WallyP

I doubt that the stock hood liner is "just foam rubber", since I have serious doubts that most standard foam would last fifteen years exposed to 200 deg F, oil, fuel vapors, etc.

The hood liners rarely "fall apart" - they are usually blasted apart by high-pressure water or air as owners try to clean them.

Greg86andahalf

Wally,

When I bought my car, mine appeared to have "Dried up" to dust and began flaking off.

dr bob

Seems like the exposure that the car has in its history is an important factor too. The liner in my car is still in good shape, hasn't suffered (yet) from compressed air, pressure washer, oil or fuel vapors, etc. But it is a bit gray/tan dusty. I might try to use a small vacuum cleaner with the dusting brush attachment and see if that does much good.

Home Depot (one of my favorite places) sells a foil-faced insulation that would do the trick nicely except that it doesn't look at all like the original foam. I've seen a few cars (Tony Harkin's is a good well-documented example) with the shiny stuff and it looks fine. Trying to remember if it's diamond-embossed, think it is. I have that insulation on the inside of the garage door. Maybe worth a look if you are thinking about a foil substitute. I have part of a roll left over if anyone in the L.A area needs a piece to try.


On a related note-- the pressure washer might be the ideal tool for removing deteriorated foam without much scraping. Plastic sheet covering the fenders and engine, and a minute or two with the water blaster would make this a quick step. Just a thought!

Cheers!

Thom1

Hi Guys,

Thanks for the praise Randy. Sorry, but I have been touching base infrequently lately. In the spirit of high speed adventure, I just spent 10 days skiing the French Alps. Since then, I have been catching up around here.

My hood liner came from 928 Int'l. Seems like it was about $70. They are usually fantastic in everything they do. However, they cut their own foam from OEM stock. I told Mark Anderson that they cut it off center. I returned the first one, but the second one was also cut aligned to the side of the hood, not the leading edge. Therefore, it was a challenge to fit. Fortunately, they cut it oversized. There was enough material to trim it to fit. Since I was visiting family over Thanksgiving, I had time to do it right. I removed the hood, and placed it upside down on a pad. I then went a couple of rounds with Mequire’s cleaner wax on the under hood paint. A little bit of touch-up paint came in handy, too. A shop vac and mineral spirits cleaned the residual foam remnants. I trimmed tiny slivers of the new foam as I positioned the foam in the hood before it ever saw adhesive. I flared the edges to slide under the ribs. I used a spray 3M adhesive on the trailing edge of the hood and foam. I then pressed the surfaces together, and glued that bit of foam into place. I trimmed and glued in a rolling manner of 4 or 5 steps toward the leading edge.

To reinstall the hood: Never close the hood all the way until the male post aligns really well with the female latch. Otherwise, you must get under the car, and grab the hood cable at the latch to release it. (The edge of the spring catches the latch edge, and gets stuck when misaligned.)

I obtained some scrap material to finish the front area, too. It should be another 12 years before that foam gets sucked into the intakes. It gives it a finished look. One of my young nephews commented that it looked Porsche when done. That is important.


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Jay Wellwood

In my case, my foam had degraded to the point it was crumbly.

I (being the purist Nuclear worker), decided that not only was removal of the foam required, but also all of the previous adhesive as well.

Spent about 10 minutes removing the original foam (used a sheet to cover the engine compartment), and about another 3 hours removing all of the old adhesive with solvent.

Afterwards, installing the foam took about 20 minutes or so. Needed a spare set of hands to control the application....but it turned out well. No trimming or other issues.

Can't really complain about the longevity of the orignal foam - sheesh - after 15 years in that environment, I'd probably be due for replacement too!

All in all, best bang for the buck in improving the engine compartment appearance IMHO.

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Tony

Hi Dr Bob...for the record i took that silver/foil stuff off. The OEM stuff looks so much better now, especially new! The main reason i took the silver stuff off was HEAT! all it was doing was keeping more heat in the engine bay. IMHO the original OEM foam liner was there for nosie, not heat. I dont think heat damage under your hood is an issue. Heck, the rest of the engine bay is painted, no issues to be seen there?
Grab an egg and Ill show ya hot my hood gets just parked in the vegas sun, engine not running! Way hotter than under the hood! I did keep the insulation on my airbox and intakke tubes however. It made a marked difference on my intake temps when idling and stopped at a light....at speed however, heat transfer isnt really a player on the tubes as the air travels so quickly through them, the air really doesnt have the time to go up in temp like it does when the car is stopped and at an idle. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Thom1

Hi Sharks,

Here is a more detailed photo of the hood liners. The front piece also came from 928 Intl. I am not sure if it is 928 OEM, maybe a different year. Anybody recognize that pattern? I only covered up the vacuum diagram because the hood is from a different year than the engine.


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Randy V

Who knew there was so much to discuss about hood liners!

It seems to me that I have seen different foam types used for this application. There is the OEM type that has a grid pattern, like on the large area of Thom's car, then there is the 'egg crate' type, similar in appearance to the forward smaller area on Thom's car.

On my '79, both areas were covered in the 'grid' type (now crumbly and ugly).

I think I may have a preference for the appearance of the 'egg crate' type. Any ideas where I could get the large and small area liners in that type material?

Tony

hmmm when you go to get the car smogged, arent they going to want to see your vac diagram and emssions stuff on the sticker under that front piece of foam?

