Topic: engine compression specs (Read 7869 times)

Chazza12 · « **on:** 26 January 2018, 22:17:30 »

does anyone know the compression specs on 20.16v engine is ? thanks going to check them and see what they are but need a base line to go from. thanks

Nick W · « **Reply #1 on:** 26 January 2018, 22:54:10 »

I wouldn't worry too much about the actual numbers unless you have an accurately calibrated gauge. Good technique, which includes cranking for the same amount of time and with the throttle open, is more important. What you're actually looking for is that all the cylinders give similar readings.

A leak-down test is more useful, but does require more expensive equipment.

Chazza12 · « **Reply #2 on:** 27 January 2018, 06:19:24 »

i have a brand new gauge, needs testing to calibrate. says test the calibration with known pressure, so thought engine compression test, if its out too much need to send it back for replacement, old one had lasted 30 year but its way out. suppose could test it on tyre pressure, just need to know if the pressure is right ? best of 3 gauges ? have 3 digitals. might work..

TheBoy · « **Reply #3 on:** 27 January 2018, 09:35:56 »

I'm with Nick W on this.

The 2.0l is not prone to wear, except cylinder 1, so looking for all 4 to be similar.

Bigron · « **Reply #4 on:** 27 January 2018, 10:08:16 »

I think the OP wants an absolute pressure rather than a relative one, to calibrate his instrument, yes? In which case, he is seeking a known and accurate pressure source for calibration/verification. Where on earth would you find one of those, cheaply? I bet the NPL would want a bucketload of money!

Ron.

Chazza12 · « **Reply #5 on:** 27 January 2018, 17:33:12 »

i will have the bucket load of money lol. thanks TB so cylinders 2 to 4 would be a good reference

.
as this is all can find
The breakdown of the engine name [2] is as follows:
X - Exhaust emissions level: 94/12/EC, stage 2
20 - 2.0 L
X - Compression ratio - 10.0–11.5:1
E - Mixture system - Injection
V - Specific version - Volume Model

Bigron · « **Reply #6 on:** 27 January 2018, 17:59:33 »

Then take your money-bucket and your pressure guage to here:-
https://en.wikipedia.org/wiki/National_Physical_Laboratory_(United_Kingdom)

Ron.

Nick W · « **Reply #7 on:** 27 January 2018, 18:03:31 »

Quote from: Bigron on 27 January 2018, 10:08:16

I think the OP wants an absolute pressure rather than a relative one, to calibrate his instrument, yes? In which case, he is seeking a known and accurate pressure source for calibration/verification. Where on earth would you find one of those, cheaply? I bet the NPL would want a bucketload of money!

Ron.

This is why we're suggesting he actually use the gauge he has, and goes from there. I'm not even sure if the cheapy gauge I have is even marked in units, just various marks.

LC0112G · « **Reply #8 on:** 27 January 2018, 20:03:14 »

The equation for converting compression ratio into pressures is :

P = Po * (CR ^ g) where

P = corrected cylinder pressure
Po = Initial cylinder pressure (at BDC) = 1 Bar Atmospheric (14.7 psi) at low RPM and with no boost
CR = Compression ratio
g (gamma) = specific heat ratio of the gas - somewhere between 1.2 and 1.4 for fuel+air.

However, The problem with a car engine is that the inlet valves don't close till after BDC - It's determined by the camshafts and typically somewhere around 50-60 degrees after BDC. This means the real compression ratio (the Dynamic Compression ratio) will be less than the book figure because the piston is already some way up the bore before the inlet valve slams shut. This is particularly true at low RPM, such as when cranking. Whilst the swept volume of the engine may be 1998cc, the swept volume of each cylinder when the valve finally shuts won't be 500cc. Therefore without knowing what the cam profile is, you can't use the above equation to calculate a reliable pressure (in PSi).

Chazza12 · « **Reply #9 on:** 28 January 2018, 10:42:55 »

just had message back from vauxhall/ well opel germany and they say minuum is 110 psi and max 30% highest and lowest engine cold. other test is running engine for 10 minutes, then test again 115 to 120 psi lowest. still max plus 30%. or cold test with 3 drops of oil in each cylinder. no more than 3 drops. so going to see what it says if it's not raining. missed a bit out max 10% drop between cylinder any more than 10% then there is a problem.

