Hi guys,

I'm fitting a reconditioned H89 head to my A12. Question is, how far should I go in cleaning the engine deck? See pictures attached of deck. So far, all I have done is cleaned the old gasket with a razor blade. Deck surface is completely smooth to the touch but there is obviously still a lot of staining still present. Engine was running well with good even compression on all cylinders but all the head bolts on manifold side had some corrosion on the bolt thread indicating some coolant leak from water passages. Head bolts on pushrod side were all clean without corrosion. Deck flatness is good.

I feel there is a need to clean deck further but not sure the best way. There are a lot of different opinions around. My instinct is to use a lapping plate backed with 80 grit sandpaper to get back to shiny metal. I'm a little concerned with debris entering oil/coolant passages though. Particularly hard bits of sandpaper grit. Can I limit grit contamination using some wd40 or similar to hold on to grit a little? Or some other technique completely?

Thanks.

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  Deck 1.jpg (129.73 KB)


  Deck 2.jpg (86.57 KB)


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  Deck 6.jpg (125.73 KB)

yes it needs a bit more cleaning. Use a gasket scraper and ether spray. It doesn't need to go to shiny bare metal, but you'll be able to remove all the gasket material

Great. Thanks. I'll give it a try.

Cleaning progress...

I've been through a few options in trying to clean the deck. Here are some pics so far. Not sure if I'm on the right track. I have tried regular engine degreasers, acetone, ether (spray starter) all with a rag or toothbrush. Nothing really got rid of the crud super well. The best result I had was with some 'Jif' cream cleanser ('Cif' in North America??) and an old blue kitchen scourer (essentially a low/non scratch scotch-brite pad on a foam backing). I'm a little anxious about either the Jif or scourer being too aggressive but it's the only thing that seems to clean it up.

The only scraper I used was a new stiff razor blade. Went through a few trying to keep a good edge on blade.

You can easily see the ridges from when it was decked about 20 years ago. They are relatively deep striations compared to the recently machined finish on the head.

Does this level of engine deck cleaning prep look ok?

Cheers everyone.

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  Deck clean 1.jpg (94.84 KB)


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Also, does anyone recommend using 'Copper Coat' gasket spray or similar? My understanding is that it is not much benefit for perfect fit ups i.se machined deck + head. It may be of some use in this case though perhaps?

Thanks again.

The new photos look great, time to bolt it back up. Just clean up the bolt holes (spray ether will do it, see bolt hole cleanup)

Copper coat is not needed for modern gaskets

Awesome. Yep, I will do the bolt holes as you suggested. Thanks for the link. Thanks for all your help mate. Much appreciated. Looking forward to getting it back together now.