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jas89
Forum Moderator
779 Posts
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 Posted - 28 Jan 2007 : 10:43:41 PM
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hi new to the site, just a few questions
first of, Ive got a standard vn v6 with a bit over 324 000 on the clock it has a sort of crunching noise that seems to be coming from under the inlet manifold, i have taken the belt of and started for a few seconds ,, still there im thinking it could be something to do with the balance shaft.
second question is what is the compression supposed to be as i gave it a compression test and all is around 170 in EACH!!
and lastly(this may sound stupid) but what does your detonation sensor do
THANKS
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mouce
National Driver
1525 Posts
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Posted - 29 Jan 2007 : 12:08:44 AM
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Welcome to the club, hope you get a lot out of it, and put a bit back into it too 
First up, taking the belt off and starting it? I'm really hoping that it wasn't more than a few seconds, that's really not a great thing to be doing. BUT...it's at least eliminated any of the pulleys, which will save a bit of time.
There's a few things under that manifold which could be making a bit of a noise. It could be that you've got some SERIOUSLY noisy lifters in there. I hope you're handy with the spanners (or know someone who is): http://www.vncommodore.com/forum/topic.asp?TOPIC_ID=422
Before you go reaching for the toolbox though, it might be worth flushing the engine oil. There's a couple of ways to do it, and a couple of possible outcomes.
1) Drain the oil, and pour in the right amount of the cheapest oil you can find, drive it for 500km and then swap it out for some good stuff.
The best part about this is that you're only using engine oil to do the flush, the worst part is that because it's just engine oil (albeit really cheap crud) it won't dislodge any of the super-sludge that forms in the engine.
2) Drain the oil, pour in a couple of liters of diesel fuel (where you'd normally pour the oil) and top up to the correct level with fairly good oil. Start the engine, let it run for a while, I do not recommend driving the car with that mixture in the engine, if for some god unknown reason you feel the urge to drive the car, no more than 5 minutes or 10km which ever comes first. Then drain the mixture (and watch the lumps that come with it), flush with some cheap oil (as per step 1), then fill up with good oil.
The best part about this is that the diesel while providing a small amout of lubrication acts as a solvent which dislodges a whole lot of super-sludge that normal oil won't move. The bad part about this is that sometimes this sludge can block the oil pump pickup pipe, which means that you need to drop the sump off to clean it by hand, which means taking the engine out.
Having a compression somewhere around 170 sounds about right, what units is that in? More importantly you have all of the cylinders reading about the same. Mine, from memory was about 170 in all of them. So long as they are all similar and all above 150 you've got no problems. If one is way above or below the others, then you've gotta problem on your hands.
The det(onation) sensor (and this is going to sound kind of blonde) detects detonation. Okay...seriously, detonation is bad (as opposed to ignition which is good), it's when the fuel ignites before the spark has fired, it's the pre-cursor to pinging. It's something that should really be avoided. The det sensor is a fairly robust little sucker, and in stock engines I've never heard of a det sensor setting off an alarm unless the engine was well and truly about to blow up...why do you ask? |
Bite off more than you can chew, and chew like hell - Peter Brock (1945-2006) |
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jas89
Forum Moderator
779 Posts
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Posted - 29 Jan 2007 : 12:45:12 AM
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thanks for posting back
the car is curently of the road at the moment as i just brought it three weeks ago and tidying it up before Roadworthy
i know it wasent the best thing to take the belt of' it was only for about Two seconds
as for the noise was thinking it might be the balance shaft as they start to make a lot of noise over time,this noise is in my parents vn and sisters vp but not as bad as mine
as for the det sensor, i was reading in the Gregory's manual and came across it,also do they need changing over time like 2 or 3 years, like the oxygen sensor does |
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SWEET
Fully Licenced
600 Posts
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Posted - 29 Jan 2007 : 02:48:21 AM
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| hi mouce me again i was just readin wat u wrote and u said put cheapest oil in in the first step after drain it and put the good oil with deisal fuel. i was just wondering y cuoldnt u put the cheap fuel in with the deisal cos ur gonna drain it out anyways. oh yeh and 500km is a very long drive lol. its like melb to phillip island and bak lol. oh yeh and wat r the chances of doing this and the sludge will block the oil pump cos i dont plan to take the engine out lol. but other than that i wouldnt mind trying the things u just said just to surely clean my engine out. and wat is a compression test and how do i do it is it easy? thanx agin b4dn xxxx |
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jas89
Forum Moderator
779 Posts
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Posted - 29 Jan 2007 : 10:16:25 AM
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yeah i Wouldn’t mind giving the engine a cleanout, but it's the risk of the pick up pipe becoming blocked thats stopping me from doing it at the moment
if the pickup pipe does become blocked is there any way you can clean it without taking the engin out as i dont have a engine crane(yet)
thanks |
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mouce
National Driver
1525 Posts
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Posted - 29 Jan 2007 : 10:30:26 AM
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The reason that I suggest putting about a 50/50 mixture of diesel and good oil in there, is because while diesel does provide some lubrication, it helps to have some really good quality slipery stuff in there at the same time. It would be possible to do it using really dirt cheap oil, hell...if you wanted to you could do it with used engine oil, but using a couple of liters of good engine oil just makes it slightly less harsh on your engine.
As for the chances of blocking the pickup when you flush it with diesel...I'd say that probably one in eight. BUT...after you've done it once, if you do it again at every second oil change the chance of it happening seriously drops.
500km isn't that much of a long drive. Not when you consider that oil should be changed at (no more than) 10,000km. Hell...I've done several trips where I've racked up more than 1,000km in a day.
A compression test isn't that hard to do, and can tell you a lot about the internal condition of the engine without having to open it up. I'll do a bit of a write-up when I get a chance. It's about time I did another comp test on my engine...so I think I've just found an excuse to get my hands dirty again. |
Bite off more than you can chew, and chew like hell - Peter Brock (1945-2006) |
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SWEET
Fully Licenced
600 Posts
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Posted - 29 Jan 2007 : 10:59:17 PM
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ohhhhhhhh ok:) did u do 1,000 ks around melbourne in a day? lol coolz cant wait for that right up do u need any toolz to do the comp test? like gadgets and stuff?
thanx again agiain again again mouce.
b4dn xxxx |
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