LC0112G · « **Reply #10 on:** 28 January 2018, 20:50:36 »

Quote from: Chazza12 on 28 January 2018, 10:42:55

just had message back from vauxhall/ well opel germany and they say minuum is 110 psi and max 30% highest and lowest engine cold. other test is running engine for 10 minutes, then test again 115 to 120 psi lowest. still max plus 30%. or cold test with 3 drops of oil in each cylinder. no more than 3 drops. so going to see what it says if it's not raining. missed a bit out max 10% drop between cylinder any more than 10% then there is a problem.

Sorry, but 110/115/120 psi is waaaayyyy too low. That's only about 7.6 bar. If the compression ratio letter is "X = 10.0-11.5" then it's going to be more like 200psi/14 bar.

Chazza12 · « **Reply #11 on:** 29 January 2018, 12:52:19 »

well went ahead and done the test.

Dry
piston.
No.1 180 psi
N0.2 185 psi
no.3 180 psi
no.4 180 psi

wet 3 drops oil

no.1 185 psi
no.2 185 psi
no.3 190 psi
no.4 180 psi
so i'm now thinking it might be leaking on the valves a bit would this be the case or does it look about right ?
as oil will seal the piston rings, so inlet and exhaust might be leaking a bit

?
would that sound about right

Nick W · « **Reply #12 on:** 29 January 2018, 13:04:44 »

Nothing wrong there.
What's the fault you're trying to find?

Chazza12 · « **Reply #13 on:** 29 January 2018, 13:51:01 »

i do get engine rock. and sometimes it dont like to go up a hill have to drop down an gear sometimes 2, just started engine up and idle has gone up so think will have to leave it till the oil has dropped down, past the rings, over night should be fine. but main problem was starting engine run up road for 5-6 miles and its gray white smoke,, but had engine head test done and no leaks on that and now water lose. could it be the fuel

?

LC0112G · « **Reply #14 on:** 29 January 2018, 14:51:47 »

Quote from: Chazza12 on 29 January 2018, 12:52:19

well went ahead and done the test.

Dry
piston.
No.1 180 psi
N0.2 185 psi
no.3 180 psi
no.4 180 psi

wet 3 drops oil

no.1 185 psi
no.2 185 psi
no.3 190 psi
no.4 180 psi
so i'm now thinking it might be leaking on the valves a bit would this be the case or does it look about right ?
as oil will seal the piston rings, so inlet and exhaust might be leaking a bit ?
would that sound about right

I rebuilt my C36GET engine last year. Book compression ration is 8.2:1. Measured wet pressures on all 6 were 12 bar (176 psi) +/- perhaps 0.5 bar.

So my take is that all these figures are on the low side for a 10:1 compression ratio - but I don't know anything about the X20XE engine, and I have no calibration data for my pressure gauge, and you have no calibration for yours So lots of unknowns.

The fact that in your results they're all very close says there isn't anything dramatically wrong with any particular cylinder. Doubt it's valve related. It could be overfueling, but you'd expect the lambda sensors to be complaining big time if it were that. How many miles on the engine? If it's a high miler could also be worn rings and/or bores.

Doctor Gollum · « **Reply #15 on:** 29 January 2018, 15:00:35 »

Quote from: Chazza12 on 29 January 2018, 13:51:01

i do get engine rock. and sometimes it dont like to go up a hill have to drop down an gear sometimes 2, just started engine up and idle has gone up so think will have to leave it till the oil has dropped down, past the rings, over night should be fine. but main problem was starting engine run up road for 5-6 miles and its gray white smoke,, but had engine head test done and no leaks on that and now water lose. could it be the fuel ?

If it's only the 8v lump, then it has its work cut out shifting an Omega sized lump around... changing down a couple of gears could be considered normal... $:-\$

120bhp when new, less about 20% to drive the slushbox

Chazza12 · « **Reply #16 on:** 29 January 2018, 15:09:51 »

its 16v. engine. Dr Gollum. pulls away ok . could it be a weak fuel pump. or would engine management say something if it was that, lose increase at 60 to 70 motorway driving, seems like its holding back

need to try and get this figured out as in hospital next week, as liver failing was hoping to get something doe before i have to do nothing for 6 weeks.

