View Full Version : My Compression test results
Cylinder Number:
150 psi
000 psi
155 psi
160 psi
165 psi
085 psi
Spark plugs #2 and #6 are not happy either (See attachment)
So I guess it's 'head off' time.
Oh dear mate, dont look good.
Could you see down into the pistons to see what they are like?
doesnt a 000 reading mean a lost valve or similar?
JB
doesnt a 000 reading mean a lost valve or similar?
Yeah I think so. Or a holed/broken piston.
Yeah I think so. Or a holed/broken piston.
what brand of fuel were you running?
I have heard of somebody who lost a piston because their fuel filter was clogged, might be worth checking that when the car is being fixed.
Terry also said he can get full engines at a reasonable price so worst case that might be the way to go.
Feel gutted for you, this would be my worse nightmare. I wouldnt be able to afford to get it fixed and the car would just sit there while I save up for a new engine.
JB
Could you see down into the pistons to see what they are like? Not really. I did try with a flashlight but all I could see was shiny blackness. Like looking into a puddle of oil.
As soon as I withdrew plug #2 from the hole some of the same white smoke drifted out. The smoke smells of antifreeze so I guess the headgasket has gone as well. BHG wouldn't cause 0 psi on the compression test though, would it?
Like you say, you need to get the head off and see whats gone on before making asumptions. Are you going to take it apart yourself?
Ouch :cry: Look like 2 Cyls down there and the plugs confirm it ....well its now down to the lesser of 2 evils..Head off ..and see if you have taken out valves ( wish and hope ) or worst worst case is fried pistons and scored bores.....so sorry to hear this you need it like a whole in the head .
Again :cry:
I wouldn't have thought compression would drop to 0 just on a HG, but may be wrong.
If you can smell anti-freeze, and HG isn't gone.... <GULP> :cry:
Don't panic yet, it's still all inconclusive. Get the head off ... you know Tel will sort you out with a new shortblock if you need it. Arnout does exchange heads for VVTi's with special bits ;)
If the engine let go you can guarentee the turbo's are dead too. :( But this is what this community is for...we'll find you the bits and save you a packet over Mr. T. But I'll say this now, don't scrimp, pay once fully and dont cut corners or you'll pay twice.
what brand of fuel were you running? It was an Elf petrol station, JB. I was desperately low on fuel and was going to do a 'splash and dash' to get me to a Shell/Esso garage but I saw they did SUL97 and thought it would be OK just this once.
It wasn't even cheap! It cost over £60 to fill her up.
ELF & TOTAL are the same, I've used TOTAL on mine and she's still here.
ELF & TOTAL are the same, I've used TOTAL on mine and she's still here.
Indeed, Lord Mycroft used to say that Elf/Total was the best fuel around. The only problem with Elf stations is they arent normally busy enough to turn over enough fuel so it could be it had degraded a little. I still think theres something else to it though, either a bad fuel pump or blocked fuel filter which caused it to run lean, and combined with the heat it just killed it. Im sure I lost my UK spec turbos last year because it was a seriously hot day and the cooling just wasnt there.
JB
Would a low mileage (less than 36,000) 1998 car have a tired fuel pump or clogged fuel filter? Seems unlikely but anythings possible I suppose.
Indeed Mycroft did used to bang on about that ;)
The cause could be so many things....getting the injectors flow tested would be good, same with the pump and the filter. The FPR, could have locked up in the heat. Could have just been a build up on the plugs inhibiting the spark...Jake, does it have an atmospheric BOV? An atmos BOV could have caused the issue cause this car has a MAF, everytime the BOV lets go the fueling would have been mad rich. Have to say it never killed my VVTi before my upgrade, but I really noticed it once I put the 650's in.
Anyway, Jake needs to do lots more investigation work before we go bonkers on ideas why it happened.
Ouch mate, this hurts.
The missing bits from the plugs could potentially render the head useless, and damage the turbos too (you got one in each set of exh runners, so both turbines could be shagged)
Sux big time.
Would a low mileage (less than 36,000) 1998 car have a tired fuel pump or clogged fuel filter? Seems unlikely but anythings possible I suppose.
That's why I thought of injectors...cause they've not been used much IYSWIM.
By the way it was a Total garage. I only said it was an Elf garage because I looked up the address on http://www.southampton.gov.uk/environment/environmentalhealth/pollution/PartB-Authorised-Processes-in-Southampton.asp
and it said 360 Hill Lane, Southampton is owned by Elf Oil UK Ltd.
