Timing Chain Lubrication

[david.g.chapman]

The timing chain is supposed to be lubricated by a "metered jet of oil" somewhere from the back of the timing case.

Does anyone know where exactly? Any idea on how to check it's working?

Dave Chapman

[types26/36]

The timing chain is supposed to be lubricated by a "metered jet of oil" somewhere from the back of the timing case.Does anyone know where exactly? Dave Chapman

The block has an oil hole drilling in the dimple on the front block face.( see pic 1)
The backplate has an elongated slot with a hole which lines up with the oil drilling. (see pic 2)
Oil is sprayed through these drillings to lubricate the chain, this is why Lotus say to assembly the backplate gasket dry to avoid blocking the hole with sealer.

[types26/36]

Forgot to add Pic3. the front of the backplate where the oil is squirted through.....the raised boss with a small hole in it.

[david.g.chapman]

Thanks Brian - That told me everything.

This morning I devised a test for the lubricating jet. It involves running the engine with the cam cover off and the engine cold.

1. The choke (for a Stromberg engine) is first of all set for a cold start. The cam cover is then removed amd carefully placed to one side. it hooks nicely over the top of the carbs. Note that once this is done the choke cables bind up - hence setting it first.

2. Get some cling film from the kitchen (or wherever you like to use it) and carefully arrange it over the inlet and exhaust cams separately. Do not allow the cling film to touch the camshafts themselves - it can be done. You can use baking foil if you like - it might be easier. Leave the cam sprockets uncovered.

3. Put newspaper down over the sides of the engine bay.

4. Refit plug leads, rub whatever charm works for you and start the engine. DO NOT REV IT! just let it idle at 1000rpm.

5. Place you hand over the straight run of the chain between the sprockets - about 20mm away. A strip of oil should be quickly sprayed onto your hand.

6. At the same time oil should be spraying over the exhaust side wing as the chain turns over the sprocket due to centrifugal force.

If this is happening then I believe the lubricating jet is working. I helps to be sure if your oil level is on the low side, or the car if jacked up at the front.

See attached picture for the result of my test. Just keep yourself away from the exposed rotating parts and run the engine for just long enough to do what I did.

Dave Chapman.