Oil viscosity and CHT etc.... WOW!

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oprn
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Re: Oil viscosity and CHT etc.... WOW!

Post by oprn » Fri Aug 24, 2018 6:40 am

twodollardoug wrote:
Thu Aug 23, 2018 10:32 am
What is your pressure at 4k rpm? Do you have a gauge?
34 to 36psi at 3000 rpm depending on the oil temp. Stock oil pump just cleaned up and re-used so it's not tight like a new one would be. At 250*F oil temp it is still a bit above 30 psi.

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oprn
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Re: Oil viscosity and CHT etc.... WOW!

Post by oprn » Fri Aug 24, 2018 6:52 am

CLKWRK wrote:
Thu Aug 23, 2018 12:14 pm
Viscosity directly affects the oil cooler bypass system ... thick oil pushes harder on the spring and opens the oil circuit that allows oil to bypass the oil cooler, this tricks it into thinking that the engine is cold even though it is warmed up or even too hot

Also oil flow moves heat away from the source, not pressure
Agreed! Monster oil pressure is not a good thing. It increases wear on the oil pump and drive tang, eats extra HP and stresses seals. All we really need is enough pressure to insure that the oil is getting to all the parts of the engine that need it. The oil film strength is what keeps the engine from wearing out not the oil pressure.

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CLKWRK
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Re: Oil viscosity and CHT etc.... WOW!

Post by CLKWRK » Fri Aug 24, 2018 7:43 am

My favorite oil pump trick is to carefuly radius the corners inside the pump (old formula vee trick), and sand the sealing face of the pump and gears flat on a granite block.
Zero tolerance on the pump side, then i use the gasket thickness to set the endplay

twodollardoug
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Re: Oil viscosity and CHT etc.... WOW!

Post by twodollardoug » Fri Aug 24, 2018 10:49 am

oprn wrote:
Fri Aug 24, 2018 6:52 am
CLKWRK wrote:
Thu Aug 23, 2018 12:14 pm
Viscosity directly affects the oil cooler bypass system ... thick oil pushes harder on the spring and opens the oil circuit that allows oil to bypass the oil cooler, this tricks it into thinking that the engine is cold even though it is warmed up or even too hot

Also oil flow moves heat away from the source, not pressure
Agreed! Monster oil pressure is not a good thing. It increases wear on the oil pump and drive tang, eats extra HP and stresses seals. All we really need is enough pressure to insure that the oil is getting to all the parts of the engine that need it. The oil film strength is what keeps the engine from wearing out not the oil pressure.
Agreed....

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oprn
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Re: Oil viscosity and CHT etc.... WOW!

Post by oprn » Fri Aug 24, 2018 8:01 pm

I have been thinking about my higher than expected oil temps and wondering if the rod mod shown in the cheap junk build thread would be the reason. The idea is to notch the side of the big end of the rod to give the bottom of the piston and the cylinder walls more splash/spray. Could it then raise the oil temps because the extra oil splash is carrying away more heat?

Just a thought.

wreck
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Re: Oil viscosity and CHT etc.... WOW!

Post by wreck » Sat Aug 25, 2018 8:17 pm

The rod mod would raise the temp a bit because your pulling heat out of the pistons so it naturally raises the oil temp . I did it to my 4.040 X 71 a few years ago but couldn't tell you how much it raised the temp because of my system is controlled by a thermostat and has overkill amount of coolers .
I do know that Autocraft type spray bars in the valve cover spraying on the valve springs/head ,drops the head temps by 15C and raises the oil temp by almost as much . (Spray bars also slow down valve stem/guide wear and increase the life of the springs . A friend of mine a professional VW engine builder worked it out years ago after being tired of having to rebuild his heads every 80,000km on his own bus. the cooling was a side benefit,no more dropped seats and 200k out of a set of AMC heads !)
No matter where you go , there you are !

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oprn
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Re: Oil viscosity and CHT etc.... WOW!

Post by oprn » Mon Aug 27, 2018 7:55 am

CLKWRK wrote:
Fri Aug 24, 2018 7:43 am
My favorite oil pump trick is to carefuly radius the corners inside the pump (old formula vee trick), and sand the sealing face of the pump and gears flat on a granite block.
Zero tolerance on the pump side, then i use the gasket thickness to set the endplay
Yes I have done that on type 1 oil pumps. Not that easy on a stock type 4 oil pump!

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oprn
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Re: Oil viscosity and CHT etc.... WOW!

Post by oprn » Mon Aug 27, 2018 7:57 am

wreck wrote:
Sat Aug 25, 2018 8:17 pm
The rod mod would raise the temp a bit because your pulling heat out of the pistons so it naturally raises the oil temp . I did it to my 4.040 X 71 a few years ago but couldn't tell you how much it raised the temp because of my system is controlled by a thermostat and has overkill amount of coolers .
I do know that Autocraft type spray bars in the valve cover spraying on the valve springs/head ,drops the head temps by 15C and raises the oil temp by almost as much . (Spray bars also slow down valve stem/guide wear and increase the life of the springs . A friend of mine a professional VW engine builder worked it out years ago after being tired of having to rebuild his heads every 80,000km on his own bus. the cooling was a side benefit,no more dropped seats and 200k out of a set of AMC heads !)
Very interesting! I wonder if those spray bars could be added after the fact to my engine?

wreck
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Re: Oil viscosity and CHT etc.... WOW!

Post by wreck » Tue Aug 28, 2018 5:54 am

easy , fit them to the rocker covers
No matter where you go , there you are !

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CLKWRK
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Re: Oil viscosity and CHT etc.... WOW!

Post by CLKWRK » Tue Aug 28, 2018 6:20 am

Hover mods have the same effect without fancy spray bars

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raygreenwood
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Re: Oil viscosity and CHT etc.... WOW!

Post by raygreenwood » Tue Aug 28, 2018 9:46 am

oprn wrote:
Mon Aug 27, 2018 7:55 am
CLKWRK wrote:
Fri Aug 24, 2018 7:43 am
My favorite oil pump trick is to carefuly radius the corners inside the pump (old formula vee trick), and sand the sealing face of the pump and gears flat on a granite block.
Zero tolerance on the pump side, then i use the gasket thickness to set the endplay
Yes I have done that on type 1 oil pumps. Not that easy on a stock type 4 oil pump!

My thread about refurb/blueprinting a type 4 oil pump.

https://www.thesamba.com/vw/forum/viewt ... p?t=699156

Ray

wreck
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Location: Brisbane Australia

Re: Oil viscosity and CHT etc.... WOW!

Post by wreck » Tue Aug 28, 2018 3:59 pm

CLKWRK wrote:
Tue Aug 28, 2018 6:20 am
Hover mods have the same effect without fancy spray bars
What hoover mods do you do to a Type 4 that sprays more oil on the back of the head ?
No matter where you go , there you are !

TZepeSH
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Re: Oil viscosity and CHT etc.... WOW!

Post by TZepeSH » Wed Aug 29, 2018 2:56 am

Great tutorial Ray! Now I am eager to try to restore my type4 oil pump and use it in the 2056 instead of the type1 pump.

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