Perspex cylinderhead

[RobThomas]

https://www.youtube.com/watch?v=icoBqTEZbbw

6 minutes in. Interesting video.

[Mark Wilson]

The whole film is fascinating, thanks for posting it.

Mark

[alanworland]

Great bit of film especially the fish tank test on the windscreen!

Alan

[myoldjalopy]

Perspex cylinder head - good for checking TDC!

[oliver90owner]

Perspex cylinder head - good for checking TDC!

Might be for some, but not really close enough for me! screwdriver through the spark plug hole might be as good and a lot easier.

[philthehill]

A screw driver through the spark plug hole will still be not good enough.
There is a lot of crankshaft movement in degrees either side of TDC with the piston crown appearing to stay stationary at assumed TDC.

[oliver90owner]

I quite agree. Which is why I indicated that a screwdriver was possibly no better. If I want TDC accurately, it is finding a known position on the up and down strokes with a dial gauge and halving the found distance, between the two markings made on the flywheel circumference.

The same principle applies to timing pendulum oscillations - one always times from the point of maximum velocity, not the less determinate point of change of direction (zero velocity in each of the two directions of travel).

RAB

[les]

I agree, a screwdriver is not accurate and can only be considered an indication. I read the comment about the Perspex head and TDC, as just a light hearted observation, not to be taken too seriously!

[myoldjalopy]

You are absolutely correct, Les It was, indeed, meant as a light hearted comment, if not an outright leg-pull!

[oliver90owner]

Correct!

That’s why there was a load of smileys plastered around (for those that don't notice these things).

[les]

We believe you--- thousands wouldn't.