8V Valve Spring Differences

[petert 590]

I was surprised to find some differences in 8V valve springs recently. I had dismantled a 1.6L XU5JM head and was surprised to see that the wire diameter was slightly thicker compared to the springs from an XU9JAZ head. My initial thoughts were this might be good, however, a few tests revealed otherwise. They both had the same seat pressure of 125lbs @ 38.8mm, however the solid heights differed considerably. The thicker wire means they go solid at approx. 28.5mm compared to approx. 27.5mm on the 1.9L springs. This means there's no chance of using a GTi cam with those springs.

 

This information differs considerably from the parts book, where the XU9JAZ and XU5JM spring part numbers are the same.

 

 

[welshpug 1,662]

What is the jm engine?

 

I know the xu5m which is spi and the xu5jp which is multipoint, both with coilpack.

[petert 590]

Sorry, I meant XU5M.

Edited July 9, 2014 by petert