How important is this foam? (LR4 spark plug change woes)

[TrungH]

How important is it that the insulating (or vibrational?) foam on the drivers side of the spark plugs be absolutely seated in it's place? I battled that thing trying to get it back to where it started for at least an hour. It's down further than pictured (forgot to take a photo before I left it for the night) but it's not fully seated and some of the ridges are wedged between the ignition coil and that metal pipe to it's right.

Anyone have any tips or advice to getting this PoS down in it's place? The ECU box is removed (again) and while that helped, it still is constantly getting wedged

 

[scapistron]

I just never put mine back.

 

[BBLR3]

Probably there to help quiet down injector/valve train noise more than anything functional.

 

[txfromwi]

I removed mine when doing the crossover pipe project, but it went back in just fine.
I don't think it has much purpose other than vibration and sound reduction.

Maybe just cut back the bits that are hanging up?

 

[powershift]

On the drivers side of my V8 I tried pulling out the material but failed. Luckily didn't need to remove it for the rear xover. But since then I had the valve cover gaskets and spark plugs changed and its still in place so there is a way to get it in and out of there.

The piece looks like its for sound deflection purposes because that is where the 2 camshafts are plus all the valve springs, rocker arms, etc all that rotating mass makes noise, especially at say 5K RPM. It has an advanced valve-train that is still state of the art making a lot of power per liter. I was out at the offroad park yesterday and climbed the biggest hill in 4L coming up from a pit in the ground then crested up over a hill and down the other side and times like that I wanted more noise. It was a lot of fun because there were dirt bikers and RVers watching. The V8 sounds so good when it has a hard load on it in 2nd 4L climbing without spinning even with quiet exhaust.

 

[scapistron]

The fuel injectors are noisy and it is there to cut down on NVH. I run no injector covers, no main cover*, and no hood insulation.

*On some vehicles (Audi?) that foam engine cover prevents the paint on the hood from overheating.

 

[TrungH]

Thanks for the insight everyone. I wasn't sure if it was vital to insulate the ECU box or something. I ended up trimming down some of the stiff triangular portions to get it to fit in there. Figured kind of in there was better than not at all.