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Fri Aug 01, 2014 5:16 pm

as41 case tapped and drilled for Full flow
external oil filter
30mm pump - new no wear - drilled and tapped
primed with light grease
Oil is pumped at the sender when the engine is turned over
the light on the dash never goes out

I have tried to prime this thing but it just wont build pressure. Both relief and control pistons move freely. oil is pumped from sender hole when the engine is turned over but when sender is replaced no oil pressure registers at the dash. I have checked with three senders...one that was working before, a new one, and a spare...none work.

Any help?

Thanks.
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Fri Aug 01, 2014 5:59 pm

You need to explain this a little better , does it run ?? have you put a mechanical guage to see if its really got pressure or not ?? you cant base yourself on an idiot light ???

Fri Aug 01, 2014 6:03 pm

Pull the oil control valves and take a look at the seating surface in the case. Are u sure the bearings are correctly sized?

Fri Aug 01, 2014 6:40 pm

Does the light go out when you disconnect the sender?

Fri Aug 01, 2014 6:42 pm

mschulze wrote:
the light on the dash never goes out

Could be a problem with the wire harness.
Try to wire a little lamp direct to the sender.
Or check with a multimeter for discontinuity.

Fri Aug 01, 2014 6:55 pm

Make sure oil filter is 100% full before installing.
Does light go out when you ground it ?

Fri Aug 01, 2014 6:59 pm

I have encountered this problem before on full flow systems.
First I do not use any grease on the oil pump(after all it is an oil pump not a grease pump). I always prefill the oil filter and remove the oil pump outlet hose from the filter housing and pour the last 1/2 quart of oil down the hose then reconnect the hose and your engine will prime very quickly. On the last install that I did I installed a T on the oil filter inlet housing and use a pipe plug to seal the top port so I can remove the plug instead of the hose and fill the oil pump with oil.
Good Luck
Kenric

Fri Aug 01, 2014 7:15 pm

You need a working, accurate pressure gauge to diagnose this. Piping a tee into the full flow system and using a mechanical gauge is inexpensive and easy. Did you plug the case where the oil inlet "used" to be (from the pump)?

Fri Aug 01, 2014 8:53 pm

Light works fine...comes on when ground...goes off when not
Engine runs - I ran for 3 sec -
I havent hooked in a machanical gauge at the pressure sender opening before...good idea -> oil IS pumped from that hole pretty good when engine is turned over though
Filter was full
pump and case are both tapped and plugged
bearings were mic-ed and are acurate
control and relief valves are smooth, move freely, and seem to seat well. Seats also seem to be in good condition

Fri Aug 01, 2014 9:01 pm

If oil comes out the sender hole when you crank it, you DO have pressure. The sender is bad.

Fri Aug 01, 2014 10:10 pm

I hope you are NOT USING teflon tape on these senders?

Fri Aug 01, 2014 10:55 pm

It's your sender-go get a mechanical sender to verify.

Fri Aug 01, 2014 11:39 pm

74 Thing wrote: It's your sender-go get a mechanical sender to verify.

Its not the sender. I have tried three. 1. Proven working 2.brand new 3.spare from a previous engine. I could believe one or two going down out of the blue...but not three.

What would teflon...present or not...have to do with a lack of pressure build-up? Even if there was teflon present it would not be covering the hole in the switch and wouldnt interfere with the oils ability to actuate the little piston/spring in the pressure switch.

Sat Aug 02, 2014 5:23 am

Since teflon covers/seals the threads, it can keep the sender from actually grounding in the block. I would check the engine with a mechanical gauge.

Sat Aug 02, 2014 6:33 am

If the sender were insulated from the block the light would not come on at all.

Sat Aug 02, 2014 6:51 am

Quokka42 wrote: If the sender were insulated from the block the light would not come on at all.

Ditto....

I would use mechanical gauge to test with ... Having evidence of oil at port and having oil pressure are two different things...

Dale

Sat Aug 02, 2014 8:00 am

Go pick up one of these, screw it in and fire it up.

http://www.harborfreight.com/160-psi-dry-gauge-68248.html

Sat Aug 02, 2014 8:47 am

raul arrese wrote: You need to explain this a little better , does it run ?? have you put a mechanical guage to see if its really got pressure or not ?? you cant base yourself on an idiot light ???

Just like I said on the first reply .... just keep on trying with the "IDIOT" light ..

Sat Aug 02, 2014 9:59 am

When I did the break in, the light took about 1 minute to goes out, before first start. I used the cheapest 20W50 I found from the known brands. The filter was a Fram, don't remember the code, but a PH8A size.
After first start, when idling, the oil light never switched on and the pressure reading was slightly over 40 psi @ 3000 rpm.

After about 1.000 km I drained all the 20W50 oil and filled with a full synthetic Shell 5w30 and changed the filter to a Fram HP1.
This time, after start and when idling the light doesn't switched off, it happened only at higher RPMs.

Immediately after this oil change I did a 250 km trip. I was cruising at 2500 to 3500 rpm, the oil light was switched off all the time and the oil pressure reading was slightly below 40 psi. But when I stopped at the toll booth, after 100 km(60 miles) or so, the light switched on (idling - see video, oil light is on the 2nd gauge from left to right) and the pressure readings was about 30 psi or a little less.
I checked the oil level and everything looked fine.

At the end of the trip, the oil light was no more switching on at idle - and not even at 800 rpm range.

Currently, the light stays switched off all the time after the ignition. The pressure numbers are about 10% higher at mid to high rpms when compared with the ones of the first kilometers, and about 20% higher when the comparison is with the idle numbers

I don't have a theory for that behavior. Maybe air in the oil galleries and filter needs more time to be released with thin oils...? Fram HP1 filter is bigger then that one used under the break in.

After all my conclusion is: In the first 100 km or so, the oil pressure of thin (full synthetic only?) oil is somewhat low. Not that much, but enough to panic the idiot light :) .
Same is expected with heavier oils, but since those build more pressure, this effect is less perceptible because is not enough to activate the light.

Probably the oil light had never goes out after the rebuilt, if I was priming the engine with a thinner oil before the first start.

Just my 2 centavos.

Note: The red oil light is not blinking. The effect is because of the steering wheel spoke covering it, depending on the position.

Sat Aug 02, 2014 11:55 am

Try cracking the oil line hoses loose and turning the motor over to bleed the air out of the lines. when you have oil trickling out of them tighten them up. One other check is to make sure the oil pressure relief plungers are installed properly. Plungers go in first then the springs. I have made this mistake before.