Herald 1200 Engine Upgrade

[Seasider]

I've noticed that with some Herald 1200s, the standard engine has been replaced by a 1500cc engine from a Triumph Spitfire. The pros seem clear but are there any cons? For example, does the replacement engin accept the 1200's existing clutch and (not sports) manifold downpipe? 

[Colin Lindsay]

Match the clutch and manifold / exhaust to the replacement engine. The smaller coil clutch won't be up to the power of the bigger engine, so clutch slave cylinder and flywheel will require replacement.

The manifold is required to suit the later heads - six port 1200 won't fit the 8 port 1300 and upwards, the smaller exhaust pipes of the early cars won't have the same capacity as the larger versions, so it's much easier to match the exhaust to the replacement manifold like for like.

 

[johny]

Theres also gearing to consider as both the gearbox and axle ratios are different so as to make use of the greater torque produced by the bigger engine. As Colin says the best idea is to change over a much as possible from the 1500...

[Pete Lewis]

yes match with a 3.63 :1 diff ratio  makes sense 

there is so much more torque of the 1500  you must swap the clutch  the 1200 unit will not cope at all .

pete

[DanMi]

the clutch/flywheel will be fine if it has the later diaphragm clutch, but not the early spring (i ran a mk2 spit like that for 10 years) the 1500 clutch will need a different clutch plate to match to the gearbox. You could use a 1360 exhaust. You would also really as others have said need to up the gearing so either a 3.63 diff or spitfire OD gearbox or both.

The other option would be a spitfire 1300 or herald 1360 engine and the 1360 gearing was the same. The 1500 is more about torque the 1300 more revvy