Tidying up cylinder head mating surface with surface plate and abrasive paper?

[rcx132]

I've got a few engines and some cylinder heads left over from an old project that I want to rebuild and sell.

The mating surfaces aren’t bad enough to need professional resurfacing, but they’re not clean enough to reassemble as-is. Just to double check, would it be fine to lay abrasive paper on a surface plate and gently lap the mating surfaces by hand to clean them up?

If it's ok, what grit would you use?

 

[tom2207]

spray glue and plate glass was the way I did mower heads etc ,,, sort of 320 did me ,,, but they were only mowers
and dont rock them at the same time or you can end up with a Quaver ,,,,

 

[bricol]

Sell 'em as is?

Then if it fails, not your problem.

 

[Richiew]

My opinion is, sell as is. No-one wants others fiddling when they want it right for their purposes. The less interference, the better. They will probably get them skimmed as a matter of course anyway. I would rather buy honest old parts than something tarted up last minute by a seller who has no skin in the game going forward.

 

[Gragson]

Per @tom2207 depends on the what cylinder heads, done loads of old mowers on 8mm glass plate to "clean up" worked fine on old B&S / Villiers etc Ransoms.
If something more exacting, as said sell as is

 

[brightspark]

I've got a few engines and some cylinder heads left over from an old project that I want to rebuild and sell.

The mating surfaces aren’t bad enough to need professional resurfacing, but they’re not clean enough to reassemble as-is. Just to double check, would it be fine to lay abrasive paper on a surface plate and gently lap the mating surfaces by hand to clean them up?

If it's ok, what grit would you use?

id probably just use a piece of grade 800 wet or dry on a surface plate and give it a quick rub across .can allways rub a bit of micrometer blue across the face of the head and rub it on the surface plate and see what the coverage is for being flat

 

[jimbo84]

I did this the other week with the head off a lister D. It worked very well. Can’t remember what grit I used but think it was 600grit.

 

[Robotstar5]

I did this the other week with the head off a lister D. It worked very well. Can’t remember what grit I used but think it was 600grit.

Bet that gave you a workout, not exactly a lightweight head on those.

 

[Morrisman]

I've got a few engines and some cylinder heads left over from an old project that I want to rebuild and sell.

The mating surfaces aren’t bad enough to need professional resurfacing, but they’re not clean enough to reassemble as-is. Just to double check, would it be fine to lay abrasive paper on a surface plate and gently lap the mating surfaces by hand to clean them up?

If it's ok, what grit would you use?

I used to do that with big compressor valves, basically 8” x 1/2” metal discs with hundreds of holes in, squirt some oil on the surface plate to hold the emery paper still, no need for glue. Then some oil on the top, and get the old figure of 8 going.

 

[jimbo84]

Bet that gave you a workout, not exactly a lightweight head on those.

Yeah it didn’t need much cleaning up thankfully.

 

[Brad93]

Spray adhesive on a surface plate.

You'll need another plate to blue and check flatness.

Only problem with such a job is ensuring you remain perpendicular to the bore

 

[8ob]

I've got a few engines and some cylinder heads left over from an old project that I want to rebuild and sell.

The mating surfaces aren’t bad enough to need professional resurfacing, but they’re not clean enough to reassemble as-is. Just to double check, would it be fine to lay abrasive paper on a surface plate and gently lap the mating surfaces by hand to clean them up?

If it's ok, what grit would you use?

I would check them for flatness first, you will never straighten a warped car cylinder head with paper or paste, may get away with it on smaller stuff. For a surface clean you can always use scotchbrite.

Bob