[v12-engine] 1971 V12 compression ratio?

I have a 1971 V12 E-type with a SB engine number suffix. Can
anyone tell me what this denotes as far as the compression
ratio? I thought the SA or SB engines were high compression
and the LA or LB engines were low compression but I am
unsure as to what the exact compression ratio is.

Thanks in advance for the information.–
Steven A. DuChene - XJ6VDP XJ6C XJ12C XK120SE 3.8S E-Types
Phoenix, AZ Atlanta GA, NE Oh, United States
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In reply to a message from StevenD57 sent Fri 11 Apr 2014:

Steve:

I thought 1971 was the introductory year for the V12, and
this appeared only in the E type that year, right? The
compression ratio at introduction was 9:1, I believe.

Do you know the production date of the car you have?

-M–
Mike, 1990 5.3 XJS Conv., 5-speed, SE-ECU, TT Extractors
Lakewood, OH, United States
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In reply to a message from mike90 sent Sat 12 Apr 2014:

Steve:

Evidently, I was recalling correctly. If you look
elsewhere on this site, you will find a copy of the sales
brochure for the 1971 Series 3 V12 E-type, and this lists
the engine compression ratio as 9:1.

-M–
Mike, 1990 5.3 XJS Conv., 5-speed, SE-ECU, TT Extractors
Lakewood, OH, United States
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In reply to a message from StevenD57 sent Fri 11 Apr 2014:

SA denotes 9:1 CR. SB is 8:1 CR. The SB engines were for
the US and Canada Markets.–
The original message included these comments:

I have a 1971 V12 E-type with a SB engine number suffix. Can
anyone tell me what this denotes as far as the compression
ratio? I thought the SA or SB engines were high compression


850225/679,1E21003,2W2001BW,JNAEY3AC100218,SAJNV4841KC156072
ROSANNA, Australia
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In reply to a message from Norman LUTZ sent Sun 13 Apr 2014:

Norman Lutz said:-

SA denotes 9:1 CR. SB is 8:1 CR. The SB engines were for
the US and Canada Markets.<

That is not correct.

The first letter in the suffix denotes compression ratio.

Flat head engine:- S = 9:1, L = 7.8:1
HE engine:- S = 11.5:1, H = 12.5:1

The second letter in the suffix, A or B, denotes
bore/piston grade - differing by 0.001�.–
Roger Bywater / AJ6 Engineering
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In reply to a message from RogerBywater sent Thu 24 Apr 2014:

Correct Roger, confused the ‘‘B’’ with the ‘‘L’’ suffix.–
850225/679,1E21003,2W2001BW,JNAEY3AC100218,SAJNV4841KC156072
ROSANNA, Australia
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In reply to a message from Norman LUTZ sent Thu 24 Apr 2014:

Yeah, ‘confused’ is a word I have become more and more
familiar with as I get older.–
The original message included these comments:

Correct Roger, confused the ‘‘B’’ with the ‘‘L’’ suffix.


Roger Bywater / AJ6 Engineering
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In reply to a message from RogerBywater sent Fri 25 Apr 2014:

And I keep telling my wife she’s the confused one. But she
keeps reminding me I’m the 70 yo.–
The original message included these comments:

Yeah, ‘confused’ is a word I have become more and more
familiar with as I get older.


850225/679,1E21003,2W2001BW,JNAEY3AC100218,SAJNV4841KC156072
ROSANNA, Australia
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