<VV> LM turbos and no lower shrouds
Eric S. Eberhard
flash at vicsmba.com
Tue Oct 25 15:57:17 EDT 2011
My point! You don't buy a Corvair for speed, not any more, they are for fun. E
At 10:52 AM 10/25/2011, Ron wrote:
>If your definition of fun is just stomping on it, have your joy with
>a Corvette!
>RonH
>
>----- Original Message ----- From: <jvhroberts at aol.com>
>To: <flash at vicsmba.com>; <carlton55 at comcast.net>
>Cc: <virtualvairs at corvair.org>
>Sent: Tuesday, October 25, 2011 3:30 AM
>Subject: Re: <VV> LM turbos and no lower shrouds
>
>
>>
>>Also not to get into a war...
>>
>>Marine engines are overcooled all the time, but look at their
>>cooling source! As such, not particularly applicable to an air
>>cooled engine!! :)
>>
>>Corvair engines aren't water pumpers, no matter how much SOME
>>people want to spray water all over and into them!! <G>
>>
>>In my experience, overcooling a Corvair engine is just about
>>impossible. And yes, mine had all the seals in place around the engine, etc.
>>
>>Design parameters assumes things were designed for the intended
>>application. Given that the 80 through 180 HP Corvairs have
>>essentially the same cooling system, I have little doubt the
>>cooling system was designed based on cost. GM simply figured if
>>they didn't overheat to destruction while cruising, that's fine.
>>They didn't really care beyond that, where obviously I do! ALL
>>Corvairs, if driven hard (and if you have a 140, a turbo, or just
>>like having fun, why wouldn't you?) will run hotter than ideal, often by a lot.
>>
>>So, yeah, there's room for improvement. A LOT of room for improvement.
>>
>>
>>
>>John Roberts
>>
>>
>>
>>
>>-----Original Message-----
>>From: Eric S. Eberhard <flash at vicsmba.com>
>>To: Carlton Smith <carlton55 at comcast.net>
>>Cc: virtualvairs <virtualvairs at corvair.org>
>>Sent: Mon, Oct 24, 2011 9:01 pm
>>Subject: Re: <VV> LM turbos and no lower shrouds
>>
>>
>>Carlton,
>>
>>You are most welcome. See my response to Mr. Roberts who disagrees
>>and is knowledgeable and well respected. In this case I think he is
>>wrong, and more than wrong. What many people consider "stock
>>cooling" is not stock cooling. You can't have a lot of extra holes
>>in your firewall. You must have proper seals all around the
>>engine. The bellows must function properly including proper
>>adjustment and making sure they are good. And my caveat is "close
>>to stock car" -- meaning a 300hp 3 liter dual triple Weber monster is
>>a different can of worms. A built turbo with Weber and and big
>>pistons and big turbo, another can of worms. When you do a lot of
>>mods, you start changing everything ... and unless you know how to
>>engineer that ... for example if you put a Weber on and do nothing
>>else my guess is you will knock. So you slowly start going down the
>>road of one mod leads to another. And in the end, perhaps, the stock
>>cooling fails. My cars are all stock Corvair with the exception of
>>ignition system (I hate points and setting the dwell, just lazy) and
>>my coupe also uses the 260 cam (bet money that has no affect on
>>heat). Oh yeah -- making sure those vanes are clear and the jugs are
>>not packed with grease ... that is important.
>>
>>The car was designed to run at those temps, that is correct, and I
>>would not assume that "cooler is better" and maybe that is why you
>>get a different answer from me than Mr. Roberts. I am not say it is
>>not cooler without the shrouds. What I am saying is that a stock
>>engine will run within design parameters under any driving condition
>>(speed or outside temp) with a stock cooling system -- no matter how
>>spirited you are.
>>
>>If you run cooler and warm-ups take longer, you likely are cause WAY
>>MORE WEAR than driving it at temp. Have you ever wondered why people
>>ask when looking at a used car "city miles or highway miles" or why
>>almost all diesels are left on when drivers go into store, truck
>>stops, eat dinner, whatever? Answer -- starting a car is like
>>driving 100 miles. Starting a COLD car is like driving 1000
>>miles. That is because oil drains off the engine parts and when you
>>first start it is a little
>>dry.
>>And it is so much worse if cold and allowed to run cold, the oil is
>>NOT circulating well. Which, BTW, is why you need sure to make sure
>>you use an oil that has enough ZDDP (zinc etc). Like Mobil 1 15-50
>>(note each mfg most oils do not have enough zinc, but usually they
>>have something with enough zinc -- not all Mobil 1 has enough). You
>>can use Clarks zinc additive although I don't trust that as much as
>>an oil made right to start with. In fact, for long term wear on your
>>engine your oil choice is crucial. I hope you did not break in that
>>new engine with dinosaur oil that did not have the zinc ... hard on the cam!
