IH: Engine Mechanicals

Sub-Documents

Head Sets with Year Changes

The chart below, with head part numbers, is a compilation of parts catalogs and shows when the changes occurred and to which year models the changes affected. 1) 2) 3) 4) 5) 6) 7)
8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28)

Part NumberYear Models Used OnDate(s) Available
(F) 16677-57
(R) 16678-57
1957-1959 XL
1958 XLC
1957-1958
(F) 16677-57A
(R) 16678-57A
1959
(F) 16673-58
(R) 16674-58
1958-1969 XLH/XLCH1958
(F) 16673-58A
(R) 16674-58A
1959
(F) 16673-70
(R) 16674-70
1970-E1973 XLH/XLCH1970
(F) 16673-71
(R) 16674-71
1971
(F) 16673-72
(R) 16674-72
1972-E1973
(F) 16673-73
(R) 16674-73
L1973-1985
XLH/XLCH/XL/XLS/XLX
L1973-1978
(F) 16673-73A
(R) 16674-73A
1979
(F) 16673-73B
(R) 16674-73B
1980
(F) 16673-80
(R) 16674-80
1980
(F) 16673-73C
(R) 16674-73C
1981-1984
(F) 16673-73D
(R) 16674-73D
E1985
(F) 16673-84
(R) 16674-84
L1985

Head Identification

4 steps to head identification just from site plus head bolt spacing: 29)

1a. If these fins are present, your looking at 900 heads
for sure. In later 71 these fins disappeared.
That means:30)
1b. There are some 900 heads that didnt have those fins and no 1000 heads have these fins. If no fins go to step 2.31)2a. Decide if the heads are later 71 (900) or 1000.
Do that by looking at oil drain size
Note the size of drain compared to head bolt holes.32)

1957-71 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.440“.
57-mid 73,threads for head bolts, come all the way up to the head gasket surface on the cylinders.33)
2b. 1000 uses 3/16” oil drains. Now you know if your
looking at late 1971 900 (big drains) or 1000
(small drains). If heads have small drains go to step
3 to determine if heads are E1000 (72-E73)
or L1000 (L73-78). 34) When the change to 1000 happened in 72 the cylinders casting size was increased but for augments sake the head casting was not. Consider the cylinders: The bore was opened .094“ radius. That pushed to the oil holes in cylinder to a larger pattern. To get the matching larger pattern in the old heads, the holes needed to be reduced in size so they still fit in the 900 size casting.35)
3a. E1000 (72-E73) On 900 heads (smallest bolt circle), the bolt holes bulls-eye the casting boss. Looking close at the 72 heads you can see the bolt circle was slightly enlarged while the casting boss stayed at the original position. 36)3b. L1000 (L73-78). In later 73 the 1000 heads change to bigger bolt pattern.37) The L73+ heads have the spot facing further out on the casting boss. In other words, the PCD of the spot facing is greater than on the 72/e73 heads. 38) In L73 the bolt circle was really enlarged. Again the boss stayed at the 900 position. There is added meat around the bolt holes between the fins but that's a moot point in identifying what year heads your gawking at. 39)

72-mid 73 1000 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.540”.40)

L73 - 85 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.640“. Late 73-85 threads for head bolts are recessed in the cylinders by 1/2''41)
4. In 79 a boss was added for a/c mounting. This is a 79 only head. 1980-1983 is same as 1979 but doesn't have the intake o-ring lip. 84-85 had no intake o-ring lip either. The air cleaner boss was still present but it wasn't drilled or tapped.42)84-85 heads also had the shoulder-less valve guides and took a small washer for the inner valve spring instead of the full size lower spring collar the previous heads used. The valve guides do require machining if you want to use a seal the top spring collar will contact them. 43) While this info is accurate, don't let missing guides or incorrect vintage guide installation influence you in identifying what heads you are looking at. 44)

