Insulation under the engine sheet metal!?!

[zonker]

Greetings - new to the DAF world and today I adjusted the valves, carburetor, and ignition timing on my DAF 46 for the first time.

To my surprise, I found insulation has been placed all around the engine's cylinder head and piston barrels under the cooling fan sheet metal. Is that supposed to be there? I'm baffled (as is my DAF lol). 

Is this factory normal? Or did some previous owner have a bright idea that the car needs a blanket? It looks OEM but I cannot for the life of me think that this is good for the motor.

Looking forward to your input...  

[andrew]

Oct 2, 2019 4:49:40 GMT zonker said:

Greetings - new to the DAF world and today I adjusted the valves, carburetor, and ignition timing on my DAF 46 for the first time.

To my surprise, I found insulation has been placed all around the engine's cylinder head and piston barrels under the cooling fan sheet metal. Is that supposed to be there?. 

Is this factory normal?

Looking forward to your input...  

I would suggest it isn't! Air cooled Dafs need a good flow of air over the cylinder barrels to prevent over-heating and the insulation you have found would prevent that. I suspect a previous owner, in a misguided attempt to make the engine quieter, has fitted some sound insulation around the engine. I'd suggest you remove it before driving the car again. You'll also notice that the cylinder barrels are finned, to give a greater surface area to the flow of air, again to assist cooling. It might be worth brushing the fins, to ensure all the insulation material has been removed.  

[zonker]

Thanks! I am of the same opinion - but the person did such a good job cutting out the shapes that fit under the tin that it had me thinking it may have been factory correct!  

[joe]

Hello, this is factory my 46 is exactly the same. It’s sound deadening rather than heat insulation. I will take a photo to show you later. The sheet metal cowling channels the air from the fan at the front which means the engine relies on this fan pushing fast moving air rather than outside air passing over the fins.

I think, but I’m not 100% certain, Porsche 911s have a similar arrangement.

[zonker]

Oct 10, 2019 18:50:34 GMT joe said:

Hello, this is factory my 46 is exactly the same. It’s sound deadening rather than heat insulation. I will take a photo to show you later. The sheet metal cowling channels the air from the fan at the front which means the engine relies on this fan pushing fast moving air rather than outside air passing over the fins.

I think, but I’m not 100% certain, Porsche 911s have a similar arrangement.

Seems to me it inhibits the airflow from the cooling fan since the insulation is there. Only air that appears to be able to get to the head is between the fin cavities. It gets hot here in the summer (110 deg F) and am worried that this will impede the amount of air needed to keep it cool. Plus it seems that since only certain areas of the barrel and head have the insulation, you can create hot spots by uneven cooling. 

If DAF did it as factory equipment, I wonder if that was because the cooling system was designed to be for cooler Scandinavian type climates? Did they ever sell this car into Africa? Or the Middle East? Perhaps if they did, those models might have been without insulation.

[andrejuan]

Oct 10, 2019 18:50:34 GMT joe said:

Hello, this is factory my 46 is exactly the same. It’s sound deadening rather than heat insulation. I will take a photo to show you later. The sheet metal cowling channels the air from the fan at the front which means the engine relies on this fan pushing fast moving air rather than outside air passing over the fins.

I think, but I’m not 100% certain, Porsche 911s have a similar arrangement.

You are quite right Joe, I have also noticed it. I did post a comment earlier but for some reason it never appeared?

[dafix]

Hi,

I have checked out the engine of my DAF 46: same thing, the space between each cylinder and the housing of the cooling system is stuffed with a kind of black wool. I just hope it does not contain any asbestos . I don't see any mention of it in my workshop manual. I assume it was installed by the DAF factory for good reasons (acoustic insulation might be the reason) and it has a texture that allows the air from the impeller to flow around the fins of the cylinders.

[andrew]

Ah ha! I think I see a pattern emerging here.... I WAS going to ask if this sound insulating material should not also have been fitted to Daf 33 cars, then I realised that the 3 contributors to this thread who HAVE found it all drive Daf 46 (NOT 44) cars. I'm now of the opinion that this might, just night, have been a Volvo inspired addition. Remember, Daf 46 cars were built by Daf, but under licence from Volvo. 46s had 12 fuses (44s had 8) as well as low brake fluid & choke warning lights, all very Volvoesque, so maybe this Volvo influence extended further, perhaps into the engine bay....

None of our favourite cars have been sold for over 40 years, and we're STILL discovering things we didn't know about them-fascinating!

By the way, if this stuff works for Daf 46s it would presumably work for Daf 33s as well.... Any adea what it is & where I could find some?

[andrejuan]

Oct 15, 2019 15:13:20 GMT andrew said:

Ah ha! I think I see a pattern emerging here.... I WAS going to ask if this sound insulating material should not also have been fitted to Daf 33 cars, then I realised that the 3 contributors to this thread who HAVE found it all drive Daf 46 (NOT 44) cars. I'm now of the opinion that this might, just night, have been a Volvo inspired addition. Remember, Daf 46 cars were built by Daf, but under licence from Volvo. 46s had 12 fuses (44s had 8) as well as low brake fluid & choke warning lights, all very Volvoesque, so maybe this Volvo influence extended further, perhaps into the engine bay....

None of our favourite cars have been sold for over 40 years, and we're STILL discovering things we didn't know about them-fascinating!

By the way, if this stuff works for Daf 46s it would presumably work for Daf 33s as well.... Any adea what it is & where I could find some?

