! Came out really nice!

[aviatoreb]

Quote: allsmiles

I don't plan on an engine any time soon, knock on wood, but I was wondering. Is it ever necessary to change the engine shock mounts (before engine) much like we change the gear pucks? 

[jetdriven]

Quote: allsmiles

Thanks Cris! I don't have any sagging but was looking for an excuse to swap them and finish and paint the mount like Byron! Came out really nice!

[aviatoreb]

Quote: jetdriven

 

Note it is about 30-40 hours labor to pull the engine and mount off the firewall and reinstall. Only worthwhile to do when doing an engine change.

 

We flew it the first 3 hours today. Runs really smooth.  However, I am calculating a 153 KTAS speed wth everything full forward. This is around 8-9 knots slower than our last air race.

[jetdriven]

It takes 5 hours to get the engine into the mount and bolted up. 

[Sabremech]

Byron, the mounts can be changed in a couple of hours. Hook up the engine hoist and then loosen all four mounts. Lower the engine hoist enough to remove and replace upper mounts. Tighten upper mounts, but not all the way. Now raise the engine hoist and remove and replace the lower mounts. Tighten and torque all four mounts. Remove engine hoist and you are done with the mounts. I did have to grind on a wrench to fit the upper left mount because of the pushrod tube. It isn't hard at all and I highly recommend changing them versus shimming them. If you are going to shim them, why not replace them as they are already worn? Also a good time to start with new mounts with a new engine. Just my .02.

[PTK]

I've heard or possibly read somewhere that the engine when mounted sits a tad canted down and to the right (towards copilot side) to offset torque. Is this true? If so, is the mount designed with this cant built in or is the engine shimmed in this position?

[rbridges]

we changed mine b/c of a sag.  It had been 15 years since OH, so I had them replaced.  It turned out that one was perforated.  I would have never known without removing it.  I went back and had the thinner shims added to both lower mounts at my last annual to raise my prop up 1/4".  I did notice that it has a slight cant toward the copilot side--very slight, but I'm not planning on changing that.

[jetdriven]

Quote: Sabremech

Byron, the mounts can be changed in a couple of hours. Hook up the engine hoist and then loosen all four mounts. Lower the engine hoist enough to remove and replace upper mounts. Tighten upper mounts, but not all the way. Now raise the engine hoist and remove and replace the lower mounts. Tighten and torque all four mounts. Remove engine hoist and you are done with the mounts. I did have to grind on a wrench to fit the upper left mount because of the pushrod tube. It isn't hard at all and I highly recommend changing them versus shimming them. If you are going to shim them, why not replace them as they are already worn? Also a good time to start with new mounts with a new engine. Just my .02.

[N601RX]

Quote: jetdriven

It takes 5 hours to get the engine into the mount and bolted up.