Low Oil Pressure at Idle
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
Low Oil Pressure at Idle
I've mentioned my oil pressure problems before but I'll summarize.
Had low oil pressure before the rebuild. Did a complete rebuild but still have low oil pressure once warm. I've used 2 different used Type 4 pumps and still have the same exact pressure. Two days ago I pulled the Relief Valve, Plug & Spring from a spare case. The Valve was a slightly different shape, the spring was shorter and the plug was deeper on the spare. My plug has a bevel on the lower ledge of the groove (the spare has no bevel. just a groove). The spare plug is just slightly deeper and has a VW logo (mine has a wierd design). The pare spring is about 1 inch shorter than mine. My spring is very difficult to compress and get screwed in (sticks out about 1 inch before compressed into the hole). It shoots out when you remove the plug. The spare fits perfectly.
With the new valve & plug (old longer spring) my oil pressure increased just slightly. But still barely comes on once warm and goes out with the slightest tap of the pedal.
Should I try the smaller spring from the spare? Or is there something else I can do.
Before anyone asks. Bearings are new and clearance is perfect. No leak at the sender. Slight oil leak between 3/4 head & cylinders.
I tried to put in 30mm Schadek but the lower shaft boss just barely hits the cam bolts. They were clearanced for the Type 4 Pump but apparently this is not enough for ther Schadek. Is there a way to clearance the pump and not the cam bolts? I'd hate to split the case just to grind down a couple of bolts. Especially if this might not even fix the problem.
Had low oil pressure before the rebuild. Did a complete rebuild but still have low oil pressure once warm. I've used 2 different used Type 4 pumps and still have the same exact pressure. Two days ago I pulled the Relief Valve, Plug & Spring from a spare case. The Valve was a slightly different shape, the spring was shorter and the plug was deeper on the spare. My plug has a bevel on the lower ledge of the groove (the spare has no bevel. just a groove). The spare plug is just slightly deeper and has a VW logo (mine has a wierd design). The pare spring is about 1 inch shorter than mine. My spring is very difficult to compress and get screwed in (sticks out about 1 inch before compressed into the hole). It shoots out when you remove the plug. The spare fits perfectly.
With the new valve & plug (old longer spring) my oil pressure increased just slightly. But still barely comes on once warm and goes out with the slightest tap of the pedal.
Should I try the smaller spring from the spare? Or is there something else I can do.
Before anyone asks. Bearings are new and clearance is perfect. No leak at the sender. Slight oil leak between 3/4 head & cylinders.
I tried to put in 30mm Schadek but the lower shaft boss just barely hits the cam bolts. They were clearanced for the Type 4 Pump but apparently this is not enough for ther Schadek. Is there a way to clearance the pump and not the cam bolts? I'd hate to split the case just to grind down a couple of bolts. Especially if this might not even fix the problem.
- Piledriver
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Tuna, this or some version of this needs to be a sticky or on your site. Permission granted to snarf it.
Unibonger---
Food for thought:
The longer relief spring and/or piston will have absolutely zero DIRECT effect on hot idle oil pressure, but they will have an effect on oil temperature, which does.
Ideally, at low pressure, the piston is sealed up against the top of the bore, and ALL the oil goes through the cooler.
The compression force of that spring determines when the oil cooler starts seeing oil flow.
The STRONGER it is, the sooner the cooler gets flow.
Thick oil or a big pump, esp BOTH, WILL likely try to roast a motor w/o a HD spring kit, since the stock "thermostat" sees high oil pressure as the oil being cold, and bypasses the cooler.
By design.
Not a bug.
No, Really.
Works VERY well with a stock clearances, pump, and factory recomended oil viscosity.
...visualize tooling down the road with 60 PSI oil pressure at 4000 RPM... (20/50 and a 30mm pump)
I guarantee the oil cooler is seeing zero flow with a stock bypass spring/piston, as that is FAR over stock pressure, and the stock "thermostat" is pressure operated...
This is where a true full flow setup and real oil thermostat come into play. IMHO ALL engines should have this.
A full fow setup will also largely avoid "loose pump" issues with some cases.
question:
How "low" is "low pressure", and what are you measuring it with? VDO gauges are not known to be correct. Ever. Just self consistent.
