1. Introduction

The precise size and type of the fan belt for a particular Jaguar XK is often very hard to determine and the information given by many suppliers is confusing or at times even misleading. But if you use your existing belt as an example for a new one, it is most likely that the original fan belt on your engine has already been replaced (several times). So what was the original fan belt like?

To complicate the problem of finding the correct belt for the Jaguar XK even more, fan belts have been (and still partly are) developed and manufactured according different (inter)national standards. The most important ones are BS3790 (or an earlier version of that standard) in the UK, the “Standard for Light-duty or Fractional-horsepower V-belts” of the Rubber Manufacturers Association RMA in the USA and the German DIN 2215 standard for Classical V-belts. Today all V-belts are ISO standardized and practically all manufacturers in all countries adhere to these standards. But unfortunately this does not help as the original 1950s fan belt dimensions have been modified into “something close” but certainly not identical.

Early Jaguar XK 120s initially used a Dunlop  ¾” (19 mm) wide 32° V-angle belt type. Around 1952 the length of the belt changed but otherwise remained identical. With the arrival of the XK 140 in 1954 the fan belt became narrower with a width of only 13/32” (10.3 mm) and an angle of 40°, which version was continued for the XK 150 until 1959 when a wider belt type was introduced with a width of 0.526” (13.4 mm) and 40° angle which changed later to ½” (12.7 mm) 40° belt for standardization reasons.

 Original 1950s fan belt on XK 140

Belts with the original widths and 32° V-angle for the early 120s are no longer manufactured or supplied but belts with a 36° V-angle are still available and fit without problem. Wider V-angles like 40° as a replacement for the 32° V-angle belt are widely available but will have some effect on e.g. the correct length (so care is required when using these modern belts). “Notched” belts are a development that started in the late 50s and have been applied on the last version of XK 150s.

On XK engines the fan belt is driven by the crankshaft pulley and runs over the water-pump and generator (dynamo) pulley. The required size, type and length of a belt is determined by (amongst others) the width of the belt type and the individual diameters of the 3 pulleys. Any modification to one of the pulleys introduces the necessity to change the fan belt dimensions. The information given below tries to highlight these changes and to provide information on the required belt per XK type. Please keep in mind that (1) the recommended fan belt dimensions relate to the original situation and furthermore (2) differences in dimension are possible per standard, brand or manufacturer: therefore a ± 10 mm tolerance on the length indication should be kept in mind.

Factory assembled engines most likely had Dunlop fan belts as standard equipment. Note that fan belt dimensions given hereafter refer to Dunlop manufactured belts as much as possible. Other (contemporary) original fan belts, recommended by the manufacturer for this particular type of car, may deviate from these (Dunlop) dimensions: when available these dimensions have been included in the survey of alternative/replacement belts.

2. Jaguar XK 120 fan belts

2.1 Early Jaguar XK 120 engines from W1001 up to W5464 (July 1952) with crankshaft pulley C2469 (4¼“ or 108 mm outer diameter) used pulley C2246 (6“ or 152 mm outer diameter) on the (round hub) water pump with the cast 5 blade fan and a cast iron pulley C2579 on the C45PVS generator (3½ ” or 89 mm outer diameter). The fan belt was coded C2240. 

Replacement belts:

• An original belt can sometimes be found at auctions or auto-jumbles, but after 50 years of degradation the quality should be thoroughly checked. However, carefully stored fan belts might do the job for several thousands of miles (but always take a spare one with you). Examples of original belts:
  • Dunlop D305 (see above)
  • Ferodo V340  (W :13/16″ (20.6 mm); IC 37 43/64″ (957 mm); OC 40 13/16 (1037 mm)
  • Raybestos R330
  • John Bull V177 
  • B.F. Goodrich 38
• The Gates TR24400 Green Stripe Truck & Bus series (or equivalent from different brands) is a ¾” (19mm) wide belt with a 36° angle and an outside length of 40⅝” (1030 mm). As the belt-width (19 m) is slightly less than the original belt (20.6 mm) the somewhat shorter length (7 mm) will be compensated.
• If not the “next in size” belt Gates TR24403 with an outside length of 1040 mm might be an option.
• An interesting candidate with the correct width comes from a different source: the old German ‘Klassischer Keilriemen’ version according DIN 2215/ISO 4184. Although the 20 mm version will be (has been?) phased out, several 20 mm wide belts (with a 12.5 mm correct height) are still available on the market. Example: 20 x 950 Li with an inside length of 950 mm. According the DIN2215 standard the outside length is about 80 mm longer than the inside length meaning La = 1030 mm and the “effective” length Ld = 1000 mm. The V-angle is however 40°, but this belt may fit depending on the adjustability of the generator and the appearance comes very close to the original 13/16″ belt type.

