Rebuilt Mi16 Oil Pressure Issue

[unariciflocos 49 1 Cars]

The oil pressure on my rebuilt Mi16 seems to drop off to 0 or below under hard throttle. Low pressure or stop light never come on, not even when the needle is way under 0, but can't test that extensively as I need to take it to the limiter for the it to do this and that's not really appropriate around town .

 

I did search and some people had it down to loose crank pulley bolt, defective oil pressure sensor or poor wiring. Before I check all these I want an expert opinion on something I read which kind of scared me. Someone said that under hard throttle the rod bolts stretch and that's where the oil pressure goes. Is this possible?

 

Now that I;ve run the engine in, I have to change the oil. What should I chose between Agip Racing 10w60, Agip Racing 5w50 and Castrol Edge sport 10w60? On hot days after some abuse the oil I have now disintegrates and oil pressure is really poor at low revs, on the first line.

 

Thanks,

Andrei

[Anthony 1,003]

If the low oil pressure and STOP light are not coming on then initiailly I'd suspect the oil pressure sender and wiring as both cause problems.

 

A mechanical oil pressure gauge is ideal for confirming that the engine itself is fine and there's not an oil pressure issue

[unariciflocos 49 1 Cars]

Bought 6 liters of Agip Racing 10w60 Synthetic motor oil, Castrol was almost twice as expensive and I've not had trouble with Agip in the past. Hoping this will improve pressure with the engine hot.

 

Am I ok to trust that the engine is fine if the stop light doesn't come on? Both the low pressure and stop light come on before I start the engine, so I know it's working.

[large 33]

TBH no one in there right mind is going to say "yes the engine is fine, rev the nuts off it".

 

As Anthony has said as the oil pressure and stop light are not coming on it points to the pressure sender or the wiring. Fitting a mechanical pressure gauge would be the way forward.

 

I get this problem from time to time and I found it was down to a bad connection on the pressure sender.

[unariciflocos 49 1 Cars]

That makes sense.

 

It's just that I've been working on it million times more than I've been driving it and I'm just a bit tired to be honest. Was just hoping someone would tell me to just drive it and enjoy it and not think about it so that I wouldn't have to deal with it any more and then if something happens place the blame on him.

 

I'll just change the oil and investigate over the weekend. I've search and seems that the low pressure light comes on at under 14 psi or just under 1 bar, so I'm a bit relieved and I think the car will be ok if I keep it under 5k rpm until I sort this. If I think about it I didn't do a really good job on the sensor wires and the oil pressure wire is added in two places with just insulation tape over and no soldering.

 

Thanks for the advice guys.

Edited April 14, 2011 by unariciflocos

[macaroni 17 1 Cars]

I had exactly the same symptoms on my car, after a bottom end rebuild, and changing the oil pressure sensor for one I know showed good pressure, sorted it out.