Help Id Jahns pistons

deuce5wndw

deuce5wndw

Well-known member
Hello guys, I have a set of Jahns pistons and printed on the end of the box is 8-985 RP, FORD, and 3 15/16 std. I have searched on the internet but no luck with that number. I don't know of a Ford engine with a 3 15/16 bore! I looked in a Motors repair manual and the only engine I could find that had that size bore is a 1955 Lincoln 341.Thanks for your help, Dale.
 
Here is a link to an EBAY auction for and old 1956 Jahns Piston catalog. One of the photos shows 985 H is for a Ford or Merc Y-Block V8 high compression with a dome. Only trouble is that the biggest Y-Block V8 (312) has a 3.80" bore. 3 15/16" is 3.9375". Way too big of an overbore for a 312. Plus your box says Std. bore. Maybe 985 RP is a forged piston for a Lincoln Y-Block 317, 341 or 368 ? I know they made forged pistons too.


Sal


https://www.ebay.com/itm/VTG-1956-J...290603&hash=item3d5f753638:g:YZsAAOSw53NY9k0z
 
Thank you scicala, Mine are 985rp where those are 985h. I measured them and they do measure 3.9375. They appear to be cast pistons from looking at the inside. Thanks again, Dale.
 

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All MEL V8's had bores well over 4" so they can't be for a MEL. I agree they do look like cast pistons and no dome like the 312 Y Block 985 H piston. Since the box says Ford, they have a good chance of being 1955 Lincoln 341 pistons. Like you said, it's the only Ford V8 with that standard bore.


Sal
 
They are parts I have for sale and just wanted to represent them correctly. Thank you for your help, Dale.
 
Shown is an ILL of an early MEL combustion chamber showing unique MEL piston top-


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Correct. MEL's were like 348 and 409 Chevy's, in that the head was flat with no real combustion chamber in the head.


Sal
 
scicala said:
Correct. MEL's were like 348 and 409 Chevy's, in that the head was flat with no real combustion chamber in the head.

Sal
Click to expand...

You mean the CHEB was like the MEL don't you? ;)

The 1963 LINC MEL 4V re-design did have combustion chambers in the cylinder heads.
 
The 348 Chevy and MEL came out at the same time (about 1958), so they were like each other at the same time.


I didn't realize the '63 Lincoln MEL had combustion chambers. Still learning after all these years.


Sal
 
scicala said:
The 348 Chevy and MEL came out at the same time (about 1958), so they were like each other at the same time.
Click to expand...

THE 410 MEL was to be introduced in the 57 MERC but foundry problems delayed the intro.

It went to the 58 EDSEL (intro JUL 57).


EDIT-

Below is a 64 430 CYL HEAD and PISTON-


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deuce 5, thank you for doing your homework before selling the pistons. I frequently find parts on ebay, the sellers of which have no idea what they have.
 
B-ster said:
I don't suppose these pistons are still available. I am looking for 341 pistons
Click to expand...

Are you the gentleman with the 1953 LINC? Your machinist has no lead on replacement pistons? He hasn't machined anything yet has he?

492880
 

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I meant yes, I'm the guy. But no. Mechanic hasn't found any yet. Saw some 368 pistons new for sale but not sure if the 317 will bore out safely to that size
 
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