Please note that the Jaguar Mk IV and Mark VII used a similar pulley, part number C1076, however with a 3¾” or 95 mm diameter. These larger pulleys may have been used as a replacement on XK 120 engines and will affect the required length of the fan belt. So check the part number of the pulley which is stamped in the casting between the vanes!

2.2 There is much confusion about the exact fan belt dimensions of the later Jaguar XK 120s from engine number W5465 (July 1952 till end of production). This engine still had the same crankshaft and generator pulley but the water-pump pulley had changed: this much smaller pulley (102 mm or 4” outer diameter) had been integrated with the water pump hub and the combination was coded C5054. There was a 4 bolt flange for the new 6 blade fabricated aluminium fan. The new shorter fan belt was coded C5056.

Replacement belts:

• Original belts can sometimes be found at auctions or auto-jumbles, but after 50 years of degradation the quality should be thoroughly checked. Examples:

 

• • Dunlop D355 see photo below
  • Ferodo V144: (.75” W x .44 H x 39.41” OC x 36″ IC x 32°); see photos above
  • Raybestos R265 
  • Mintex TK339 (unconfirmed)
  • John Bull V516: (47/64” W x 15/32” H x 37 1/16” IC x 32°)
  • Quinton Hazell DB322
  • Gates Vulco V-belt 500 (23/32″ W x 23/32″ H x 39¼ ” OC x 32°)

                                    Original Dunlop D 355 packaging                  Original Gates Vulco 500 fan belt

• Gates offered a  23/32″ (18.2 mm) fan belt, claiming this suited the Mk VII, XK 120 and XK 140 in the period 1950 – 1956. This survey is incorrect as this fan belt only suit some XK 120s and Mk VIIs with the C.5060 belt. The length of the Gates belt is 39¼ ” which is close to the Ferodo V144 with 39.41″.
• There seems to be no properly fitting ¾” (19 mm) Gates Green Stripe Truck & Bus series 36° belt, but Gates TR24379 might come close with an outside length of 38½” (980 mm) which is only 14 mm too short, provided the generator can be sufficient adjusted towards the block.
• We noticed that some Jaguar part suppliers provide the TR24400 also in this case, which however is with 57 mm by far too long and cannot be recommended.
• The B36 belt (from various suppliers like Gates Hi-Power® II) may fit because, although with a width of 21/31” (17 mm), it has the correct outside length of 39” or 990 mm. It will run deeper in the 32° V-groove which again is somewhat compensated by the wider V-angle of 36°.

2.3 There are sources mentioning that some very late XK120s (and Mk VIIs) may have been executed with an 8 blade fan and the pulleys of the XK140. The required fan belt is described in the following chapter.

3. Jaguar XK 140 fan belts

3.1 Jaguar had been experimenting with narrow belts on the XK 120 C-type to minimize power losses in the “auxiliary” engine parts. The width and angle of the belt changed therefore with the introduction of the XK 140: a 40° V-angle belt instead of the former 32° V-angle and a much narrower type of about 10 mm versus the much wider 19 to 20 mm of the XK 120. The crankshaft pulley had changed (now C7275) with a 5” or 127 mm OD, the water-pump pulley was new (C7644) with a 5¼” or 134 mm OD, as was the dynamo pulley (C7427) with a 3½” or 90 mm outer diameter. All XK 140s over the entire production run had the same fan belt which was coded C7898.

  Early (orange) branded FEROGRIP and later (red) FERODO box

Replacement belts:

• Original belts can sometimes be found at auctions or auto-jumbles, but thoroughly check their quality. Some examples:
  • Ferodo V917 (dimensions see above)
  • Raybestos R80 (dimensions as above)
  • Quinton Hazell DB808
  • Dunlop D333
  • John Bull V529  (3/8” W x 5/16” H x 38 ¼ “ IC x 40°)
  • B.F. Goodrich 1014
  • Goodyear 1014 (13T412)
• The 36° angle Gates 7400 XL belt seems a good candidate with a width of ⅜” or 9.5 mm and an outside length of 40⅝” or 1030 mm. This belt is “notched” so not entirely original.

• Because these belts are actually somewhat wider than their code indicates and rise somewhat out of the groove, the Gates 7400 belt could turn-out to be too short. Gates recommends a Gates 7410 XL “notched”belt (also 36° angle) with an outside length of 41⅝”or 1055 mm as a replacement for Jaguar code C7898.
• A modern 40° angle generic belt type AVX10x1035 could also do the job and is available from various manufacturers, however this is “notched” belt.
• Another modern version is the SPZ1012 with an inside length of 974mm and an outside length 1025mm. This belt has the correct belt height of 8mm. If this fan belt is too short the next longer version SPZ1024 will fit with inside length 986 mm and outside length 1037 mm.
• The German Classic belt type 10 x 1000Li is another possibility although the height of this belt is only 6 mm (instead of 8 mm for the original version). Outside length is La = Li + 38 mm for this belt type, meaning outside length is 1038 mm (instead of the original 1030 mm).

