Jowett Javelin compression test.

[Barry20383]

Hi i am renovating a 1953 Javelin and am trying to sort the engine out have carried out a compression test and found the results are 140 to 130 psi is this ok .
Barry.

[Forumadmin]

Yes. it depends on the compression ratio. Anything above 120 psi should be OK provided within 10 psi across all cylinders.
Modified higher compression engines will reach 180 psi.

[Barry20383]

Am renovating a Javelin which has stood for a while it is starting on choke but will not pick up on the accelerator
It seems to be sucking air on the left side only. The plugs are in poor condition and it has mixed plug caps. I have ordered new plugs. caps. and leads will change these to eliminate them and then see how it runs.
Will post the results Thanks Barry.

[Forumadmin]

Put new petrol in it, empty out the old stuff.
Disconnect throttle linkage so the carbs operate independently, many linkages have an adjustable connector. Balance the suck from both sides on the idle throttle adjuster. Check both carb strangler flaps open and close fully. Check throttle butterfly opens and closes fully.
Reconnect linkage and adjust so even suck on both sides. Best done with a flow meter but a pipe in the ear works.

Check petrol pump stops pumping when manually operating and petrol is not dripping into carb intake. This would indicate float valve issues.

Read my fault finding guide.

viewtopic.php?f=2&t=5598

[nigel jarrett]

I did have this problem once with mine ,this time it was caused by an air leak at the carb fuel bowl and the fuel dispensing beak not seated correctly in the Venturi body (possibly not the correct terminology for these parts)

[Barry20383]

Have fitted new plugs and now the engine is picking up on the accelerator. The engine still has vacuum on one side only. Both the heads are getting hot. Am waiting for new plug leads to arrive and caps. The plug caps fitted are mixed 2x2 resistor and none resistor will fit the new ones then investigate further.
Thanks all.
Barry.

[Barry20383]

Am now changing the plugs and plug leads it looks like the coil is old .It is working but i will change it for a new one. Is there a better alternative which will give a better spark. Not sure weather to fit electronic ignition or a new electronic distributor..

[Forumadmin]

Please search on JT ..there is lots about electronic ignition.