bad compresion

[gregwilliams333]

Went to rs tuning today and found out that i am lossing at least 30- psi at the head, i think i am right in saying that should have about 180-190 mines got 150 at every one, been told might be a head skimming job (so i am sad)

 

[gregwilliams333]

any1 know how much it would cost to have it done as in head taken out and skimmed by someone

 

[tyni_clio]

ive heard when you get skimmed for performance your talkin 200quid so i dunno if it will be the same, probaly around 150quid you cud be lookin at mate, can u not just get a new head from the scrappy?

 

[gregwilliams333]

dont know if thats possible might be but you dont know if that head will be just as bad, gdi give me a quote of around 800 quid if its the head that is the problem but that taken everything out and putting it all back

 

[tyni_clio]

what! 800quid, ok i dunno if this is just me, but england sounds like criminals are runnin the garages, why does everything cost so dam much there, im in northern ireland an i know to change the head here is about 150quid 200 at the most, are you using dealer garages? change the head if you can man, just get to the scrappy an rip one out head to a LOW cost mechanic an get it ripped in.

 

[ditz]

it wont be the head itself.
have a look in to how an engine works it will prevent you from being done over

it could be the head is warped,, but its unusual to get the same reading on each cylinder.
if this is the case its just a simple skim we chare 40 quid for this plus the head on/off job.
could be valves not sealing properly may want valve seats cutting or just lapping in but again unlikely
could be sticky valves ie the hydraulics are holding the valves open.
is your car not running cams? dont forget this in itself will affect the compression readings.

imo its very unlikey to be related to the head if it is a problem at all

 

[ashy_gtt]

I wouldn't do anything, if the readings are all within 10% it should be fine... 150 sounds low but doenst mean theres a problem with the head gasket, could be the rings or could be nothing at all...

 

[tyni_clio]

true... drive on as they say laddy! if it blows then ya know..lol

 

[Gray]

true... drive on as they say laddy! if it blows then ya know..lol

LOL...

tick, tick, tick......... tick BOOOOM! :rasp:

 

[gregwilliams333]

Re: bad compression

yeah got 428 cat cams and went on rr and readings where low, Low down torque really, gdi have been help full they said they will do a leak test to see if there is anything wrong then work from there really, i would leave it but i would like to see the car running at 100% but thats just me

 

[ditz]

no mate you are dead right you want it perfect.
leak test is the best option as you can see where its loosing pressure
id imagine its sticking valves

 

[gregwilliams333]

i hope its something easy i dont really wanna pay out nearly a grand again to get it right,

 

[tyni_clio]

if shes that bad then i suppose u've know choice, at least the pressure test will tell ya.. good luck:boring:

 

[gregwilliams333]

yeah hopefully i dont have much luck with things though so prob wont lol

 

[gregwilliams333]

Ditz is it possible your garage could do the work as i am in essex myself rather than going to gdi as they are nearly 2 hours away

 

[tyni_clio]

i'd say they would be closer to you than me mate, im in northern ireland which is prob a good days drive ova, lol, soz.

 

[gregwilliams333]

sorry mate i said DITZ's garage lol thanks anyway

 

[rob_clio197rs]

i had same prob mate but mine blew blue smoke and lots of it, i did a compression test and i got 177,175,176 and 165psi so wasnt bad but sumthing obviously went wrong. just a quick question, is the engine block a dry liner or wet liner? can it have the bore sleves changed or must it be re-bored on a 172?

 

[gregwilliams333]

lol your asking the wrong man mate i aint got a clue

 

[ashy_gtt]

i had same prob mate but mine blew blue smoke and lots of it, i did a compression test and i got 177,175,176 and 165psi so wasnt bad but sumthing obviously went wrong. just a quick question, is the engine block a dry liner or wet liner? can it have the bore sleves changed or must it be re-bored on a 172?

Its a solid block, it doesn't use liners. Looking at those results I wouldn't think it was anything major i.e. deep scoring of the bores probably just the rings on the way out. Whats the mileage?

Do you find you get blue smoke on idle? What happens if you remove the oil filler cap does it clear or reduce? Are you sure you dont have a blocked breather system? Might just need a clean out rather than a rebuild?


- Greg -

Have Gdi done the work on your car? If its had bigger cams fitted that might have an effect on the comp test, there may be a load of overlap on the cam, I don't know what the profile is? other thing is the cam could be timed up wrong or badly which would give similar results and mean you being down on power on the rollers!

As all the pots are reading the same this is a much more likely cause than the head gasket or worn rings etc. I'd ask them their thoughts before shelling out a load of cash to have the head skimmed or replaced as its probably not that. As for valves sticking youd need all 8 to be sticking to get consistent readings on all 4 pots... My moneys is on the cam timing ot overlap on the cam.

 

[ben_p]

yup, check the cam timing, was the car down on power before?

 

[Andy GDI]

the car was faster afterwards.
cam timing was done useing locking tools and pins and checked
cams are not wild enough to cause loss of compression
no oil usage, so dont think there is ring wear.
we have seen a few with simply low compression for no reason.
it might be coked up valves ... but again leak down test is needed before going anywhere.

head off, skim and on is about £650 inc vat. (inc new gasket, bolts, labour, oils etc)

 

[ashy_gtt]

the car was faster afterwards.

How was that measured Andy?

head off, skim and on is about £650 inc vat. (inc new gasket, bolts, labour, oils etc)

Do you think thats required tho, based on all 4 pots reading the same? Do you ever get problems with aftermarket cams for the clio's as I know on the R5's the some of the aftermarket cams have been found to be upto 10 degrees out :dead:

 

[Andy GDI]

The owner commented

I simply said it was an option.
Aftermarket cam grinds are not always 100% (but we have not experienced anything with these)

 

[sideways danny]

How was that measured Andy?

head off, skim and on is about £650 inc vat. (inc new gasket, bolts, labour, oils etc)

Do you think thats required tho, based on all 4 pots reading the same? Do you ever get problems with aftermarket cams for the clio's as I know on the R5's the some of the aftermarket cams have been found to be upto 10 degrees out :dead:

As Andy told Greg, we need to do a leakdown test to see what's happening, the quoted price was just for what he directly enquired about

Perfomance increase was percieved by Greg when he test drove the car

 

[gregwilliams333]

lol I am happy with the work done by gdi and cant fault their help andy has been very helpfull with info on what COULD be the problem and i am going to them in a few weeks to let them have a look. So no problems with GDI at all

 

[bradfincham]

Head skim is about £40 its just the labour removing it, fitting new gasket and refitting it.

Personally i wouldnt bother untill its very noticeable