Head Off -> Piston Head/Top Cleaning

[RobST162]

Hey guys,

Got the head off one of my 185s here and there's a significant amount of carbon build up on the piston heads. My first thought was to just drive it hard for a while after I got it back together, but i'm wondering if I should consider giving it a nice clean while it's all there

what do you think?

And if it's worth cleaning up the piston tops now, what's the best procedure/method?

I could use some strong ass solvent etc... I just don't want to shove anything down the bores

[tomvale13]

Does carbon on the top of the pistons mean something wasn't running correctly or just that they've been heavily used?

(got some spare pistons, trying to figure out if they're any good)



I'm interested in what to clean them with as well as mine are black as the night.

[RobST162]

I think it usually means the former as far as I'm aware

a hard-driven car that's set up well shouldn't have build up

blackness I don't think is uncommon.. I just have chunky cheese

[tomvale13]

Yeah mine is a thick-ish black film, was curious if that was normal or not

when you say the former, is there a specific ailment that the carbon build up is a symptom of, i.e running too rich?

[RobST162]

yeah running rich is a big cause of it I think

in my case the car was very very poorly serviced so I'm not sure what went on.. perhaps the spark plugs were just so old and non-performing and yeah the fuel didn't get burned up

[tomvale13]

Ahh, cool so I had a basic understanding of what may have caused it

*first time for that high five*

The 4efte runs super rich from factory, they are the pistons/rod combo I have.

[HAVABEER]

you can try getting some of the subaru upper engine cleaner.

works really well to get built up carbon out of your engine. i used it on my van when it was dieseling (engine kept running after i turned it off). but the engine needs to be running for it to work.

[RobST162]

hey bro

hmm that won't work real well with the head off.. lol might just give it a basic clean up and then let teh FIYAR! sort out the rest once it's running

[JustCallMeOrlando]

Get it all back together and run a bottle of Redex (?) through one of the vacuum hoses when it's running. Get it up to 3000rpm or there abouts, stick the tube in the bottle and pinch the tube to control flow. Oh, and apologise to the neighbours for the noise and the massive cloud it produces

[IN 05 NT]

no harm in giving them a buff up while there in the car, just give it all a good clean down after and a blow out with an air gun,

[andy]

you could also try spraying some throttle body cleaner onto the top of the pistons(since the heads off) and using a rag to wipe it up. it cleans carbon out of throttle bodies pretty well, dont see why it wouldnt work with pistons.

i have black shit on my pistons too. engine still runs. blows no smoke. meh.
i saw it with one of them fiber optic thingos. then i proceeded to stick it up my nose to see what was up there

[TooF]

ive always cleaned thecarbon build up onpistons with some carby cleaner no worries. just give it a good spray and let it soak up a bit and all cleans up bar the really stuck on crap.

[TERRA Operative]

I gave my pistons a scrub with a brass wire brush attachment on my battery drill.
Be sure to mask off your oil galleries before you do.


Mine came up like new when I did mine.

[StuC]

all of the above work. I use suby cleaner a hell of a lot at work Rob and i love it. Carby clean works and so does a wire brush. Wont hurt giving it a clean now and then the redex treatment when the car is running again.

Something i have noticed with Jap engines compared to Euros is that they do tend to carbon up a fair bit. I think they just run hella rich from factory and dont have as hardcore polution gear on them. Taken heads off 250,000kms poorly serviced 4cyl motors and no carbon on the tops, whereas the 3s will have huge carbon deposits by 100,00kms or less

[distant0]

throttle body cleaner + scrub with tooth brush for me......