As Alex said, Elf own Total so that makes sense.
Would a low mileage (less than 36,000) 1998 car have a tired fuel pump or clogged fuel filter? Seems unlikely but anythings possible I suppose.
First thing I did when I bought the car was change the fuel filter, right after the oil change. You never know.
As for fuelling in general, without a wideband you're in the dark really.
So much for my theory of the VVTi 'overprotective' ECU, eh?
Sorry to hear about this mate. Hope you get it sorted out and keep us updated.
cheers
So much for my theory of the VVTi 'overprotective' ECU, eh?
It can't perform miricles. :)
Jake, does it have an atmospheric BOV? God no. I can't stand the things. Anyway, Jake needs to do lots more investigation work before we go bonkers on ideas why it happened. 'Head off' is the next step, right?
I haven't had a car cylinder head off for like 15 years. I've done a few though. Anyone know of a "How to take your Supra head off" guide?
I'm not looking forward to this job but hopefully with you guys support I'll struggle though.
Thanks fellas, you're all stars
:respekt:
There's a manual source on MKiV or bung me an email addy and ill see if i can PDF you the guide. Lets just hope you see none of this when you take it off
sorry to hear that mate! :( car's are nice when they work, worse than a mother-in-law when they decide to break :(
hope you get it sorted mate, and hope it doesn't dent your wallet too much
Chris Wilson
24-06-05, 21:08
I'm sorry to say that i think you should get a short motor ordered up now... I'll put a fiver on detonation causing this, for what reason I don't know, but it needs to be traced so it doesn't happen again.
Sorry to hear of your problems Jake
Before you start ripping it apart, it may be worth getting someone to borescope it.
It will give you a good idea of any damage without having a million pieces lying around your garage.
Hope you get it sorted soon (and you CJ)
Before you start ripping it apart, it may be worth getting someone to borescope it. I was thinking about that Gordon. If an endoscope can confirm that there is piston/bore damage (and there very likely is) the engine will have to come out so there's no point me struggling to get the head off in situ.
How do I find someone with an endoscope who can come to me? I could look up "Endoscopy" in the yellow pages but I don't think I'll have much luck there.
You should also be able to have a good look around the head as well
I would say without a doubt pull the engine. I have found it way quicker to get to short block with it out (and more knuckle skin left intact!) With those compression readings and plug condition, you will almost certainly have major piston/valve damage. Feel for you mate.
Couldnt a BHG cause 000 compression on a JZ engine? It did on an old RS2000 I had, and on 2 cylinders!
Sad to hear this Jake:(
... If an endoscope can confirm that there is piston/bore damage (and there very likely is) the engine will have to come out so there's no point me struggling to get the head off in situ..
A leakdown test can also confirm if the block has to come out.
Not too hard to do, provided that you have an air compressor and the gizmo (you can DIY it or get one from the internet, less than £80 if you look around). You can still turn the engine by hand right?
A leakdown test can also confirm if the block has to come out.
Not too hard to do, provided that you have an air compressor and the gizmo (you can DIY it or get one from the internet, less than £80 if you look around). You can still turn the engine by hand right? Correct me if I'm wrong but a leakdown test would fail if a valve was damaged/leaking, wouldn't it?
I did look into how to do a leakdown test but it mentioned using 70bar pressure (seventy bar! Sod that) I do have a compressor but not a 70 bar one, who does! Where can I get this gizmo you mention?
Yes, the engine turns over fine.
Anyway, I did a compression test and cylinder #2 showed 0 psi. What more would a leakdown test tell me?
Thanks
Correct me if I'm wrong but a leakdown test would fail if a valve was damaged/leaking, wouldn't it?
What do you mean by 'fail'?
A leaky valve would have air rushing through it and you'd know immediately mate. You'd even know if it's an intake or exh valve of that cylinder.
I did look into how to do a leakdown test but it mentioned using 70bar pressure (seventy bar! Sod that) I do have a compressor but not a 70 bar one, who does!
Nobody, 100psi is the norm for leakdown tests.
If your compressor outputs 100psi and the cylinder can only hold 90psi, then we say that you've got 10% leak. You don't even care about that, you just want to see where the air goes
Where can I get this gizmo you mention?