>>
>>What I am saying is when not driving in a spirited way, just toodling
>>along, you may be running so cold that the oil is NOT doing it's job,
>>the oil is thicker, and you may be harming your engine more. It was
>>designed around the stock cooling system and you cannot be hurt going
>>that way. However, when you go down modification road ... unless you
>>are very knowledgeable, one problem can lead to another or you could
>>have unintended consequences (particularly in this case from running
>>too cold). You can actually contribute to building up sludge in your
>>engine. That happens when temps are not high enough and I would
>>suspect that when you take the shrouds off you could easily be
>>running oil temp that are WAY too low. You need something like
>>200-220 oil temps. Oddly I have one car that has cylinder head and
>>oil temp gauges (my toy) ... when oil temps hit 270-280 cylinder head
>>temps are 425+ ... this is a good place as this is about max (any
>>more and the stock temp idiot light goes nuts). Cylinder head temps
>>are way more volatile than oil temps (e.g. it takes forever to get
>>oil temps up or down, cylinder temps change almost instantly from
>>super hot to cool). I would guess that if you are running 300-325 on
>>the freeway that your oil temps could easily be in the 200-220 range
>>-- meaning probably TOO COLD. http://www.synlube.com/sludge.htm
>>(note they recommend synthetic as I do, with zinc!!!!!!).
>>
>>So my recommend is still, run it stock assuming it runs within stock
>>parameters, use good oil, and a good ignition system.
>>
>>I should point that I have heard of stock manifolds cracking from
>>getting real hot and then zooming through a puddle of cold water. I
>>suspect it is a minor risk, but real.
>>
>>So that I don't get in a war with Mr. Roberts whom I usually agree
>>with -- I agree it runs cooler without shrouds. But it cools
>>CORRECTLY with the shrouds and maintains the engineered
>>tempuratures. It is possible to run too cold as well as too
>>hot. Otherwise there would not be thermostats in water cooled
>>cars. Engines are designed to operate within a specific temperature
>>RANGE for optimum efficiency. A properly functioning cooling system
>>with the correct heat RANGE is absolutely essential for good fuel
>>economy and performance as well as prevention of sludge buildup in
>>oil passages and the heads. A thermostat that causes the engine to
>>run too cold can experience up to a two mpg loss in fuel economy ...
>>
>>Here is a posting on running too cool an
>>engine:
>>http://www.sailnet.com/forums/atomic-4/53480-will-running-cold-cause-engine-damage.html
>>
>>I believe it is still better in all ways stock, due to exposing the
>>engine, possible cracks, running colder than you should. I think you
>>could compare it to removing the thermostat in a conventional
>>car. It would be slow and hard to warm up, and run too cold at
>>times. If you know exactly what you are doing and want to fiddle
>>with it, fine. Otherwise, stock works. It is a matter of do you
>>trust the original engineers to make a system that is best most of
>>the time, or do you want to try and do better and take the risk of
>>doing worse?
>>
>>Eric
>>
>>
>>
>>At 04:02 AM 10/23/2011, you wrote:
>>>Hi Eric,
>>>
>>>Thanks for your opinion. I am seeking those with experience and you have
>>>shared yours.
>>>
>>>I have owned my particular 1965 turbo Corsa since 2007. The previous owner
>>>had rebuilt the engine in 2000. It was totally stock with the exception of a
>>>Clark's 260 cam. On the highway in the Midwest if I went over 65MPH for any
>>>length of time on a 75-80 degree day the head temp would reach 425-450
>>>degrees (the gage is accurate as I have a infrared temp gun). The engine
>>>always had a couple of (loud) clacky valves that were lifter/cam oriented. I
>>>decided to have the engine rebuilt last winter by a professional Corvair
>>>mechanic. The engine was totally rebuilt stock, head veins cleared as much
>>>as possible, correct valve geometry restored, etc. We discovered the bad
>>>Clarks cam grind on 2 lobes is what was causing the 2 clacky valves and
>>>replaced it with an Isky cam of the same 260 spec. (I checked with others
>>>and found they also had problems (on occasion) with this particular Clarks
>>>cam). Anyway I now have normal quiet engine now. However, with the shrouds
>>>on I still would go to 425-450 degrees on long distance highway traveling.
>>>So I decided to try the shrouds off option and it usually travels at 300-325
>>>degrees and on a hot day might go to 350. I am told by may turbo owners and
>>>the folks at Clarks that the shrouds on temperatures are absolutely normal
>>>for a turbo. Also that those temperatures will eventually shorten the life
>>>of the engine as compared to a standard engine. I drive the car every day in
>>>the summer and garage it in the winter. I drive it as long as I can every
>>>year so that does involve fall and spring days in the upper 30s and 40s. I
>>>can still get heat in the cab from the upper shroud hose so that is ok with
>>>me. However, I don't like having the bottom of the engine exposed all of the
>>>time to possible road debris (rocks, etc.). I am a little worried about the
>>>start up/warm up factor although it seems it warms up fairly quickly. So you
>>>can see I am already at the point of making a possible mod decision. I am
>>>interested to know what John Roberts is suggesting.
