engine tin to body seal really necessary?

[ldj1002]

I read over on thing forum that 2 folks don't have that seal and no heating problems. I have had 1 replica that didn't have that area sealed off and no heating problem. I have saw other replica cars on vw pan and dune buggies and trikes with no seal and again no heating problems. When the fan blows the hot air over the cylinders and under the car, wouldn't you outrun that air and not be pulling the hot air back up to the fan? I just don't understand why so many cars are running with no separation between fan intake and and under the car with no overheating problems but a bug gets hot without that separation.

[79SuperVert]

If you're talking a non-stock set up, then each situation has to be evaluated on its own merits. But a stock set up benefits from the seal for two reasons that I can think of: first, because the engine compartment stays clean and free of dust and dirt from under the car; second, because you are not always going fast enough to "outrun" the hot air from under the car (such as when you are in slow traffic, for instance), and so in those situations you will want to suck in cooler air from the slots below the rear window or on the engine hood.
_________________
Central Jersey VW Society

Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt.

[ashman40]

Also, warm air is not only bad for the fan intake cooling the engine, warm air being sucked into the carb/intake raises engine temps too. This is why modern cars/trucks run air scoops from the air cleaner to the engine grill area so the engine doesn't intake warm air.
Interestingly, the heat riser hoses on the stock air cleaner takes advantage of this hot air coming off the engine to quickly heat up the engine. If it didn't work to quickly heat up the engine it wouldn't have been added as an engine warm up function.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[airschooled]

Some of it also has to do with the slip-stream effect of air passing over the car and carrying the tailpipe emissions away. Without the seal, designed airflow is interrupted and CO can make it into the heater system. ANY microscopic exhaust leak would also poison the occupants without the seal. This got so bad that car reviewers noticed it in the seventies, and VW went with a dense foam seal on the later buses around their engines. Of course the bug has the aerodynamic advantage of getting rid of gases because it's not a rectangle..

There aren't any cases where someone on the Internet can say "you will overheat if."

Most of the smart ones on here safely assume that you'll want to drive your car on the freeway in mild weather. That is not too much to ask of a car at all, but the seals and tin all contribute here. If you drive your car two miles a week to the ice cream shop and back, you might not even need any tin at all. I drove a VW around a farm last month without a fan.

Point is, over time you'll gain a situational awareness of what your car needs and wants. And the people who say "you need it!" drive their cars like cars. The people who say "you don't!" probably go to a lot of car shows, and then tell me all about their VW while they're filling up a Prius at the gas station.

Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[Bob Brugge]

Yes you need it. It is there for a reason. I replaced mine, and yes it was a bitch, but it dropped my engine bay temps at least 50 degrees. I am not a vw purist, but like I said, it is there for a reason. I drive my bug daily, weather be damned, about 20 miles each way to get to work. I wouldn't have wanted to take it on a road trip then, but I would chance it now. That slight amount of gap that I filled with the rubber let in enough hot exhaust air to overheat the car in about 50 miles.
_________________
Keep on Dubbin'!

[Joel]

Unfortunately with no coolant to boil it takes them blowing up or bursting into flames before many owner realise they were actually hot.
_________________
Quick little bug, you got a Porsche motor in that?
1974 Germanlook 1303 2.5 Suba-Beetle

[David_nc_72std]

[runamoc]

I learned a long time ago to give the Germans the benefit of the doubt. They wouldn't have put it on there if it didn't need it.
_________________
Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires

[EVfun]

[sjbartnik]

[andk5591]

Have seen replicas without proper tins and yeah they seem to be OK. BUT I wont do that with any of my cars. I have a project that I have been working on off and on and this is what I did (have since enclosed the sides, etc. It really doesnt take that much work to make the stock tin work. Some sheet metal and access to a brake is nice.

_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[sjbartnik]

[Cusser]

[airschooled]

[hitest]

All the engineering decisions did not happen by mistake. The volume of fan at variable speeds, the requirements to adequately cool and preheat an air cooled engine, the surface area of cylinder head fins, and on and on. All of this is counting on a sealed compartment to run right. A sealed compartment is the one constant in the design chain. As engine sizes increased, so did fresh air intake (decklid vents) and compartment exhaust capabilities.

Perhaps VW found or learned that type 3s expel their own compartment air well enough by drawing the intake air so remotely? The flat back design of the car would also affect how air is exchanged back there. We know they were not perfect with the type 3 however, for this I submit, the fastback...
_________________

[sjbartnik]

[JKLNHYD]