mx5cartalk.com

So as part of my regular servicing routine I cut open my oil filters. About 5000kms ago I did an oil change after a track day at Mallala, cut open the filter at work and found a lot of metal inside. Ran a magnet underneath and I'd say 10-15% of the particles were magnetic and the rest were non magnetic. Great.

Ran the car on Penrite HPR15 for another 1500kms and a hillclimb day at Collingrove and did another oil change but also had an oil analysis carried out. FIlter turned up with some particles but i=Id say only 50% as much as the previous filter (the first filter had done roughly 5000kms and the sprint day).

I received the results from the analysis today (attached). The guys at the analysis shop said the aluminium content was slightly high but not in the area for concern (around 15-20ppm). This is only my first analysis, so I will do another one to form some kind of trend and have a baseline to work from.

6000kms ago I had the head overhauled (new valve springs, valve guide seals, re-cut valve seats etc) and a new head gasket fitted. When I found the metal in the first filter I went into the workshop that did the overhaul and spoke with the owner thinking that it was let over swarf or something of the like. He assured me that everything was 100% clean and that with this amount of metal something bad was happening.

I was hoping someone could shed some light on this for me as I'm a bit confused with the info I have. My filters are saying that something is failing but the oil analysis is showing everything is relatively okay.

Could it be left over bits from the head overhaul? Should I be concerned with what I have found so far? Would pictures of the filters help?

Any help is much appreciated!

Note: We have a proper tool at work for cutting filters open, not a hack saw like some people.

Hi.
I would say the debris is from the head job as you say it is reducing over time and it has a high concentration of alloy. Nobody who does any engine/head work will ever admit they do not always ensure the job is as it should be. ( the man you spoke to may not have done the work) I always thoroughly vacuum/blow out a cylinder head after it has been worked on.

Thanks for the reply mate. I understand no one will admit to not doing the work 100%. I did push him on the about how clean the head was when it went back on the car and he said it was 100% clean. Ill take it with a grain of salt I guess.

The particles I found in the filter are not all small "grains". There were quite a few long slithers of non magnetic material which is why I am so concerned. I also found large chunks of metal in the drain pan after the last oil change. One piece looked like brass too.

If I only had small grains through the oil filter and the levels were decreasing I wouldn't be all that worried but seeing large pieces has me concerned that, a) poor cleaning of the head when it was assembled, or, b) something is slowly ripping itself apart.

I'll get some photos of the filter as well.

ralt wrote:Hi.
I would say the debris is from the head job as you say it is reducing over time and it has a high concentration of alloy. Nobody who does any engine/head work will ever admit they do not always ensure the job is as it should be. ( the man you spoke to may not have done the work) I always thoroughly vacuum/blow out a cylinder head after it has been worked on.

hehe..... head job....

HPR15 is pretty thick for a b series engine. Got worn oil rings?

6000kms ago I had the head overhauled (new valve springs, valve guide seals, re-cut valve seats etc) and a new head gasket fitted. When I found the metal in the first filter I went into the workshop that did the overhaul and spoke with the owner thinking that it was let over swarf or something of the like. He assured me that everything was 100% clean and that with this amount of metal something bad was happening.

I'd be concerned that the workshop who did the overhaul made the comment '...that with this amount of metal something bad was happening' but seems to not have bothered to rectify the 'problem'

Project R. I read on a forum that HPR15 was okay in the older engines (mines) due to the zinc and the viscosity wouldn't hurt anything. Car seems to run fine. Starts up fine in the morning, no smoke etc. Also quieter. What do you run?

Zero00. Yes I too have concerns with the work done, but it is a reputable workshop who is involved in racing and prepping cars, building clubmans etc. I'm a little hesitant to start claiming poor workmanship too the workshop.

Looking at options at the moment. If I pull it out/rebuild it I don't see the point putting something slow and stock back in. I'd put a turbo on it but I don't have the cash at the moment to do it properly (g/box, diff, clutch legalities).

track_addict wrote:Project R. I read on a forum that HPR15 was okay in the older engines (mines) due to the zinc and the viscosity wouldn't hurt anything. Car seems to run fine. Starts up fine in the morning, no smoke etc. Also quieter. What do you run?

I used to run HPR15 in my BPs also due to age. But told it was too thick also. Switched to HPR5 which is same viscosities at 25c, 40c and 100c as old skool mineral 10W-30. But a little smoother revving and likes 5000-6000 rpms range better with HPR5.

As you highlighted you need some history and a baseline to determine what is going on. Whilst what you are describing is of concern if it has decreased since the last oil sample then your concerns may not be needed. If it is getting worse discuss the oil samples with the engine builder and see what they make of the results. Have you already discussed the sample results with the builder?

Zero00 - I'll give HPR5 a run next time around. Only reason I've stuck with the HPR15 is for better accuracy with the oil analysis.

Magpie - The decreasing amount of metal might be due to the fact tthat the second filter only did 1600kms. Where as the first filter did 5000kms and a track day. I'm going to do another 5000 on this filter to confirm if its decreasing.

I haven't spoken to the workshop that did the head work but I spoke to the mechanic who did the removal/install of the head. He says the results aren't that bad at all. But I did find a large piece of brass coloured metal in the bottom of my drip tray at the last oil change. This was amoungst other pieces of metal. He said the only place the brass coloured metal would of come from is the bottom end as no metal of this kind belongs in the head. He was very concerned by this piece of metal.

track_addict wrote:He was very concerned by this piece of metal.

This would have me concorned enough to not drive the car until the source of the contamination was found.

My plan is to also do oil sampling every service once my build is complete. This will allow a history to be built up as well as identify any problems very early on.

Brass is usually from bearings.
Rod bearings, main bearings etc.


Generally not good.

Ask me how I know..





Note the skyline had a lifter type knocking sound on cold starts and very light ticking at idle when warm.
Still made bulk power and didn't miss a beat.
But will eventually.

Magpie - That is exactly what the mechanic has said. I'm going to sell the car and upgrade to an SE but this has really thrown a spanner in the works. I couldn't sell the car to someone and not tell them about the problems but I don't want to let it go for a few grand. I think my best option is to get another, good condition motor and put that in. Im just hesitant because I dont want to go spending another $2000 on a car I just want to get rid of.

TTT - Thats exactly how my drip tray looked last oil change! Did you fix the skyline or sell it on?

Sold it. Showed the guy the pics and explained the noise. He is a mechanic and didn't care all that much. Replacement motor is about a grand.