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Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: Max Roeder ()
Date: November 17, 2017 03:41PM

Although I wasn't able to show in the pics exactly how much the oil cooler brackets are problematic, you will be able to see the actual seals as they would be when installed in your engine. Some brackets are better than others with respect to their porting locations but I haven't found any without an off center condition.

The off center condition is one that can create additional pressure drop issues which create additional loads on the pump and drive components. You will never see the pressure drop because there isn't any pressure taps until after the oil returns to the engine filter housing.

Most of the sampling I did with my testing resulted in a restriction caused by the crushed seals. Both Buna-N and the Viton demonstrated similar behavior after being crushed. Some seal installations reduced the area for the oil flow by as much as 20%. That 20% reduction would cause a total pressure drop (in and out) of about 8 psi. The interesting results were that the same seals could be installed back into the same port and a different crush profile would be created. None were perfect and none of the oil cooler adapters were either. Look at the four brackets and notice the difference in the internal porting, i.e. where the cross drilled holes end.

My best advice is to do some very light polishing/ porting in the adapter. Be sure the in and out ports match with the end housings's ports and the gasket does not interfere with any flow path. Yes this is picking the fly crap out of the pepper but if you have enough fly crap strung throughout your engine the results can be detrimental to the performance of your engine.

My Thanks to Lane66m for loaning me the extra oil cooler brackets and seals for evaluation.

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: MattNall ()
Date: November 17, 2017 04:12PM

Wow... I though my Buggy engine's adapter was the only one like that...I found it's misalignment when going remote and welding on AN fittings.





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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: jjohnsonjo ()
Date: November 17, 2017 04:14PM

I'm not sure what you used for flow calculations. The oil must get squeezed through bearing clearances of .002" or so. Its not moving very fast when its going through the cooler.

J.O.

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: Max Roeder ()
Date: November 17, 2017 05:07PM

jjohnsonjo Wrote:
-------------------------------------------------------
> I'm not sure what you used for flow calculations.
> The oil must get squeezed through bearing
> clearances of .002" or so. Its not moving very
> fast when its going through the cooler.


The bearing clearances are on the pressure relief side of the system.

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: jjohnsonjo ()
Date: November 17, 2017 05:24PM

Max I understand that, the question was, what you used for a flow to create a 8PSI pressure drop. If something else in the system stopped or greatly reduced the flow, there would be zero loss of pressure caused by the cooler because there is zero flow. You can't calculate a pressure drop through a restriction without knowing the flow. A 3/4 garden hose will flow way more than a 3/8, but if you put it through a tight nozzle it doesn't matter.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: RobertC ()
Date: November 17, 2017 06:13PM

I think you guys are making mountains out of mole hills...

Do not recall any maintained Corvair engine suffering damage from restricted oil flow.

On a side note, I feel that a high volume oil pump is useless - unless all the oil passages are enlarged.

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: MattNall ()
Date: November 17, 2017 06:26PM

And funny how things morph over decades...

In the late 60's when they came out [ 409 gears] it was for RACE engines with large bearing clearances and wide Rod side clearance....

We ran 50 wt. Valvoline Racing oil or Castrol 25 psi hot pressures at 5000 rpm..


And so I've always believed Big Smooth passages were important..for those types of engines...





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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: Max Roeder ()
Date: November 18, 2017 12:42AM

Yes there were some assumptions thrown into the calculation for pressure drop. I used the 6 gpm @ 4400 engine rpm. Obviously because the gear pump is a positive displacement device the flow is pretty much linear.
Many GM engineers were used for the corvair project and the sum total of their knowledge would fill truckload information. What I'm attempting to do is look for obvious areas of concern and how to improve the performance in those areas. If you've ever worked in a large GM plant (or any other auto plant) production runs the show. If the parts will work within limits out they go to assembly.

After all who wouldn't want a volume knob on their electric guitar amplifier that goes to 11 instead of 10?

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: davemotohead ()
Date: November 18, 2017 07:11AM

What if GM designed them that way for a reason? I am sure they took into consideration the I.D. of the crushed seal, Finding problems with things that have no problem is a problem, I will run them the way GM designed them as I have on every engine I have ever built as well as 99.99% of everyone else who has built a Corvair engine since they have been built, the part works as designed and as long as it does not leak, ITS GOOD! smoking smiley





Email me at: Dave Motohead

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: vairmech ()
Date: November 18, 2017 07:17AM

Did you factor in the pressure relief valve? While the oil pump is a positive displacement the pressure relief valve bypasses about 80%, or more when cold.

Also keep in mind that the oil cooler seals neck down to about 3/8" and could be an issue when cold but then again there is a built in bypass valve.

Does this make a difference to us? For a stock engine with millions of test miles, NO.

Most of you don't want to know what we do with race engines but there is very little connection between a street version and a full out race engine. Not even hot street engines!

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: American Mel ()
Date: November 18, 2017 08:22AM

vairmech Wrote:
-------------------------------------------------------
> Did you factor in the pressure relief valve? While
> the oil pump is a positive displacement the
> pressure relief valve bypasses about 80%, or more
> when cold.
>
> Also keep in mind that the oil cooler seals neck
> down to about 3/8" and could be an issue when cold
> but then again there is a built in bypass valve.
>
> Does this make a difference to us? For a stock
> engine with millions of test miles, NO.
>
> Most of you don't want to know what we do with
> race engines but there is very little connection
> between a street version and a full out race
> engine. Not even hot street engines!


Actually Ken, I am sure that there are many more than just me who have now had their curiosity piqued.
Please, do tell ! ! !
Might make a GREAT new thread !

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
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Re: Oil Cooler Bracket(s) and Crushed Seals, See Them!
Posted by: RobertC ()
Date: November 18, 2017 09:01AM

Curious question about "crushed seals" - in the first pic of the first post in this thread.

It looks like the seals are flush with the face of the adapter. Why?

From my feeble memory plus I have only changed cooler seals a couple times (decades ago):

I recall the seals sticking out of the adapter about 1/16" - not flush.

There is a matching indentation in the stock oil coolers.

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