why deck lid vents

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ProMetalShop
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Re: why deck lid vents

Post by ProMetalShop » Sat Dec 24, 2016 10:20 am

Lots of great information ! !
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Clackety Clack
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Re: why deck lid vents

Post by Clackety Clack » Wed Dec 28, 2016 6:28 am

Yeah, I thoroughly enjoyed this thread. Is there a book out there that walks you through in detail Porsches design of the beetle step by step. For example why there are vents in the deck lid, why he chose this over that etc....love to read it if it exists.

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Re: why deck lid vents

Post by tattooed_pariah » Fri Aug 10, 2018 11:45 am

FJCamper wrote: The metal rain tray that sat under the decklid of 70 models was also discontinued when dual ports started as it obstructed the air flow.
I've seen a lot of people fit those to later cars scared of a little water on their engine.
Holy ancient thread batman!

My 1972 beetle had a rain tray when I bought it back in 2002.. but I was younger and dumber back then, and didn't think I'd ever be living outside of California, so I took it out and threw it away..

Fast forward to about 3 weekends ago.. I live in Maryland now and we had some really bad rain storms.. While sitting parked for the weekend, I got about 3/4 a cup of water in #1 cylinder.. my only speculation is rain came in the louvers, soaked into the air filters (dual IDFs) and pooled in the air filter bases before dripping down the intakes under the velocity stacks (no gasket under the stacks..)

I went ahead and drilled some tiny drain holes int he bases, and put gaskets under the stacks and also bought a new rain tray.

I put the tray in last night, and driving to work this morning, CHT's were about 20-30 degrees F hotter than without the rain tray. so it DEFINITELY obstructs airflow.. but I don't want to get stranded with a flooded engine, so I'm gonna keep it and see what I can do to bring in more airflow.. right now I'm thinking of the standoff that raises the bottom of the decklid further from the apron..
-pariah

"I never trust a fighting man who doesn't smoke or drink or at least cause a little trouble." -Admiral William Frederick Halsey Jr.

1972 VolksRod Build Thread

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FJCamper
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Re: why deck lid vents

Post by FJCamper » Fri Aug 10, 2018 7:51 pm

Hi Pariah,

You need Porsche style "rain hats" for the Webers.

The stock air filters do absorb water like crazy when they can. Get yourself a couple of enameled loaf pans that, fitted upside down, cover the top half of the filter. Find a way to bolt them down so they are suspended over the filter for air flow.

It works.

FJC

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Re: why deck lid vents

Post by Ol'fogasaurus » Fri Aug 10, 2018 7:56 pm

FJCamper wrote:
Fri Aug 10, 2018 7:51 pm
Hi Pariah,

You need Porsche style "rain hats" for the Webers.

The stock air filters do absorb water like crazy when they can. Get yourself a couple of enameled loaf pans that, fitted upside down, cover the top half of the filter. Find a way to bolt them down so they are suspended over the filter for air flow.

It works.

FJC
Now that is do-it-yourself enginuity! Impressed FJ 8)

Lee

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Piledriver
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Re: why deck lid vents

Post by Piledriver » Fri Aug 10, 2018 11:11 pm

Bakers Secret loaf pans rock.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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Re: why deck lid vents

Post by saggs » Wed Aug 15, 2018 5:05 am

Good thread, with all this being said do you think I should add some fresh air in through the front firewall tin of my T4 powered 56 oval? There isn't a lot of slots on this model. Havent tried propping the decklid open at the top or bottom yet to see if there's a difference? My CHT is around 350 at 65-70 mph.

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Re: why deck lid vents

Post by aussiebug » Wed Aug 15, 2018 10:57 pm

350cht is about as hot as you'd want to get.

The early bugs with solid lids and doghouse engines WILL run short of cooling at at higher speeds as the larger fan just can't pull the required amount of cooling air through the under window slots. Try cracking the engine lid open at the bottom and see what happens to your temps. This will (I expect) demonstrate the need for extra cooling slots. A cabrio lid, a standoff licence plate with a slightly smaller hole behind it, or slots grafted into your lid. Any of those will help.
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Rob
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Re: why deck lid vents

Post by saggs » Fri Aug 17, 2018 7:44 pm

good info, I will try propping the lid open this weekend.

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Re: why deck lid vents

Post by tattooed_pariah » Fri Aug 17, 2018 10:13 pm

I haven't done much.. I don't leave the house too often, mostly just daily driving to/from work, and it seems like mid afternoon (1530ish) cruising at about 70-80mph, #2 is getting to about 315F, #3 gets to about 290F and #1 and #4 go between 250 and 270F, so I'm concerned, but not overly concerned..

and if you're wondering why #2 is my hottest cylinder, my best guess is because I don't have the forward (bellhousing) cooling tin, or the rear-most cooling tin in place right now, I need to buy new ones and make em fit.. so I'm guessing the exhaust heat is hitting #2 the most because that's where my header merges and the muffler begins..
-pariah

"I never trust a fighting man who doesn't smoke or drink or at least cause a little trouble." -Admiral William Frederick Halsey Jr.

1972 VolksRod Build Thread

Bruce.m
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Re: why deck lid vents

Post by Bruce.m » Sat Aug 18, 2018 10:50 am

What!

Running an aircooled engine without a full set of well fitting cooling tinwear causes overheating.

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