The following post comes to us courtesy of Mugen aficionado Jerimiah Styles! Many thanks to him for another contribution of his time and insight!
Back again for some more Fakespotting. This time we will discuss the first generation Mugen oil filler cap.
Mugen Formula engines, including those for Formula 1, naturally require components manufactured with high precision. Mugen meets such requirements by machining to exacting specifications at its factories. These oil filler caps are manufactured individually from aluminum at the same factories in the same way. "Formula Quality" is a result of the attention to detail that Mugen pays to its vehicles and products.
Upon first inspection of these caps they appear to be very similar, but a closer look tells a different story. The first thing you'll notice is the quality craftsmanship of the genuine piece. The replica is oddly shiny and lacks the brushed aluminum finish of the original.
The center medallion of the genuine Mugen piece is etched aluminum. The medallion comes from Mugen Scotch-taped (not yet attached) to the oil cap. The medallion has an adhesive on the back and is to be applied by the user after the cap has been screwed into place so the Mugen logo appears straight in your engine bay.
The "medallion" of the fake cap is more of a print, and comes pre-installed from the manufacturer. So fake caps may end with crooked Mugen logos once screwed into the head cover.
The underside of the cap reveals some more secrets. The genuine cap again shows top notch machine work seen in genuine Mugen craftsmanship. The fake cap has noticeable ring marks where the inside of the cap appears to have been shaved away, far from the quality of the genuine Mugen part.
The black sealing rings around the base of the two are also noticeably different. The grooved, flat seal of the genuine cap has more surface area, creating a better seal than just the o-ring of the fake part. Also the material and heat-resistant properties of the fake o-ring are unknown. Also notice the rough edges around the threading of the fake cap as opposed to the smooth precise edges of the Mugen oil filler cap.
The side profiles of the two oil caps shows more of the differences in quality. The edges of the real Mugen are much more defined. The brushed look of the genuine cap is very evident in this photo as opposed to the cast look of the replica.
Below is another version of a replica Mugen oil filler cap that I recently saw. This one has an obvious ring around the base, suggesting that it is more than one piece. This as well as the inferior finish should be obvious signs of a fake. The high quality of the Mugen cap will not oxidize over time -- it should retain its original luster if kept after properly.
Why does it matter?
Fake parts are passed off as genuine every day, knowing how to identify real from fake could mean saving you potential headache down the road. In the case of an oil cap, an improper or inferior seal could cause oil to leak from the top of your head cover, potentially causing harm to your engine. Always buy genuine Mugen products from an authorized dealer such as King Motorsports Unlimited.
I would like to thank Roy Brantley for providing photos.
Visit the King Motorsports store to get your genuine Mugen oil filler cap!