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Jubbly Bug
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Joined: September 21, 2008
Posts: 79
Location: Skelton North England
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 Posted: Thu Nov 30, 2017 1:19 pm Post subject: Type 4 oil pressure issue |
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As above . Ive got a issue with a type 4 engine at the moment ,when cold the oil pressure light and gauge read 0 ( light on) for around 40 seconds then go out and read 50 ish psi ,once warm the light gos straight out and reads good pressure ,warm at idle its around 15 20 psi and increases with revs . Any ideas . Ive changed oil and filter ( castrol 20"50) checked the bypass valve in the filter housing, made sure the strainers clean and had out and checked the oil relief valve in the case ( clean and free) . The engine sounds and drives well no sign of overheating or problems .only thing I can think is there is and obstruction in a oil gallery ?
Cheers in advance Jim
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mikedjames
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Joined: July 02, 2012
Posts: 3447
Location: Hamble, Hampshire, UK
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| Posted: Thu Nov 30, 2017 1:40 pm Post subject: Re: Type 4 oil pressure issue |
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Ideas:
1. There is a a slow air leak in the oil pick up pipe feeding the oil pump, so for a while the pump sucks air and then builds pressure as it finally primes. When the engine is warm, the air leak has not had time to let the oil back out.
2. The tang in the oil pump is about to slip out of the slot in the cam shaft. When the engine is cold it is not gripping, and when things expand a bit it grips. Unlikely as it would very quickly chew the end off the tang and fail totally.
I would take the oil sender out, disable the ignition and crank the engine to see if oil comes out the pressure sender hole.
If it does not appear almost immediately, you have a real problem that needs fixing.
It will be increasing the wear on the bearings, starting with no oil pressure regularly.
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raygreenwood
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Joined: November 24, 2008
Posts: 23524
Location: Oklahoma City
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| Posted: Thu Nov 30, 2017 2:04 pm Post subject: Re: Type 4 oil pressure issue |
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Are you using that damn VDO dual pole oil pressure sender unit?
Its notorious for this problem and several others. It was primarily designed for working in the differential pressure derction system of the mk 1 and mk 2 watercooled cars. Also there is more than one part #.
Put a normal oil pressure sending unit in and verify that you have pressure.....and while you are playing....check it with a good mechanical pressure gauge at the oil pressure sender port.
While its possible you "might" have a loose pickup tube joint.....its highly doubtful because it would be most inclined to pick up.....when stone cold and all of the oil is in the crankcase and at its thickest.
Tang not engaging......vaguely possible.....but if so you would hear it and in general....if you are using a type 4 stock pump.....its virtually impossible. There is no place for it to slip back into the pump...and in fact they usually have the oppoiste problem when they do have a shaft slippage problem.
Also....unless you live in very hot climate with mild winters....like Dallas or Phoenix....or unless your bearings and pump are shot (and if so....therin could be your issue) is there is no reason to use 20-50 oil in a type 4. There is no benefit....and the downside is that its common on type 4 that the excessive pressure bypasses the oil cooler. Ray |
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nextgen
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raygreenwood
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Joined: November 24, 2008
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Location: Oklahoma City
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| Posted: Thu Nov 30, 2017 2:59 pm Post subject: Re: Type 4 oil pressure issue |
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| nextgen wrote: |
| I had the gear on the oil shaft with the tang move and the tang slip out, on my wife's Sqbk. No warning, engine seized. Never seen or heard of it on a T-4 |
Yep...mit can happen on some type 1 pumps.....but unless wokething has been swapped around inside of the type 4 pump.....there is usually no room for the drive/tang shaft in the gear to slip inward. Its usually bery nearly flush with t he gear top. Ray |
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Jubbly Bug
Samba Member
Joined: September 21, 2008
Posts: 79
Location: Skelton North England
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| Posted: Thu Nov 30, 2017 3:13 pm Post subject: Re: Type 4 oil pressure issue |
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Thanks for the reply's . Yes it is a two pole vdo sender . Yes ive also fitted a standard op switch and had the same results . ( I originally found the issue wile behind the dash as someone had wired the oil light to the ignition light to hide the fault ) , the bus ins in the UK , 2050 w oil was recommended i could change it to straight 30 but I've ran both in type one motors with no problems . But new to type 4s
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raygreenwood
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Joined: November 24, 2008
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Location: Oklahoma City
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| Posted: Thu Nov 30, 2017 3:47 pm Post subject: Re: Type 4 oil pressure issue |
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| Jubbly Bug wrote: |
| Thanks for the reply's . Yes it is a two pole vdo sender . Yes ive also fitted a standard op switch and had the same results . ( I originally found the issue wile behind the dash as someone had wired the oil light to the ignition light to hide the fault ) , the bus ins in the UK , 2050 w oil was recommended i could change it to straight 30 but I've ran both in type one motors with no problems . But new to type 4s |
I will not speak for type 1.....but 20-50 is not good for type 4 with stock oil pressure valves unless you are operating in hotter climates than you will find anywhere in the UK.
