Oil Pressure / Water Temp - Impala Tech
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post #1 of 20 (permalink) Old 06-24-2017, 08:18 AM Thread Starter
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Oil Pressure / Water Temp

Hello The Team.

I need opinions about my operting oïl pressure and water température.

When my Impala is cold (less 190-200°) my oïl pressure is 75 psi for 2500rpm, is it too much ? (rebuilt 350 SBC with high pressure / volume pump)

In sitting trafic and hot weather (about 95°) my water can go To 220-230° it is too hot? (mecanical gauge and sending in driver side head)

Thank You, Charly.

'66 Impala
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post #2 of 20 (permalink) Old 06-24-2017, 12:56 PM
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What oil viscosity are you using, and what did your builder recommend?

Two doors, four doors, wagons, and ragtops.
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post #3 of 20 (permalink) Old 06-24-2017, 06:21 PM
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Quote:
Originally Posted by jayoldschool View Post
What oil viscosity are you using, and what did your builder recommend?

Good questions.

GM recommended 10w30 oil (normal outside temps) and spec'd the small block v8s oil pressure at 40 psi (minimum) at 2k rpm. The 409 was 50 psi (minimum) a 2k psi. That's just info. Your engine may require something different.

Those temps are not abnormal for those conditions. My '63 gets to those temps occasionally in those conditions. Because I rarely drive in those conditions, and because a 50/50 mix of anti-freeze/water at 15 psi pressure boils at 265 degrees F, I've chosen to do nothing. IF I routinely drove at those temps, I would try to reduce them.

High temps at idle, or at very low speed, tend to be fan related. My car NEVER gets over 190F at any outside temp (up to about 98F, I haven't experienced any temps higher than that) if I have forward speed of 20 mph, or more. In my opinion, that means my radiator is sufficient.
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post #4 of 20 (permalink) Old 06-25-2017, 11:19 AM Thread Starter
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Thank You for your answers.

The builder use 15w40 and has made a modification on my original radiator cap and add an over flow tank.

I put a new fan shroud (missing befor) and there is à 17" fan inside and no clutch.

I want to buy a 18" fan and à clutch (original style) but I think I will need à radiator spacer because It seems To be so far From water pump.

'66 Impala

Last edited by Charly; 06-25-2017 at 12:07 PM.
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post #5 of 20 (permalink) Old 06-25-2017, 01:37 PM
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Quote:
Originally Posted by Charly View Post
Thank You for your answers.

The builder use 15w40 and has made a modification on my original radiator cap and add an over flow tank.

I put a new fan shroud (missing befor) and there is à 17" fan inside and no clutch.

I want to buy a 18" fan and à clutch (original style) but I think I will need à radiator spacer because It seems To be so far From water pump.
If you have the OEM 4 blade fad w/shroud, a six blade fixed (same diameter, going to 18" likely will just require you to buy a different shroud) fan will provide more flow throw the radiator at idle/slow speed. That should help cool things a bit at idle.

The fan clutch doesn't 'cool' better. It 'de-clutches' the fan when the engine doesn't need it. It allows the torque required to turn the fan to be applied elsewhere (propulsion for example). Not a bad thing, but adding a fan clutch to fix a cooling problem is counter productive. The ones I've seen actually reduce the fan speed even at idle. I'm not saying don't add one, they do what they do quite well. Just don't add one to make things 'cooler'.

The ideal location of the fan is just outside the shroud (I forget the measurement, 1/2"? maybe). If you had a clutch and removed it w/o adding a spacer (on the water pump shaft) to place the fan back where it should be, your fan may be too far away from the shroud, costing you flow and cooling. It should look something like the attached pic.
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post #6 of 20 (permalink) Old 06-25-2017, 03:24 PM Thread Starter
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Ok thank You for explications and picture.

I actually have an aftermarket 17" 6 blades and spacer.

I want a clutch for a stock look and because during winter engine run too cold : 180-190° max (I think)

I already think that fan needs to be in the "middle" of shroud (half in). This is my configuration:
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post #7 of 20 (permalink) Old 06-25-2017, 05:23 PM
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A stock clutch fan will cool better than the aftermarket fan with spacer. It will also take less HP at higher RPMs.
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post #8 of 20 (permalink) Old 06-25-2017, 05:33 PM
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Quote:
Originally Posted by Charly View Post
Ok thank You for explications and picture.