If the idiot light is coming on at hot idle, (~7 PSI), I'd replace the idiot light sender _first_. They fail. Frequently.
Flaky as a 15 year old date.
As I have memory loss...
2: Full flow or no?
(bit harder to do on a Bus, but not impossible)
The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.
Unibonger---
Food for thought:
The longer relief spring and/or piston will have absolutely zero DIRECT effect on hot idle oil pressure, but they will have an effect on oil temperature, which does.
Ideally, at low pressure, the piston is sealed up against the top of the bore, and ALL the oil goes through the cooler.
The compression force of that spring determines when the oil cooler starts seeing oil flow.
The STRONGER it is, the sooner the cooler gets flow.
Thick oil or a big pump, esp BOTH, WILL likely try to roast a motor w/o a HD spring kit, since the stock "thermostat" sees high oil pressure as the oil being cold, and bypasses the cooler.
By design.
Not a bug.
No, Really.
Works VERY well with a stock clearances, pump, and factory recomended oil viscosity.
...visualize tooling down the road with 60 PSI oil pressure at 4000 RPM... (20/50 and a 30mm pump)
I guarantee the oil cooler is seeing zero flow with a stock bypass spring/piston, as that is FAR over stock pressure, and the stock "thermostat" is pressure operated...
This is where a true full flow setup and real oil thermostat come into play. IMHO ALL engines should have this.
A full fow setup will also largely avoid "loose pump" issues with some cases.
question:
How "low" is "low pressure", and what are you measuring it with? VDO gauges are not known to be correct. Ever. Just self consistent.
If the idiot light is coming on at hot idle, (~7 PSI), I'd replace the idiot light sender _first_. They fail. Frequently.
Flaky as a 15 year old date.
As I have memory loss...
2: Full flow or no?
(bit harder to do on a Bus, but not impossible)
The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
So The shorter spring is the correct stock spring (doesn't shoot out when the plug is removed) and the longer one (takes tremendous force to install it, shoots out when removed and is about 3/4 of an inch longer) I'm using is the after market?Piledriver wrote:The longer relief spring and/or piston will have absolutely zero DIRECT effect on hot idle oil pressure, but they will have an effect on oil temperature, which does.
Ideally, at low pressure, the piston is sealed up against the top of the bore, and ALL the oil goes through the cooler.
The compression force of that spring determines when the oil cooler starts seeing oil flow.
The STRONGER it is, the sooner the cooler gets flow.
What is a good temp? I hover around 180 and see 210 on the highway. I have the stock type 4 pump. With the heavy spring. I'm currently running 15-40 Shell Rotella (your recomendation). Could that mean it's not enough pressure to push the valve & big spring down and bypass the cooler?Thick oil or a big pump, esp BOTH, WILL likely try to roast a motor w/o a HD spring kit, since the stock "thermostat" sees high oil pressure as the oil being cold, and bypasses the cooler.
By design.
Not a bug.
No, Really.
Works VERY well with a stock clearances, pump, and factory recomended oil viscosity.
...visualize tooling down the road with 60 PSI oil pressure at 4000 RPM... (20/50 and a 30mm pump)
I guarantee the oil cooler is seeing zero flow with a stock bypass spring/piston, as that is FAR over stock pressure, and the stock "thermostat" is pressure operated...
Can you suggest a Full FLow kit I could check out.This is where a true full flow setup and real oil thermostat come into play. IMHO ALL engines should have this.
A full fow setup will also largely avoid "loose pump" issues with some cases.
VDO Gauge and My new Mechanical Gauge. Both read about 5 PSI at idle. 20 PSI at 3000 RPM.question:
How "low" is "low pressure", and what are you measuring it with? VDO gauges are not known to be correct. Ever. Just self consistent.
I've tried 2 stock senders and a VDO Dual Post Sender. all have the same readings.If the idiot light is coming on at hot idle, (~7 PSI), I'd replace the idiot light sender _first_. They fail. Frequently.
Flaky as a 15 year old date.
Stock Type 4 setup.As I have memory loss...
2: Full flow or no?
