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Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: DaveO90s4 ()
Date: November 23, 2017 02:19AM

Hi (again) all,

Before installing my engine I fitted two new oil bypass control valves in the alternator housing - one for the oil filter and one for the oil cooler (ex Clarke's). Sure it has a remote oil filter attached with AN fittings to the original connections but the oil filter flow is as per normal.

I am intrigued to have read (somewhere) that these valves open at about 10-12 psi. Is my memory on that correct?

And doesn't that mean that at oil pressures above that oil will bypass the cooler?. If so I don't understand - no oil cooling at high revs when oil pressure is high? Surely I must be wrong.

Similarly no oil filtering at high revs when oil pressure is high? Once again I must be wrong.

(Please I am not asking about ways to circumvent the bypass valves with glued in coins etc - I just want to understand the dynamics of the stock standard system).

Once again, and as always, I appreciate any wise counsel.

Thanks

DaveO
Bne
Oz

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 03:22AM

Specify "original connections".
On a stock sealed system, there is no place to attach oil cooler connections.
Then we might be able to answer accurately
Adding a remote cooler and lines will raise back pressure enough to bypass oil through one or more of the bypass valves.
Depending where the system is broken into to attach oil cooler lines.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: DaveO90s4 ()
Date: November 23, 2017 03:33AM

Hi Dryenko,

Thanks for your reply. Much appreciated.

To clarify I am using a standard 12-plate Corvair oil cooler in the stock location. No change at all to the OEM cooler system.

It is the oil filter that is remote mounted with very short AN10 hoses. This has been done by removal of the original filter housing, tapping into the original inlet and outlet locations with AN10 fittings and mounting the filter down low at the same end of the engine (no drain back).

So in an bog standard stock engine is my understanding of how things work - as per my post above - correct? I hope not.

Cheers
Dave O

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 04:03AM

Hi Dave, Happy Thanksgiving.
I looked at your other postings about the car showing the plumbing mods.
The oil cooler bypass under the top oil filter mount must be plugged to assure all oil goes through the filter.
I understand they can bypass as low as 7 psi.
I remove the valve and tap the hole for a 1/4 inch pipe plug with sealant.
The one in top of the rear housing, for the stock oil cooler, is fine as is.
In my Corvair powered race cars that valve gets plugged, as we replace the cooler with a adapter for a remote cooler in the front of the race car where the license plate would normally reside.
I own a 1975 914 with a 160 HP 2.4 L [4 cyl ] with Weber carbs
Years ago I installed a 180 Corvair Turbo engine in a 914 for a client.
I used a flipped ring gear transaxle approach and it operated fine for years with no issues.
I also did the same for another client, but in a 912 with a 911 /915 transaxle, flipped.
In fact, doing this change in a 914 transaxle puts the ring gear in the normal location for a 911 or 912.
VW /Porsche designed the earlier 901 and 911 series transaxles so this could be done.
Look up ZEROL gear sets for more info if desired.
The work you have done is exemplary. Congrats.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 04:04AM

Correction OIL FILTER bypass under the top mount for the oil filter.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: DaveO90s4 ()
Date: November 23, 2017 04:20AM

Hi again Dryenko,

Thanks again for your reply (and comment about the workmanship)

You say "...The one in top of the rear housing, for the stock oil cooler, is fine as is" - can you please explain to me why it is OK to bypass the oil cooler at just 7psi oil pressure or more? (I understand that both the oil cooler and oil filter bypass valves are the same part no. and have the same pressure bypass settings).

Thanks again,
DaveO

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 04:31AM

In normal operation the stock oil cooler will only bypass if it gets clogged.
Since it is after the filer, this seldom happens.
The addition of the lines to a remote cooler, and the laminar fluid drag induced, especially when cold, will great enough back pressure across the oil filter bypass valve to open it.
It eventually will close when the oil, lines and filter are warm enough, but no filtering will [obviously ] be done when open.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: DaveO90s4 ()
Date: November 23, 2017 04:47AM

Hi again DrYenko,

Thanks for the additional explanation.

I think, given the info you have provided, that I can be reasonably confident that my stock oil cooler (with the stock cooler bypass valve and the stock filter bypass valve and with good clean oil) is functioning correctly to cool my engine oil.

JUst trying to be as sure as possible I'm not about to stuff anything before I drive it properly tomorrow.

Good night all
Dave
Down Under

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 04:51AM

I am sure you can tell if the oil filter stays cold to the hand after starting and running the engine ....

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: DaveO90s4 ()
Date: November 23, 2017 05:01AM

The oil filter is certainly hot - with hot oil through it.

I'll try the touch text on the cooler tomorrow after a short-ish drive (to the auto electrician to have the oil temp gauge connected).

DaveO

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: Bob Helt ()
Date: November 23, 2017 05:55AM

Hi Dave,
What a runaround! Here is what you are looking for.

Oil from the pump flows thru the filter as long as the filter is not plugged with debris or as long as the oil is not viscous to the point where it will not flow thru the filter.

But, if either one of these conditions occur (plugged filter or really thick oil due to low temperatures) then the oil trying to flow sees a back pressure from the filter due to the restrictions. When the filter presents a back pressure (resistance to oil flow) of 10 or greater psi, then the bypass valve opens and the oil skips the filter and follows its normal path.

Same for the oil cooler.

Bob Helt

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: dryenko ()
Date: November 23, 2017 07:04AM

OK Bob Helt please explain by what you mean by using the term runaround.

Bob C aka Dryenko
Dobson, NC 27017

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: Brizo ()
Date: November 23, 2017 08:17AM

Another way to look at it is, if nothings plugged up there's ALWAYS around "10 psi." of oil flowing through the cooler.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"



Edited 2 time(s). Last edit at 11/23/2017 08:19AM by Brizo.

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: vairmech ()
Date: November 24, 2017 07:20AM

Bob Helt explained it best but the term differential pressure needs to be used.
Oil will always flow through the filter and oil cooler BUT if the oil is cold and/or the filter or cooler gets plugged up oil will still flow! That is what the bypass valves are for. Is it better to run un-filtered or cooled oil for a little bit than to have none at all to the engine? Most racers do take the time to warm up the engine/oil before they ever move the car. Do you do that for the street?

Here is an EXAMPLE ONLY; Let's say you have SAE 50 oil in the engine and the outside temp is 50 degrees. How much oil do you think is going to flow through the filter with cold 50wt? Not much I'm sure. That is where the by-pass comes in and will let oil flow around the filter as the oil heats up. The warmer the oil the more oil goes through the filter. That is the literal explanation of the by-pass valves.

Now, If you have remote mounted anything you have extra resistance to flow of any oil and it is possible to have the by-pass valve partially open all the time, hence Bob C's mention of blocking the by-pass function totally with a plug. I have used a Nickel! I do use the term "worth a plug nickel" now and then.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Intimate workings of the oil filter and oil cooler bypass valves?
Posted by: American Mel ()
Date: November 24, 2017 10:53AM

Uh, the phrase actually is, . . . Plugged Nickel. grinning smiley

"Search Results
obsolete Completely worthless or useless; having little or no value. (A variant of "not worth a plugged nickel.") Refers to coins (not only nickels) that were "plugged"—that is, those that had a hole drilled in their center and were filled with cheaper metals—which made the coins illegitimate and worthless if spotted."

.
-----------------------------------------------
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.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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