How important is this drive shaft heat shield?

[Midnight_Raven]

Hey guys,

So When I purchased my NSX I told you guys that there was a weird ting ting ting sound that would occur at 2,500RPM in 4th gear. I at first thought it was my exhaust but it seems like I was wrong.

I just started cleaning the bottom side of the NSX as a pre-winter project. Since the car is up on jack stands and someone could get under the car to listen, we did a test. We pin pointed it to this item that I've highlighted in red.

It's called a COVER, HALF SHAFT HEAT on the acura parts catalog. I pulled it off to see if there is any contact points that can verify that this is the problem. It looks like there is some scoring to the metal so I'm going to assume this is the culprit. I tried to bend this piece but it's very hard. Do you guys think that leaving this off would be a problem? Or could this imply there is something wrong with the half shaft assy #15 in the diagram.

 

[Larry Bastanza]

Pic??

The heat shield will play a role in the longevity of the CV grease in that joint. If exposed to more heat the grease will break down sooner. I see this alot when headers are installed, and even with that shield the grease breaks down sooner, then with the stock exhaust with heat shields.

What is it scraping on? Is it the boot clamp? Also are you sure the bearing for the shaft is good? Maybe wobbling?

Regards,
LarryB

 

[Midnight_Raven]

That's what I'm thinking maybe the bearing for the half shaft is starting to go. Although it's just being held up by two screws and the part is 20 years old. I wonder if it's just warped a bit and now vibrates more at a certain frequency.

I'll take a picture of the part tomorrow.

 

[pgilliam1]

The shield on my 1991 is solid as a rock. No vibration or looseness to it. Maybe one of your bolts are stripped? If your shaft was loose enough to contact the shield (unless the shield is bent or loose) it would be making all sorts of bad noises.

 

[Midnight_Raven]

The shield on my 1991 is solid as a rock. No vibration or looseness to it. Maybe one of your bolts are stripped? If your shaft was loose enough to contact the shield (unless the shield is bent or loose) it would be making all sorts of bad noises.

While inspecting it I got a feeling that the shield has a slight inward bend that could be causing it to just barely tap into the drive shaft. It could be my imagination though. The shield itself is like yours, solid as a rock. I was surprised how hard this thing was when attempting to bend it a little. I guess Honda engineers didn't mess around with this heat shield design lol. The hardware was good when I pulled it off. The car doesn't make any other strange noises while I drive besides that "ting" noise at specifically 2,500 RPM in 4th gear and very rarely it'll happen when moderately accelerate past 3,000 RPM in 3rd gear.

 

[Midnight_Raven]

So I looked it over again and took some pictures. During my second more careful inspection I found a dent in the shield. I wonder if this is what is making the initial hit and causing the rest of the scoring to occur. Although the scoring starts before the dent so maybe that's not it.

Bad picture of dent circled in red.

Picture of scoring circled in red.

 

[pgilliam1]

That scoring looks about where the boot clamp would be. Where the OEM boot clamp is cinched it is almost flat. Did someone put a aftermarket clamp on the boot?

 

[Midnight_Raven]

Final update on the situation. I was finally able to look at the axle while the motor was running at that 2,500RMP in 4th. The axle doesn't look to be wobbling. When I removed the plate I remembered I had removed 2screws but it looks like the heat shield takes 3. I found it odd because from under the car you can't see or feel a 3rd hole to screw into. Well when I looked from the side it appears that there is a hose with a bracket that this screw should thread through. But the bracket hole was no aligned with the heat shields 3rd hole. The scoring was near that end of the heat shield so I'm assuming this is what was the problem. Since I didn't want to mess with the bracket I just ended up bending the piece away from the shaft. Test drove it today and the "ting ting ting" noise is gone.