Chazza12 · « **Reply #17 on:** 29 January 2018, 15:18:43 »

Quote from: Doctor Gollum on 29 January 2018, 15:00:35

Quote from: Chazza12 on 29 January 2018, 13:51:01
i do get engine rock. and sometimes it dont like to go up a hill have to drop down an gear sometimes 2, just started engine up and idle has gone up so think will have to leave it till the oil has dropped down, past the rings, over night should be fine. but main problem was starting engine run up road for 5-6 miles and its gray white smoke,, but had engine head test done and no leaks on that and now water lose. could it be the fuel ?
If it's only the 8v lump, then it has its work cut out shifting an Omega sized lump around... changing down a couple of gears could be considered normal... $:-\$

120bhp when new, less about 20% to drive the slushbox

its done 149,634 miles ??

Chazza12 · « **Reply #18 on:** 29 January 2018, 15:21:55 »

I rebuilt my C36GET engine last year. Book compression ration is 8.2:1. Measured wet pressures on all 6 were 12 bar (176 psi) +/- perhaps 0.5 bar.

So my take is that all these figures are on the low side for a 10:1 compression ratio - but I don't know anything about the X20XE engine, and I have no calibration data for my pressure gauge, and you have no calibration for yours So lots of unknowns.

The fact that in your results they're all very close says there isn't anything dramatically wrong with any particular cylinder. Doubt it's valve related. It could be overfueling, but you'd expect the lambda sensors to be complaining big time if it were that. How many miles on the engine? If it's a high miler could also be worn rings and/or bores.
[/quote] its done 149,634 miles,

sorry dont know how this quote thing works lol

Marks DTM Calib · « **Reply #19 on:** 29 January 2018, 15:30:03 »

Those pressure are pretty good, particularly given the typically low ambient pressure and the variance in gauges.

Also, the oil test is pretty much useless as next to nothing will get to the rings due to where the plug holes are (centre of the bore) and the slight dish in the piston tops. It will give a slight increase in compression purely down to the fact there is now less space at TDC.

If you are getting the behaviour you describe, check the timing carefully and also check the coil pack (it should fire a spark across a 40mm gap at ambient pressures)

LC0112G · « **Reply #20 on:** 29 January 2018, 15:35:11 »

Quote from: Chazza12 on 29 January 2018, 15:09:51

its 16v. engine. Dr Gollum. pulls away ok . could it be a weak fuel pump. or would engine management say something if it was that, lose increase at 60 to 70 motorway driving, seems like its holding back
need to try and get this figured out as in hospital next week, as liver failing was hoping to get something doe before i have to do nothing for 6 weeks.

If it's your only mode of transport then I'd leave well alone till after you're well enough to fix it - which hopefully will be swift.

Bad lambda sensors can cause similar effects. Not sure if I'm supposed to reveal ABS secrets on here - but the C30SE has an IanM wooo-waaa test and it may work on other Bosch fuel systems. Basically on a warm engine, in neutral, hold the throttle part open - say 3000 rpm. If the engine speed varies slowly the noise you hear will be like a Woooo-Waaaaaaa-Woooooo-Waaahhh sound rather than a constant Woooooooo. Try it at other RPM's. On a C30SE this is symptomatic of a failing lambda sensor, and if you know what you're listening for it can be detected long before the engine management light comes on.

Marks DTM Calib · « **Reply #21 on:** 29 January 2018, 16:16:51 »

I should also add, when was the fuel filter last changed?

Chazza12 · « **Reply #22 on:** 29 January 2018, 16:25:19 »

Quote from: LC0112G on 29 January 2018, 15:35:11

Quote from: Chazza12 on 29 January 2018, 15:09:51
its 16v. engine. Dr Gollum. pulls away ok . could it be a weak fuel pump. or would engine management say something if it was that, lose increase at 60 to 70 motorway driving, seems like its holding back
need to try and get this figured out as in hospital next week, as liver failing was hoping to get something doe before i have to do nothing for 6 weeks.

