Compression test

[JAMZ]

Ok as ive got my manifold off im sure the compression reading will be underpar..someone corret me if im wrong..

Bare in mind my Turbo problems and the fact its been blowing Oil right through the system and burning it in the chambers etc..this is hopefully the cause of the oil caking of my plugs

All 6 were like this and ive drove the car approx 30 miles tops since fitting em in from new


This is the gauge reading i had..all 6 were like this which is a good sign..the 2 that i tested 2 days ago with the manifold ON gave me a reading of just below 190Psi on both and today the reading in this picture so that tells me that all 6 cylinders are running approx 190psi which is good?


So firslty in the state of the plugs reflective of my turbo/oil problems and secondly will not having a manifold on cause these compression readings?

rgds

[Turbo-Brown]

Would guess that most of the oil being blown through will have dropped out of the air stream long before it reaches the engine (that is just a guess though). I'd work on the assumption that it's running very very rich, but don't turn the pressure on your devicey thing without checking that with some kind of bum sniffer!

Seem to recall that my compressions are about 210psi but that's on an engine that's done less than 2000 miles so again at a guess 190 and them all being the same isn't bad

[JAMZ]

2 days ago i checked that very plug and it was nothing like that so that makes me think this whole turbo/oil syndrome caused this to happen..

im using 3.5 19lb's with a vortex 12:1 fuel reg and just a modified AFm so running rich is 100% true but not that bloomin rich!

[JAMZ]

Also someone just suggested even getting that reading from a compression test 'without' a manifold is V.good?

[jamesc]

Manifold shouldn't make any difference to compression as it's measured when both valves are closed?

[JAMZ]

well hopefully someone will know for sure....

If thats the case then i got serious problems on ALL 6 cylinders and its happened in the last 2 days

[jamesc]

But didn't you say in the first post you got around 190 both times? Or had you done another test prior to this?

[JAMZ]

Well the mani i had fitted restricted me getting to 4 plugs so i tested the 2 nearest the bulkhead which creeped up to 190psi this was 2 days ago... as i took the mani off yesterday i tested the same 2 again..now there showing where the picture above states but i assumed this was because i have no manifold fitted.. from that reading on them 2 i transfered this info to the outher 4 i tested which were all showing the same...thus come to the conclusion that all were/should be running 190ish psi if indeed a manifold was present..

[jamesc]

Ah I see. Sorry not sure of the answer but i thought the compression only happened when the valves are closed so it should be the same with or without manifolds. I wait to be corrected by someone more knowledgeable.....

[JAMZ]

Not only that the engine was cold..couldnt let it run without the manifold on :S

Also ive cranked it and let it run for literally 2-3 seconds probably a dozen times yesterday when i was testing that Turbo oil feed so i coulda soaked the bits in fuel which doenst help

[johnna]

Jamz, was it a wet test or a dry test?
A wet test is when you spurt a little oil into the plug hole before the test. A big improvement there suggests worn piston rings/ slight bore wear.

190 psi sounds okay I would think...

[JAMZ]

Sup m8,

It was a Dry test..

Things i gota find out are:

Does not haivng a manifold fitted at the time ulter the compression readings?
The engine being cold make any difference?

And the fact ive pretty much drowned em in fuel yesterday donesnt help i wouldnt of thought..

Everything is just too dam hard now..

I have to take Turbo off to get to 4 of the plugs
I have to take manifold off to take turbo off cuz its on upside down so bolts are obscured by manifold if that makes sence..PITA to say the least

[sheila47]

if you need to do a compression test then,irrispective of whether the exhaust manifold is on or off all the plugs should be out, and on cranking, your throttle should be fully open on every cylinder pressure check,and as already explained add oil to find out whether the problem is rings or valves.however looking at your plug which i must stress isn't ultra clear! it looks to me more like over fueling the plug doesn't looked coked up with burnt oil i would have been tempted to get a gas reading before stripping engine.

[Jeff_200]

Ah I see. Sorry not sure of the answer but i thought the compression only happened when the valves are closed so it should be the same with or without manifolds. I wait to be corrected by someone more knowledgeable.....

The compression value is the max pressure within the combustion chamber (i.e. both/all valves closed), so not having the mani on shouldn't affect it

EDIT: Ideally the engine should be warm when you test it (as any tiny gaps expand with the heat) but it can then be a bastage getting the plugs out The values you've recorded sound ok to me but if you think you have a compression issue then a leak down test may reveal more.

[JAMZ]

if you need to do a compression test then,irrispective of whether the exhaust manifold is on or off all the plugs should be out, and on cranking, your throttle should be fully open on every cylinder pressure check,and as already explained add oil to find out whether the problem is rings or valves.however looking at your plug which i must stress isn't ultra clear! it looks to me more like over fueling the plug doesn't looked coked up with burnt oil i would have been tempted to get a gas reading before stripping engine.

Someone's not been following..

Thks for yer responce anyway

[JAMZ]

Ah I see. Sorry not sure of the answer but i thought the compression only happened when the valves are closed so it should be the same with or without manifolds. I wait to be corrected by someone more knowledgeable.....

The compression value is the max pressure within the combustion chamber (i.e. both/all valves closed), so not having the mani on shouldn't affect it

EDIT: Ideally the engine should be warm when you test it (as any tiny gaps expand with the heat) but it can then be a bastage getting the plugs out The values you've recorded sound ok to me but if you think you have a compression issue then a leak down test may reveal more.

Cheers.. then il take it mani doesnt effect readings here then..

On my experience so far and the fact that i doubt very much it can read 190psi then 100ish 3 miles later tells me and as already stated i got bad overfueling going on..

That is most defo the case as described above i was idleing for 3-4 seconds a time then switching off to test an oil feed i had..i must of done this a dozen times without letting the engine burn waht was in the chambers..i didnt care about that...my goal was my test at hand.. all the time this was happening i got no AFM connected/3.5 injectors and a Vortex Fuel reg throwing fuel in... So this is the cause of the soiled plugs i hope..

Problem i have now is that when the maifold is back on and i give the engine a good run to burn this shit off i wont be able to access 4 of the plugs to check em again...

Never ever do a TD manifold conversion to save money on a turbo setup..not worth the time,hassle or money saved