Type 1 Oil Pressure Relief Mod

[FJCamper]

Our Type 1 road racing endurance engines are dry-sump, with CB Performance 2-stage pumps. The CB pump is made by Schadek, with 26mm scavenge (inner stack) case to tank and 21mm pressure stage, (outer stack) tank to bearings.

That means we have 21mm pump gears pressuring the engine, and 26mm gears sucking oil from the case back to the tank. Each stage has its own oil passages.

Of course, comparing a one-stage pump to a two-stage is not quite apples to apples because a single stage has to expend all its flow through one set of passages to both suction and pressure.

As the VW community has so painfully learned, bigger oil pumps alone are not the fix for oil pressure problems. The condition where a bigger pump and/or thicker oil can keep the oil pressure relief valve depressed and force hot oil to the bearings while providing low flow to the cooler is a race engine killer.

Like many (most?) VW engines racers, once we reach high oil temperatures (generally over 220° F), our low RPM oil pressure goes away. For us, this is on a 96-plate cooler with a 9-inch electric fan, 10w30 and 10w40 oil. Three gallons of oil ... all of which is usually up against 90° F southwest US summer days and a minimum of 7-hour enduros per day.

And, we're about to add Type 4 power to our armory. The Type 4 uses the exact same CB pump. Which means a remote oil cooler, filter, everything.

So, when I found out about Head Flow Masters Racing Oil Check Valves, it gave me hope for the better.

Audirac Racing Oil Check Valve kit
http://www.headflowmasters.com/vw-oil-p ... -body.html

The trouble is, no one answers the phone or e-mail there. Not for weeks.

Bernie Bergmann
http://www.bergmannvw.net/

Next, I tried Bernie Bergmann who has a similar steel ball check valve kit he used to sell, but to my surprise, Bernie warned me off them. "You need a new case to use the kit," he said. "If you have a worn bore and that sleeve comes loose, it'll destroy your engine. I wouldn't do it. It doesn't make that much oil pressure difference anyway."

So, I have to revert to Plan B. Here they are:

CSP Full Flow Adapter
http://tinyurl.com/llbezxp

EMPI Full Flow Adapter
http://tinyurl.com/krrugqs

Neither of these fit Type 4's, but what I learn from the Type 1 application should apply, especially with an external oil thermostat and perhaps an external pressure relief device such as these full-race devices at Jegs.Com

http://tinyurl.com/mtmf3wj

My idea is to use the full flow adapter design at least as far as it replacing the relief spring and piston, so 100% of the oil goes to the external filter and cooler all the time. CSP shows little respect for the factory piston and spring design, calling it a cheap thermostat. Read their ad.


The Porsche Type 547 dry sump racing engine used an external thermostat.

With an external thermostat to aid quick warmups before the oil goes to the cooler. Here's the device I've picked. It has 1/2" not 3/8" fittings.

Disabling the stock oil pressure relief valve at the pulley end of the engine does not affect the oil pressure control valve near the flywheel. It will continue to dump overpressure back into the case, which is it's job.

http://tinyurl.com/ot38uxg

This all leaves the filter at risk, of course. Here I trust in FRAM HP-1, for it's can strength. HP-1's and I have been through a lot together, from my first VW IMSA road racer Superbug in 1975 and '76, and they have never let me down.

The goal here is lower oil temps and better idle pressure.

I'll let you know how it works.

FJC

[Piledriver]

The stock relief valve can easily be modified to return to the dry sump tank, rather than the case sump.
(plug the return passage and install an outlet in the exterior plug location--- the same hole is used to plug the inner passage)
This works on T1s or T4s.

One can also block it off completely, use it as the oil feed, and use an external relief valve.

This came from Racer Chris CFR welding Eprod 914, which IIRC won the championship that year.
This info/pics and commentary may be found on the STF, but I strongly suspect it was posted on Jakes old site and is now probably "lost wisdom".