(bit harder to do on a Bus, but not impossible)
I read a post from Jake that said not to grind the lower shaft boss because it might make the shaft come out and tear up the cam gear. I only need about 1 mm to clear the bolts with a Schadek 30mm pump..The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.
- Piledriver
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- Joined: Sat Feb 16, 2002 12:01 am
Probably. Use the long spring AND the long piston.the-unibonger wrote:
So The shorter spring is the correct stock spring (doesn't shoot out when the plug is removed) and the longer one (takes tremendous force to install it, shoots out when removed and is about 3/4 of an inch longer) I'm using is the after market?
Sounds excellent.the-unibonger wrote: What is a good temp? I hover around 180 and see 210 on the highway. I have the stock type 4 pump. With the heavy spring. I'm currently running 15-40 Shell Rotella (your recomendation). Could that mean it's not enough pressure to push the valve & big spring down and bypass the cooler?
Some people would kill for that.
Should get even better after break in, and even moreso when you swicth to the 5W40 Synthetic.
Note---Motor has to come apart for this, unless you are insane.the-unibonger wrote: Can you suggest a Full FLow kit I could check out.
If you have ALREADY done all the plugs, "just" full flowing it could probably be done safely, you'd have to pull the filter housing and flush everything out good, but full dissassembly probably not required for THAT.
Jake sells a nice setup.
Cam gear, bolts, plugs/fittings, pump, cover.
Fits Without Guesswork.
His pump is only clearanced on the drive snout, and the input shaft is pressed up into the pump gear a few mm IIRC.
Didn't have instructions, probably figured I didn't need them. (I don't, but for anyone else it could be an oversight)
I think he even sells a "version" that includes the drill, tap, and a video
Seriously.
I have done it myself before.
Pays to just buy his.
I did for my new motor, but am currently modifying a CB dry sump setup, and will use the 30mm pump from Jake on _another_ motor. The dry sump IS getting his beautiful billet full flow cover
Ouch, but just a tad low. 7-10PSI hot is good.the-unibonger wrote: VDO Gauge and My new Mechanical Gauge. Both read about 5 PSI at idle. 20 PSI at 3000 RPM.
I've tried 2 stock senders and a VDO Dual Post Sender. all have the same readings.
You do know Shadeck sells 26mm pumps, too?
Your stock pump could just be worn out.
(Even the Schadecks have been known to need a little lovin out of the box, 1200 grit and plate glass... Lap that sucka) The stock pumps are essentially un-blueprintable.
(can't take out the end play)
The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.
Pin it and grind to your hearts content.the-unibonger wrote: I read a post from Jake that said not to grind the lower shaft boss because it might make the shaft come out and tear up the cam gear. I only need about 1 mm to clear the bolts with a Schadek 30mm pump..
1/16" cobalt drill bits are a buck, and a roll pin is 5 cents.
I have pressed out the shaft, and reintalled it with red locktite at a different level after sanding the boss for fit
...I never noticed a taper in the fit, but I'll take Jakes word for it. (The taper he described would probably be noticable when hand fitting)
IIRC I also peened the crap out of it.
You want an extra mm+ for clearance btw, to allow for cam thrust bearing wear.
Last edited by Piledriver on Sun Dec 03, 2006 6:04 pm, edited 2 times in total.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
I just found a site that says if you have a Type 4 Bus case with the fuel pump boss drilled out, you shouldn't tap the gallery plug by the fuel pump. You'll eliminate the brass push rod guide and it will drop your pressure.
http://www.danallum.com/aircooled/case_prep.htm
I didn't do this, but someone did. Because I have that gallery tapped and plugged. Someone had mentioned that I should install the pushrod even though I didn't use the pump. But it felt so sloppy in there. Now I know why. So I guess I need the brass push rod sleeve. Now I need to figure out where to find one.
http://www.danallum.com/aircooled/case_prep.htm
I didn't do this, but someone did. Because I have that gallery tapped and plugged. Someone had mentioned that I should install the pushrod even though I didn't use the pump. But it felt so sloppy in there. Now I know why. So I guess I need the brass push rod sleeve. Now I need to figure out where to find one.
- Piledriver
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That would do it.
That's the end of the lifter oil gallery IIRC.
There's a fix for that...
