chris_barry

I sand blasted (actually, silica carbide blasted) a few TCT's on my race engine that had a rattly chain. It only helped for short while before the noise returned.

I put a new chain on and the problem was solved. Putting the new/old chains side by side there was a small but measureable difference in length. The new chain positioned the TCT piston approx 4mm deeper into the TCT housing due to less slack in the chain. it appears that a tiny amount of slack translates into a much larger movement of the swinging chain guide.( the one the TCT pushes against).

SpitfireS

What is keeping the main TCT piston in, creating chain slack?
#1 - Its spring loaded, allthough that spring isn't very strong.
#2 - It has oil pressure pushing it out - with a running engine.

As far as I understand the worm has to stop the piston retracting - like a reverse cable-tie - but does not hold the piston in.
The piston & worm move out as 1, nothing holding it in.

Oil pressure - x amount of psi and y amount of piston surface - should be able to push that piston out and keep the chain at tension.. right?

Billman250

Yes # is the same, just modding existing parts.

Glass bead will work, sandblast will work better.

My car was really bad this last time around. It was echoing off the walls and people were looking at me funny

Modded TCT only cured it totally, even on startup.

Carl Bourbon

Sorry for dragging up the past guys but I have a question ..
Mr Billman, how has your VGC TCT held up?
I intend to do mine the same way if you give it the green light.
I've had my TCT in bits recently and the wear patches are obvious so something needs doing.

Looking forward to your response!
Carl

s2000maniac

I'm sorry but what does "VGC" stand for?

Billman250

No more VGC, I have a modified TCT available.

s2000maniac

^^ okay lol yea already got one your TCT thanks!

Carl Bourbon

May I ask in what ways are they modified?
I've just finished using VGC and I'm about to clean it up and put it back in.
I've drilled the oil supply out to 1mm which is 0.039"
It used to be about 0.75mm which is 0.03"

what are your thoughts on what I've done and anything else you'd suggest?

Cheers
Carl

Forgot to mention, this TCT is reasonably new, done about 4000 miles so I'm not particularly crazy about buying another one.

Carl Bourbon

Valve Grinding Compound.

It's an abraisive material (like a paste) available in different grades used to mate two surfaces together, for instance valves and their seats in the cylinder head.

Carl Bourbon

TCT is back in, can't believe the difference! Almost don't want to fanny about putting on the timing chain and guides I have!