30mm vs. 26mm oil pumps

[neil68]

26 mm Berg oil pump and full flow kit in my Beetle.

32,000+ street miles and 650+ trips down the drag strip on the same crank, bearings, etc, and never a problem with oil pressure.
Rev limiter set at 8,000 rpm and I usually hit it at least once every race
Your 1915 cc should be fine as well. Use 10W30 or 5W40 or similar oil to keep oil pressure down on a cold engine.
_________________
Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[58ragman]

[quii]

[58ragman]

[Danwvw]

So much depends on your engine, They all behave a little different. Oil Pump fit makes a big difference with the stock oil pump but if the fit is good and the engine good it will produce more than enough oil pressure. What is it 21mm I think. And you don't have to worry about too much pressure blowing the oil cooler or oil filter or more likely a full flow hose.
I have been however running 26mm oil pumps and 5W 30 or 0W40 motor oil with no problems once I got them right.
Years ago on a single relief case I had a 30mm aftermarket filter pump twist it's engagement tab off and the engine seized. Also that same 30 filter pump would sometimes cavitate due to too much suction on a small pick-up tube when the engine was too cold and got revved up.

The only problem I have had with the 26mm full flow pumps is I have blown off my full flow oil lines a couple of times. But that is my fault. Got to use two hose clamps at each fitting.

Always Idle it and drive it at low rpms when cold.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[mark tucker]

2 hose clamps per fitting..... there is no room for hose clamps on my AN hose assys. the filter pumps need thin oil. they have small passages in them.

[Skulptorchaz]

Got my new CB 26mm full flow kit and oil filter on and took her a spin today. I used 5w30 Brad Penn oil.
My oil pressure, once warm, was always about 20-22 lbs. Idle or 3000 rpm.
A buddy of mine says it should be around 40psi.
The engine still gets hot but, that is another thread.
Is that OK oil pressure? The engine, a 1915, and it has only about one year on it. MAYBE 8k tops.
Thoughts??

[modok]

if you rev it up and the oil pressure stays at only 25 then I'd guess the oil valve must have a weak spring on it, or more likely the oil pressure gauge is no good.
Pressure ALWAYS follows rpm up until the relief valve opens, and it's supposed to open around 40PSI

[Howard 111]

I like posting on these old posts that come alive again.

I run a 30mm pump, but it has a turbo mounted up high, and it's FF. I also run the Berg pressure relief cover on the oil pump.
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1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270

[spencerfvee]

right on modok I learned years ago on using to big of a oil pump. blow buy big time .oil all over the motor . I can see using a 30mm oil pump if your using 5- 30 oil .that like pumping water . I use full synthetic 50 w oil in my street motor with a .26mm oil pump with stock springs .I never drive the bug in the winter only summer .runs great . spencerfvee

[mark tucker]

ok spence Im lost how does the oil pump have any thing to do with blow by???
also the 40 pis relief was for a stock motor that saw 4000 rpm?more rpm.. more pressure required..
I run mine yearound or Ill be walking.synthetic 5-20&30mm pump for me.

[raygreenwood]

It is different from engine to engine.....and those who say this problem does not exist unless you are doing something else wrong.....are wrong.

I cannot speak for type 1 engines but it most assuredly happens on type 4 engines.

The first time I saw this was on a bone stock 1.7L with D-jet....with about 50k miles on it.

It ran cool as a cucumber. Oil temp gauge in the taco plate. Stock pressure with the 26mm type 4 pump was 15 psi at 900 rpm idle with Valvoline HPO 30 oil.

It had a minor drip drip from the oil pump gasket. With the PITA it is to get type 4 pumps out I planned to try to fully rebuild it while it was out for a new gasket......but thats not a 15 minute deal.
So.....For giggles and grins I swapped in a 30mm melling pump I aquired on sale ($35 on sale for a really nice pump.....who can resist?).

Same weather, same outside temp...same tank of fuel.....and oil temps on highway go from 225 to 230.....up to 300+. Scratching my head.