If it's your only mode of transport then I'd leave well alone till after you're well enough to fix it - which hopefully will be swift.

Bad lambda sensors can cause similar effects. Not sure if I'm supposed to reveal ABS secrets on here - but the C30SE has an IanM wooo-waaa test and it may work on other Bosch fuel systems. Basically on a warm engine, in neutral, hold the throttle part open - say 3000 rpm. If the engine speed varies slowly the noise you hear will be like a Woooo-Waaaaaaa-Woooooo-Waaahhh sound rather than a constant Woooooooo. Try it at other RPM's. On a C30SE this is symptomatic of a failing lambda sensor, and if you know what you're listening for it can be detected long before the engine management light comes on.

, I had the lombard sensor changed a 2 years ago, after garage stripped the threads on it, hum spark plugs done last year with new leads, new coil pack as well, oil changed august with oil filter, timing belt and water pump and runners feb last year or march. replaced manifold as had what looked like a crack in between 2 and 3 ports. replacement cat (garage changed) did this and brock the sensor. had a water pressure test last week, leaks friend of mine did this has he had the tool at the time. have loads of other things done before i received the car, nearly a full history from second owner. fuel filter was changed 4 years ago according to previous own and fuel line. but nothing on the fuel pump in paper work. brake lines abs bit of welding steering idler and other stuff like cambelt changes etc,
i've tried the valve on the injector rail it don't exactly squirt out, bit hard to explain. its like a wibbwibed out. not squirty sound. get more from a fish fart it that helps lol bit hard to find the words.

Marks DTM Calib · « **Reply #23 on:** 29 January 2018, 16:30:18 »

How many miles since the fuel filter was done?

I have seen them where they get clogged and effectively become a rev limiter!

Chazza12 · « **Reply #24 on:** 29 January 2018, 16:30:27 »

I going to have to leave it for today my brain etc is finding it hard to see what my eyes are seeing, everything getting blurry.

Chazza12 · « **Reply #25 on:** 29 January 2018, 16:32:40 »

Quote from: Fuse 19 on 29 January 2018, 16:30:18

How many miles since the fuel filter was done?

I have seen them where they get clogged and effectively become a rev limiter!

4 years ago at a garage. says extra replaced fuel line so think that means the connections for the filter. brain and eyes fogging up. i will have a look later when things come back to normal going to have to have a lay down.

Chazza12 · « **Reply #26 on:** 29 January 2018, 17:05:18 »

hi this chazzas wife it was last changed 42thou miles ago if that helps.

Chazza12 · « **Reply #27 on:** 29 January 2018, 21:11:49 »

feel a bit better now had a kip. cannot wait till friday and see if they can sort me out, anyway think the filter is well past its change and been looking around, is this one any good says GM poland made 25313359 says it fits a lot of vauxhalls OMEGA B 1994 - 2003 but also has this product code as well 818568 on this one site.

but this one has a pic and it says GM on the sticker https://www.ebay.co.uk/itm/Genuine-Vauxhall-In-Line-Petrol-Fuel-Filter-With-Clips-25313359/292296981550?_trkparms=aid%3D333008%26algo%3DRIC.MBE%26ao%3D1%26asc%3D49925%26meid%3D25858cd5b6f9487f9d3a11544af585c5%26pid%3D100010%26rk%3D1%26rkt%3D6%26sd%3D112752806563%26itm%3D292296981550&_trksid=p2047675.c100010.m2109 but know these can be faked.

Chazza12 · « **Reply #28 on:** 29 January 2018, 21:46:38 »

a friend of mine has just told me over the phone there is a filter in the fuel regulator( on the fuel rail ) can this one be changed as well or dose it need to be replaced if foul up as cannot see a reference number for a part of the filter just diagram of how its fitted ?

