Fraser Young
Member
Registered: 26th Dec 02
Location: Dundee City Drives: 58 Impreza WRX
User status: Offline
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I know a few of the guys on here have had theirs replaced...
How much work does it involve etc. On my C16xe, burns quite a steady amount of oil, not huge clouds, but a wee bit on acceleration always been meaning to do something about it...
cheers -f
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lee mitchell
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Registered: 26th Jan 01
Location: kent...drive's: eveyones conversion cars hard lol
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head off and all valves dropped. bit off work involved. then the gasket will need replacing asweel as head bolts. could be the piston rings aswell mate
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Fraser Young
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Registered: 26th Dec 02
Location: Dundee City Drives: 58 Impreza WRX
User status: Offline
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any way to find out which/both it is before the head comes off?
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Mistamist
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Registered: 16th Jul 03
Location: Gillingham, Kent
User status: Offline
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try doing a compression test between cylinders.
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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Get the engine up to temp, then disconnect the injectors and coil pack
A) do compression test
B) put about 5-10ml of oil in each bore and repeat above.
If results of A nd B are signifcantly different then the rings are leaky, and if not too dofferent then it's the valves.
While you have the head apart, new rollers, cam belt, water pump as a mater of course, and lap in the valves esp the exhuast valves as this will help things aswell.
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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Get the engine up to temp, then disconnect the injectors and coil pack
A) do compression test
B) put about 5-10ml of oil in each bore and repeat above.
If results of A nd B are signifcantly different then the rings are leaky, and if not too dofferent then it's the valves.
While you have the head apart, new rollers, cam belt, water pump as a mater of course, and lap in the valves esp the exhuast valves as this will help things aswell.
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Fraser Young
Member
Registered: 26th Dec 02
Location: Dundee City Drives: 58 Impreza WRX
User status: Offline
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wicked, cheers guys
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X 60RSA
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Registered: 20th Aug 01
Location: Lincoln
User status: Offline
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If its your stems, your car might smoke when left over night and you go to strike it up in the morning say. Over night the oil has had time to run down the stems to the combustion area, strike her up in the morning and it might smoke for a bit.
If you get a bit of smoke coming from the dipstick as you remove it, can this be ring wear?
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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do ya have to take the head off??
can you not plum up an airline to yer spark plug holes to stop the valves from falling?
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Greasemonkey
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Registered: 17th Apr 02
Location: Drives a Tractor
User status: Offline
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Yes you can pressurise the cylinders so the valves dont drop, this is how my mechanic does it, still tricky though
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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taking the cams out makes sure the valves can't drop, since they have a big f**k off spring pulling them shut.
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
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^ yeh but u have to take the springs out to do th the seals dont ya ?
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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The head also has to come off.
I'll be doing this at the weekend, so will get some pics and maybe get it commited to the tutorials section.
Will also be lapping in all the valves too.
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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lapping the valves... sounds dirty or sumthing... WTF?
[Edited on 16-12-2004 by Siberia]
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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It's a fine cutting paste you use to remove the pitting you get on the exhaust valves, ensures a better seal and as such better burn and betewr emissions.
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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sure wouldnt new ones be a better solution.....
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James R
Member
Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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no, why throw away perfectly good valves when you can just lap them back in, it's not like I'm gonna put them on a bench grinder, it's like toothpaste consistancy.
And if you put in new valves then you should re-cut the seats.
So spend a few hours lapping, it many more re-cutting seats.
No brainer really
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Stu_22
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Registered: 25th Mar 02
Location: Luton
User status: Offline
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Oh yeah lapping paste I knew i'd forggoten somthing.
Yep pics up next week
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Greasemonkey
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Registered: 17th Apr 02
Location: Drives a Tractor
User status: Offline
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The pressure in the cylinders keeps the valves closed so when ya take off the spring cap and spring the valves dont drop, its easier to do it with head on and cheaper
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James R
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Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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not if you are gonna lap them in too.
Whis if the stem seals have gone, the engines probably covers enough miles fo lapping to make a posotive difference.
Stu_22, how many times have I said about the paste
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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what do ya have to do with the paste?
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James R
Member
Registered: 4th Feb 03
Location: 205GTi16/306GTi16
User status: Offline
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you smear a fine layer on to the contact area between the seat and the vlave then rotate the valves in the seat and the paste laps the valve back in.
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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u should write and encyclopedia(sp) the amount of stuff i learned in the last 2 weeks from you... mr broster and mr greasmonkey.....
hope yous are all not full of crap
[Edited on 17-12-2004 by Siberia]
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Greasemonkey
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Registered: 17th Apr 02
Location: Drives a Tractor
User status: Offline
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Just to add ya use a special valve lapping tool, its a stick with a sucker on the end, ya stick it on to the flat end of the valve and use it to spin the valve in its seat against the runbbing compound, usually use two grades, course and a fine finishin paste
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Siberia
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Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
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were are the valve 'seats'?
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