Cleaning engine block for new Head Gasket

DublinDilbert

Hi All,

Wondering what the opinions are out there on cleaning an engine block before fitting a new HG.

Some people say brake cleaner, IPA & plastic scraper. Other say use the finest wet & dry you can find to just take the dirt off the top and leave fresh metal....

The block isn't too bad, just the usual discolouration from residue of the old HG.

Thanks

Voodoomelon

I'd use fine sandpaper before using a scraper. If your block is aluminium, a heavy scratch with a scraper could cause a bad seal.

L-M

Are you fitting a new hg after it's over heated? I thought they had to be skimmed in this case?

lifer_sean

Limerick man wrote: »

Are you fitting a new hg after it's over heated? I thought they had to be skimmed in this case?

Head should be skimmed, block is rarely / never skimmed.

Interesting thing to note that these days a secondhand engine is often a cheaper way out than head gasket / machining the head.

Gary ITR

Limerick man wrote: »

Are you fitting a new hg after it's over heated? I thought they had to be skimmed in this case?

You skim the head. Block just needs to be cleaned.

I'm going to be using a very fine wet/dry paper

L-M

My bad! Confusing myself, I knew a sent something off to be skimmed.

DublinDilbert

Limerick man wrote: »

Are you fitting a new hg after it's over heated? I thought they had to be skimmed in this case?

Thanks for the replies.

The cylinder head is out to be skimmed today + valves fixed. It didn't over heat the Timing belt broke.

My question was regarding the cylinder block. I wanted to get it all cleaned up this evening, ready for the head when it comes back tomorrow.

I'm paranoid about damaging the cylinder block, and removing any metal. I guess very fine wet/dry sand paper is what they use on paint work, so shouldn't remove any metal.

If the block is cast iron it will be *VERY* difficult to damage it. I cleaned a Brava block just recently using a knife edge. I didn't aim for perfect finish, just made sure that it was clean from oil and remaining bits of the old gasket. The new gasket has black glue type of stuff on it so should adhere on any dry surface.

http://www.flickr.com/photos/hentunen/3469754877/

I just was careful not to score the surfaces around the cylinder themselves (where the headgasket has metal rings and no additional sealing agents).

Interesting to see how long it will last. The original gasket lasted for 60k only.

Darragh29

DublinDilbert wrote: »

Thanks for the replies.

The cylinder head is out to be skimmed today + valves fixed. It didn't over heat the Timing belt broke.

My question was regarding the cylinder block. I wanted to get it all cleaned up this evening, ready for the head when it comes back tomorrow.

I'm paranoid about damaging the cylinder block, and removing any metal. I guess very fine wet/dry sand paper is what they use on paint work, so shouldn't remove any metal.

What I use OP is an old type stanley razor blade to take the bulk of the gasket off and then use fine wet sandpaper after that to finish the job.

DublinDilbert

Darragh29 wrote: »

What I use OP is an old type stanley razor blade to take the bulk of the gasket off and then use fine wet sandpaper after that to finish the job.

Hi Guys,

Thanks for the good replies.... The old gasket came off in one piece, so there isn't any of that left.... I'll just use some wet/dry to clean up the top of the block tonight, its mainly just some discolouring....

Anyone know off hand what grade wet/dry would be best?

DublinDilbert

Thanks all...

The wet and dry + some elbow grease worked perfectly (i used 1200 in the end)...

All ready for the head when it comes back tomorrow....