[ringoism]

Mine might not quite qualify in many minds as "old-school" (2001 Marshal DI 4x4 NGCS), but the idea is the same: How to best quieten diesel clatter and drivetrain noise in a crude, spartan, unrefined traditional Jeep body / interior. I plan to do some long drives with family / friends from Manali to various places in Ladakh, Spiti, Lahaul, etc, and would prefer to not be deaf by the time we arrive back. What have forum members used and how have been the results? I saw a thread elsewhere in team-bhp related to dampening materials for audio systems, but not sure if these are applicable / practical towards this purpose. We don't have a lot available up here in Manali, but I do get to Delhi occasionally if someone knows of sources there.

Regards,
Erik

[GTO]

Damping, damping and more damping. The best you can do is heavily insulate the cabin, and the area around the engine (bonnet, firewall etc.). But even then, a Marshal DI will never be satisfying from the NVH point of view. Then, because of the limited power on tap, the old-school engine also runs at too high an rpm on the highway (deafening sound + drone).

Here's some threads to get your started:

Damping external sound

Tata Safari : Reducing noise

Noise cancellation?

Reducing Car Noise

[DirtyDan]

You can use pieces of old carpet under the hood. Glue them in place after making sure they are not touching something hot or covering something your mech needs to access.

You can lay pieces of carpet on the floor of your interior. This way, when it comes to cleaning you can just remove the carpet pieces and wash the interior and clean the carpet(s) separately. If you hang, or glue, fabric on metal interiors you may make your interior hard to clean and hard to rid yourself of the dust you will pick up on the road to Leh and other places. A fabric interior roof should be possible, though, and not too expensive. I got this done for my Invader. The whole cloth interior was done after market by a shop. It did not cost too much but I don't know the exact price because it was packaged with some other mods. I opted for a brown/beige color that would mask the dirt. It deadens the sound a bit.

Earplugs are another option.

[ringoism]

Have driven a number of older Jeeps (540, Commander, Armadas) and just bought a Marshal DI 4x4. DI vs. Peugeot debates aside, I have found them all more or less distinctly, reverberatingly noisy and am hoping for some slight relief, at least, for my tinnitus. The only existing team-bhp thread I saw was more related to Audio system performance, and I'm more interested, I guess, in how engine / drivetrain noise passes into and bounces around in Jeep interiors and what various members have done to reduce it.

Many Thanks,
Erik

[honeybee]

The only thing I could suggest is add layers of insulation on the floor. There's hardly any other place where you could use it, anyways.

[dhanushs]

What I have done and found effective.

• Cover the firewall both from the engine side and cabin side, with sound insulating material.
• Cover all the holes which lead wires into the cabin. I mean use proper bushes, or Thermocol. Try to insulate cabin from engine bay as much as possible
• Make sure the Gear Box sheild, and nearby areas have proper beadings, and if possible use insulation below the beading.
• Also, use proper boots for GB and TC, it will reduce the whining sound a lot.
• Use lubrication and grease liberally to avoid squeaks.

After which use lot of mats on the floor!



Still, I guess as DD suggested, ear plugs will be a better option.

[ringoism]

Originally Posted by GTO

even then, a Marshal DI will never be satisfying from the NVH point of view. Then, because of the limited power on tap, the old-school engine also runs at too high an rpm on the highway (deafening sound + drone). ]

Tata Safari : Reducing noise

[/url]

If a Safari is loud, he'd die in any Jeep...

Well, I hope and pray I will eventually be able to find some level of satisfaction... FYI (GTO) I was strongly tempted to go for a locally available '99 Armada 4x4, where an XD3P conversion would've been easy and made for a smoother / more powerful car, besides being a lot cheaper to buy / build (didn't feel that any XD4.9P's I drove offered any NVH advantage vs. the DI). But no good used XD3Ps are available here; also Armadas have even lower gears (5.38 vs. 4.28:1?) and 4x4 5-speeds seem nearly impossible to source for the Peugeot setups. More importantly, with the cold up here in Manali, batteries go bad in 1-2 years on the Peugeot "heater" (engines), sometimes they don't start at all (a French ex-pat I know has a well-maintained one-owner '95 Armada and says if you want to head out before 10AM in the winter (assuming it's sunny), you'd better go down and run it for awhile the evening before). Then there's the 2kpl. advantage, significant these days. Amazingly, Himachalees consider the Peugeot-based M&M's a "failure". I could've bought an XD4.9P Commander for 1/3rd the price of the Marshal DI. Maybe I erred, let's see. The newer Turbo DI's seem even louder, and they're using them in new Boleros, which a lot of people do manage to use for long-distance travel. In my case, I am unlikely to see a real highway more than maybe once a year (if even that much). I'm going to keep my eyes open for a suitable 5-speed gearbox, though, as I see some of the local 4x4 DI Bolero Campers using.

Some of this will be subjective, I suppose. My long-haul experience till now has been mainly Scorpio / Qualis / Sumo IDI. I rode a few hours south in a friend's Marshal DI a few weeks back and spent time behind the wheel. Not too sluggish on the hills. It was on the noisy side, but then again, he didn't have any boots on his gear levers!