I actually have an aftermarket 17" 6 blades and spacer.

I want a clutch for a stock look and because during winter engine run too cold : 180-190° max (I think)

I already think that fan needs to be in the "middle" of shroud (half in). This is my configuration:
Fan placement looks fine to me. Would not move it any farther into the shroud (closer to the radiator).

Those temps in the winter would be about what I would expect/want.

"Stock look"? In 1963 (the only year I remember), engines with less than 300 hp, and engines w/o air-conditioning, were 'stock' with a 4 blade fan and no clutch. If one had either a/c, or 300 hp, GM installed the fan clutch. I think w/your 350, you could go either way and call it 'stock'. Also, the 'stock' fan w/the clutch was the 5 blade (unsymmetrical).

I was told a while back by a source I considered knowledgeable (but I've found no documentation) that the 'red' HOT light comes on at approx 240 F. I've never reached that temp on my gauge, and my 'light' has never illuminated. My max was about 225 F while sitting in highway construction traffic for close to an hour in 95 f summer temp. I was concerned but I had no where to go. The car never 'burped' out any coolant and when I was able to move, the car cooled off rapidly back to it's normal 190 'ish' F.

Again, I'm not trying to talk you out of of the fan clutch. Just trying to be helpful.
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post #9 of 20 (permalink) Old 06-26-2017, 07:44 AM Thread Starter
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Thank You Japete92. Interesting your message. I know the same situation in sitting trafic, 230 very max and diminution of température 200°) when trafic restart.

I don't have a Big culture about Impalas (constructions) I need to search on Google, forums or dealers like Classic Industries, Bob, Eckler's... To find OER or OEM equipements.

An electric fan is installed but not not connected for the moment, It's maybe a good solution, but I prefer that cool better without before To connect It.

In 66 I thought that the 4 blades fan was installed on 6 cylenders. 6 blades on SBC and 7 blades on BBC and May vary with AC... It's not clear for me.

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post #10 of 20 (permalink) Old 06-26-2017, 10:36 AM
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Quote:
Originally Posted by Charly View Post
Thank You Japete92. Interesting your message. I know the same situation in sitting trafic, 230 very max and diminution of température 200°) when trafic restart.

I don't have a Big culture about Impalas (constructions) I need to search on Google, forums or dealers like Classic Industries, Bob, Eckler's... To find OER or OEM equipements.

An electric fan is installed but not not connected for the moment, It's maybe a good solution, but I prefer that cool better without before To connect It.

In 66 I thought that the 4 blades fan was installed on 6 cylenders. 6 blades on SBC and 7 blades on BBC and May vary with AC... It's not clear for me.

Here's a link to some info you may find useful (the first page is blank, scroll down):

https://www.gmheritagecenter.com/doc...-Chevrolet.pdf

It has a section on engines and cooling but I didn't look up what it says. It may give you the info you need.

Another source would be the Shop Manual and the Assembly Manual. Both have reliable data on the cars as they were built. A small investment may pay great dividends.
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post #11 of 20 (permalink) Old 06-27-2017, 07:09 AM Thread Starter
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Wow Thank You again Japete92, there are tons of informations !!!

My dad was offered To me the Body Fisher and Châssis Service Manual there are many informations too.

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post #12 of 20 (permalink) Old 06-27-2017, 08:25 AM
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Sorry I have been locked out for the past week and a half over password issues.

As to the oil pressure you do not need a high pressure high-volume oil pump unless you have built a race engine with chamfered bearings and loose clearances to reduce internal friction. (these engines are for short burst wide open throttle applications where it is torn down and rebuilt after a race not driven for a couple of hundred thousand miles on the street). All you are doing is putting a strain on the oil pump drive and wearing out the timing chain and the cam gear that drives the distributor. You run a high volume pump to compensate for the massive internal oil leak caused by using chamfered bearings.

A high pressure pump was a way of raising oil pressure to force oil through restricted oil passages in an old used poorly maintained motor so that your honest used car salesman could move a clunker off his lot with nothing more than new pedal covers on the clutch and brake pedals a high pressure oil pump and a fresh coat of paint on a steam cleaned motor then all he had to do was to roll the speedometer back to create a low mileage cream puff of a car.

