Tips on removing carbon from the head and pistons of a 850

photoguy_43420 · Apr 17, 2009

I removed my head from my 74 850 and it has carbon build up on the head and top of the pistons. Is there any product to use or a good way to remove this. Also any one tell me a good jug and head paint to use.

Guy

L.A.B. · Apr 17, 2009

I use the rounded end of a hacksaw blade to scrape the worst of the carbon deposits off, then use green scotch pads with oven cleaner or paint stripper to finish off.

Paint?

I tend to use whatever heat proof paint is on the shelf at the local auto parts store.

maylar · Apr 17, 2009

The factory manual says to use a wooden scraper, so as not to scratch the aluminum surfaces. Scraping with a screwdriver is a bad idea.

There are no chemical decarbonizer products that I know of. My own method is to use a fine Scotch Brite pad and carb cleaner spray. Very time consuming, that carbon is stubborn stuff.

BrianK · Apr 17, 2009

Mine doesn't have enough buildup to warrant physical removal yet (I think) but I like to run seafoam through the combustion chambers - drop in a few ounces through the spark plug holes, let sit, and then start and run and kill every mosquito within six city blocks.

GavinJuice · Apr 17, 2009

amsoil powerfoam, and i've seen blasting with walnut shells they seem to be very safe to use.

oven cleaner on aluminum will eat it

L.A.B. · Apr 17, 2009

GavinJuice said:
oven cleaner on aluminum will eat it

I've used oven cleaner for years and never had that happen.

BillT · Apr 17, 2009

Re: Tips on removing carbon from the head and pistons of a 8

photoguy_43420 said:
Also any one tell me a good jug and head paint to use.

Guy

I like VHT paint. Since I've got a '73, I used their 'FlameProof' High-temp paint for the barrel and head, #SP-117 - Flat Aluminum

They also make a paint specifically called 'Barrel Paint' in gloss black, which should work well for your '74 Cylinders. I used it when I first put my bike together, then repainted the barrel the correct, for me, color after sorting the bike out.

I pay about $6.50 a can at the local speed (hot rod) shop - Murray's

79x100 · Apr 17, 2009

My favourite tool for carbon removal is an old 2p piece. Rounded edges and soft enough not to damage. That the Queen gets her nose rubbed in the dirt whilst I'm doing it is a welcome side effect :twisted:

Ron L · Apr 17, 2009

I've used oven cleaner for years and never had that happen. /quote]

That's because you use it sensibly and don't soak the pistons in it! :lol:

Oven cleaner is sodium hydroxide (lye) and it will most definitely react with aluminum. Heat accelerates the action, but if applied cold and scraped after a half hour or less you should not have a problem. If you spray it on and stick it in an oven all bets are off!

GavinJuice · Apr 17, 2009

Ahhhh, very good!

L.A.B. · Apr 18, 2009

Ron L said:
Oven cleaner is sodium hydroxide (lye) and it will most definitely react with aluminum. Heat accelerates the action, but if applied cold and scraped after a half hour or less you should not have a problem. If you spray it on and stick it in an oven all bets are off!

Possiby US oven cleaners contain different substances to UK ones?

I compared the US & UK safety data sheet information of two supposedly similar cleaning products, and while "Sodium Hydroxide" is certainly listed as an ingredient in the US product, it doesn't appear to be listed for the UK one,-unless anyone can identify one of the UK ingredients as a substance that contains or may be related to Sodium Hydroxyde?

Didecyldimethylammoniumchloride C: R22-34
Alkyl alcohol ethoxylate Xn: R22-41
Ethoxylated alcohol Xi: R36/38

US data: http://www.kandelandson.com/msds/Mr.%20 ... leaner.pdf

UK data: http://www.futures-supplies.co.uk/downl ... 7.047o.pdf

I've certainly tried spraying large amounts of UK oven cleaner on more than one test piece of aluminium, and then left them overnight to see what would happen. The result being that oven cleaner dried out to a White powder that could be easily rubbed off, with no apparent damage to the test pieces whatsoever.

However I certainly agree that it would be wise to proceed with caution when using any type of caustic cleaning solution.

photoguy_43420 · Apr 18, 2009

You that have used scotch brite pads have you used them on the pistons? That oven cleaner worrys me a bit.

Guy

L.A.B. · Apr 18, 2009

photoguy_43420 said:
You that have used scotch brite pads have you used them on the pistons?

Yes, certainly (why not?)

photoguy_43420 said:
That oven cleaner worrys me a bit.

If it worries you then don't use any, just scrub harder with the Scotch pads!

I've always found it good for loosening carbon, especially for cleaning piston ring grooves, but if the formulation of certain oven cleaners are different to what I've used, then test it first?

Jason Curtiss · Apr 18, 2009

I soak my piston tops in Berrymans carburetor cleaner; they come out like new!

Ron L · Apr 18, 2009

Les,

The MSDS you posted is for a kitchen cleaner, which is a little different from an oven cleaner. If your kitchen works on cleaning off carbon, it would be a lot safer to use than a lye containing oven cleaner.

Ron

L.A.B. · Apr 19, 2009

Ron L said:
Les,

The MSDS you posted is for a kitchen cleaner, which is a little different from an oven cleaner.

That UK COSHH data sheet was linked from this oven cleaner page but I think you are right it's the wrong data sheet:
http://www.futures-supplies.co.uk/produ ... e=007.047O

I will check further on that.

[Edit] Yes you're right, that is the wrong COSHH data sheet!

http://www.scjproducts.info/corporate/i ... leaner.pdf

However, I can only go by my own experience, as I have actually used this product on aluminium parts with no apparent detrimental affects.

dpmellish · Apr 20, 2009

Go to any Gm dealership's parts department and purchase "Top engine cleaner" Pour it into your inverted cylinder head and let stand for a couple of days. Then get a wooden dowel rod from a hardware store. Use the dowel rod to further loosen the carbon and follow with a scuff pad. Then put your pistons upside down in an aluminum pan with the Top engine cleaner in the bottom. Let soak for a few days and follow with the dowel rod- scuff pad . The dowel rod can be made into several pieces, about 6" long works well.

pommie john · Apr 21, 2009

I use paint stripper to remove carbon. Never had any problems with it reacting with aluminium.

Tips on removing carbon from the head and pistons of a 850

photoguy_43420

L.A.B.

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maylar

BrianK

GavinJuice

L.A.B.

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BillT

79x100

Ron L

GavinJuice

L.A.B.

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photoguy_43420

L.A.B.

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Jason Curtiss

Ron L

L.A.B.

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dpmellish

pommie john