4. Jaguar XK 150 fan belts

4.1 Early XK 150s (with engine number to V1597; about September 1957) continued to use the XK 140 fan belt C7898. Crankshaft pulley was still C7275 of the XK 140 engine, as was the water-pump pulley (C7644) and the dynamo pulley (C7427).

• See previous chapter on XK 140 fan belts.

4.2 The second belt type was used for XK 150 standard engines from number V1598 to V5732 and “SE” engine number VS1001 to VS1522. The somewhat shorter fan belt was now coded C13595/1. Jaguar had increased the speed of the dynamo by mounting a new pulley C13594 with a reduced diameter (from 3½ to 3” or about 76 mm). The crankshaft pulley remained C7275 and the water-pump pulley C7644. As these two pulleys remained unchanged, fan belt C13595/1 is still a 13/32” (10.3 mm) wide and 40° V-angle belt. Please note that some manufacturers make no difference between fan belt C7898 and C13595/1.

The Jaguar Mark 2 2.4 litre had a similar change involving a new pulley with reduced diameter (in order to increase the speed of the dynamo). The 2.4 litre pulley (Jaguar C.15592) , however, has a diameter of 3⅜” or 86 mm and should not be used because fan belt C.13595/1 will not fit.

  Jaguar C15595

Replacement belts:

• An original belt can sometimes be found, but thoroughly check its quality. Examples are:
  • Ferodo V904 (see above)
  • Goodyear 476 (unconfirmed)
  • Goodyear 1173 (13T391)
  • Quinton Hazell DB800 (dimensions 1016 La x 9.5; also incorrect reference to XK 140)
  • Dunlop D322
• The Gates 6275MC belt seems a good candidate with a width of ⅜”or 9.5 mm and an outside length of 39⅞” or 1013 mm.
• Mintex WFT400 is apparently identical to Gates 6275MC.
• Modern 40° V-angle types of belts are coded AVX10x1025 may fit, but are teethed or notched.

 Perfect Original QH fan belt DB800

4.3 The third belt type was introduced in November 1958 from 3.4 litre engine number V5733 and VS1523 and also used for all 3.8 litre engines from engine numbers VA1001 and VAS1001 onwards. A wider belt was introduced and this required all pulleys to be changed although their diameters remained the same and thus the outside length of the fan belt remained the same (1015 mm). This was in fact for the first time a “notched” type of fan belt on Jaguars (initially indicated by most suppliers with suffix N). The new water-pump pulley was coded C14588, the crankshaft pulley was now C14589 and finally the dynamo pulley C14590 (the fact that these parts have sequential code numbers may indicate that the Jaguar development department changed the complete belt system in one operation). Jaguar initially introduced a 0.526“ (13.4 mm) wide and 40° V-angle belt type coded C14535/1. However, some years later this belt type had been changed (or standardized?) to a ½” (12.7 mm) version with an inside length of 37.08” or 942 mm and an outside length of 39.78” or 1010 mm.

Replacement belts:

An original belt can sometimes be found, but thoroughly check its quality. Examples:

• BMLC MOWOG 13H1840 
• Ferodo V4895N (unconfirmed)
• Ferodo V6985N (see above)
• Mintex WKT394 (slightly shorter: OC 39⅜ ” , IC 36¾”)
• Quinton Hazell DB2920N
• Raybestos R6000
• Goodyear 16 (18T401)

      Original Mintex WKT394                                                     Later BMLC MOWOG fan belt 13H1840

•  Gates recommends the 36° angle Gates 9400 XL belt with an outside length of 40⅜” or 1025 mm. Again the extra length is because of the different width definition of this belt type and the fact that this belt “sticks out” of the groove.
• NAPA 25-9400 is related to the above however with a correct 17/32” width (13.5 mm) and a 40” outer length (1016 mm).
• Reference is made of the Goodyear 17401 which is a 0.53″ (12.7 mm) x 40″ (1016 mm) belt; this is a “notched” belt but is correct for the later type of XK150s.
• Modern 40° V-angle belts coded AVX13x1015 may fit depending on the adjustability of the generator.

5. Fan belt overview XK 120, 140 & 150

 

6. Overview of fan belt data for other early Jaguars from 1936 to 1960

During the “research” done in order to retrieve the original fan belts and their dimensions, a lot of additional information was found on other earlier Jaguar cars, that may help other Jaguar enthusiasts in their attempt to find a proper fan belt for their particular car. This information can be found in the table underneath.