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Re: Hymac 690

Posted: Fri Jun 02, 2023 8:56 am
by Jeremy Rowland
Well it's been a while since I've had a chance to have another go at this old beast but as I was off work on holiday I managed the trip up there yesterday. There are some annoying diesel leaks which I have to cure on the CAV DPA fuel injection pump, I cured a couple of other leaks on another part of the system, but alas not here.
I knew there was a leak from No3 injector pipe; this was cured by robbing a pipe from the spare engine and making sure the washers on the pumps connection did not leak, success there :D however there was still a leak from the pump body, it looks like the small steel plate that covers the timing marks was leaking, it was loose but even after tightening the two retaining pins it still leaked.
I opted to take it off and put some gasket sealer on each side of the gasket; I left this to set, so I will try it again when I next travel up there.

Jeremy


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Re: Hymac 690

Posted: Fri Jun 02, 2023 9:50 am
by mechman
Hi Jeremy.
Maybe that plate has a slight buckle in it ( I know you will have not let it go unnoticed) but if it still leaks I would knock a thicker plate up, if it still leaks, er er well er er :?

Re: Hymac 690

Posted: Fri Jun 02, 2023 7:57 pm
by Jeremy Rowland
mechman wrote:Hi Jeremy.
Maybe that plate has a slight buckle in it ( I know you will have not let it go unnoticed) but if it still leaks I would knock a thicker plate up, if it still leaks, er er well er er :?


Norm; I have put plenty of gasket sealer on it so if it does leak then I suspect there is another problem, guess I'll find our next time, I also have a spare plate on the other engine, so that's another option. :thumbup:

Jeremy

Re: Hymac 690

Posted: Fri Jun 09, 2023 9:00 pm
by Slooby
Fingers crossed it's not like the problems I am having with the Bosch VE type pump on my BMW M51 2.5td in my P38...I'm having to rebuild the whole thing after replacing the usual suspects steels at the distribution head in situ resulting in it leaking somewhere else, fixing each sucessesive leak just moved the leak on until we came full circle and the distribution head started leaking again....it's now on the bench waiting for me to be a$#@d to pull it apart properly...and has been for 7 months :/

Re: Hymac 690

Posted: Fri Jun 09, 2023 9:49 pm
by Jeremy Rowland
Tim, if it leaks the next time I try it then I think I will look for a half decent second hand unit, lets hope it does not come to that, it ran a lot better last time after I had replaced no3 injector pipe. :thumbup:

Jeremy

Re: Hymac 690

Posted: Fri Jun 09, 2023 11:25 pm
by Slooby
Sadly I can't swap the pump out on the P38 without getting the replacement 'coded' to the ECU :( On the positive though the full rebuild kit was under £25

Re: Hymac 690

Posted: Tue Jun 11, 2024 8:52 pm
by Jeremy Rowland
Well after the poor start to the year weather wise, I have finally made a start on this machine, I have decided rather than mucking around and kidding myself that the engine passing oil issue will simply go away, to strip the lump and take a look inside. I have whipped the head off, the bores appear to be okay, hopefully I will know more when I next go up there to take out the pistons.
At the moment, my suspicion is that the oil is passing through the valve stem seals, my plan is to remove the pistons, replace them if required along with a set of big end shells and then glaze bust the cylinder bores with a light hone and finally rebuild the cylinder head. I also intend curing the diesel leak on the fuel pump. :thumbup:

Jeremy


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