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engine tins
Posted by: redrocket ()
Date: July 30, 2022 05:22PM

has anyone run a street car without the back and side tins? the heater tins have been removed but the top tin is still installed.

Re: engine tins
Date: July 30, 2022 05:42PM

by "tins" you must mean "shrouds"

They are there for a reason when a Corvair engine is installed in a "normal" car.

Many have removed the lower shrouds with the regulator flaps in areas that experience NO cold weather, but When GM was developing the Corvair engine for use in all climates and production vehicles - the designed and installed everything you see on a stock Corvair engine.


Dan Davis ~ Pierce County, WA ~ CCF admin ~
CORSA +Corvairs NW + North Cascades Corvairs + Corvanatics
1966 Corsa Turbo coupe ~ ~ 1966 Corsa 140 Coupe ~ ~ 1965 Monza 140/4 Convertible Sierra Tan/Fawn ~ 1964 Monza Spyder Convertible ~ 1960 Monza Ermine White/Red PG ++ ~ 1965 Monza 140/4 CoupeEvening Orchid w/ ivory/black interior ~ 1962 Monza Wagon 102/4 ~ 1963 Rampside/Scamper ~ 1963 Red/Greenbrier ~ 1969 Ultra Van #468

Re: engine tins
Posted by: cnicol ()
Date: July 30, 2022 08:15PM

redrocket Wrote:
-------------------------------------------------------
> has anyone run a street car without the back and side tins? the heater tins have been removed but the top tin is still installed.

Well, there are two basic things about an air cooled engine: 1) They require cool air and 2) The fan has to develop pressure above the heads and cylinders to force air through.

We'll cover the "pressure" part first. To develop pressure the top shroud can't have major air leaks (spark plug grommets, dip stick grommet, closed airflow at the heater hose by cylinder number five).

Also, to develop pressure the four vertical tins (left heater, right heater, distributor, and oil cooler) must also be in place. Those four tins plus a sealed top shroud allow the fan to develop pressure over the engine and push air through the heads and cylinders. Any large holes or missing vertical tins bleed off almost all pressure so cylinder head temperature soars.

Now, let's cover the "cool air" part. The engine fan creates substantial "vacuum" at its inlet. This should be no surprise because it flows up to 1800 cubic feet per minute.

As designed, the top-side of the engine is isolated from the lower side so the fan inlet can only draw cool air from the engine compartment louvers. Below the perimeter shrouds we find the hot exhaust system and the 200-400F cooling system exhaust. Without the perimeter shrouds, the fan pulls-in super-heated cooling air and exhaust heat. In certain conditions, the fan also pulls-in actual exhaust (poisonous) and puts exhaust directly into the cabin heater. Because heater seals leak notoriously, this puts carbon monoxide into the cabin.

Rather than "helping cooling", removal of the perimeter shrouds causes the engine to run much hotter, shortening its life and increasing odds of a dropped valve seat which is usually a catastrophic failure. That plus the 'exhaust gasses in the cabin' problem.

There is no benefit to running without perimeter sheet metal, only negatives which are either expensive or deadly. It's just a bad idea.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Re: engine tins
Posted by: redrocket ()
Date: July 31, 2022 06:09PM

Thank you for this info. Now the fun begins to find the missing parts.

Re: engine tins
Posted by: American Mel ()
Date: July 31, 2022 06:16PM

Easy to acquire parts.
Create a signature line telling us WHERE you are, and what YEAR, and MODEL Corvair you own.
If you are on the East side of the Country, you've got Clark's and Corvair Ranch.
West Coast has California Corvairs, and Davemotohead.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

Re: engine tins
Posted by: irfgt ()
Date: August 01, 2022 02:33AM

Explain how dune buggies survive then.

Re: engine tins
Posted by: Lane66m ()
Date: August 01, 2022 03:03AM

I wonder if dune buggie engines survive 60k miles? Hmmmmm.

Re: engine tins
Posted by: NMCarNut ()
Date: August 01, 2022 05:38AM

Simple. If you removed the engine lid, fenders, and rear panel from your car to allow unrestricted surrounding air to the fan similar as a dune buggy then the rear and side shrouds probably would also serve little purpose.



irfgt Wrote:
-------------------------------------------------------
> Explain how dune buggies survive then.

Re: engine tins
Posted by: cnicol ()
Date: August 01, 2022 05:51AM

irfgt Wrote:
-------------------------------------------------------
> Explain how dune buggies survive then.

Craig replies: Dune buggies survive because the engine load is a fraction of what they have to provide for a road car.
Maybe 1/3?


Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Re: engine tins
Posted by: Wagon Master ()
Date: August 01, 2022 06:52AM

You can say that again!