Pics of Iron Heads

1969 Iron Heads 45)

Pistons

Standard Piston Grading

  • From a Service Bulletin in October of 1981, all standard sized pistons are graded for size in .00025” increments. This is done for production purposes on­ly and does not apply to oversized (.010“-.070”) pistons. 46)
  • The grade number is stamped on the dome of all standard pistons. In the case of a grade 10 piston, the number 10 is stamped on the dome. This is a standard sized piston and should not be confused with a .010“ oversized piston which also has a number 10 stamped on the dome. If there is any doubt about a piston's size, it's largest diameter should be measured.
  • In the future, all grade 10 standard pistons will be marked “G10” for ease of identification. All oversized pistons used in oversized cylinder bores (.010”-.070“) will continue to be stamped in the usual manner.
  • Example:
    • Standard Grade 10 piston range: 3.18725”-3.18700“ stamped with “10” or the new G10 stamping (old style).
    • Oversized .010” piston range: 3.197“-3.196”

Valves

Sub-Documents

Intake Valves and Components with Year Changes

The chart below, with valve component part numbers, is a compilation of parts catalogs and shows when the changes occurred and to which year models the changes affected. 47) 48) 49) 50) 51) 52) 53)
54) 55) 56) 57) 58) 59) 60) 61) 62) 63) 64) 65) 66) 67) 68) 69) 70) 71) 72) 73) 74)

Intake Group 1957-1959 XL
1958 XLC
1958-1969 XLH/XLCH 1970-1979 XLH/XLCH 1980-1985 XL / XLS / XLX
Valve 18070-57
1-11/16“ Dia
(1.6875”) 75)
18070-58
1-13/16“ Dia
(1.8125) 76)
18070-70
(1.937”) 77)
18070-70 (last use in 80)
18027-80 (Nittan)
18028-80 (Eaton)
(1.937“) 78)
either brand is standard
for 79-85
18027-80 (Nittan)
18028-80 (Eaton)
(1.937”) 79)
either brand is standard
(added in 81)
(replacement for 1979)
Valve Guide 18176-57 (Std)
18179-57 (.001“ OS)
18180-57 (.002” OS)
(replaced in '59 by ↓)
18176-57 (Std)
18179-57 (.001“ OS)
18180-57 (.002” OS)
(replaced in '59 by ↓)
18176-57A (Std)
18179-57A (.001“ OS)
18180-57A (.002” OS)
(replaced in '80 by ↓)
18176-80 (Std) (80 only)
18176-57B (Std) (80)
18179-57B (.001“ OS)
18180-57B (.002” OS)
18191-79 (.004“ OS) (81)
(shouldered valve guides)
(All replaced in '83 by ↓)
18176-57A (Std)
18179-57A (.001” OS)
18180-57A (.002“ OS)
18176-57A (Std)
18179-57A (.001” OS)
18180-57A (.002“ OS)
18176-57B (Std)
18179-57B (.001” OS)
18180-57B (.002“ OS)
18191-79 (.004“ OS) (81)
(shouldered valve guides)
(for 79-82)
18176-57C (Std)
18179-57C (.001” OS)
18180-57C (.002“ OS)
18191-79A (.004” OS)
(shoulder-less valve guides)
(for 79-85)

