26mm pump may be better for cooling than a 30mm?

An OEM bypass spring for the oil cooler opens at 75psi. The oil pressure bypass spring opens at 45psi. I do not agree that a 30mm pump will hold the oil cooler bypass open when the oil pressure relief spring is controlling the pressure 30-40 psi lower than the oil cooler bypass.

   BTW, all OEM VW engines produced in by VW of Mexico used 30mm oil pumps.

I'm running the smaller pump (26mm or so - I'd have to look) and it seems to be providing more than adequate oil pressure.  Once started, my oil light never comes on, although I do not have an oil pressure gauge.

 

I remember Berg saying that the 30mm was only needed if you were running hydraulic valves (to keep the lifters pumped up) or if you were running an all-out race engine (reving a lot over 6 grand or so).

 

 

I've heard the argument that the larger pump moves so much more oil than necessary that the the increased friction causes slightly higher oil temps, but never seen measurements to back it up.  

Oh-oh......Where's "Air-cooled Bruce"??

Yup...I'm here....and yup....I'm thinking about it....don't need to pull the engine to test this out. What if the pump is pumping way more GPM than what can be bypassed by the pump bypass thus punching the cooler bypass to wide open as well? These pumps are positive displacement and unforgiving in certain circumstances.

I kind of think that the oil cooler in/out temps wouldn't change but possibly a higher volume of oil would be cooled thus reducing overall engine oil temps.....Don't know....Just a thought ....and how would I test this effectively?..........Bruce

http://www.thesamba.com/vw/for...ewtopic.php?t=280293

Bruce is on it!

Thanks Justin......It looks like my thought process was pretty close to what is actually happening. Now I wish I had paid closer attention to what size holes/passageways I had in my case before I assembled it. Based on the info you forwarded to me I think it's pointless to pursue this. That info was very valuable and informative (the best I've seen) on what's really happening in our lube systems. Obviously there is a lot more going on than one would think........Bruce

If the pressure is below 70 psi, the oil pressure bypass is not maxed out. Think about it, the pressure bypass opens at 40 psi, the cooler bypass opens at 75psi. The only time the cooler bypass will be open is when the oil pressure can not be controlled by the oil pressure bypass, When the engine is cold. This is exactly why VW moved to the dual relief case, so oil coolers were not blown in cold climates. I run hundreds of engines with 30mm pumps and oem bypass springs. At operating temp, I never see oil pressure above 50 psi, unless the oil is cold or the engine is at extremely high rpm.

I used this awhile back to splain it to self. Just follow prompts.

 

http://www.vct2.com/vwtech/Pag...20Valves%20Works.htm

I agree with Pat's post. But the other important factors are the type of oil, fit of the oil pump in the case, And what type clearances you have on your bearings. I have most customers who we did the motor running 10-40 rather than the past norm 20-50.

Anthony....Pat Downs recommended to to to use Brad Penn straight 30 wt. Also Daniel who works at the counter said the same thing.  According to them, this is the original wt. oil that was recommended by VW....Bruce

That recommendation was made when multi-weight oil was considerably more expensive, and the objective of the VW (as an economy car) was to be inexpensive to run as well as buy. Yes, it worked, but when you consider how much more we put these engines through now, why would you use a single weight oil when a multi-weight does the job so much better?

Engine builders have their theory's on what is the best to use. Think about when the engineers designed this platform. There was no full flow systems and 30 mm punps. So on that same thought, oil products have improved over the years and lubrication theorys. Multi weights help on those cold starts and flow with less effort which AIDS in cooling.  Again it's all depends on your engine builder

Yes.  There are lots of theories...

I recommend 30wt Brad Penn break in oil for the first 500 miles. After the first oil change at 500 miles, I recommend 10-30wt Brad Penn.

Three Questions for Pat Downs:

 

1. What is your logic to use 30wt for break-in?

 

2. Why switch to 10-30 thereafter?    

 

3. Did all the OEM engines produced in Brazil by VW with 30mm pumps have a larger (than 5mm) passageway back to the sump from the oil control valve?

 

 

BTW... I think Brad Penn is good stuff especially for our engines. There are others out there of course, that will do as well

I think Pat will tell you that straight 30w is non detergent and allows faster break-in. A lot of builders recommend single weight. Gene Berg even suggested going to 20w if it was colder, to get better (faster) flow.

 

You switch because non-detergent oil is for short term use (and to clean out the crankase, although the filter in theory should be taking care of it), and you want the multi-weight in there for cold start lubrication. I'll let Pat comment on #3.

Bruce, That's an easy question to answer. The only non detergent break in oil Brad Penn produces is 30wt.

  

Bruce, The bypass port on all newer model engine cases is 6.2mm from what I have seen. This includes the new Magnesium case manufactured by Rima for VW.

How great is it to have a world class engine builder on the SOC site and so willing to share his knowledge!

 

Getting the real scoop directly from Pat Downs is priceless.

 

Thank you, Pat!

Thank You All ! Especially Justin and Pat ! It looks like I just finished school again on a subject that I just took for granted before.

 

I still have another question that still plagues me. Why is there such little difference in the oil temperatures going in and out of the stock oil cooler ? Of course I have my own theory but I have no hard data to explain or verify it. Anyone out there have some info about this to share ?..........Bruce