Removing Rust Spots from Cylinder Walls

Hi all,

I've had my engine block bored/honed and has since sat for a while. Just beginning assembly and I've noticed some small rust spots on the cylinder walls - pics attached below.

Would these spots be a concern that needs addressing before assembly?

If so, is there any safe way to remove this without damaging the fresh hone, or would I need to have the cylinder re-honed?

I've tried WD40 with some paper towel, no improvement. Reluctant to take anything more abrasive to it as of yet.

Cheers

Blair,

The vertical scoring caught my eye in the first picture as well. From the picture I can't tell how significant those scratches or the marks you've labelled are in terms of depth.

WD40 and a paper towel is certainly a safe start.

Beyond that in order to remove material you'll likely need something more aggressive.

Having your local machine shop give an in person opinion is likely best.

If you drag a finger nail across each area, do you feel them at all or is it just a visual blemish?

Neither the scratches or rust spots catch a finger nail running across them. I've since sent pictures to the machinist & they've suggested it would be okay to assemble as is.

Though measuring the bores it seems I have .0025" clearance & the JE 2618 spec sheet I have suggests I need .0030" to .0035" for a bore within the 2.500" to 3.625" range, mine being 3.051".

Perhaps you could advise whether I should have the bores redone to meet the minimum spec, if the .0005" is significant? It seems logical to suggest that they should at least meet the minimum clearance? I suppose it would resolve both issues!

Appreciate the response Mike

I would believe that when the entire acceptable range is only 0.0005", then being 0.0005" off the minimum clearance is certainly not acceptable. You should have the machine shop confirm your measurements, and bore to get the clearance spec'ed.

Did you have the correct clearance before the surface rust appeared?

I almost always run significantly tighter PTW than JE and Manley suggest and prefer the outcome to engines with their suggested clearances, but I don't know the full story on your application so that may not be ideal for your use.

What engine, how much power, what fuel, how will the engine be used?