What oil pump are you running? If its the stock pump.....how old is this motor? While its rare for the o-ring in the pump to totally crap out to the point of losing pressure into the case....but it can happen. If you also have large main bearing tolerances this could be a combined issue.
How many miles?
What is your ambient temperature? If its even in the 40s F......50 psi when cold.....is actually quite a low reading for 20-50 oil. With 20/50 when cold.....typically 75 to 85 psi is common. 50 psi after 30-40 seconds..... is a primary indicator that you are bypassing the oil cooler.
Have you checked your oil pressure relief valve and spring length? If its the wrong spring....it could be making it worse.
Also.....did your engine originally have carbs? And if so.....and still....are you using the stock pump near the transmission? If not.....and if it originally had a pump there and now has q block off plate....insure that the bushing for the pushrod is still there .. and that the plunger and spring in the control valve under number 1 cylinder are still intact. Ray |
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Jubbly Bug
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Joined: September 21, 2008
Posts: 79
Location: Skelton North England
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| Posted: Sat Dec 02, 2017 2:38 pm Post subject: Re: Type 4 oil pressure issue |
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Mileage on engine is unknown . Far as I know its a stock oil pump . Temps at the mo are 8 -0 degrees c I run 20 50 in my bug and other classics with no problems . Ive had the valve out near the oil filter ( big flat screw head plug) was lean and free ,don't know spring length but could re check . Why would bypassing the oil cooler make for low pressure ? .
Thanks again for the help
Jim
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busdaddy
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Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Sat Dec 02, 2017 4:14 pm Post subject: Re: Type 4 oil pressure issue |
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What brand oil filter are you using?
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thesatanicmechanic
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Joined: November 30, 2008
Posts: 102
Location: Charlotte, NC
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| Posted: Sat Dec 02, 2017 5:29 pm Post subject: Re: Type 4 oil pressure issue |
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Chiming in with my .02P
20w50 is way too thick in a type 4 in almost any circumstance, and especially in your climate. "Have used with no problems" isn't the case. Increased oil temps, diminished lubrication at cold starts, and an overall shortened engine life span. Those are the problems you've been experiencing.
I keep mechanical oil pressure gauges on hand to verify suspected oil pressure problems. Verify your instrumentation. Your FLAPS has cheap mechanical gauges available I'm sure. |
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raygreenwood
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Joined: November 24, 2008
Posts: 23524
Location: Oklahoma City
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| Posted: Sat Dec 02, 2017 5:56 pm Post subject: Re: Type 4 oil pressure issue |
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| thesatanicmechanic wrote: |
Chiming in with my .02P
20w50 is way too thick in a type 4 in almost any circumstance, and especially in your climate. "Have used with no problems" isn't the case. Increased oil temps, diminished lubrication at cold starts, and an overall shortened engine life span. Those are the problems you've been experiencing.
I keep mechanical oil pressure gauges on hand to verify suspected oil pressure problems. Verify your instrumentation. Your FLAPS has cheap mechanical gauges available I'm sure. |
Yes....you beat ne to it.
The type 4 engine does not care what you used with no problem in your type 1. Its not a type 1.... 
As similar as they seem.....the oil galley volume, the filter system, the control valve system and the different pump design.....insure that you do not need 20-50......except maybe in the hottest climates....like Texas at 120° F ground temperature when amhient temp is 105° F....and even then you can have excessive oil pressure at start up for a short period on a tight engine even at 85° at sunrise.
