What's this all about on the engine . . .?

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Happytrails

NAXJA Forum User

Location

USA

• Sep 28, 2013

• #1

Below each spark plug on the engine block is this symbol. It looks like a hand painted upside down "P". I am guessing some sort of manufacturing mark. But is it from original factory, or is this from some rebuild shop?

 

ParadiseXJ

NAXJA Forum User

Location

Paradise, CA 95969

• Sep 28, 2013

• #2

Happytrails said:

plug......"P".

Click to expand...

Hmmmm.

The link does not work...at least for me.

 

Lowrange2

NAXJA Forum User

Location

Abbeville, SC

• Sep 28, 2013

• #3

I see the link.

No clue what it means but it's certainly not from the factory.

 

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cruiser54

NAXJA Forum User

Location

Prescott, Az

• Sep 28, 2013

• #4

It's something they did at the engine factory to denote which "size group" piston would fit each cylinder the best upon assembly. They had A through F sizes.

 

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Happytrails

NAXJA Forum User

Location

USA

• Sep 28, 2013

• #5

WOW! Hand built engines? No wonder they last 500,000 miles.

 

C

cruiser54

NAXJA Forum User

Location

Prescott, Az

• Sep 28, 2013

• #6

5 million of them were built on worn out machinery!!

 

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SuperRA

NAXJA Forum User

Location

Santa Clara, CA

• Sep 29, 2013

• #7

cruiser54 said:

It's something they did at the engine factory to denote which "size group" piston would fit each cylinder the best upon assembly. They had A through F sizes.

Click to expand...

So what would that size be? Lower case "d"? haha

 

A

Alexia

NAXJA Forum User

Location

Huntsville, AL

• Sep 29, 2013

• #8

Piston Size Chart
98.438 to 98.448 mm (3.8755 to 3.8759 in.) . . . . . . .A
98.448 to 98.458 mm (3.8759 to 3.8763 in.) . . . . . . .B
98.458 to 98.468 mm (3.8763 to 3.8767 in.) . . . . . . .C
98.468 to 98.478 mm (3.8767 to 3.8771 in.) . . . . . . .D
98.478 to 98.488 mm (3.8771 to 3.8775 in.) . . . . . . .E
98.488 to 98.498 mm (3.8775 to 3.8779 in.) . . . . . . .F

 

H

Happytrails

NAXJA Forum User

Location

USA

• Sep 29, 2013

• #9

Variance of .002 kind of surprises me. I was thinking may be half a thousanth across the range. This is very interesting information.

 

C

cruiser54

NAXJA Forum User

Location

Prescott, Az

• Sep 29, 2013

• #10

Happytrails said:

Variance of .002 kind of surprises me. I was thinking may be half a thousanth across the range. This is very interesting information.

Click to expand...

Sure you're reading those numbers correctly?

 

H

Happytrails

NAXJA Forum User

Location

USA

• Sep 29, 2013

• #11

3.8779 largest "F"
-3.8755 smallest "A"
-------------
.0024

I was just rounding off the last bit.