Lotus Elan

Piston code

PostPost by: Donels » Wed May 01, 2019 9:09 am

Does anyone know what the lettering on the pistons in the attached picture mean? The initial letters are followed by 1.016. This cannot be bore size as it would be .020.

Dave

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f501771f-00e9-4792-ad2b-7986f43dfaf6.jpeg and
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PostPost by: rgh0 » Wed May 01, 2019 11:04 am

Dont know but I presume it is some sort of part number. If you know the manufacturer they can probably explain.

Are the pistons still connected to the crank as the variation in orientation of the valve cut outs would be a concern if they are.

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PostPost by: vxah » Wed May 01, 2019 11:13 am

Not to mention the unusual firing angle 360 degrees? ;-)
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PostPost by: Donels » Wed May 01, 2019 11:47 am

No disconnected from the crank so they’ve turned a little. No idea who the manufacturer was as these are the only marks I can find. They look like standard compression pistons but the 1.016 suggested they may be oversize somewhere?
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PostPost by: rgh0 » Wed May 01, 2019 11:53 am

Often pistons have some manufacturers mark on the underside in the forging or casting so if removed from crank pull out the pistons and look underneath

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PostPost by: jono » Wed May 01, 2019 1:00 pm

My pistons have the same - 'BRF +1.016' and it's at +40''

I recall posting exactly the same question on here some years ago and someone explained the meaning and essentially concluded that my engine is at +40 (which I know to be the case). Sorry, I can't recall the explanation and I'm useless with the search function!

Found it!:

0.040" x 25.4 = 1.016mm
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PostPost by: Donels » Wed May 01, 2019 3:32 pm

Excellent, thanks. I now know what I’m dealing with.

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PostPost by: Billmack » Wed May 01, 2019 8:38 pm

Dont know but ive seen that i.d. number on hepolite pistons before. The fact that they are stamped and not dot printed dates the pistons as fairly old.
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PostPost by: Donels » Wed May 01, 2019 9:25 pm

The engine has not run since 2003 so pistons pre-date this but no idea by how much, hence the engine strip. However it’s in pretty good condition and has completed little running since its last overhaul.
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PostPost by: Chrispy » Thu May 02, 2019 12:45 am

I found very similar pistons in my engine. The code on mine was ID6 S41 +1.016.

Same style stamping and the same FRONT stamping, same flycuts and recess on the edge. No idea on what the actual code means though!

I found a AE pistons logo on the underside, and they took standard size rings.
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PostPost by: jono » Thu May 02, 2019 6:34 am

....look three posts up and you'll find the answer
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