This is interesting Andrew and you may be onto something. I first noticed this insulation material on my Bergina 44, I assumed it was on all models and maybe I had just missed it. That car however is quiet when driven (compared to other 44s I have driven), I always put that down to it being well cared for, not so, it simply has sound insulation. This is the thing though, it's a late model "P" reg. Volvo design changes were already appearing by this time, hence the mystery of "some have it some don't"

[Nick the man with a daf....]

as Joe said its factory, it's purpose apart from noise reduction is to seal the very tops of the fins so the air is forced to go through the channels of the fins rather than just over the top, i had one set of cowlings where it had been removed and the engine was never quiet with them fitted, trust the daf engineers they knew their engines, if it's original it looks almost like a brown hessian sort of material

[Nick the man with a daf....]

just looked and my 1972 daf 44 ago has the material in its cowlings

[starider]

Hi,the definitive answer,the material should be there,it was standard on all air cooled Daf engines as far back as I can remember; so don't remove it!If you do the rattle is horrendous.............starider

[andrew]

Does anyone know if this stuff is commercially available under a trade name? I'd try it in my 33, but want to know I'm fitting the correct stuff!

[Nick the man with a daf....]

the red estate i bought from kidderminster had had its insulation replaced with axminster carpet !!!

[gromsound]

yes gentlemen, this is factory spec and the dafs were always tested before production started in any climate including the sinai desert and above the polar circle. this explains too why an aircooled daf is so much quiter than a 2CV/Dyane/AMI with similar arrangements - minus the sound deadening. i know firsthand, got both of them.

The stuff is rather dense, fibrous and about 3-4 mm thick.

OVLOV did not want to have anything to do with the 46 that is why it was never rebranded and quietly faded away, probably to get rid of the enormous stock of 2cylinder engines. however they did ''redesign'' the 66, which was only just acceptable to the tank buiders. small wonder it lasted until 1981.
they were after all only in it for the P900/daf77 (V343).

[andrew]

I must confess to never having removed the cowling around my 33's engine, so I don't know what, if anything, is in there..... Given the clips that keep the cowling in place hold things together pretty tightly, I'm curious to see how there would be enough clearance for the sound insulation and an allowance for the air to passover the fins to keep everything cooled. Am I missing anything?

[gromsound]

like someone said before: >> is to seal the very tops of the fins so the air is forced to go through the channels of the fins rather than just over the top,<< they are not completely sealed all around the perimeter, the air is driven around them by the radial turbine from the front and leaves at the back somewhere. i seem to remember that my 33 also had felt lining. soaked in engine oil of course...

now it's on electrons, it makes no noise whatsoever and certainly spills no oil :-)

[Nick the man with a daf....]

without the material the cowlings never sit tight and rattle about all over the place

[bobdisk]

There was no lining on my 33 when I dismantled the engine. I dont think previous owner did anything to the engine, so I dont think there ever was.

[andrew]

Dec 8, 2019 13:14:12 GMT andrew said:

I must confess to never having removed the cowling around my 33's engine, so I don't know what, if anything, is in there..... Given the clips that keep the cowling in place hold things together pretty tightly, I'm curious to see how there would be enough clearance for the sound insulation and an allowance for the air to passover the fins to keep everything cooled. Am I missing anything?

I appreciate this thread is somewhat "dated", but it's funny how things come around again! I'm intrigued about this insulation material, but an extensive rummage through the Daf 33 parts list I have makes no mention of this material. In addition, there was a comment earlier in this thread to the effect that the cowlings would rattle without it, but my cowlings fit together very tightly, so I'm wondering if I'm missing something or something's missing in my engine. These random thoughts are prompted by the engine sounding "as sweet as a nut" up to 3,000 R.P.M., after which it sounds "harsh", so I am wondering about this insulating and sound deadening material and if anyone knows what it is and where it could be bought.

[starider]

The material[looks like coconut matting]was as mentioned, used to prevent resonous noise from the metal shrouds,plus it had the benefit of ensuring that the heating and cooling of the cylinders was equal all over each of the cylinders surface area.

[andrew]

This is proving very interesting..... In the absence of anything else to do (it's pouring down today and I'm conserving petrol!) I'm investigating this matter more.

Thinking about this logically I cannot believe that the cylinder heads and barrels would ever be totally wrapped in any material that would prevent the heat dissipating from them, and so therefore this material (whatever it is) should be fitted in such a way that the airflow from the fan at the front of that car is NOT restricted, but is aimed (focused) at the cylinder heads.

Those of us with air-cooled Dafs may have removed the "tinwear" around the cylinders at some point in the past. I've a set of Daf parts manuals and studying them this morning I've found these covers are called "air vent jackets", and are made up of 4 parts; 2 per cylinder, and they're all different. Remember that the off-side cylinder (driver's side in a RHD car) is set slightly back from the near-side one, so the off-side front air vent jacket is therefore slightly longer than the near-side one. The rear air vent jackets are similarly different, not only for the reason already given, but also because the near-side rear air vent jacket has a vertical opening, to pass pre-heated air to the carburettor intake in cold weather. For reasons I've yet to comprehend the design of this part changed after engines coded 74E BL, but more on this later!

What I also noted were some slots inside the air vent jackets, which would permit pieces of material to be placed underneath and above the cylinders & barrels, but not in front or behind them and the clips on the outside of the jackets would hold the material in place inside them. I've a number of diagrams taken from the Daf parts catalogue, but am unable to download them here, owing to the restrictions imposed by the Forum as to size.

I'm going to contact a V.W. Beetle spare parts company I've used before and take their advice. I also have a spare set of engine air vent jackets, with which I shall be experimenting in the future!

[andrew]

(Quick update) I spoke to "Just Kampers" of Odiham, in Hampshire, from whom I've bought many V.W. Beetle parts in the past. They've never heard of this insulating material being used in any air-cooled V.W.s, which is a problem, as I thought they might be able to shed some light on this. Investigations will continue......