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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22732
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Hi, I have a 1964 jaguar mk2 3.8 M.O.D. I had the block rebored

Customer Question

Hi, I have a 1964 jaguar mk2 3.8 M.O.D.
I had the block rebored and fitted NURAL pistons, I set the valve clearances and set the camshafts using the gauge and reassembled the engine and installed it back in the car.
The problem is it will not start.
I have checked the timing of ignition and valves over and over again,I only managed to get it to run for a few seconds after putting oil in the bores.
There is a good spark and the carbs have been overhauled and there is petrol getting through to wet the plugs. The compressions are down, only 100-130 psi. and doing a leakkdown test i get 25-35%. Do you think this problem is due to the rebore and bad honing of the cylinders and what can be done to correct this?
Submitted: 3 years ago.
Category: Jaguar
Expert:  Matt replied 3 years ago.


I'd say that the compressions will come up once you can get the engine running as new rings on a new bore tend not to seal that well until they've been run

arguably they should be sealing better than this but the engine should still start with this sort of compression
so I'd suggesting drying the plugs right out 1st and then setting the ignition advance to about 3-4 degrees BTDC statically as it should start easier on this setting

can consider using a squirt of 'easi start' into each carb mouth as well and make sure that the battery is fully charged as a high cranking speed always helps