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Previous Next Up Topic Engines / Corvair Power / Use lower engine shrouds in a buggy? (13884 hits)
By Anthony M 1559 Date 2009-06-08 16:01
I'm wondering if other Corvair-powered buggy owners keep the lower engine shrouds on their buggies (the ones with the thermostat-controlled doors).  It seems to me that they are for air cooling when the engine was mounted in the Corvair body, but in a buggy you could just run without them. 
By Jay H (X-20) (ManxVair CC) Date 2009-06-08 19:30
If I remember correctly, the thermostat controls a damper that open to allow air to pass through the oil cooler. I believe without the lower tins, you won't have air directed through the oil cooler.

I suppose you could mount an external oil cooler probably with no adverse affects.

Hopefully some other Corvair guys can confirm.

Jay
By Anthony M 1559 Date 2009-06-09 14:17
It appears to me that the air for the oil cooler comes from air directed by the upper shroud - the one with the fan.  I've never seen anyone run the engine without this.  But the lower shrouds seem to manage the flow of hot air - air that comes off the head.  I've been looking at some pics of Corvair-powered buggies, and it does look like some cars aren't using the lower shrouds.
By Darryl B 967 Date 2009-07-17 04:40
I Run a buggy and a sand rail. Both no lower sheet metal. I've been everywhere in the buggy. The lower tin was to help warm up the engine in winter. After it warms up the dampners open the engine will not overheat. That and it helps warm air for the passenger compartment faster in winter.

I built custom tin on the bell housing "side" of the motor to keep the air running around the end cylinders. But nothing under.

Darryl
By the 'Maniac Date 2009-07-25 04:32
On a buggy, you do not use the lower shrouds on a Corvair engine, unless you are trying to run some sort of a heater. Other than that, it saves about 20 lbs!!!
By Bob E 1463 Date 2009-11-25 18:22
I run without them and feel this is correct for a buggy without any heat.
Boston Bob E.
www.bimelliott.com - www.deserterownergroup.org - www.the-bug-club.com
By ManxRob Date 2009-11-25 18:59 Edited 2009-11-25 19:04
First, I must point out that I live/drive the buggy in the Northwest. Even running through the desert in eastern WA, the temperatures are rarely over 100.

I run my buggy with full stock cooling tins for several reasons:

1) The lower shrouds act as a lite duty skid plate to keep from banging the Corvair exhaust clamps which are otherwise pretty exposed. This buggy doesn't go off-road.

2) The thermistatic operation of the doors helps to get the engine up to operating temperatures quicker. Ive heard that most engine wear is during the 'warmup cycle'.

3) I have plans (dreams?) of hooking up the heat in my buggy if I ever get a top and curtains first.

I have heard that the cylinder head temperature can be lowered about 50 deg by removing the lower tins in warm weather. I have a working cylinder head temp gage. The hottest I've seen the gage go (full throttle over 4000 foot pass) was 400 degrees, so I have not needed the extra cooling.

Rob

By Rick M 333 Date 2011-03-04 02:07
Hey Rob,
Do you have any photos of your lower shrouds and your headers? I'm starting to fit headers to my engine and would like to retain as much of the shroud as possible.

Rick
By ManxRob Date 2011-03-04 06:53
Rick

Here are a few shots of how I did the cooling tins around the buggy headers. It's been several years since I performed that work. I do remember that due to the shapes of the stock shrouds and the different curvatures of each header pipe it was labor intensive to clearance the shrouds to clear the headers without 'excessive' gaps. I tried to keep the clearance between shroud and header tube about 1/8 inch. I used (2) original Corvair shrouds to make each side so they slip together and are held by the stock bolts. I think I also burned a pair of junk tins as rough templates. Fortunately Corvair cooling tins are not rare around here. You can see where we built up some edges that had too much gap with a weld bead:

The bottom shrouds are at the top of this shot

The slip-in side tins are at the top of this shot, the modified for headers heater boxes are at the bottom:


I had the engine tins powdercoated, and had the headers jet coated. Both coatings held up well. I was concerned that the powdercoat would burn-off and the tins would start their rusting thing if they came in contact with the hot header, thus the extreme care taken in clearancing.


Rob
By Rick M 333 Date 2011-03-04 13:18
Nice, thank you! That at least confirms what I thought I needed to do. I'm currently wrestling with having the headers actually seal well - one of my exhaust ports was/is pretty well rusted and the donut is hanging on by a thread!
By ManxRob Date 2011-03-04 16:21
I was told to use aluminum 'donut seals' rather than the stock manifold seals when installing Corvair headers. They are supposed to 'crush' a little better. The stock exhaust tubes are just pressed into the aluminum head. Although I have never done it I know they can be removed/replaced. Make sure you align the indents on installing or you won't be able to get the head off. Please don't ask me how I know.

BTW, when I replaced the buggy's rear drum brakes with discs I ran into an interference with the right header/caliper. The brake upgrade won, I'm back to using a custom exhaust based on the stock Corvair logs
By Rick M 333 Date 2011-03-04 20:54
:-) Yeah, I've got the graphite donuts. The main issue I'm facing at the moment is that the header wants to rock outwards when I mount it with the standard nut and stud arrangement. I'm going to have to try to weld a little 'lip' on the ends of the flanges to get the tubes to push up straight and back towards the engine, sort of mimicking the factory log setup. The factory manual has the exhaust tubes being removed after the heads are heated to 250 and re-inserted by cooling the tubes in dry ice, and heating the heads back to 250.... I think I'll wait on that for the moment unless I absolutely have to do it!
By Jay H (X-20) (ManxVair CC) Date 2011-03-07 23:53
Rob, those look familiar! :-)

I'm in Texas or I would have shot some photos of the parts. Glad you posted up!

Jay
Previous Next Up Topic Engines / Corvair Power / Use lower engine shrouds in a buggy? (13884 hits)

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