Jump to content
SAU Community

Recommended Posts

R33 Series 2 1997 RB25DET

Rattle from cold coming from top end.

Doesn't reduce, as it gets warmer.

Never run for more than a minute as it sounds scary.

Oil Cap off whilst running has no oil sloshing or splashing inside.

Cam lobe on show is almost dry

Oil Pressure on guage seems to stay a little elevated

Normal Service History and Oil/Filter changes

Oil is a little dark but not too bad

Noise all of a sudden came on according to Driver

Car has now been parked gathering dust

160k on odometer.

Blocked Oil Feed Galleries?

Is there a screen filter installed somewhere in the head/block or into camshaft followers ?

Where does the oil enter the Camshafts

Any ideas... apart from Oil Flush and Change.

Is there something that could be blocking the oil access to the top of the head ?

Very perplexing...

Normal service history means what exactly?

There are check valves in the oil feeds/restrictors if they are factory which stop oil from draining back if I remember correctly

If it were me I would start by pulling the cam covers off and having a proper look. Probably also worth pulling some cam caps to make sure that the oil starvation hasnt caused major issues (pull them off one at a time or pull them off evenly)

There is no real way to diagnose it without starting to pull it apart. There is still oil pressure which is a positive signt that the bottom end is likely still getting oil. It also points to a problem in the head or where the head gets its oil feed from the block which is through the restrictors and up through the studs holes

Thanks Callan,

From what I understand, normal service history means regular oil changes although, I am not sure the grade of oil.

Coolant looks good, there are no leaks and apart from a couple of broken exhaust manifold studs the engine appears to be in good order aside the poor clatter from the top end and the obvious lack of oil in the head.

So there are restrictors in the head for the oil supply? Where are they and can you clear, or change them from under the rocker covers?

Good idea on pulling the rocker covers off and having a look... I will try that soon.

Stephen

Some times loosening up all the crap will be more likely to block oil galleries , so I wouldn't bother in this case.

Sounds like it's minimum head off, and to do it properly it's engine out.

I would go head off. Poke into restrictors to clear blockage, crank engine to spit out chunks in the oil, repeat. Or tap a thread into stock restrictors to pull them out and crank engine over to get rid of blockage and swarf caused by tapping. Then replace with new restrictors. Assuming the engine is worth saving.

Is it worth putting through an engine detox or engine flush plus (leaving it in longer) or is it way past that ?

Going to try that first... bathe the top in some oil and then add some cleaner and see if the noise disappears or changes.

Some times loosening up all the crap will be more likely to block oil galleries , so I wouldn't bother in this case.

Sounds like it's minimum head off, and to do it properly it's engine out.

I would go head off. Poke into restrictors to clear blockage, crank engine to spit out chunks in the oil, repeat. Or tap a thread into stock restrictors to pull them out and crank engine over to get rid of blockage and swarf caused by tapping. Then replace with new restrictors. Assuming the engine is worth saving.

There are no visible signs of damage and it has been only ran for seconds not even a minute. Sure it will be fine.

Edited by Stephen Thorpe

No I haven't... car is just parked for the moment. I will do this soon though. The one cam lobe I can see looks really good so hopefully all the bearings and cam is the same.

are you sure its not just the usual lifter noise that these motor can develop when older like they all are these days?

Im unsure of your experience with the origin of the problem based on your write up. is it your car n it just started one time or is it a car you are helping out on? did it start on a drive or on a start after sitting for a long time?.

  • Like 1

You get some oil via the VCT as well. Your engine is not going to get anywhere near operating temperature in one minute. When did you last have an oil and filter change?

what exactly does it sound like?

https://www.youtube.com/watch?v=HtKMpKTZFYo

otherwise

are you sure it isn't some form of cam belt n harmonic noise that a lot of people experience?

https://www.youtube.com/watch?v=m7RvBYe1o4A

https://www.youtube.com/watch?v=YgKneqCQLi4

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...