Doctor Gollum · « **Reply #29 on:** 29 January 2018, 22:21:27 »

There isn't

Pre (coarse) filter on the pump, main (fine) filter next to the diff

Chazza12 · « **Reply #30 on:** 29 January 2018, 22:35:24 »

Quote from: Doctor Gollum on 29 January 2018, 22:21:27

There isn't

Pre (coarse) filter on the pump, main (fine) filter next to the diff

oh looked on the fuel rail diagram and inside the regulator there is a filter, (injector fuel rail), shows a flat filter on the fuel pump attached to the fuel filter. say flat funny looking thing sticks out from the pump, and then an inline one, is it just the inline one that you just change ?
Filter, assy., fuel, electrical gm 90466030
just checked the number on fuel injector rail and its this one thats fitted, has a filter on the bottom. http://www.blacktop-tuning.com/TheShop/hardware/103-bosch-35bar-fuel-pressure-regulator.html

Chazza12 · « **Reply #31 on:** 29 January 2018, 23:01:16 »

Fuel Pressure Regulator OEM Rail 90411542 For Daewoo Opel X20XEV Omega 2.0 2.2 90411551
http://nemigaparts.com/cat_spares/epc/opel/v94/g/25/ ( its number 3 )

Doctor Gollum · « **Reply #32 on:** 29 January 2018, 23:17:00 »

That's a pressure regulator, not a filter...

Nick W · « **Reply #33 on:** 29 January 2018, 23:38:26 »

Quote from: Doctor Gollum on 29 January 2018, 23:17:00

That's a pressure regulator, not a filter...

And it won't be your problem.

Chazza12 · « **Reply #34 on:** 30 January 2018, 00:34:11 »

i know its a pressure regulator but it also has a filter on it in it , i will have a look at it, no harm no fowl,
friend said he would get under and do the fuel filter. he said his the filter in his went and it was causing problems with fuel, made from nylon, and bits sticking in the in the valve. so replaced it. and his fuel pressure went back up, he pressed the pressure valve and (he said) its piss poor pressure, his is a c20sel engine, same type rail.

Chazza12 · « **Reply #35 on:** 30 January 2018, 00:49:04 »

http://www.blacktop-tuning.com/TheShop/140-thickbox_default/bosch-35bar-fuel-pressure-regulator.jpg filter is the orange bit with 3 nylon filter mesh in it. friend says they go brittle over time.

Marks DTM Calib · « **Reply #36 on:** 30 January 2018, 08:12:40 »

Quote from: Chazza12 on 30 January 2018, 00:49:04

http://www.blacktop-tuning.com/TheShop/140-thickbox_default/bosch-35bar-fuel-pressure-regulator.jpg filter is the orange bit with 3 nylon filter mesh in it. friend says they go brittle over time.

Well he's wrong

Chazza12 · « **Reply #37 on:** 30 January 2018, 13:02:10 »

hi, well i took off the regulator and its shot, its not closing permanently open, so replaced it.

ordered fuel filter here tomorrow.

Chazza12 · « **Reply #38 on:** 30 January 2018, 14:00:52 »

well the hole engine has changed no rocking idles steady, and hardly any gray smoke. were as be for with the pipe on or of it was the same engine speed, now had to drop the idle/throttle screw, as think it most of been gone a while and they just screwed it up to get the reves. but it runs a lot better now went for a drive and no problems even went up the hill 30% incline with no trouble.

, so get the filter changed tomorrow and it should all be good.

its nice stopping at the traffic lights and not seeing the gear stick wiggling all over the place and pulling off with out a drop in power then speeding up its a lot more responsive.

Shackeng · « **Reply #39 on:** 30 January 2018, 19:32:24 »

Well done, and I hope your hospital visit goes OK.

Sir Tigger KC · « **Reply #40 on:** 30 January 2018, 20:13:00 »

Yes good news and I hope your repair is as straight forward!

Chazza12 · « **Reply #41 on:** 30 January 2018, 22:09:39 »

Thank you think i will be ok,, its only 2 years ive had this, have good days and then some really bad days, and then there is days i don't or can't remember, probably just more observation, think im a guinea pig lol more meds more needles same ooh same on. is one benefit i come out 3 stone lighter lol, see how it goes this time. may have found out why by now, would be nice.