I used to rebuild motors for many used car lots in the Tampa Bay area when I first started my engine building business. They were not interested in warranties or power but in cost. So I sold them a goof motor and made my money in the installation of the rebuilt motor (It helped that I bought the engine to rebuild from a scrap metal yard).

Your cooling issues have been addressed already.

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post #13 of 20 (permalink) Old 06-27-2017, 02:33 PM Thread Starter
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OK Big Dave, thank You.

I need to buy new parts, so I will take a new standard oil pump with.

'66 Impala
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post #14 of 20 (permalink) Old 08-08-2017, 02:31 PM Thread Starter
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Little news.

18" fan blade and fan clutch installed. The fan is a little bit far from radiator and not at all in shroud.

I will buy a radiator spacer To solve this problem.






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post #15 of 20 (permalink) Old 08-11-2017, 12:30 AM
 
 
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Quote:
Originally Posted by Charly View Post
Thank You Japete92. Interesting your message. I know the same situation in sitting trafic, 230 very max and diminution of température 200°) when trafic restart.

I don't have a Big culture about Impalas (constructions) I need to search on Google, forums or dealers like Classic Industries, Bob, Eckler's... To find OER or OEM equipements.

An electric fan is installed but not not connected for the moment, It's maybe a good solution, but I prefer that cool better without before To connect It.

In 66 I thought that the 4 blades fan was installed on 6 cylenders. 6 blades on SBC and 7 blades on BBC and May vary with AC... It's not clear for me.
The 396 in my 1966 SS had a 4 blade fan (no A/C). It was not liking the summer driving around here (Tampa area), especially in heavy traffic. I had my mechanic install a Northern aluminum radiator & dual electric fans. It is taking a while to get used to. The fans will come on up to 10 minutes after I park the car and it makes my garage extremely hot, but I do feel a little more assured if I get stuck in traffic or by a train. My factory gauge is still not reading correctly (coming close to pegging out, sometimes), but I know of at least one ground strap that is dangling off the firewall, not connected to the engine. I need to find out where all of them are supposed to be and check them. I was told the engine was taken out a couple of years ago for a valve job, so who knows if everything was hooked back up correctly (like I said, I know one ground strap wasn't)
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post #16 of 20 (permalink) Old 08-11-2017, 07:14 AM Thread Starter
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Thank You buccaneers37.

So You have a température sender for for electric fans? In radiator or in water circuit?

I think to do the same thing with my single electric fan but with a switch.

'66 Impala
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post #17 of 20 (permalink) Old 08-11-2017, 09:13 AM
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Quote:
Originally Posted by Charly View Post
Little news.

18" fan blade and fan clutch installed. The fan is a little bit far from radiator and not at all in shroud.

I will buy a radiator spacer To solve this problem.






Fan/shroud looks good to me from the pics. I would drive it a while before buying anything else (but I still don't think your temps are abnormal, nor detrimental).
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post #18 of 20 (permalink) Old 08-11-2017, 10:35 AM
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Fan is the correct size for the shroud. It has to have room to allow the engine to move in it's rubber mounts. You need that room for clearance.

A fan blade is a wing and like a wing it generates a pressure differential moving through the air. If you look at newer planes compared to older designs (727 vs a 757) you will notice the ends of the wings have the ends bent up. This is to prevent air from sliding off the end of the wing. This means the whole wing surface is generating lift so that they can stuff more bodies in the cabin.

Your fan has the same issue. That high pressure area on the back side wants to slide off the end of the blade. Without a shroud, only about a third of the total blade area is effective. With the shroud about two thirds becomes effective, doubling the amount of air it will move through the radiator (the hub is still mostly dead air).

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post #19 of 20 (permalink) Old 08-11-2017, 04:12 PM Thread Starter
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There is the space of one finger between fan / shroud. Picture deform a little bit the reality, fan blades are about 1/4 of thickness in shroud (not totaly in, more outside of shroud)
So it's sufficient, I don't need a spacer ?

'66 Impala
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post #20 of 20 (permalink) Old 12-10-2017, 04:15 PM Thread Starter
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New fan shroud spacer installed.
I didn't have a moment to test this new application during hot weather.






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