what was the cause 
No Oil pressure!
No Oil pressure! Well, doing cam install changed out the springs , pushrods, timing chain, oil pump, and cam. Got it all back together fired up great, and since I do have a oil sending unit to tell me how much pressure I was getting we took valve cover off, and watched. No Oil. Ok thinking we not getting any pressure at all. Tried to take the oil filter off and tons of oil. Which we are getting oil pressure down low I beleive but none on the top end.. Anybody have any ideas?
Thinkin either the oil pump o ring is pinched or bad oil pump I bought it used.
Thinkin either the oil pump o ring is pinched or bad oil pump I bought it used.
well ring was fine put old pump back on cause we knew it worked, and still didn't fix the problem.
While taking down the motor yesterday we noticed that a rocker lost off of its needle bearings and most of them were at the bottom of the oil pan.
Could a spun bearing do this? Any other things cause this that could possibly keep us from having pressure up top?
While taking down the motor yesterday we noticed that a rocker lost off of its needle bearings and most of them were at the bottom of the oil pan.
Could a spun bearing do this? Any other things cause this that could possibly keep us from having pressure up top?
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When GM has a lemon engine they drain all the oil from them and turn them on their side and run them until they lockup. LS based engines run up to 48 hours like this. Now I'm not advising for anyone to run with no oil psi. but it shows you how tough these damn engines are..
What type of timing chain did you install? If it was a double roller, did you install the spacers between the oil pump and the block correctly? The driver's side spacer can be installed backwards and block oil flow to the rest of the engine. Either that or a pinched O-ring like you already mentioned.
I'm going through this right now. The current idea is a a cam bearing may have slipped and the oil restrictor isn't doing is allowing too much oil to go by causing very low oil pressure.
The high speed fan was dead on the car without my knowing it, the car would run at or just below the 210 mark on the stock gauge but HP Tunners showed it at 230 when its reading 210 on the stock gauge. The gauge once did reach 3/4 the way to the red line on the temp gauge but I shut it off. We're thinking that if the stock gauge was off by 20-30 degrees then it may have allowed the engine to heat up to the point where the cam bearing could have slipped slightly. Then when the new cam was installed this made the problem worst.
So far we have went through 2 oil pumps, a few new o-rings, 2 oil filters and everything else has been double/tripple checked.
The car starts fine then builds oil pressure then when it starts to reach op. temp, the oil pressure drops off to where at idle the lifters start to clatter.
We plan on pulling the motor and putting a mic. on the cam journals and making sure everything is within spec. then if possible replacing the cam bearings. We're hoping its just a bearing thats slipped and not allowing the oil restrictor to do its job.
We started with 10w-40 and then went to straight 40 and it just takes longer to loose pressure. The pressure loss occurs only at idle after 45-60 minutes of driving/idling.
Anyone with any experience or good sugestions please reply.
~Brad
Car is a 2000 Z28 A4 with 81K
The high speed fan was dead on the car without my knowing it, the car would run at or just below the 210 mark on the stock gauge but HP Tunners showed it at 230 when its reading 210 on the stock gauge. The gauge once did reach 3/4 the way to the red line on the temp gauge but I shut it off. We're thinking that if the stock gauge was off by 20-30 degrees then it may have allowed the engine to heat up to the point where the cam bearing could have slipped slightly. Then when the new cam was installed this made the problem worst.
So far we have went through 2 oil pumps, a few new o-rings, 2 oil filters and everything else has been double/tripple checked.
The car starts fine then builds oil pressure then when it starts to reach op. temp, the oil pressure drops off to where at idle the lifters start to clatter.
We plan on pulling the motor and putting a mic. on the cam journals and making sure everything is within spec. then if possible replacing the cam bearings. We're hoping its just a bearing thats slipped and not allowing the oil restrictor to do its job.
We started with 10w-40 and then went to straight 40 and it just takes longer to loose pressure. The pressure loss occurs only at idle after 45-60 minutes of driving/idling.
Anyone with any experience or good sugestions please reply.
~Brad
Car is a 2000 Z28 A4 with 81K
Last edited by LSWon00; Aug 21, 2006 at 10:18 AM.
Well after the gentleman who put my cam in (MrNitrous) made a few phone calls (thanks Futral!) it looks as though my problem is the old lifters that have 80K on them cannot handle the additional spring load at idle generated by the new springs (lol...go figure) and are collapsing at idle when the oil gets hot and thins out. Time for some new bad-*** lifters.
Originally Posted by JMBLOWNWS6
You got it. The O ring is not installed correct. Do not what so ever start the car anymore. Replace the O ring and the oil pressure sending unit.
There is a screw in these oil pumps that is taken out when ported and it may not have been put back in correctly, if you did buy a ported pump. The other thing is a small dumbbell looking piece in the back of the block ( if the motor was recently freshened up) that may not have been put in or is there but has popped out some. Its a $5 part that sends oil to the top of the motor and also shows no oil pressure because nothing is getting to the top of the motor where the sensor is.....
Try these and also check the other things mentioned. im betting on the oil pump itself as the culprit though.
