1.4 head conversion

[mark4newman]

Is converting a

1.4 to have a ported and polished 1.6 head is normal and beneficial?

[oilyhands]

Some 1.4 heads are the same as the later 1.6/1.8 castings, some arent. Provided the head hasnt had the valves enlarged you should be OK and there will be some benefits to be had.

 

Oily

[mark4newman]

 

What advantages?

 

 

[Tony J]

Most answers can be found here

 

Edited by - Tony J on 26 Apr 2002 15:02:01

[oilyhands]

Tony, there is a slight typo in your link to the K page..

 

Oily

[simonwelton]

I think what Mark is asking here (correct me if I'm wrong) is why would a 1.4 supersport have a ported and polished 1.6 head on. Is there a real benefit? Are there big differences between a 1.4 and 1.6 head originally?

 

Mark, take a look at the 1.4 to 1.8 thread as well.

 

Si

[oilyhands]

There are two types of castings in general use on the K series, the low port and the high port, early 1.4 engines may use either, but 1.6 and 1.8 engines useonly the high port. High port castings have a greater nominal airflow then low port and a lot more potential for modifcation. Dimensionally they are very similar with the same sized valves and combustion chambers etc.

 

Porting either of these heads while retaining the standrd valve sizes can increase the airflow by up to 30% at peak lift, these gains in airflow contribute towards higher volumetric efficiency and therefore increased power and torque. It makes more sense to use a high port head as the basis for any modification since you start with a better head and the ultimate potential is higher. If the original head were a low port casting, that might explain why a 1.6 head has been used.

 

Oily