I would drop to SAE 30 or 10-40....plug in a machanical gauge after checking the relif valve springs and pistons and see what you get. Ray |
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Jubbly Bug
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Joined: September 21, 2008
Posts: 79
Location: Skelton North England
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| Posted: Sun Dec 03, 2017 10:57 am Post subject: Re: Type 4 oil pressure issue |
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Ok so so change oil to 30 . Filters a Bosch made . Valve looks ok any one have the length the spring should be? . Il try get hold of a oil pressure gauge to re check figures ..
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Jubbly Bug
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Joined: September 21, 2008
Posts: 79
Location: Skelton North England
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| Posted: Sun Dec 03, 2017 12:41 pm Post subject: Re: Type 4 oil pressure issue |
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Just dug out my copy of Bentley manual bus 68-79 and oil type 20 50 will cover from around -10 to around 40' c. The Manual only say to match oil type to ambient temp not a specific viscosity to year/ engine type. . Also shows the oil gallery diagram ,now seeing how its layed out. Where on a type 4 case is the oil pressure control valve ,ive had the relief valve out the case but not the other . . I believe its a t25 engine if this helps . ( different heat exchangers and front case) I'm starting to wonder if it I a pump or pickup problem as the pressure sender is before the relief valve . .
Thanks for the help still understanding hows these engines work .
Jim
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modok
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Location: Colorado Springs
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| Posted: Sun Dec 03, 2017 1:08 pm Post subject: Re: Type 4 oil pressure issue |
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It is reasonable to follow the service manual, they were probably correct at the time, but
Where will you be getting this antique oil to match?
I'd say it's common for the relief plunger and the oil pump and the oil pickup are all messed up on an old type4.
You can't get to the pickup tube without splitting the case but you can check out the plunger(s) and possibly the oil pump. Do the easiest thing first and see what happens. |
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raygreenwood
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Joined: November 24, 2008
Posts: 23524
Location: Oklahoma City
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| Posted: Sun Dec 03, 2017 1:53 pm Post subject: Re: Type 4 oil pressure issue |
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| Jubbly Bug wrote: |
Just dug out my copy of Bentley manual bus 68-79 and oil type 20 50 will cover from around -10 to around 40' c. The Manual only say to match oil type to ambient temp not a specific viscosity to year/ engine type. . Also shows the oil gallery diagram ,now seeing how its layed out. Where on a type 4 case is the oil pressure control valve ,ive had the relief valve out the case but not the other . . I believe its a t25 engine if this helps . ( different heat exchangers and front case) I'm starting to wonder if it I a pump or pickup problem as the pressure sender is before the relief valve . .
Thanks for the help still understanding hows these engines work .
Jim |
The pressure control valve is underneath the #1 cylinder. It has a 12 pt socket bolt for its cover.
I will tell you....I do not give a damn what the Bentley manual says. It has far too many errors in it to blindly take all of its advice when I have many, many, many engines of experience strictly on type 4....and probably a million miles to boot with about 500,000 of them directly in 411/412.
While the viscosity index of an oil can be matched to "running" in a given ambient condition to take advantage of the expected rise or fall of the oil temperature and viscosity due to changes in the cooling air temperature......and 40*C (104 F)...is fair weather for 20/50 (its also fine weather for 10/40 and sae/30 in a type 4) ....the Bentley oil advice does not take into account "starting" temperatures.
At -10* C (14*F).....I and others....have literally exploded filters. Your oil pressure with 20/50 even at just 32* F can exceed 125 psi. This is oil "TYPE" and formulation dependent...not just basic viscosity dependent. The Bentley advice also does not take RPM into the equation....and at what temperature. If you are using 20/50 in the winter.....you had better be pretty well warmed up before cranking out the rpm on the highway.
While 20/50 is a great oil weight for a type 4 running high miles and high speeds...at the upper end temperature of 40 C/104 F....I would never use it below 10 C/50 F.
They also do not note engine condition ...meaning oil clearances etc. A nice tight engine has higher oil pressures. The whole point being that once the oil relief bypass moves and relieves pressure it can get stuck depending on condition.
It is a known problem with type 4 that excessive oil weight and cold weather can bypass oil cooling. It may also be causing fluctuation of your gauge pressure.
