Chain Tensioner Piston Extension - 3.2 Carrera

mikedsilva · 07-11-2021, 06:53 PM

Just posting this here as a reference.
I'm no means an expert here, and have only rebuilt a fraction of the motors compared to others here, but I wanted to post these pics of the chain tensioners installed in this 3.2 Carrera Motor I am putting back together.

Up till now, most times I have disassembled a motor, the chain tensioners are extended a little more than the 'norm'... which would make sense with worn chains, sprockets and idler arms (where they contact the tensioner piston).

This motor I pulled apart with unknown history, did not seem to be too bad. The case was within spec and the heads cc'd at 89.8cc which made me think they had not been machined before.
The cams thrust plates were well centred in the chain box housings.

Upon reassembly, I installed the tensioners and noticed that the pistons on each tensioner had not extended anywhere near as far as on my previous motors. At first I thought the chains were not sitting on the sprockets correctly, or perhaps the chain guides were not properly installed and that the chains were riding on the high ridges of the guides.
Turns out, everything was installed properly.

Reaching out to a couple of experts, there is mixed opinion.

There are very few pictures on the net (that I could find) showing the installation of new chains etc..

So here are my contributions.
Of course, if you think there is an issue here, please reach out and make a suggestion.
Left Side Before

Left Side After

Right Side Before

Right Side After