Jerry 87 928S4

Throm. First of all the Engine looks Fantastic.

I also replaced my hood liner last year and got it from 928 intl. It did not fit right either. I struggled for a long time and figured I was doing something wrong.

I installed it without trimming it and so it does not look perfect.
Just figured that it had to made right coming from Porsche. I have thought a few times about replacing it as that is all I can do now that it is glued.
Didn't know that they made it - sure which I had <img src="graemlins/soapbox.gif" border="0" alt="[soapbox]" />

Thanks for the post!

Porsche928Driver

I'm going to add my 2 cents...

I ordered a roll of silver foiled insulation blanket from JC Whitney to replace the foam in my hood. Only $28 for a 6'x4' roll. Cut it to shape and used spray adhesive.

Looks good actually and insulates well. I was amazed that not one auto parts store sold anything and the price for some of the insulators at the parts counters at the dealerships was a joke!

dshulik

Its been awhile since anybody discussed this but I have a new liner from 928 Intl. and have removed the old crumbling liner. There's still some old adhesive however. I'm ready to tackle the old adhesive but now wondering if replacing the insulation really matters or not. Noise is not an issue with me, I'm only concerned about heat damaging the paint. It seems the hood was hot as a frying pan even before I removed the insulation. Any thoughts on just leaving it w/out the insulation?

Randy V

Hey Dave - the hood liner topic returns <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> !

There's no need to remove the old adhesive residue - just scrape away any loose areas and wipe down with lacquer thinner to establish a solid base for the new liner.

My opinion - the hood liner gives the engine compartment a finished look, in addition to protecting the hood from heat:

Thom1

Hi Dave and other Sharks:

I thought I would put together a hood essentials document. Hope this helps with liner installation.
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HOOD ESSENTIALS:

HOOD SHOCK REPLACEMENT:

Prop or tape a broom or stick under the high edge of the hood. Put a dense pillow, folded carpet scrap, pad, etc. behind the trailing edge of a hood sharp corner. Tape a pad or rag around the sharp trailing edge corner. Put your replacement shock where you can install it with your free hand. Loosen the 2 clips on one shock only with a little screwdriver. Grip that side of the lid because it will move during the next step. Pull the shock off of its ball joints. Replace one shock at a time. Just push each socket over the corresponding ball. Repeat on the other shock. The thick canister of each shock is higher than the thin rod.

HOOD REMOVAL AND INSTALLATION:

See above padding and support data. Disconnect upper hood shock clips. Loosen all 4 upper hinge bolts. Have a friend to remove bolts while holding hood, as you remove the 2 bolts on your side. Lift hood away. Reverse procedure for installation.

HOOD ALIGNMENT:

Never close hood completely unless male and female portions of latch are matched up pretty well. If you get the hood stuck closed, reach up through the front grill. Grab the hood release cable right where it goes into the latch, and pull. If necessary, push on the pointy cone shaped thing that goes through the latch hole to center it while pulling the release cable.

If the hood was previously aligned correctly, and you are removing and re-installing the hood, align using only the 4 hinge bolts at the hood interface: See padding and support instructions above. Before hood removal mark the position of the hinges with a chalk or grease pencil for future reference. Upon hood installation, tighten one side. Get the bolts almost tight on the other side. Push the hood around on that loose side until you think it is close. Tighten those bolts. Gently lower hood, and check alignment at edges and latch. Repeat procedures on both sides through as many iterations as it takes. You can push the hood way down onto the hinge by pushing on the hood with one hand, and tightening bolts with a ratchet socket wrench in the other hand.

Rear height is controlled mainly by hinge adjustment. Front height is controlled by turning the threaded male post of the latch.

If the hood was misaligned before, or you have trouble getting it aligned, remove the upper portion of the latch, align with the hinges, replace the upper latch portion.

You may want to adjust the rubber bumpers for non-interference, and readjust them after alignment is complete.

HOOD LINER PREPARATION & REPLACEMENT:

I did the initial hood prep with the hood on the car. When it gets to the step of prepping with KleanStrip PrepAll, Remove the hood. Overspray and poor adhesion can result from working with the hood overhead. You have practically no overspray when you work with the hood off.

Preparation is everything. Applying adhesive or paint is potentially the simplest part of the job. Cleaning, masking, and final prep are essential. Touch-up paint, clean, and wax the hood ribs before you install the liner. I used 3M Super 77 adhesive on my 928 International supplied OEM? – who knows - hood liner. After 8 months, it looks as fantastic as anything I have ever done with restoration – no sags! In preparation, I vacuumed off the old liner residue. I cleaned the heck out of the hood at the self service car wash with a high pressure wand. I washed and rinsed several times.

I removed the hood. I vacuumed all loose residue out of there, and cleaned that inside surface with KleanStrip PrepAll. ( It removes wax, etc.) I set the liner in place, and very, very carefully trimmed the liner, flaring the edges to fit under the lip multiple times. When I was totally satisfied with the way the liner sat in the hood, I sprayed the adhesive on the hood about in 6” strips. I very carefully placed the trailing edge of the liner in its adhesive prepped place. I kept the liner rolled back until I shot the next 6” of adhesive mainly on the hood, and some on the liner. I carefully monitored the orientation. I then rolled the liner forward a few inches. I then repeated the adhesive process until I rolled the liner to the front. I also trimmed some more as the liner rolled forward. Use 3M adhesive cleaner or Turpentine for clean-up.
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