I just had a new idea for how to quiet the cab down a bit. I get a lot of engine noise through the dash, and although I don't mind it it gets really old if I'm on the freeway for a couple of hours. So I was thinking about putting some Dynamat or something similar on the valve covers to see if it works. I'd also put some on the underside of the aluminum cover piece. I was also thinking the oil pan since a lot of noise comes through it but little oil seeps would make the adhesive obsolete. I've seen those fancy blankets out there, but that is a LOT of coin for those! I'm hoping this nets me some sort of gain. Do you guys think it would be effective? Anybody ever do this? I'll probably get around to it this weekend, I'll be sure to report back with results.

 

IMHO, every little bit helps. The bottom side of the hood, and firewall would be good places to put some more sound dampening into as well!

Chris

 

Yeah, I'd like to get some more insulation on the firewall, after 13 years the stuff on there now is pretty beat up.

 

From what I have read, the oil pan is also a worthy target for sound insulating.

Jim

 

I haven't done anything on the valve cover as the stuff I was using for sound deadening would probably fall back off with the heat it is subjected to. But it is true that most of the motor noise is heard from the top and bottom of the motor. I actually used some inch thick aluminum foiled foam on my oil pan, it was partially to keep the oil warmer longer in the winter, and partially for noise reductions.

I was thinking one of those stainless mats for over top of the valve covers and over the exhaust manifold, figured it should help lower the underhood temperatures at the least.

 

Did you notice any difference when you did the oil pan? I still haven't gotten around to doing mine, we're currently repainting one of the company trucks....

 

Honestly, the difference of doing the oil pan was very minimal. I don't think the sound deadening I've done to the truck so far really accomplished that much. I've got a double layer on the roof, double floor, double back wall with triple corners, and single front door panels. Just as long as most of the sound comes out of the exhaust and I don't have any interior drone I'm fine with it. I was pleasantly surprised after towing a trailer down to NC and back I wasn't sick of hearing turbo whine or partially deafened so it isn't horrible.

 

If you can overcome the adhesive issues the only other draw back would be the heat retention in the engine. I would think that stuff would hold the heat in the engine.

 

I wouldn't worry about it holding heat in, if anything that should help in the winter. Motors are designed to be cooled solely by fluids, surely Cummins wouldn't count on heat dissipation from the block. For example, look at the same 5.9L Cummins motor in a 2.5yd loader, it doesn't move fast enough to dissipate heat without a radiator or fan and I'm sure the motor is crammed in there tight.

 

What kind of deadener did you use? I hear there are better options than dyna-mat now, like the B-Quiet and hush mat stuff.

 

Stuff (Gutter Guard) from Home Depot Racing. It helped, no doubt, but I guess I was expecting more. The stuff sticks unbelievably well.