Oil jet spray

Hi guys, sorry if the title is a bit confusing but i think thats what the part is called. Anyway i took my car in for its service on saturday and when the mechanic removed the oil filter he mentioned that it looked like one of the oil jet sprays had snapped off. Heres a picture of the part i mean, This is from a focus but it has the jets in each cylinder. Is it a big issue if one of these has come off, just to clarify it looks like the tube part has come off and the main bit is still attached. Ive had a look on several pictures of the 996 engine but i can't find these bits anywhere. Is it an engine out job to fix? Cheers guys Chris

The oil jet spray is generally used for piston crown cooling rather than lubrication Chris. I don't know if your engine actually uses pipes (as on the Focus illustrated) or if spray nozzles are incorporated in the crankcase. It might be worth contacting someone like Hartech or Autofarm for a definitive answer to this and advice as to whether or not access can be obtained without removing the engine. Keep us posted. Jeff Edit: Just found this on rennlist for a related issue: http://forums.rennlist.com/rennforums/996-forum/669153-cooked-piston-damaged-oil-spray-jet.html It appears as though the 996 engine uses spray nozzles. Unfortunately, it raises the question of what your technician has actually found! Jeff

Bazhart has put plenty of info on the forum concerning cylinder scoring where he talks of the cylinder oil jets, best for a quick answer to call him at Hartech or read some of his output if out of hours. Expect it to be an engine out job. Do you have the part they found? So that it can be positively identified?

Just as Jeff & Kevan say:

Richard, an extremely informative diagram and useful to know the opening pressure which I expect is sprung closed at the low pressure. It raises one question and that is what is the oil pressure at what rpm for instance in the 944's when hot the oil pressure once above 2,000rpm was usually above 4 bar so provided we don't load the engines at low revs the oil spray should be spraying the oil into the cylinder, little ends and piston cooling. Is this correct?

I might give those guys a ring. I'm just surprised nobody else has had this problem.

Chris, Go to the Hartech site and read the info on the buyers guide section 5 also, they do an engine rebuild much cheaper than the OPC. I bought my first Porsche from them a long time ago, they're probably more knowledgeable than most OPC tech's but don't have to stick to Porsche rules.

I miss the oil pressure gauge of my previous 911s, but assuming the Cayman is the same, the jets must be spraying from startup when cold. If my memory server me correctly, when hot I seldom saw pressures below 1.5 bars at tickover. Anything above 1500 rpm when hot, and I would think the valves must be open. Of course, the flow would likely also be dependant on pressure and engine speed. What you say sounds right to me. I avoid high loads during warm-up and let the engine rev a little freer, without going above 3000 rpm. The trouble is that the Cayman 3.4 almost has too much torque for its own good. Even when it is warm, I never let the engine labour. I believe it keeps the side loading of the pistons down, which helps to reduce the possibility of cylinder scoring. Just my 2p's worth, of course. Chris - I agree with what's been said. Have a word with Grant or Barry at Hartech. Edit: I find it hard to believe one of those jets would have found its way to the filter. Do you have a picture of the piece they found?

Likewise, on the pressure gauge I really miss having one and it's not even available as an option! I rarely go above 3000 until warmed up and if I do to pass something safely then no higher than a lightly loaded 4000 and even then it's above the first bar of the temp gauge. As you say, with the CS and with the modern engine management systems these engines will pull easily from around 1200-1500 which means comparatively low oil pressure and flow. When warm I like to only load the engine heavily from 3000+ for the same reasons as you state but in traffic I run as low as 2000 on a light throttle. After all when we learnt to drive cars with carburetors they wouldn't pull at all from low revs so it isn't that difficult to drive with one eye on the revs.

Sorry i dnt, ill ring the garage today and see if he still has the bit.

Chris, I take it that they did show you the bit so if they haven't go it then get in touch with Hartech and they will know best what it is, as Richard said it seems surprising that it should have made it all the way to the filter unless that is a small but identifiable part came away from the jet. You don't say which part of the country you're in but Hartech are situated just outside Bolton so it may be a case of getting the car or engine transported to them if you go the way of asking them to carry out a repair. It is a good idea for forum members to enter their approximate location to their profile as it helps others to give quick advice on local dealers, etc

According to the attachment in your original post Richard, the nozzles have an opening pressure of 1.8 bar, so I'd be surprised if they weren't operative from tickover (even with the incredible "demand-controlled" oil pump used in the Gen II engines!?). It's not clear from the diagram whether or not the nozzle protrudes from the main bearing case (the picture in my original post seems to indicate that it doesn't) and might fall off but, as you say, it would be interesting to get Hatech's input. I agree that an oil pressure guage would be a nice addition to the Cayman instrumentation - a bit penny-pinching really. Jeff

It looks like the spray jets/valves are pressed into the main bearing journal webs of the crankshaft carrier, prior to putting in the bearing shells. The oil must spray out the holes in the outside of the carrier. So I don't really see how they could fall out.

As Richard says, they press in when the carrier is separated. A worthwhile change as they are only about 4mm indiameter. I just picked up a set from my OPC today at the cost of about £4 each so not expensive. The small ends are not pressure fed so rely on the squirts of oil for lubrication. Alasdair

So are you stripping the engine down to fit them or is there an easier way?

Chris, Looking at the info' in the pictures supplied by Richard it's a case of splitting the crankcase and carrier removing pistons and crank etc in order to fit a new jet, have you managed to get the piece or confirm it is what they said? It must be a part of a jet which they have identified but whether it needs replacing depends on how critical it is, these jets have a spring closing valve so at low oil pressures this one may actually be passing oil needed by the crank. Have you talked to Hartech yet? And have the OPC confirmed their analysis of the fault.

I'm going to ring hartec on saturday as i get in from work at about the time they shut. He did show me the piece but he has thrown it away now.

Unfortunately Chris, from the diagrams provided by Richard and Alasdair's comments, it looks as though it's an engine and crank out job. It's a pity that you don't still have the offending item for identification. It still does seem unlikely that it was a nozzle since they are a press fit in the journal webs of the carrier. Let's hope it's something less critical. Jeff

Chris, Rereading the thread I see tat you don't actually mention an OPC just the mechanic but did he say it needs stripping or did he just say "I found this" if it was just a small piece of the tip of a jet or a larger piece will make a difference so ask his opinion. A description of size etc. As they say they don't now have it, it becomes less easy for you to make your decision. Where are you, maybe someone can recommend a local specialist who may be able to help either with a borescope inspection ( although access may be difficult ) or just be able to give a straight answer. I hope this all helps. Kevan

Sorry if i have confused you guys, i did see the part and it was approximatly 1 inch long and the hole was around 2-3mm in diameter. I live near hull and i think the nearest specialist in porschetek in leeds. Dont know if they would have the gear tho.

I've not heard any complaints of Porschetek but they're half way to Bolton from you and I have dealt with Hartech many years ago, I would expect that Porschetek are more than capable but to do this job it is a bottom end strip and rebuild so best to get quotes from both after telling them both what you have been told is wrong. Hartech have done some development on improving the oil jets and a few other things but read about it on their buyers guide. Kevan