I do have some good earplugs that a friend who's into guns gave me. Trouble is my wife gets mad when I don't respond to her voice And I've got to know when my baby is making noise - 'cause when he's quiet, it means he's getting into trouble.

I'll look into purpose-made soundproofing mats. Can I find them somewhere in Delhi?

Many Thanks for everyone's inputs,
Erik

[ringoism]

Originally Posted by DirtyDan

You can use pieces of old carpet under the hood. Glue them in place after making sure they are not touching something hot or covering something your mech needs to access.

You can lay pieces of carpet on the floor of your interior. I opted for a brown/beige color that would mask the dirt. It deadens the sound a bit.

Your interior looks great in "dirt tone". I'm definitely going to look for some of that.

Fortunately I am (mostly) my own mechanic

[honeybee]

Originally Posted by dhanushs

• Cover all the holes which lead wires into the cabin. I mean use proper bushes, or Thermocol. Try to insulate cabin from engine bay as much as possible

Wouldn't using thermocol be bad from a fire perspective? Will it be able to take the heat generated in the engine compartment? IMO it should be avoided, though it looks tempting.

Originally Posted by ringoism

... and 4x4 5-speeds seem nearly impossible to source for the Peugeot setups. .... In my case, I am unlikely to see a real highway more than maybe once a year (if even that much).

Sorry if I am being ignorant here, but I think you may not need a 5-speed gearbox after all, if you aren't driving on the highways as much.

Alternatively check out ADC's travelogue of Arunachal Pradesh. He reports that people there just discard their vehicles after an accident, instead of getting them repaired and claiming insurance. He has also reported meeting a chap who deals in such vehicles, i.e. procure such 'scrapped' vehicles and sell them for parts. Maybe you can get lucky?

[rakchow]

What about water rention and subsequent rust...IIRC GTo had all floor mats of his Classic removed on delivery cause they retain water and act as a rust accelerator.

[ringoism]

Originally Posted by rakchow

What about water rention and subsequent rust...IIRC GTo had all floor mats of his Classic removed on delivery cause they retain water and act as a rust accelerator.

That's right. It's normal to see otherwise rust-free vehicles with rotted out floorpans on account of the rubber floor mats. I've owned a couple. Cars with carpets have relatively fewer problems, though if carpets aren't removable, even they can hold quite a lot of dampness. I suppose that if the damping sheets are applied well enough that no water can get between them and the sheetmetal (which I suppose is ideally how it should be), there would be no problems.

In the sound deadener thread (ICE forum) I found that these dense purpose-made deadening materials seem to be oriented mainly towards dealing with low frequencies (i.e., bass), and that foam and other materials are somewhat effective for higher frequencies. So I'm wondering where the most offensive components of diesel clatter fall in the frequency range.

[ringoism]

Originally Posted by honeybee

Wouldn't using thermocol be bad from a fire perspective? Will it be able to take the heat generated in the engine compartment? IMO it should be avoided, though it looks tempting.



Sorry if I am being ignorant here, but I think you may not need a 5-speed gearbox after all, if you aren't driving on the highways as much.

Alternatively check out ADC's travelogue of Arunachal Pradesh. He reports that people there just discard their vehicles after an accident, instead of getting them repaired and claiming insurance. He has also reported meeting a chap who deals in such vehicles, i.e. procure such 'scrapped' vehicles and sell them for parts. Maybe you can get lucky?

Yeah, 5-speed definitely optional. There's a little problem with 2nd gear my the KMT90 (pops into neutral on deceleration). Easy enough to rebuild, but just figured if a 5-spd turned up it would be better for noise and mileage and etc, and I'd have less dread of traveling to places with long, straight highways like Rajastan (just a dream at this point).

I don't think Thermocol can spontaneously combust at typical underhood temperatures. If you had an engine fire already underway, of course it would burn - but that's not as common with diesel-powered vehicles. If in doubt, check out the MSDS (material safety data sheet) for any similar U.S. product, which would provide such info (mind you, we call it "styrofoam" over there).

Will check into Arunachal parts supplies. Planning to be in the Northeast for several weeks this winter. Saw nice hardtop Invaders in Aizawal earlier - looked like maybe police units awaiting disposal.

[condor]

Originally Posted by ringoism

I don't think Thermocol can spontaneously combust at typical underhood temperatures.

I dont think @Dhanush said you can use Thermocol in the hood area. It is more logical to use it inside the cabin - below the carpets or inside roof lining.

[Desmosedici]

Originally Posted by condor

I dont think @Dhanush said you can use Thermocol in the hood area. It is more logical to use it inside the cabin - below the carpets or inside roof lining.

+1 to that. My recently purchased Gypsy has thermocol pasted onto the floor and the inside of the hardtop. Does a great job to keep the heat out and an average job of keeping the sound out.

[Live To Jive]

Use Heatlon and foil for the firewall and bonnet. Tighten all bolts, replace worn out bushes etc. All these contribute to amplifying the engine noise. If all fails the only option is a pair of Bose noise cancelling headphones for each occupant.