As Modok noted....after all this time....anything might be the condition of your oil pressure relief and control valves. Ray |
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nextgen
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| Posted: Sun Dec 03, 2017 3:04 pm Post subject: Re: Type 4 oil pressure issue |
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Ray, as you know I have run t-4's engines in my bugs, but only in the last 10 years on my high milage bug no longer run my bug in the winter, rarely does it see 32f. One Reason is it will be hell to get it to running temp. Question I run 20 w 50 Mobil One high milage Oil , do you think the synthetics have an edge on the pressure issue or 20 w 50 can be expected to act the same as dino.
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Jubbly Bug
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Joined: September 21, 2008
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Location: Skelton North England
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| Posted: Sun Dec 03, 2017 3:14 pm Post subject: Re: Type 4 oil pressure issue |
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Ok cool thanks for the advice . Il inspect the oil relief valve and get back to you . Can I ask again what was the fuel block off bushing I need to check ?.
Thanks again for the advice
Jim
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raygreenwood
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Location: Oklahoma City
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| Posted: Sun Dec 03, 2017 3:36 pm Post subject: Re: Type 4 oil pressure issue |
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| nextgen wrote: |
| Ray, as you know I have run t-4's engines in my bugs, but only in the last 10 years on my high milage bug no longer run my bug in the winter, rarely does it see 32f. One Reason is it will be hell to get it to running temp. Question I run 20 w 50 Mobil One high milage Oil , do you think the synthetics have an edge on the pressure issue or 20 w 50 can be expected to act the same as dino. |
Very good question!....Here is my answer.....in a nutshell....yes.....and it gets into things that are a lot more detailed than we want to get into in this thread
Bear in mind a 20-50 oil.....is a 50 weight oil. It does not magically turn into a 20 weight oil at some point. Oil is thixotripic. It is shear thinning by nature.....some more or less than others depending on base and additive package. Like most shear thinning fluids... it also thins somewhat by heat rise. In reality its less of a viscosity drop than it is a flow rate change.
While those two factors are joined at the hip.....they are not interchangeable.
A 20-50 oil is a 50 weight oil that has been shear stress modified to have....when cold....a 50 weight viscosity with a 20 weight flow rate.
It does not have an effective 20 weight viscosity. And.....as others have noted.....the flow rates and viscosity stability of modern oils are worlds away different from the oils of 40 years ago. Also.....with almost any multi-weight oil....once they start heating up and shearing......they are never exactly the same viscosity wise as their single weight counterparts. Typically.....a straight 50 will handle a little more heat and shear and drop viscosity slower.
From what I have seen and experienced....the modern synthetics appear to be a little more accurate with regard to cold weather flow. Ray |
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raygreenwood
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Location: Oklahoma City
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| Posted: Sun Dec 03, 2017 3:41 pm Post subject: Re: Type 4 oil pressure issue |
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| Jubbly Bug wrote: |
Ok cool thanks for the advice . Il inspect the oil relief valve and get back to you . Can I ask again what was the fuel block off bushing I need to check ?.
Thanks again for the advice
Jim |
If yours originally had a stock mechanical fuel pump for carbs.....under cylinder #1 down near the bell housing bolt.....the pushrod for the pump went through a pressed in bushing. That bushing plugged the acces hole for the drill that made the bore. A very gew make the mistake when they remove the pump and pushrod and install a block off plate.....of pulling this bushing out. It causes oil to dump back into the case and negates the spring pressure effect of the control valve just upstream. It can be the cause of chronic low oil pressure.
But...you note that once warmed up...pressure is fairly stable. I am betting you have a pressure relief issue at the piston and spring......or a gauge sender issue. I would check with a standard mechanical pressure gauge. Ray |
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nextgen
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Location: CONGERS, N.Y.
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| Posted: Sun Dec 03, 2017 9:00 pm Post subject: Re: Type 4 oil pressure issue |
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OK Ray seeing I am on a roll, one last oil question. If you have a dish with Dino oil and one with Mobil I Synthetic, and hit them both with a blow torch, the regular oil will burn and char, while the Mobil 1 will look the same.
So if you have a high mileage car and you use regular oil and find out you are burning 1 quart in 1500 miles ( no leaks ), seeing the Mobil 1 does not burn will it last loner in the same engine?? Actually have a car burning regular oil at 160000 miles and after my last question this popped into my head. I personal have done the blow torch test.
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