In either case, returning the bypass oil to the dry sump tank is ~essential with the CB pump due to the limited size of the scavenge stage. (no point pumping the bypass oil out of the case over and over to no gain)

JayCee makes a nice external relief, racer Chris used a Parker adjustable relief valve on the case to feed back to the DS tank, the 26mm pressure stage doesn't really overwhelm the T4 oiling setup.(stock size, essentialy, just with less air bubble milkshake effect in the oil)

[turbobaja]

FJC, won't you need an oil outlet from the pump in order to feed either one of those Full Flow adapters? Have you fully "blueprinted" your CB pump? Decked the housings, covers and gear faces on glass wetsand, etc.? I ran a 96 plate cooler years ago and fought oil temp issues (probably due 30mm pump and thick oil among other things ) now I have one of the large Setrab coolers mounted out back and MANY more reasons for high oil temps, yet I run right at the T-stat regulated 180F 90% of the time, regardless of ambient temps (into the 90s F) and only rise above 200F when idling around town (no fan on the cooler). My 10psi "idiot light" rarely comes on even then, and I ignore it with the gauge reading just under 10psi , Mobil 1 0W-40 w/small dose of break-in additive. I just added a 3rd fitting on the left side of the external gear housing to act as a "full flow" cover. Block off the internal passage that would have sent the oil through 2 (small) 90° bends back through the stock pressure port at the pump body-to-case port (great opportunity for pressure loss!). Plug the case inlet port from the oil pump as well. I filter the oil right before it goes to the engine using the 21mm pressure pump, have not tried feeding straight to the engine and filter on the scavenge stage to compare pressures. Scavenge pump only has to push up through the cooler and to the tank this way, so possibly slight improvement in scavenging the case as well.

The stock relief valve can easily be modified to return to the dry sump tank, rather than the case sump.
(plug the return passage and install an outlet in the exterior plug location--- the same hole is used to plug the inner passage)
This works on T1s or T4s.

This sounds like a great idea, need to add this next chance I get!

[FJCamper]

Hi Karl,

I won't be using the CSP/EMPI style adaptors to feed oil into the case, just the upper part that replaces the relief spring and piston ... or I'll be making a device to block an oil piston in the full "up" (flow to cooler) position. I just want to see how either CSP or EMPI has designed their upper feed tube.

Piledriver's idea of plumbing bypass oil out of of the case to the dry sump tank is a good one. We in fact are already using an external 12v oil scavenge pump to keep the 3-4 cylinder valve cover and head drained to the oil tank.

All experimentation requires there be a constant, and having the oil pressure relief valve locked into the "all oil to cooler" position creates a constant. Obviously I'd never do this to a street car, but for the let hell bend for leather world of racing, if it's stupid but it works, it ain't stupid. And its hard to get our drivers to give we techs feedback. We were strapping one in tight at Barber and he was banging his helmet over and over on the steering wheel saying "Stupid! Stupid! Stupid!"

We didn't know if his meds were wearing off or if was changing his mind about racing. --- FJC

[Piledriver]

I can't claim the idea, it was racer Chris's Setup... plus most of the other parts were off the shelf and made for that purpose already, like the relief valve location oil feed.

plug off the return to sump passage, pull the piston/spring entirely and use one of the bottom oil feed adapters available (they probably block off the return passage themselves) and use an external relief, feed the bypass to ds tank...
...easy, simple, and trivial to troubleshoot, don't even need to pull any existing plugs.

I bought a nice large bore Swagelok (internally) adjustable relief in Naval Brass for $35.
Available in SS as well, all with several seat material choices.

Chris spent a lot more on a Parker in SS with an external knob.... Your money, your call.

[4agedub]

FJC
Are you sure that you are not simply trying to mask the problem here?

On both our cars we run the stock relieve valves and springs. The 1810cc n/a runs the CB dry sump pump and the turbo car is on a Bugpack dual scavenge pump.

On the 1810cc the cold idling oil pressure (1000rpm) is in the region of 2,5 bar and goes up to max 4 bar when you rev the engine up. At operating temperature the idling pressure is still over 1,5 bar and max pressure still 4 bar when you rev the engine up. We rarely see oil temperatures in excess of 190'f even on a hot 86'f day.

