That brand new look for engine cases

Alan L

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Apr 13, 2021
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Hi all,
I look in awe at the photos of owners bikes whose engine cases (both inside and out) look absolutely brand new, as if they are straight out of mould. Of course I’ve spent enough time with metal polish but I can never achieve the look that other do.
What is their secret?
Alan
 
If the cases are bare I think vapour blasting is very hard to beat and can make cases look brand new. Be very careful to blank off any oil galleries before the blasting.
 
In 46+ years, I have never done nothing special to my cases only a good soaking in kerosene when doing engine rebuilds or pull down and as for polishing covers just good old elbo grease with auto sole and cotton impregnated polish in a tin, my bikes only gets a good polish once a year on its birthday when I rolled it out the shop new as for any other times when dirty just a good spray with a degreaser detergent in a pressure spray container when the motor is hot and a good hose off, I do this with all my bikes the less effort I do the better but doing it this way they come up pretty good and the degreaser/detergent I use is very good and makes alloy shine but the polish cases only hand polish once a year and a quick wipe down if I get caught out in rain when I get home.
More time riding less time polishing but my bikes are always kept clean without a big effort on my part, dust is my biggest problem if they sit for a week or two but a quick wipe down fixes that before going out.

Ashley
 
Alan L said:
Hi all,
I look in awe at the photos of owners bikes whose engine cases (both inside and out) look absolutely brand new, as if they are straight out of mould. Of course I’ve spent enough time with metal polish but I can never achieve the look that other do.
What is their secret?
Alan
Click to expand...
Both cNw and Comstock have a "tumble" method that works very well - there are white beads involved but that's all I know. I have a method that makes them look new on the outside every time and usually on the inside as well. However, many cases (especially 850 cases) are quite porous on the inside and when heated to put the bearings in oil comes out so the insides don't remain new looking.

No big secret. I have it documented here: https://www.gregmarsh.com/MC/Norton/EngineGearbox.aspx Start reading at Jan 23, 2023. If you're not a careful and thorough person - do not attempt!
 
WD40 and scotchbrite pads make cast alloy look fresh out of the mould. Use lots of WD so it soaks in and provides a bit of protection.

The tumbling that Greg mentions is best, that smooths out the surfaces and closes up some of the pores and thus makes it very easy to keep them looking very nice.
 
Clean the cases so they are mould fresh and you remove the protective coating of aluminium oxide. This wants to always come back, so to keep this just out the mould look you need to be cleaning regularly or stop it by applying wax such as wax for alloy wheels.
 
When Jim Comstock did my head work,it came back looking brand new.He told me it was done with a mill tumbler that I think he made it himself.Like Nigel said, it closes up the pores somewhat and still looks great.
Mike
 
Greg does a great job on cases as do others of course however, keeping alloy looking good is difficult, there is a post on here about a product called “ shine seal “ formerly zoop
Supposed to be really good, I’d link a page but not on my pc at moment just using a phone.
 
Alan L said:
Hi all,
I look in awe at the photos of owners bikes whose engine cases (both inside and out) look absolutely brand new, as if they are straight out of mould. Of course I’ve spent enough time with metal polish but I can never achieve the look that other do.
What is their secret?
Alan
Click to expand...
Silver paint on my 850 crankcases, like it came.
 
Grandad said:
Greg does a great job on cases as do others of course however, keeping alloy looking good is difficult, there is a post on here about a product called “ shine seal “ formerly zoop
Supposed to be really good, I’d link a page but not on my pc at moment just using a phone.
Click to expand...
This stuff ?
 
Grandad said:
That’s the stuff, never tried it before though.
Click to expand...
I've not looked into or used that particular product either..but there are alot of 2 step... isopropyl based nano tech sealers etc around these days..alot of them are usually available ...more for stainless and chrome ...alloy is tricky imo
 
Alloy sure is tricky
I’ve spent too many years polishing alloy wheels with Solvol only for the satisfied smile to fade quicker than downing a pint. Chrome rims for me now.

I used to buff up tyre sidewalls with boot polish for a great look without the garish glare of tyre paint.
 
I believe AMC used to dip aluminium alloy castings in Muriatic acid to finish them. For how long, & at what dilution, I have no idea. I use vapour or dry bead blasting followed by hot water & Brillo pads to close the surface. More recently I have been using Stephen Smethurst in Manchester to vibro finish cases, with I have to say, superb results. I think it will be the same as Jim Comstock offers.
 
Matchless said:
I believe AMC used to dip aluminium alloy castings in Muriatic acid to finish them. For how long, & at what dilution, I have no idea. I use vapour or dry bead blasting followed by hot water & Brillo pads to close the surface. More recently I have been using Stephen Smethurst in Manchester to vibro finish cases, with I have to say, superb results. I think it will be the same as Jim Comstock offers.
Click to expand...

I used Stephen (I think based on your recommendation) on the 920 and can confirm the finish matches that done by Comnoz, it looks great and is SO easy to keep looking great !
 
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