Hello there, first time use for this site so please be gentle,haha. I work in the Mining industry and have been asked by my supervisor to carry out a case study on retrofitting a 3512 EUI engine into an old 785 watercart truck, which is currently running a MUI engine. Or swapping over the water tank body onto a 785B truck. But that comes with other drawbacks relating to contracts.. If you are able to shed some light on this conversion or have done it before that information would be greatly appreciated. My concern are compatiblity with the other powertrain components, electrics and eletronics of various systems and also time frames and cost. Thank you Pete
I assume your 785 will be an 8GB Serial Number prefix. There is a Cat Special Instruction SEHS9562 that details the work required to retrofit an EUI engine to this model. Try contacting your local Cat dealer and ask them if they will supply you an electronic copy, there is no reason for them to refuse. Any problems post back here and we'll see what we can do.
Oh great thanks Nige, yes, that's correct, she's an 8GB. Will check that out tommoro. Thank you.
I need to point out that for this retrofit to work the EUI engine must be of the ADEM-I (early electronic) variety as opposed to ADEM-II (later electronic 3500B engine). The easy way to tell what type of engine you have is to look at the ECM on the front of the engine. The ADEM-I ECM has a single large rectangular wiring harness connector, the ADEM-II ECM has two smaller square electrical harness connectors. If you already have 785B (6HK S/N prefix) trucks on site then they will have ADEM-I electronic engines installed in them.
Great thanks mate, we have a donar engine out of a 6HK. Would the cab need to changed over as part of the retrofit or is that only required for later model engine arrangements.
The cab itself will not need to be changed although certain items like the throttle control will have to be modified. AFAIK the latest generation OHT cab with electric windows, etc, will not be retrofittable to a machine as early as your 8GB truck, but I could be wrong. I have to apologise, the document reference I gave you above is the wrong one. It's for converting a 3512 MUI engine into an EUI one, not for installing an EUI engine into an originally MUI-equipped 785 truck. You need to talk to the dealer and ask them to go hunting for Spceial Instruction for the in-frame modification. I know there was a Special Instruction for converting early MUI-equipped 793 trucks of 3SJ prefix to EUI engines. Either the same document will work for your 785 or there will be a separate document specifically for the 785, because apart from the 12 vs 16 cylinder engine all the rest of the conversion will be the same. The first-generation large OHT models that were originally equipped with MUI engines (785 8GB, 789 9ZC, and 793 3SJ) all shared the same cab and controls.
Thanks mate, great help.