I had found one for £60odd a few months ago ("Lawson HIS" I think was the internet shop, not sure though)
You could even make one yourself, I've got a guide on my website. I made one for less than £20
Yes, the engine turns over fine.
You need to turn the engine bit by bit until each cylinder is at TDC (of compression). Then you pressurise that cylinder. You may need someone to hold the rachet though, as the piston might want to move downwards turning the engine.
Anyway, I did a compression test and cylinder #2 showed 0 psi. What more would a leakdown test tell me?
It would tell you WHY
if you get bubbles in the coolant, you know
if you get air from the sump, you also know
hissing from the intake or exhaust --- you also know ;)
What do you mean by 'fail'?
A leaky valve would have air rushing through it and you'd know immediately mate. You'd even know if it's an intake or exh valve of that cylinder.
Nobody, 100psi is the norm for leakdown tests.
If your compressor outputs 100psi and the cylinder can only hold 90psi, then we say that you've got 10% leak. You don't even care about that, you just want to see where the air goes I don't understand how I could tell *where* the escaping air is going. Isn't a leakdown test not just pressurizing the cylinder and seeing how quickly the pressure drops? How can I tell if it's leaking past a valve or a hole in the piston or whatever? Please explain.
I borrowed an endoscope today. The two pistons with the dodgy compression appear to be intact although the one with no compression at all has two marks in the top of it. I've seen a lot worse though.
Would I be right in thinking an exploratory probe with a telescopic magnet would be an idea? If it brings out bits of piston you know you are in trouble.
If it's the HG it's a head off job, if it's pistons you still need the head off, I'd crack on with taking it off :( It's the only way you'll know for sure.
When mine let go all those years ago, the tops of the pistons looked OK but the edges had eroded away like a lollipop, might not be visible from a borescope exam. Also, my hybrids survived 100% intact, so all is not yet lost on the tubbie front. I guess you'll be taking them off to get at the head anyway, so that's Shit Job No1 on the MkIV you'll soon have under your belt. I'd start putting WD40 on the manifold bolts now :)
Drop me a line if you want to chat about this offline mate.
-Ian
Chris Wilson
27-06-05, 19:27
A leakdown test will show where the compression is escaping, if it's a bad leak by being audible down the exhaust if it's an exhaust valve seat problem, out the intake with the throttle wedged open if it's an intake valve leak, and up the dipstick tube or crankacase breather if it's ring or piston failure. Simple ;)
Would I be right in thinking an exploratory probe with a telescopic magnet would be an idea? If it brings out bits of piston you know you are in trouble. Pistons aren't made of ferrous meterial though.... are they? :conf:
Chris Wilson
27-06-05, 19:29
Would I be right in thinking an exploratory probe with a telescopic magnet would be an idea? If it brings out bits of piston you know you are in trouble.
If it's the HG it's a head off job, if it's pistons you still need the head off, I'd crack on with taking it off :( It's the only way you'll know for sure.
When mine let go all those years ago, the tops of the pistons looked OK but the edges had eroded away like a lollipop, might not be visible from a borescope exam. Also, my hybrids survived 100% intact, so all is not yet lost on the tubbie front. I guess you'll be taking them off to get at the head anyway, so that's Shit Job No1 on the MkIV you'll soon have under your belt. I'd start putting WD40 on the manifold bolts now :)
Drop me a line if you want to chat about this offline mate.
-Ian
He really will be in trouble if he's using magnetic pistons! Cast iron ones? Hewn from steel billet? :D
Ian, your coats hung up over there mate :run: :tongue:
Yeah, that's what I thought.
Magnet for aluminum parts, WTF!?
It's bad enough that many valves aren't magnetic, let alone alloys...
A leakdown test will show where the compression is escaping, if it's a bad leak by being audible down the exhaust if it's an exhaust valve seat problem, out the intake with the throttle wedged open if it's an intake valve leak, and up the dipstick tube or crankacase breather if it's ring or piston failure. Simple ;)
yep, I thought it would be obvious enough Jake.
You see bubbles up the coolant tank, or hissing from the sump or the intake or the exhaust. You get a pretty good idea what doesn't seal ;)
He really will be in trouble if he's using magnetic pistons! Cast iron ones? Hewn from steel billet? :D
Haha I had no idea if the stuff was magnetic or not, metallurgy isn't my bag :) That's why I said "would I be right..." <- hmmm, no then!
