Jump to content

Cleaning Valves


agent_zed

Recommended Posts

Hi,

so i've taken off the head to swap the camshaft and fit new valve seals and after looking at the vlaves and piston heads and combustion chambers there is a lot of carbon build up.

 

The valves have a lot of the top side as well as the flat face.

 

I'm wondering if tehre is a chemical that i can put on to remove it or is it just abrasives all the way?

 

for the valves i can put them in a pillar drill and sand them if i need too.

 

For the piston tops and combustion chambers whats best? rotary wirebrush?

 

any thoughts appreciated.

Link to comment
Share on other sites

Guest robinj66

I've always used a blunt scraper to get the worst off the piston crowns etc and then a wire brush attachment in a drill. Just be careful not to difg into the surfaces.

 

As you suggested, put the valves in a pillar drill. A mate of mine then uses a screwdriver or other suitable iomplement to clear the carbon from the rear of the valves. Again as you suggested, finish off with emery cloth/ wet 'n' dry

Link to comment
Share on other sites

Guest chris brown

I use a bit of hard wood cut to make a scraper for the pistons. Oil will usually make it easier to get the last bits off. I wouldn't touch the piston crown with a wire brush or anything metal its better to leave it dirty rather than risk putting the slightest scratch into it as that a guaranteed way of getting a carbon build up. The old way we used when fitting new or very clean pistons was to give them a good coating of soot from a candle so as to get an even build up of carbon.

Link to comment
Share on other sites

Guest erichetherington

When you do clean the top of the pistons take them down from TDC, run some grease round the bore, then bring the piston back to TDC to clean top. Stops bits getting down the side wilst you clean the tops. Obviously clean yhe grease off when you finish.

Link to comment
Share on other sites

Guest mower man

The best thing to do with piston crowns is LEAVE WELL ALONE the tiny bit of carbon on there is not worth bothering with in a road spec engine, clean the valves as suggested also the exhaust ports then clean thoroughly ,I dont mean a quick wipe ,wash with suitable solvent and dry carefully ,cleanliness on engine builds is of utmost importance HTH mowerman :good:

Link to comment
Share on other sites

Hi Zed I can only apologise for the stupid comment was logged on at work in the fire station & got called out some A&%S went on the computer as I was still logged in & thought they would have a laugh.

 

Andy

Link to comment
Share on other sites

hahahah no worries. I don't mind the odd bit of randomness :)

 

Well my valves were incredibly dirty with baked on carbon all on the backs and big bits on the faces. Bit of sanding in the pilar drill and they look a lot better.

 

all my valve seats are pitted so a bit of grinding in is called for.

 

What with having properly ground in valves, no carbon on them and a 2ltr camshaft i'm hopeful that it will be quite a noticeable improvement to my little 1.6. And new valve seals will hopefully stop the oil dropping onto the backs of the valves.

 

Is it worth using a fuel additive to clean it a little further once its running again?

 

 

thanks for all the suggestions.

Link to comment
Share on other sites

Provided you can wash the parts off with water afterwards use Fairy power Spray....

yes I know it sounds unlikley, but I clean all my engine bits with it...works incredibly well. Its designed to get rid of baked on carbon...sound familiar? If youre not sure, just try one valve first

Bob

Link to comment
Share on other sites

Guest Ascari

Hey,

 

not looking to upset anyone but in the marine industry we are taught to ensure that the dull, satin finish you are discussing on the valve seats and valves is to be kept to a minimum. The reason being that usually the seat and valves are cut at slightly different angles, ie, seat at 43 degrees, valve at 45 degrees (or visa versa!) this means that there will only be a small area where the two meet, minimising the chance of the valve closing on a loose piece of carbon or dirt preventing the valve from sealing or causing damage to either part. The wider the sealing area, the more chance of damage. If you find that when lapping in your valves the width of the band is quite wide I believe you should be having your valves and seats re-cut. Like I say, thats marine and based on big American V8`s and not automotive. hope this helps and doesnt offend, Regards, Anthony

Link to comment
Share on other sites

hi,

thanks for the info, certainly appreciate different point of views. I can see your reasoning. I'm not overly concerned if i don't get it perfect as its a 1.6 pinto on 120k so anything will be an improvement on the pitted valve seats it currently has. I don't think the band is particularly wide at the moment about 2-3 mm after grinding down past the pits.

 

hopefully give me back a bit of performance/efficiency.

 

after re-reading the above posts i was reminded of when i did a head gasket years ago and to keep the bores clean when i was cleaning up the block surface i put newspaper down all of the bores. wondered why it smelt of burnt paper and wouldn't start when i'd got it back together. spent an hour fishing paper out of the spark plug hole :fool: :rofl: lesson learnt!

Link to comment
Share on other sites

Guest mower man

There is another way of seating valves ,if they have been refaced to 43deg and the seat cut to 46 degs 1 smart tap with a one lb hammer in the centre of the valve when seated will provide a working seat which gets better the longer its used ,it might sound crude but Ford used to reccomend it ! .Waiting for incoming mower man 8P :wacko: :wacko:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...