We have tried big 96 plate setrab coolers on the dry sump return line before, but found that they restrict the oil flow too much causing the single stage scavenge not to keep up. After making our own oil cooler that problem was solved and the car ran cooler than before.

IMG_1114.JPG

IMG_1107.JPG

The other difference is that we have the oil filter on the original oil cooler channel and not on the return line. There is also an external oil cooler on the original cooler's channels.

oil cooler.jpg

[FJCamper]

Above: Oil lines directly off case top adapter to oil cooler.


Hi 4AgeDub,

I understand that lowering our oil temp might in itself be the answer. A second (nonrestrictive) oil cooler on the return line might be exactly what we need.

What has kept me tinkering with this oil pressure relief problem is the blatant circumstance I'm seeing from too much oil pressure -- even hot -- overwhelming the relief piston.

Last year, for sprint races (15 minutes at a time) I plumbed up our wet sump 1965 Pan Am Ghia with oil lines feeding straight from the top of the case to the front, nose-mounted oil cooler.


Above; IN-OUT pump, 32mm single-stack gear set.

The FRAM HP-1 filter was fed directly by a 32mm gear in-out master pump,

The result, even with half-inch ID oil lines from the cooler adapter to the very nose of the car, where a secondary oil pressure gauge has been fitted to check oil pressure at its apogee away from the engine, was 300° F. temps inside of those 15-minute sprints.

We were getting engine lubrication, but only hot oil. We did infrared scans on the oil cooler and hose, and the 300° F. temp was consistent.

What was happening was the 10w40 oil we were using was too thick, and the pressure was keeping the oil pressure relief valve piston from closing and diverting all the oil to the cooler. The 32mm pump gears were keeping the piston hovering exactly where it would not allow full flow to the cooler, beyond filling the lines.

That forced the engine to lube its bearings on hot, hot oil. We had to do a bearing change on that engine after that weekend.

A weaker pump might have helped, or a lighter oil.

Or a second oil cooler on the return side, to keep temps down so the stock oil pistons and springs can do their jobs.

FJC

[4agedub]

You are already using a pretty thin oil, which should help to scavenge the case properly. At this stage we use Shell Helix HX5 20w40 in our engines. It's not a synthetic oil.

I have tried a couple different weight oils before and ended with the 20w40. The full synthetic oils are just too thin. The Mobil 1 is 5w35 I think. Hot oil pressure was below 1 bar. We once even experimented with some 25w50 oils... which was a disaster. It was so thick that the scavenge side of the pump could not keep up at high RPM and the case would fill to the point where it would pump liters of oil out the breathers.

I'm not sure how effective our rear oil cooler is... maybe also due to the relieve valve opening and bypassing oil. The front cooler I would say does at least 90% of the cooling work.

[jhoefer]

Above: Oil lines directly off case top adapter to oil cooler.

With that type of setup, yes, you need to just jam something in the cooler bypass bore (or use a very heavy spring) to lock the piston closed. Running probably what, 30 ft of line back and forth, oil filter, plus one or two oil coolers up front off of that adapter? That's going to introduce a flow restriction that will increase the oil pressure at the point of the bypass valve. Because the cooler bypass valve is a pressure controlled thermostat instead of just a temperature controlled thermostat, that pressure increase is going to hang the valve open until the oil reaches much higher temperatures and the viscosity drops enough to get the pressures low enough to close the valve again. Same reason oversize oil pumps and too thick oil cause high oil temperatures.

If you want to use the adapter in the picture, force the cooler bypass valve closed, insert a standard temperature controlled bypass thermostat between this case adapter and the oil lines to the front oil cooler(s). Then oil flow looks like this (assuming wet sump, standard oil pump setup):

Cold oil -> case adapter -> oil filter -> thermostat -> case adapter -> bearings
Hot oil -> case adapter -> oil filter -> thermostat -> oil coolers -> thermostat -> case adapter -> bearings.

