Author Topic: Lpa 2 rack stuck  (Read 106 times)

Bog77

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Lpa 2 rack stuck
« on: October 14, 2018, 10:42:36 PM »
Hi just joined. I have just bought a benford tv750 non runner with lpa 2 lister engine have removed hydraulic pump housing and front engine cover rack for engine stop is stuck solid any ideas how to resolve. Would it be injector pump seized . Is it best to only remove one injector pump and leave the other in place at all times havent worked on this type of engine before

ajaffa1

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Re: Lpa 2 rack stuck
« Reply #1 on: October 14, 2018, 11:58:46 PM »
Welcome Bog77, never had my hands in a LPA twin but I am assuming that these injectors are similar to other Lister engines. There are several reasons why the racks might seize: mechanical failure, water ingress causing corrosion, diesel fuel drying into a sticky varnish, rack linkage misalignment, seized governor or throttle linkage assembly.

What you need to know: The spill timing on these is probably set with thin shims under the body of each pump. Photograph the assembly as it is, the pumps should be identical but have different serial numbers, note which goes where. Disconnect the linkages between them and to the governor/throttle, is there movement in either rack, without the linkages? If not, you are going to have to strip the pumps to find the problem. Remove the fuel lines and remove one pump and it`s shims, place in a plastic bag to keep the sh1t out of it). Now remove the other and bag it. Take photos as you go it will help you when it comes to reassembly.

Do not be tempted to use any brute force, the inner workings of these pumps are fragile. Depending on what you find, they can usually be freed by soaking in various solvents. I have heard that a mixture of acetone and automatic transmission fluid works well.

If the problem is corrosion then the elements are probably pitted and will need to be replaced, everything else can be cleaned up and put back into service, with luck.

Couple of pics of what you are probably looking at (ST2 injector pumps) and a generic drawing of an injector pump assembly.

Bob