>>>
>>> Thanks for your input Eric!
>>>
>>> Regards,
>>> Carlton Smith
>>>
>>>
>>>
>>>-----Original Message-----
>>>From: virtualvairs-bounces at corvair.org
>>>[mailto:virtualvairs-bounces at corvair.org] On Behalf Of Eric S. Eberhard
>>>Sent: Sunday, October 23, 2011 2:29 AM
>>>To: virtualvairs at corvair.org
>>>Subject: <VV> LM turbos and no lower shrouds
>>>
>>>
>>>
>>>I am always puzzled by this discussion which comes up every so
>>>often. The car was designed well from the factory. If you have
>>>everything correct -- all the shrouds as well as seals and so forth,
>>>there is no better system. I am in AZ, totally bone-stock, at
>>>altitude (3500-8000 feet), summer temps of 110 ... and I NEVER have
>>>even gotten remotely close to overheating. Our speed limit is 75 and
>>>I can go up a 6% grade at 80, no over heating. From my 3500 to 7500
>>>feet happens in 6 miles, no overheat even at 80.
>>>
>>>I believe that those that overheat and think they need to
>>>remove/modify shrouds simply have other problem they are compensating
>>>for. Mine is a 62 EM and perhaps it is different, but I have had to
>>>EM turbos as well and neither ever had a heating problem.
>>>And we get 20 degrees in the winter, so having those shrouds on then
>>>is crucial and I don't need the hassle of swapping them on and off.
>>>
>>>One writer pointed out the correct heat is required for quick
>>>boost. Correct. Some people even wrap their exhaust to push temp
>>>even higher, for that reason. Some people mistakenly use a "free
>>>flowing" muffler which actually reduces boost and is bad. I used an
>>>NOS turbo muffler.
>>>
>>>Keep it stock and it will be absolutely reliable (my only mods are
>>>electronic ignition and related upgrades).
>>>
>>>If you have heating problems -- are your plugs too hot? I use Nology
>>>Silverstone plugs and they perform very well with a 38 gap and hot
>>>ignition, no overheating. They are made for vintage cars. They are
>>>expensive, but I have over 30k on them and they are clean as a whistle.
>>>
>>>BTW -- opinions are like belly buttons and so I have one. I respect
>>>others, as other people have done neat things. I am not a good
>>>enough amateur mechanic to re-engineer things. But I believe a
>>>properly set up stock system -- not all that hard to achieve -- is
>>>going to be reliable. Doing the ignition and putting a Judson on one
>>>of my cars is sort of the limit of my explorations. However, my
>>>Spyder always has instant boost (no lag), boosts at 2000 rpm in 4th,
>>>pulls to redline, and I can't overheat it.
>>>
>>>So if you are in the mood, you might try making it factory spec
>>>first, seeing how that goes, and then modify. Otherwise, you might
>>>mask a problem that later gets ugly.
>>>
>>>Eric
>>>
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>>> _______________________________________________
>>
>>
>>Eric S. Eberhard
>>(928) 567-3727 Voice
>>(928) 567-6122 Fax
>>(928) 301-7537 Cell
>>
>>Vertical Integrated Computer Systems, LLC
>>Metropolis Support, LLC
>>
>>For Metropolis support and VICS MBA Support!!!! http://www.vicsmba.com
>>
>>For pictures: http://www.vicsmba.com/ourpics/index.html
>>
>>(You can see why we love this state :-) )
>>
>>_______________________________________________
>>This message was sent by the VirtualVairs mailing list, all
>>copyrights are the
>>property
>>of the writer, please attribute properly. For help,
>>mailto:vv-help at corvair.org
>>This list sponsored by the Corvair Society of America,
>>http://www.corvair.org/
>>Post messages to: VirtualVairs at corvair.org
>>Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
>>_______________________________________________
>>
>>
>>_______________________________________________
>>This message was sent by the VirtualVairs mailing list, all
>>copyrights are the property
>>of the writer, please attribute properly. For help,
>>mailto:vv-help at corvair.org
>>This list sponsored by the Corvair Society of America,
>>http://www.corvair.org/
>>Post messages to: VirtualVairs at corvair.org
>>Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs
>>_______________________________________________
>
Eric S. Eberhard
(928) 567-3727 Voice
(928) 567-6122 Fax
(928) 301-7537 Cell
Vertical Integrated Computer Systems, LLC
Metropolis Support, LLC
For Metropolis support and VICS MBA Support!!!! http://www.vicsmba.com
For pictures: http://www.vicsmba.com/ourpics/index.html
(You can see why we love this state :-) )
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