Right now you've got:
Cold oil -> bearings
Hot oil -> bearings
Really hot oil -> case adapter -> oil coolers -> case adapter -> bearings

[buildabiggerboxer]

4agedub, if this is this the motor you posted about the wide hot valve gaps,? I can see that cooler in the engine bay giving you grief, taint doing anything there but running hot air into the fan, It's an overheater, dump it m8, FJ,s post above gets right to it, but better yet, run a proper full flow oil system with a full time pressure fed cooler.

[4agedub]

Buildabiggerboxer, no it's not the same car. The turbo engine with the pushrod problem was solved by installing cromoly pushrods. That engine has a bugpack dual stage pump with full flow.

[Dan Dryden]

I've just stumbled across this subject, trying to find if the pressure relief valve at the pulley end of the engine needs to be removed when running a dry sump system.
It looks like you guys are on to a problem my engine (running a wet sump currently) has had since the day I first bought it and still exists after 2 (investigative) rebuilds... Low hot oil pressure at idle.
Both rebuilds revealed nothing untoward with bearings showing very little wear and all parts still comfortably within tolerance.
I run 20W 50 oil with a full flowed system. External cooler and original cooler. Schadeck 30mm pump. CSP pump cover with pressure relief valve.
I'm wondering whether to ditch the original cooler and the aforementioned pressure relief valve and run a system as recommended above???....

FJ, did you try the mod in the end? How did it perform?

[Marc]

On all the drysump engines I've built that used that little pump (mine were Schadeks but the CBPerformance one looks identical in the photos) I never used the stock cooler outlet/inlet passages, just a bypass plate to connect them. Coolers & filters were all plumbed into the drysump tank circuit somewhere.
Done like that, the stock pulley-end plunger essentially controls nothing besides which end of the main oil galleys receives more flow.
The flywheel-end one, which is there to protect the stock-location cooler from pressure over ~65 psi, doesn't serve much purpose either because it's a rare occasion when that pump will even give you that much with warm oil, and you shouldn't be winding it out when cold.
But since both have a bleed hole at the bottom to allow leakage past the piston to return to the sump so a hydraulic lock doesn't occur (which would incapacitate the relief/control action) if you leave the pistons out those holes must be plugged or you'll have NO pressure at hot-idle.
I took the pragmatic approach and just ran stock plungers & springs in both locations, never had a problem.
Nor did I bother with the complexity of adding a thermostat, we simply ran the engine when we got to the track for long enough to bring the tank temp up to 100-120° to avoid having excess pressure when the green flag dropped. Some guys used heating blankets around the tank on cold nights, I never found that necessary either.

K.I.S.S.


BTW, the ONLY good thing you can say about a Fram HP-1 is that it'll take more pressure than a PH8A. Inside they're both lousy filters. I prefer OEM Rabbit Diesel filters (068 115 561B) - they handle the 150+ psi that those motors make when revved cold, far more than you're ever going to see with that little pump. Never need a filter wrench to take'em off, either.

[Piledriver]

Dan Dryden---ditch the molasses, that in combination with the 30mm pump is a killer if you don't have an external cooler etc.

Since you do have an external cooler, it is probable that your oil pump is a loose fit to the case and is both leaking pressure internally to the case and sucking air from same.

If you have an Non NOS pump, there is a ~100% probability of a loose pump<>case fit.
Very common and easily overlooked.

They sell oringed pumps as a good but imperfect fix, but it usually has to go in with the case split or you cut the orings.

A dry sump setup like the CB unit oddly can also be set up to "cure" this as the pressure stage can neither suck air or leak oil to the case if set up properly, plugging the winding to-case passages and using a steel "full flow" cover out to the usual suspects.
(It can leak/suck as shipped, and should be oringed and modded as described for best results)

It also has a 21mm pressure stage so you are not overwhelming the stock pressure relief/oil cooler system logic.

Note that on the stock relief/cooler system, the oil cooler gets bypassed over ~42 PSI.
I bet you are making much more than 42 PSI at cruise.

I'm leery of long lines coolers and filters on the scavenge side, the 26mm scavenge stage of the CB DS pump
is marginal for keeping up pumping all that milkshake back to the tank as is.