So pull the drivers side sheet metal and screw in a mechanical gauge to the inlet port galley of the oil cooler. At idle oil pressure was only marginally higher than the 26mm at about 23 psi at idle.
Rev to 2000 and its pushing 60 psi on the dash gauge and normal pressure on the galley which reads about 45 psi. Rev to highway rpm...about 3400.....and dash gauge says a fluctuating 80 psi and the galley gauge says about 15 psi now.

So.....its bypassing.

Next test was to put a large shim.....no spring....under the pressure relief piston and test. Idle was still in the 23-25 psi range and high rpm was a steady 80......with 60+ at the cooler port. Too high......but proved the point.

Since then....I have seen this on several type 4 with 30mm pump and stock configuration oil system.

And to those who are listing experiences with items like the Berg pressure relief pump.....different animal. It has its kwn preszure relief circuit in addition to the engine relief system from the factory. It shouldn't give an issue.....but is not a factory system.

Also....I would think an external cooler and filter also totally changes the equation. Few people add in the frictional loss from lines and elbows. I would think a 30mm pump would be ideal in those cases. Ray

[spencerfvee]

hi mark large pumps. pump oil into the valve cover the oil cant drain fast enough at high rpm so the oil goes up the valve cover vent hose into the breather box and spills oil all over the motor .it even gets real bad when you run a 88mm crank or a 82mm crank the term I should have used was windage from the crank . even a 69mm crank can do the same thing .that's why you will see big 2 " vent hoses on some race cars .even some small block chevy race car motors have crank scrapers to slow down the oil and to try to keep oil in the oil pans hell some guys used to knife edge the cranks in the old days to stop wind age .my 421 SD motor in my 1964 GTO I used to race would blow oil out the valve covers if I over wound the motor off the line. I wish I had that car back nothing like the roar of dual 4 S..and open headers and the smell of rubber those were the days my friend I though they would never end .blood sweet and gears I sold that car for $3,400.00 back in 1968 spencerfvee

[SamT]

Nothing wrong with a 30mm pump if your gonna run a 3-4qt sump.

I can't say I've ever seen an engine that died from a 26mm oil pump. But I've seen several that died because they pumped the sump dry with a 30mm pump.
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[Skulptorchaz]

Good info guys.
Modoc, I took her for a spin again today and at start up, she shows 60psi + but as the 5-30 oil warms up, she settles down to around 20-23psi almost consistently.
Is this too low of pressure?? Should I address the springs?? I "thought" the springs were stock, but I did not build the engine. Would this have any contribution to it getting to hot on the interstate?? I know I may have other issues contributing to that but, could this be one also??
Thanks guys!
Chaz

[modok]

Yeah I'd be looking at the springs. I have not seen the oil pressure behave like that before, it is odd.

[Skulptorchaz]

Just my luck.
Thanks buddy!!!

[Skulptorchaz]

Hey, I was also thinking about putting some Lucas Oil Treatment in my motor. I was going to do it for the supposed benefits of the stuff. I doubt it makes much difference here but, is there any drawbacks to the stuff??
thanks!

[mark tucker]

sorry spence but the oil pump had nothing to do with blow by. but the valve cover filling could be attributed to it it isant the windage from the crank there is a camshaft&lifter's&case in the way for that.it's the pressure relief valve exhaust port spraying on the #3 lifter and pushrod&flowing up the pushrod tube into the rockerbox. add a stiffer pressure spring.or redirect the pressure exhaust port. as far as the v8 thats dead rings or hole in the piston or bad bore/hone job. but the valve covers can fill if the drains are blocked. blow by is combustion pressure&gasses passing by the piston rings into the crankase.
skraperchase stay away from the mucas stuff.

[Skulptorchaz]

Well guys, I believe I may have a problem. I took her out this weekend to the CIncy VW Reunion. It's about an hour away so the motor got plenty warm getting there. After the motor got up to temp, 185* for awhile, when I came to an idle, the oil psi would come down to about 6-7#. It has never done this before BUT, I did change to the 26mm pump from a 30mm and I am running 5-30 oil where I use to run 10-40.
I'm guessing, from what you all said, it could be the springs. I have never messed with them so tell me which way should I go with them (heavier, lighter) to try to increase the pressure??
Thanks!!