Timing chain tensioner - help please

[Bazzman]

I've just changed the head gasket on my E200, M111 engine .

All went really well, until I can to refit the timing chain tensioner.
I followed the Haynes book really carefully, adjusting the plunger in line with the tensioner body, fitting that to the block, but when I came to fitting the spring and end piece - it was all but impossible, because of the strength of the spring!!!

I took two of us to do it finally. One to push the end piece onto the spring, and another to turn the hex head on the end piece with a spanner. Should it be that hard?
Have I over-tensioned the timing chain?
I've finished for the night now, but I've got the manifolds to fit and so on tomorrow.
Please advise me!

Thanks all.

Bazzman
Surrey UK
W124 '94 E200.