Been aircooled since 1973
Northwest Ohio 45840

Re: engine tins
Posted by: wittsend ()
Date: August 01, 2022 08:26AM

This darned Chromatic Encryption is making it hard to decipher the message. smiling smiley Where is my Enigma machine. confused smiley

------------------------------------------------------------------------------

***'61 Lakewood, a "Freebie" in hibernation for 27 years - In the process of applying CPR.***



Edited 1 time(s). Last edit at 08/01/2022 08:28AM by wittsend.

Re: engine tins
Posted by: cnicol ()
Date: August 01, 2022 08:41AM

cnicol Wrote:
-------------------------------------------------------
> irfgt Wrote:
> -------------------------------------------------------
> > Explain how dune buggies survive then.
>
> Craig replies: Dune buggies survive because the engine load is a fraction of what they have to provide for a road car.
> Maybe 1/3?


______________________________________________________________________________

Craig replies (again, this time readable): Dune buggies survive because the engine load is a fraction of what they have to provide for a road car.
Maybe 1/3?

Sorry about the "chromatic encryption" (great phrase by the way). The unreadable green (33FF00) is next to the very readable blue (0000FF) and I selected it by accident. Sorry


Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Re: engine tins
Posted by: Timothy Shortle ()
Date: August 01, 2022 08:53AM

I believe every engine tin (cooling system shroud) should be in place for the cooling system to operate properly. J M O (and also the engineers).

Re: engine tins
Posted by: steve c goodman ()
Date: August 01, 2022 09:25AM

Another reason that air cooled rear engine cars including Corvair?VW/Porsche have shrouding to separate 'above cool air intake by fan' from 'below engine heat' is the engine in the car is trapped in a box. The sides of the fenders trap the hot air underneath and without the shrouds would be drawn back into the cooling fan. The heat from the sides and rear of the engine is being held below the cooling fan intake. In the case of the Corvair the exhaust is at the sides of the engine too and since heat rises there must be that separation.

In the case of buggy/baja bug installations the engine is completely open in the breeze so hot air simply goes away. Again no matter which engine is being used.

Kit cars that have enclosed engine bay such as my Amante GT as well as most others (Fiberfab etc) need the shrouding to separate top from bottom in the same manner as I describe the 'engine in a box' above.

Seat ring failure is no more prominent in buggy installations using any of the engines than what it is in cars no matter if Corvair/VW/pushrod Porsche power.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

Re: engine tins
Posted by: joelsplace ()
Date: August 01, 2022 10:31AM

Unless you run your car full throttle all the time (and I know some do) then I would think a dune buggy would tend to have a much higher average load since I would think most of them are run full throttle most of the time.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

Re: engine tins
Posted by: steve c goodman ()
Date: August 01, 2022 01:13PM

joelsplace Wrote:
-------------------------------------------------------
> Unless you run your car full throttle all the time (and I know some do) then I would think a dune buggy would tend to have a much higher average load since I would think most of them are run full throttle most of the time.
---------------------------------------------

Joel it is difficult to run a maanx clone buggy on the street at full throttle. Turbo would really have its tongue hanging out. Plus my car only weighed 1300lbs.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

Re: engine tins
Posted by: joelsplace ()
Date: August 01, 2022 01:28PM

I was thinking dune buggies used as that not on the street.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

Re: engine tins
Posted by: steve c goodman ()
Date: August 01, 2022 02:21PM

Full throttle and moving will not allow much air to be trapped around the engine if engine is hanging out in the open. Plus off-road buggy usually weighs less than street buggy so engine load is less too.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC/V8 Registry

Re: engine tins
Posted by: cnicol ()
Date: August 01, 2022 02:42PM

joelsplace Wrote:
-------------------------------------------------------
> I was thinking dune buggies used as that not on the street.

Regarding throttle time, my experience with dune / off-road buggy use in California was that there was infrequent use of wide-open throttle, i.e. 30-60 seconds on a hill-climb run-up or dune. High-speed runs in sand-washes or dirt/sand roads requires very little throttle but lots of throttle "jabs". Even on the dunes at WOT the engine is still only pushing 1200 pounds or so and you're only in 2nd gear and then only for the duration of the climb. Off road is not a high-load use most of the time.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Attachments:
Re: engine tins
Posted by: irfgt ()
Date: August 02, 2022 02:13AM

If you think that air exiting the bottom of an engine at 200MPH in a car going 60 MPH down the road is going to reverse itself and reenter the fan shroud, I have a bridge I want to sell you. The only purpose of the engine sealing around the body is for cleanliness and the heater odors.

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