TheBoy · « **Reply #42 on:** 31 January 2018, 08:06:44 »

Good luck with checks Chazza, hope the cause is found and not too painful

Chazza12 · « **Reply #43 on:** 09 February 2018, 09:02:42 »

well i'm back now. that was fun. still no joy. more tablets. pain is better anyway, have another set of blood tests in 6 weeks to see if the meds is working any better. My friend was not able to do the fuel filter as he said it was to wet to get under to do it. but he has cleaned out the intake the idle control valve. said he removed it all and cleaned it all out and looks like new. will be nice to have a look when im feeling ready to. also changed the screw on the adjuster. and set idle to 800 rpm with all electrics on, and 930-960 with no drain. don't know if that right but said its stable. but he did not know what the idle was supposed to be. he said he checked it in the morning on a cold start and it was 1200 and after about 3-4 min it dropped down to 930 is that right ? cannot wait to get out and have a look. but will be at least a week.

Doctor Gollum · « **Reply #44 on:** 09 February 2018, 09:46:49 »

All sounds a bit high... $:-\$

Idle on my desmond is 800 rpm load or no, and about 950 during cold start enrichment (fast idle). this can be stopped by blipping the throttle or putting the car into D/R if auto

Chazza12 · « **Reply #45 on:** 09 February 2018, 10:19:02 »

Thanks will ask him to have a look. had to change the adjuster screw as it had broken off on the adjuster part. but when he had it out it was idling at 430 but did not sound right to him so put it up. he coming round later as just been on the phone with him. Thanks Doctor Gollum

Marks DTM Calib · « **Reply #46 on:** 09 February 2018, 13:23:34 »

You do NOT use the adjuster screw on the throttle to set idle.

It should be adjusted so the throttle butterfly closes, but does not stick, no more

Chazza12 · « **Reply #47 on:** 09 February 2018, 18:49:47 »

He put it back so its just touching the throttle, holding at 800-860. with without all electrics on. does dorp to 780 but backup to 800. is that better ?

Doctor Gollum · « **Reply #48 on:** 09 February 2018, 18:56:26 »

Certainly sounds more like it

Are specs not in Haynes BTW?

Chazza12 · « **Reply #49 on:** 09 February 2018, 19:21:16 »

I've not looked but he said he could not find idle information, he took book so will see tomorrow. at least i can read lol not much ells.

Chazza12 · « **Reply #50 on:** 09 February 2018, 21:07:43 »

found this online
Year: 1995-1998: Engine code: X20XEV: Engine size: 1998ccm: Power:100kw: Compression: 12.0-15.0bar: Minimum compression: 9.0bar: Fuel system

Year: 1998-2000: Engine code: X20XEV: Engine size: 1998ccm: Power:100kw: Idle speed: 730-960rpm: Compression: 12.0-15 .0bar: Fuel system.

so must be in the right ballpark now.

Marks DTM Calib · « **Reply #51 on:** 09 February 2018, 21:12:28 »

The only way you can change the idle speed is via the settings in the ECU

Chazza12 · « **Reply #52 on:** 03 June 2018, 13:39:46 »

just done another check on the compression after been using engine restorer, and think its worked quite well.
piston 1 = 230 psi
piston 2 = 243 psi
piston 3 = 245 psi
piston 4 = 248 psi

so think its done some good compression is up. only used the 1 liter can and done over 1000 miles, ( don't drive much) only problem have is hit a speed bump on the exhaust and think its done something to the manifold. was only doing 3 mph but the landing was not good it was way to high for a speed bump. been making some strange sounds after so will have to have that off to have a look. ( hit the joint where the 2 downpipes make into one). glad it was not the sump.

Raeturbo · « **Reply #53 on:** 04 June 2018, 00:10:17 »

Engine restorer? What stuff did you use.? As per the information you posted re:
12 to 15 bar.. that’s 176 to 220psi looks like the restorer must have stuck to
The top of the pistons therefore reducing the size of the combustion chamber
Giving the high compression figures. But if it ain’t broke don’t fix it.
On another note hope you get better soon.

Chazza12 · « **Reply #54 on:** 04 June 2018, 13:36:56 »

Thanks it's engine restore from USA that's it's name comes in a can just add to oil not cheap but seams to do the job. It's like aluminium in a can. Think it cleans and recoats engine. These is no sticking to the pistons. Bit of carbon on piston tops but not thick. Going to do oil change soon do will put oil though a filter and see if anything comes up in the filter.

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Author Topic: engine compression specs (Read 7869 times)