front oil cooler thermostat

[r lane]

Attempting to understand the behaviour of the 4 way thermostat for the front cooler on a 85 Carrera. Examining the thermostat, it would appear that the scavenge oil from the engine would pass straight through the thermostat and go directly to the cooler apon cold crank up. Doesn't make sense to me, what am I missing. Anyone explain this to me. Thanks, Bob

[Trackrash]

Stock thermostat? '72 thermostat?

[911 SLANT]

I run the MOCAL oil thermostat to my front 9 row cooler.

[boyt911sc]

Bob,

I will try to explain how the oil from the engine flows through the auxiliary oil thermostat. Imagine the four (4) oil line connections for the thermostat:
A...........from scavenger oil pump inside motor.
B...........oil return line to the oil tank.
C...........oil line to the auxiliary oil cooler.
D...........oil line from the auxiliary oil cooler.

• Oil pick up by the oil scavenger pump is delivered directly to the aux. oil thermostat (A). The initial flow of cold oil goes to (B) and (C).
• Cold oil flows straight thru thermostat (C) to fill the oil line and cooler and to the oil tank (B). At this stage all the oil from the engine goes to the tank after filling the oil lines and cooler.
• At temperature below 185°F, the valve @ B is fully opened and valve @ D is fully closed.
• This oil circulation goes in cycle until the engine oil gets warmer and warmer.
• At around 185°F, the slide valve inside the thermostat will start to move. The opening/closing of the valves orifices is the same to maintain the flow of oil.
  For example:
  Valve B (100% open)/ Valve D (100% close or 0% open)
  Valve B (80% open)/ Valve D (20% open)
  Valve B (50% open)/ Valve D (50% open)
  Valve B (fully closed)/ Valve D (fully opened)
  Etc.

This is how the auxiliary thermostat operates in conjunction with the oil cooler. Below are some of the auxiliary thermostats I used for the tests.



Tony

[winders]

[chrismorse]

How “fine” is the temp controll on the stock, or mocal thermostat. Aren’t. Both water and oil thermostats controlled by a melting wax pellet?? My water cooled stuff goes from cold to a rock steady “normal” very quickly and stays there consistently, even in traffic or when driven hard.
It seems that the 911 thermostat does the same, except that it would appear that it reaches max thermal capacity fairly quickly, then the temp starts to rise, as in sitting in traffic, or hammering it in the hills and watching the needle rise.

This begs the question, why not put in a bigger cooler, or another one as well???

Given the eye watering cost of pulled head studs and worn guides, I submit that this would be cheap insurance?? When was the last time you overheated a water cooled car?

Interested,
Chris

Ps, as a side note, I have a 308 that has a ducted oil cooler, but no thermostat - it would take forever to get the oil up to temp for spirited driving. When the stock cooler sprang a leak, I sourced a mocal cooler, thermostat and -12 aeroquip lines, bingo, car warms up much quicker.

[911 SLANT]

Chris, that was the same with my car. I had no thermostat, just the 9 row oil cooler in front. Car would only get to 160 degrees. That's why I added the MOCAL, so I would have the correct oil temperature at 180 degrees.

[r lane]

Thanks for your input on this. I am using the factory thermostat as it is on my shelf and my understanding is that it has a safety feature that keeps the oil circulating to the engine if a line downstream of the thermostat gets pinched. Was a problem with the factory hard lines, not so much with Aeroquip type I guess. Tony, wonderful description on the thermostats function. Will take your text and convert it into a drawing. Appears on cold cranking, the tank serves as a pressure buffer to the coolers, at least that is how I am reading your note. Bob

[Mark Henry]

I thought most T-stats were more of a 90/10% deal, never fully opened/closed bypass?

[Mdleder]

I am a new owner of a 77’ 911 and just took my first long trip of 500 miles. It’s a relatively low mile car that wasn’t used much in the last few years so I was expecting that after some stretching of the legs some things would pop up. Well I developed an oil leak from a hose at a connection between two fittings.

As a relatively new owner I need some clarification as to what the hose name is. Leak is coming form the connection point and not the rubber hose itself.

It is the hose just in front of the engine oil cooler.


Can somebody identify the proper name of the hose. To fix the leak does it require replacement of the entire hose or just the seal between the connection points? Is the seal formed by a crush washer, o ring, flat faced seal. Picture with this points has the connection and hose in question circled, relative to some of known parts on the right side of the car. I appreciate any and all help

[boyt911sc]

Originally Posted by Mdleder

I am a new owner of a 77’ 911 and just took my first long trip of 500 miles. It’s a relatively low mile car that wasn’t used much in the last few years so I was expecting that after some stretching of the legs some things would pop up. Well I developed an oil leak from a hose at a connection between two fittings.

As a relatively new owner I need some clarification as to what the hose name is. Leak is coming form the connection point and not the rubber hose itself.

It is the hose just in front of the engine oil cooler.


Can somebody identify the proper name of the hose. To fix the leak does it require replacement of the entire hose or just the seal between the connection points? Is the seal formed by a crush washer, o ring, flat faced seal. Picture with this points has the connection and hose in question circled, relative to some of known parts on the right side of the car. I appreciate any and all help

Post some pictures if you want better responses to your question.

Tony

[The Watson]

Originally Posted by Mdleder

I am a new owner of a 77’ 911 and just took my first long trip of 500 miles. It’s a relatively low mile car that wasn’t used much in the last few years so I was expecting that after some stretching of the legs some things would pop up. Well I developed an oil leak from a hose at a connection between two fittings.

As a relatively new owner I need some clarification as to what the hose name is. Leak is coming form the connection point and not the rubber hose itself.

It is the hose just in front of the engine oil cooler.


Can somebody identify the proper name of the hose. To fix the leak does it require replacement of the entire hose or just the seal between the connection points? Is the seal formed by a crush washer, o ring, flat faced seal. Picture with this points has the connection and hose in question circled, relative to some of known parts on the right side of the car. I appreciate any and all help

I see you’re new to these forums. As a courtesy you shouldn’t hijack an unrelated thread. You cut and pasted your same question to two different threads having nothing to do with your dilemma. Post your own thread and it will get the attention you need. Also, download a 1977 PET to get part numbers and diagrams. Hope that helps.