Personally I'd have tried it and gone "hmmm, guess they aren't magnetic then". I refuse to feel foolish as I've learnt something new ;)
-Ian
gutted to hear about this jake. hope everything gets sorted at minimal cost for you. :cry:
Just seen this - bummer Jake :(
... I refuse to feel foolish as I've learnt something new ;)
-Ian
Quite right, if we wanted to look and feel foolish they we'd have joined a comedy club, I guess.
I see this as a meeting place where we exchange information and learn from each other.
The only foolish thing for someone would be to avoid asking and make the wrong assumptions later. :)
Mig and I once had a half drunken conversation about using the head as an electromagnet and using it to create a force on the pistons.... we were chatting about it for quite a while I seem to remember, but unfortunately was lashed so can't remember much of what we were saying.
As for aluminium, Everything is magnetic to some degree - even people! ;)
Electromagnetic piston movement with no need for cranks or rods or pins.... + electromagnetic camless valve actuation....the stuff of dreams :) Well Lotus etc have the valve thing but not the crankless engine ;)
Well IIRC it was more like using it to give the piston a bit more of a shove, than replacing components.
Electromagnetic piston movement with no need for cranks or rods or pins.... + electromagnetic camless valve actuation....the stuff of dreams :) Well Lotus etc have the valve thing but not the crankless engine ;)
Crankless engine? Wouldn't that be like having a wheeless car? :tongue:
Need4Speed
28-06-05, 19:18
but not the crankless engine Not sure a crankless engine would be much use.
I would have the engine out. It's got to be easier to check and rebuild in a workshop (assuming you have one) or garage than with the engine still in situ. I must admit, I'm surprised it's not holed pistons.
Best of luck and I hope it turns out simpler than it appears Jake.
Crankless engine? Wouldn't that be like having a wheeless car? :tongue:
Hello, there are pistonless engines out there...
Think I had a brain fart. lol
Winston Wolf
28-06-05, 23:03
I was thinking about that Gordon. If an endoscope can confirm that there is piston/bore damage (and there very likely is) the engine will have to come out so there's no point me struggling to get the head off in situ.
How do I find someone with an endoscope who can come to me? I could look up "Endoscopy" in the yellow pages but I don't think I'll have much luck there.
Jake ,have only just seen this thread.I have somewhere an endoscope burried in my loft from back in the day of detonating 350 lc engines at an alarming rate.
If you havent already decided on the head strip i can try and locate it some time this week.(have not used it for 10 years)
let me know i would gladly lend you if it would help.
Mig and I once had a half drunken conversation about using the head as an electromagnet and using it to create a force on the pistons.... we were chatting about it for quite a while I seem to remember, but unfortunately was lashed so can't remember much of what we were saying.
As for aluminium, Everything is magnetic to some degree - even people! ;)
Blimey ..I do sorta remember that one .....we was a bit lashed at the time ...but hey good ideas happen in a bar all the time ...SHHHHHH you have just given our top secret idea away :p wonder if it could be done :rtfm:
electromagnetic camless valve actuation....the stuff of dreams :) Well Lotus etc have the valve thing but not the crankless engine ;)
VAG group were looking into this in a big way to eliminate cams all together ....I once delivered a prototype engine to the VAG stand at a show at NEC I attended in 1999 and was talking to head tech ...the problem they were trying to overcome was finding solenoids that could react quick enough ...dont know what happened to it or if it got shelved or not ...but think of the possibilities.....very ajustable cam timing
:thumbs:
VAG group were looking into this in a big way to eliminate cams all together ....I once delivered a prototype engine to the VAG stand at a show at NEC I attended in 1999 and was talking to head tech ...the problem they were trying to overcome was finding solenoids that could react quick enough ...dont know what happened to it or if it got shelved or not ...but think of the possibilities.....very ajustable cam timing
:thumbs:
Yeah same with lotus too it, it ran but couldn't be packaged small enough to be practical...but yeah, camless, digitally controlled/adjusted lift and duration, any position at anytime would be fantastic.
Jake ,have only just seen this thread.I have somewhere an endoscope burried in my loft from back in the day of detonating 350 lc engines at an alarming rate.
If you havent already decided on the head strip i can try and locate it some time this week.(have not used it for 10 years)
let me know i would gladly lend you if it would help. Thanks mate but I managed to borrow an endoscope locally.
350LC eh? Fine machines, I've owned a couple of those.
Me too. RD500 as well.
Aaaaaahhhh those were the days....
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