What are these marking?

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petty437

petty437

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I have a couple of questions about the 225 from my 63 Dart;
I have read that assembly plants would put various markings on engines as they went down the line but does anyone have any idea what these may mean? This is what was underneath the grime.
dart motor.jpg


The second question is about the spark plugs. I've read conflicting thoughts on whether or not I should remove the sealing ring at the base of the plug so it reaches deeper into the chamber. I'm using RN14YC plugs with 3/4 length thread. The motor is bone stock & never been apart. Thanks!
 
the 63 is designed to use the plug tube ends as the gasket so you need to remove the factory spark plug washers. IIRC only the pre 63 and the later peanut plug (no tubes) heads needed the factory washer.
"..The '63-up heads have a redesigned counterbore at the top of the spark plug hole; the spark plug tube itself seals the plug, and if you use the washer it interferes with heat transfer from the plug to the head. The '60-'62 heads don't have the special counterbore and need to use the plug gaskets. This is factory info..."
SS Dan.

<< Dont know what that graffiti is on that motor but I would be a little pissed if I saw that on the showroom floor model! >>>
 
I don't know about the makings, but the spark plug gaskets COME OFF on drool tube heads. The drool tubes ARE the gaskets. Leaving the gaskets on will have them leaking.
 
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I was just writing a love letter in code to his girlfriend at the end of the assembly line...
 
I know what the markings are. Those are the engine bore specs carried out to the fifth decimal place. They are only published in the FSM for the 426 Hemi. Example- 69 FSM, page 9-98 Cylinder Bore (standard) "A" Size 4.24975" "B" Size 4.25025, etc. There must have been more information at the engine plants for all the engines.

I found the same thing when I re-ringed my 383. A testament to Chryslers engineering and machinist history. They must have had a piston-sorting system that was very precise. They measured the bores out to four or five decimal places, and the pistons as well. A slightly larger piston was matched to a slightly larger bore. We're talking about a range of .002. the 426 Hemi section lists 5 sizes, "A" through "E".
 
Demonic said:
I know what the markings are. Those are the engine bore specs carried out to the fifth decimal place. They are only published in the FSM for the 426 Hemi. Example- 69 FSM, page 9-98 Cylinder Bore (standard) "A" Size 4.24975" "B" Size 4.25025, etc. There must have been more information at the engine plants for all the engines.

I found the same thing when I re-ringed my 383. A testament to Chryslers engineering and machinist history. They must have had a piston-sorting system that was very precise. They measured the bores out to four or five decimal places, and the pistons as well. A slightly larger piston was matched to a slightly larger bore. We're talking about a range of .002. the 426 Hemi section lists 5 sizes, "A" through "E".
Click to expand...
Small blocks have the letters stamped for each cylinder in the oil pan rails.
 
petty437 said:
about the spark plugs. I've read conflicting thoughts on whether or not I should remove the sealing ring at the base of the plug so it reaches deeper into the chamber.
Click to expand...

Yes, you remove and discard the metal ring washers with a '63-'74 head, see here. Also remove and discard that Champion junk and put in good spark plugs as described in the tune-up parts and technique suggestions in this post (which also contains links to details on the ring washer matter).
 
slantsixdan said:
Yes, you remove and discard the metal ring washers with a '63-'74 head, see here. Also remove and discard that Champion junk and put in good spark plugs as described in the tune-up parts and technique suggestions in this post (which also contains links to details on the ring washer matter).
Click to expand...
Thanks!
 
Demonic said:
I know what the markings are. Those are the engine bore specs carried out to the fifth decimal place. They are only published in the FSM for the 426 Hemi. Example- 69 FSM, page 9-98 Cylinder Bore (standard) "A" Size 4.24975" "B" Size 4.25025, etc. There must have been more information at the engine plants for all the engines.

I found the same thing when I re-ringed my 383. A testament to Chryslers engineering and machinist history. They must have had a piston-sorting system that was very precise. They measured the bores out to four or five decimal places, and the pistons as well. A slightly larger piston was matched to a slightly larger bore. We're talking about a range of .002. the 426 Hemi section lists 5 sizes, "A" through "E".
Click to expand...
When I worked at Trenton Engine (Chrysler engine plant in Michigan) I had to run the boring line, the rod line and the crank line. I had to do that for every block and crank I ran off the line. (I was on the RB line for a year, hemis were a line you couldn't get on unless you had 20 years seniority , I had 2) I watched (in awe)women on the piston line ring pistons(4 to their 2) faster than the guys could slam them into the bores of the blocks and they were shooting 2 at a time into the block. thankfully I got moved to another plant and off the "grunt" production line. Glass is much lighter than /6 crankshafts
 
On the small blocks they had A B and C pistons that were all considered standard bore but slightly different in size to fit the bore variations . Today with computer controled machinery there are no variations . It was the same for many motorcycle manufactures back then . On my 2 stroke Yamahas you have a .97mm .98mm .99mm variation on all standard bore sizes .So,those letters could have been how they were marked before assembly .
 
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