General 3/4 cylinders carboned

[x Alex x]

Hey fellas

just the Cylinder head off the car there and i've noticed 3 pistons have a fair emount of carbon on them (on par with the last punto i done, 110k miles!) but cylinder number 1 is clean as a whistly!

i could probably come up with some sort of theory but my heads in bits after working 25 hours this weekend!

cheers!

 

[mnbrennan]

Haha, I contacted you earlier int he week re skim.

I've got the head off mine today too, and I have exactly the same. Pot 1 is clean and 2,3 & 4 are covered in carbon deposits. By any chance was the break in your HG on this cylinder?

 

[x Alex x]

Haha, I contacted you earlier int he week re skim.

I've got the head off mine today too, and I have exactly the same. Pot 1 is clean and 2,3 & 4 are covered in carbon deposits. By any chance was the break in your HG on this cylinder?

ohh yeah hi mate! the breaks on the opposite side strangely

 

[x Alex x]

Why's the title ! :S

 

[rallycinq]

You think the break is on the other side. Look very carefully around the head and block for a crack.

Cheers

D

 

[x Alex x]

You think the break is on the other side. Look very carefully around the head and block for a crack.

Cheers

D

aye, i've gave it a good looking at and can't see anything, thanks!

 

[mnbrennan]

You think the break is on the other side. Look very carefully around the head and block for a crack.

Cheers

D

Would one clean cylinder indicate a crack in the head?

 

[rallycinq]

Would one clean cylinder indicate a crack in the head?

One clean cylinder will indicate that water under pressure has been there.

If the gap in the gasket is not there I would get the head pressure tested when the skimming is being done.

Cheers

D

 

[D4nny8oy]

ohh yeah hi mate! the breaks on the opposite side strangely

Sure you haven't flipped the gasket over without realising?

If the piston's squeaky clean it just shows the failure has been going on for a while. Won't know if the head's cracked without testing (though it's rare).

 

[onlypuntos]

Re: !

When a small amount of water leaks into a cylinder (ie when the HG blows into a cylinder or between two cylinders) then the heat of the combustion turns the water into very hot steam, therefore you effectively are steam cleaning that piston(s).

It probably means that the HG has been leaking for sometime before it final blew badly enough to be really obvious.

D.

 

[x Alex x]

yep, that's exactly what i've done, flipped the HG over without realising, i noticed when i went out to check the block for cracks LMAO!

feel rather daft but at least it clears it up!

thanks all!!

 

[mnbrennan]

Thats good to hear AlexR.

Unfortunately there is no visible break in my HG, so i guess the head is warped!

 

[x Alex x]

Thats good to hear AlexR.

Unfortunately there is no visible break in my HG, so i guess the head is warped!

sometimes they're very hard to see, head would need skimming anyway so that takes out any warping.

 

[rallycinq]

Thats good to hear AlexR.

Unfortunately there is no visible break in my HG, so i guess the head is warped!

Head is warped because the gasket blew. I might only be a wee weep, but, as mentioned you'll be getting the head skimmed anyway.

Cheers

D

 

[rallycinq]

yep, that's exactly what i've done, flipped the HG over without realising, i noticed when i went out to check the block for cracks LMAO!

feel rather daft but at least it clears it up!

thanks all!!

At least you have the answer, and I knew I was right that water was getting in there.

Cheers

D

 

[x Alex x]

At least you have the answer, and I knew I was right that water was getting in there.

Cheers

D

as always haha cheers mate!

 

[DaveMcT]

Smear some grease around the cylinder wall and turn the piston to the top. Scrape off the carbon. Drop the piston and clean the now claggy grease. Any grease around the piston should still be clean. Repeat fro the other cylinders.

Another option is to vacuum the gap between cylinder and piston but there's still a good chance of carbon coke dropping between the piston rings.

Now find out why its so coked. Maybe the Lambda isnt switching properly making it run rich. Well worth checking it out.

 

[x Alex x]

Smear some grease around the cylinder wall and turn the piston to the top. Scrape off the carbon. Drop the piston and clean the now claggy grease. Any grease around the piston should still be clean. Repeat fro the other cylinders.

Another option is to vacuum the gap between cylinder and piston but there's still a good chance of carbon coke dropping between the piston rings.

Now find out why its so coked. Maybe the Lambda isnt switching properly making it run rich. Well worth checking it out.

great tip!

was trying to work out a way of not dropping carbon into the block too

just ordered a timing belt too, i know it doesn't matter if it breaks, but in this cold weather i don't fancy me or the GF conking out with no heat, plus for £12 delivered it's worth doing while it's apart i rekon!

 

[rallycinq]

for £12 delivered it's worth doing while it's apart i rekon!

Always. Make sure the tensioner is not 'gritty' in its action.

Cheers

D

 

[x Alex x]

Always. Make sure the tensioner is not 'gritty' in its action.

Cheers

D

yeh cheers mate, checked it over before i opted for the belt instead of the tensionor and pump