See also
1983 Valve Guide Changes
18176-57C (Std)
18179-57C (.001“ OS)
18180-57C (.002” OS)
18191-79A (.004“ OS)
(available in 83)
(shoulder-less valve guides)
(for 79-85)
Valve Guide
Retainer Ring
18120-80 (80 only)
Valve Seat
Repair Insert
18055-58 (added in 74)
(for 58-69)
18055-58 (added in 74)
(for 58-69)
18055-70 (added in 74)
(for 70 up)
18055-70
Spring Collar
(lower)
18220-57 18220-57 18220-57 18220-80 (80 only)
18220-57 (57-E81)
18220-81 (L81-E83)
18220-83 (flat washer) (L83-85)
Valve Spring
(inner)
18204-57
(replaced in 71 by ↓)
18204-57
(replaced in 71 by ↓)
18204-57
(replaced in 71 by ↓)
18204-57A (71-E83)
18204-83 (L83-85)
18204-57A
(for 57-E83)
18204-57A
(for 57-E83)
18204-57A
(for 57-E83)
Valve Spring
(outer)
18203-57
(replaced in 71 by ↓)
18203-57
(replaced in 71 by ↓)
18203-57
(replaced in 71 by ↓)
18203-57A (71-E83)
18203-83 (L83-85)
18203-57A
(for 57-E83)
18203-57A
(for 57-E83)
18203-57A
(for 57-E83)
Spring Collar
(upper)
18221-57
(replaced in '59 by ↓)
18221-57
(replaced in '59 by ↓ )
18221-57A
(replaced in 82 by ↓ )
18221-57A (L58-81)
18221-57B (82)
(for 79-85)
18221-57A
(for 57 up)
18221-57A
(for 58 up)
18221-57B
(for 79-85)
Valve Keepers
(keys)
18228-30 18228-30 18228-30 18228-30
Valve Stem Cap X X X X

Exhaust Valves and Components with Year Changes

Exhaust Group 1957-1959 XL
1958 XLC
1958-1969 XLH/XLCH 1970-1979 XLH/XLCH 1980-1985 XL / XLS / XLX
Valve 18080-57
1-1/2” Dia
(1.5000“) 80)
18080-58
1-9/16” Dia
(1.5625“) 81)
(58-62 XLH)
(58-61 XLCH)
(obsolete for 63)
18080-58A
1-9/16” Dia
(1.5625“) 82)
18080-58B (last use in 80)
18033-80 (Nittan) (81)
18036-80 (Eaton) (81)
1-9/16” Dia
(1.5625“) 83)
either brand is standard
for 79-85
18080-58A
1-9/16” Dia
(1.5625“) 84)
(63 and up XLH)
(62 and up XLCH)
(58 and up replacement)
18033-80 (Nittan)
18036-80 (Eaton)
1-9/16” Dia
(1.5625“) 85)
either brand is standard
(added in 81)
(replacement for 1979)
Valve Guide 18170-57 (Std)
18171-57 (.001” OS)
18172-57 (.002“ OS)
18170-57 (Std)
18171-57 (.001” OS)
18172-57 (.002“ OS)
18170-57 (Std)
18171-57 (.001” OS)
18172-57 (.002“ OS)
(replaced in '80 by ↓)
18170-80 (Std) (80 only)
18170-57A (Std) (80)
18171-57A (.001” OS)
18172-57A (.002“ OS)
18168-79 (.004” OS) (81)
(for 79-82)
(shouldered valve guides)
(All replaced in '83 by ↓)
18170-57A (Std)
18171-57A (.001” OS)
18172-57A (.002“ OS)
18168-79 (.004” OS) (81)
(shouldered valve guides)
(for 79-82)
18170-57B (Std)
18171-57B (.001” OS)
18172-57B (.002“ OS)
18168-79A (.004“ OS)
(shoulder-less valve guides)
(for 79-85)
See also
1983 Valve Guide Changes
18170-57B (Std)
18171-57B (.001” OS)
18172-57B (.002“ OS)
18168-79A (.004” OS)
(shoulder-less valve guides)
(available in 83 for replacement)
(for 79-85)
Valve Guide
Retainer Ring
18120-80 (80 only)
Valve Seat
Repair Insert
18052-58 (added in 74)
(for 58-85)
18052-58 (added in 74)
(for 58-85)
18052-58 (added in 74)
(for 58-85)
18052-58
Spring Collar
(lower)
18220-57 18220-57 18220-57 18220-80 (80 only)
18220-57 (57-E81)
18220-81 (L81-E83)
18220-83 (flat washer) (L83-85)
Valve Spring
(inner)
18204-57
(replaced in 71 by ↓)
18204-57
(replaced in 71 by ↓)
18204-57
(replaced in 71 by ↓)
18204-57A (71-E83)
18204-83 (L83-85)
18204-57A
(for 57-E83)
18204-57A
(for 57-E83)
18204-57A
(for 57-E83)
Valve Spring
(outer)
18203-57
(replaced in 71 by ↓)
18203-57
(replaced in 71 by ↓)
18203-57
(replaced in 71 by ↓)
18203-57A (71-E83)
18203-83 (L83-85)
18203-57A
(for 57-E83)
18203-57A
(for 57-E83)
18203-57A
(for 57-E83)
Spring Collar
(upper)
18222-57
(57-E58)
18222-57
(57-E58)
18221-57A
(replaced in 82 by ↓ )
18221-57A (L58-81)
18221-57B (82)
(for 79-85)
18221-57A
(L58 up)
18221-57A
(L58 up)
18221-57B
(for 79-85)
Valve Keepers
(keys)
18228-57
(57-E58)
18228-57
(57-E58)
18228-30 18228-30
18228-30
(L58 up)
18228-30
(L58 up)
Valve Stem Cap 18234-57
(57-E58 only)
18234-57
(57-E58 only)
(L58 up - Obsolete) (L58 up - Obsolete) X X


