Cummins Marine 6BTA Timing Assistance

[Nigel Bank]

We have received an engine from an unknown source and working to get it fully operational post rebuild.

Engine – Unknown due to no serial numbers unavailable.

The engine in question is fitted with a Bosch P7100 fuel pump which we have had run and tested by the Bosch dealer.

The pump is set in the region of 260 -> 270Hp.

The only other part number available to work from is the cam shaft which is 3930378 which Peter McCullar of Cummins UK has given us a build CPL number of 2956, all parts have been order (genuine) and the engine has been built to that CPL spec.

The engine is bored plus .5.

These are the parts fitted:-

Piston Kit – 3935592 .5mm oversize
Turbo Charge – 3802915
Lube oil pump – 3937404
Fresh Water Pump – replaced
Injector Nozzle – 0433171358 (Set at 260 Bar Pressure) (Recommended By Cummins)

Injector Nozzle Installed before work undertaken were – 0433171431 (Bosch)

All other miscellaneous parts supplied by Cummins.

The fuel pump timing pin on origin pump was broken in the housing.

The engine was timed as per the CPL number.

The engine ran but failed to develop sufficient power on investigation the injectors fitted were 7mm nozzles the cylinder head was removed and injector pocket bored to accept 9mm nozzles.

The engine is after cooled with genuine Cummins heat exchanger and header tank.

We need to know the know how many degrees before top dead centre the engine should be to achieve the correct spill timing?

Any assistance would be appreciate as the data we have

1 user thanked author for this post.

Andy king

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[Tony Athens]

This is kinda over my pay grade, but if I wanted to research the timing question, I’d start with using this engine serial number based on a CPL 2956………….. 46072159 ………………………QSOL should have all the info you need for that CPL spec..

As to boring your head to 9MM ?? IMO that was a very wrong thing to do..

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