Can't remember what it is at the moment, perhaps Jake could chime in?
Depending on whow it's torn up, JB welding in a shortened fuel pump pushrod might be an option.
Better: put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal
Regardless, time to drop le motor.
Good time to install a fuel pump
That's the end of the lifter oil gallery IIRC.
There's a fix for that...
Can't remember what it is at the moment, perhaps Jake could chime in?
Depending on whow it's torn up, JB welding in a shortened fuel pump pushrod might be an option.
Better: put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal
Regardless, time to drop le motor.
Good time to install a fuel pump
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
Just pulled the Fuel Pump Block Off Plate from my engine. Slid a pushrod in there and confirmed that there is no bushing. Checked a spare case I have and there is a bushing. The bushing is a pretty tight fit around the pushrod. The bushing covers the end of the lifter gallery (I think). And without it, oil pours out of the gallery to the case. Basically an internal oil leak.
Placed a shortened Fuel Pump Pushrod in there and sealed it up. Pressure did increase slightly. But still not what it should be.
Hopefully I can find a fix for this that doesn't involve splitting the case.
Placed a shortened Fuel Pump Pushrod in there and sealed it up. Pressure did increase slightly. But still not what it should be.
Hopefully I can find a fix for this that doesn't involve splitting the case.
- Piledriver
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- Joined: Sat Feb 16, 2002 12:01 am
Previously suggested:
Put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal.
Would require engine pull, flywheel come off, pull/drill/tap plug (and make sure things will line up) NO need to split case.
Put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal.
Would require engine pull, flywheel come off, pull/drill/tap plug (and make sure things will line up) NO need to split case.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
What is coaxial? I know what this means in reference to wiring. How does it apply to screws? I'll give it a try when I drop the engine to fix the cylinder oil leak.Piledriver wrote:Previously suggested:
Put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal.
Would require engine pull, flywheel come off, pull/drill/tap plug (and make sure things will line up) NO need to split case.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
I just got this suggestion over at my mine & Colin's forum.
I like the first idea. Anyone see any danger in trying this out?chitwnvw wrote:what about getting a bigger rod that fills up that hole better...
Orrr what about jb welding your hole and then leaving a pin hole for a little bit of drainage...
- Piledriver
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"What is coaxial?"
on the same axis.
IOW. is the drilling for the oil passages in the middle of the hole for the plug?
If it is, the screw-in-plug thing will work well, and might be safest.
on the same axis.
IOW. is the drilling for the oil passages in the middle of the hole for the plug?
If it is, the screw-in-plug thing will work well, and might be safest.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
Duh! Tes it is coaxialPiledriver wrote:"What is coaxial?"
on the same axis.
IOW. is the drilling for the oil passages in the middle of the hole for the plug?
If it is, the screw-in-plug thing will work well, and might be safest.
Very busy. I don't plan on trying the JB Weld thing.bottomend wrote:Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff likes to stay dry.
(Man, you've been busy since I've been gone!)
I went & checked that engine you (Bottomend) have split in my basement. I measured the bore for the Fuel Pump Pushrod Bushing and got a rod the same size. When I went to fit it in, it didn't fit. Got a look in there as best I could (with the engine still in) and it looks like they drilled through the bushing then tried to remove it by drilling it out. They didn't drill it out all the way. They just made the ID bigger. So I found a rod that fits. My oil pressure has boosted a lot. Not perfect, but the light doesn't come on. I'll be trying Piledrivers idea when we drop the engine to fix that cylinder leak.
Speaking of, now that my oil pressure has boosted, that leak is bigger and the flywheel seal leak returned.
- dr. no
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I used JB Weld to close off the cut-0ff oil filler/dipstick I use (you know, the normal T4/bus one). It lives in oil (now for 18mos) and is not soft.Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff like to stay dry.
- the-unibonger
- Posts: 105
- Joined: Wed Feb 01, 2006 10:22 am
I did the same thing. Kept the fill but plugged the dipstick and relocated it. I don't like it for this application though.dr. no wrote:I used JB Weld to close off the cut-0ff oil filler/dipstick I use (you know, the normal T4/bus one). It lives in oil (now for 18mos) and is not soft.Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff like to stay dry.