1) , 47)
1952-1957 HD Spare Parts Catalog for all Sportster and K Models pg 6
2) , 48)
1952-1959 HD Spare Parts Catalog for all Sportster and K Models pg 5
3) , 49)
1959-1960 HD Supplement to Spare Parts Catalog for Sportster and K Models
4) , 50)
1959-1961 HD Supplement to Spare Parts Catalog for Sportster and K Models
5) , 51)
1959-1962 HD Supplement to Spare Parts Catalog for Sportster and K Models
6) , 52)
1963 HD Parts Catalog for Sportster and KH Models
7) , 53)
1964 HD Supplement to Spare Parts Catalog for Sportster and KH Models
8) , 54)
1955-1965 HD Sportster and KH Model Parts Catalog
9) , 55)
1966 HD Sportster and KH Model Parts Catalog Supplement
10) , 56)
1957-1967 HD Sportster and KH Model Parts Catalog
11) , 57)
1967-68 HD Sportster and KH Model Parts Catalog Supplement
12) , 58)
1959-1969 HD Sportster Parts Catalog
13) , 59)
1961-1971 HD Sportster Parts Catalog
14) , 60)
1961-1972 HD Sportster Parts Catalog Supplement
15) , 61)
1962-1973 HD Sportster Parts Catalog
16) , 62)
1962-1974 HD Sportster Parts Catalog Supplement
17) , 63)
1962-1976 HD Sportster Parts Catalog Supplement
18) , 64)
1954-1977 HD Sportster Parts Catalog Supplement
19) , 65)
1954-1978 HD Sportster Parts Catalog Supplement
20) , 66)
1954-1978 HD Sportster Parts Catalog (99451-78A)
21) , 67)
1954-1978 HD Sportster Parts Catalog (99451-78B)
22) , 68)
1979 HD Sportster Parts Catalog (99451-79
23) , 69)
1979 HD Sportster Parts Catalog (99451-79A
24) , 70)
1979-1981 HD Sportster Parts Catalog
25) , 71)
1979-1980 HD Sportster Parts Catalog
26) , 72)
1979-1982 HD Sportster Parts Catalog
27) , 73)
1979-1983 HD Sportster Parts Catalog
28) , 74)
1979-1985 HD Sportster Parts Catalog
38)
Scuba10jdl
39)
DR Dick
44)
Dr Dick
46)
HD Service Bulletin #M-844 dated October 30, 1981
75) , 76)
HD Service Bulletin #392 dated 11-27-1957
80) , 81) , 82) , 83) , 84) , 85)
Listed to standard size from this article by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1946196
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