Problems with McDonald 2.5NA continue

[martin.beek]

Hello all -

I'm in need of some assistance/advice relating to the 2.5NA Diesel McDonald engine i purchased a couple of weeks ago. The previous thread is http://forums.lr4x4.com/index.php?showtopic=18879&st=0

In short, engine was bought, ran with huge smoke issues and leaking injectors. Had injectors checked and checked the timing. Both were off. Injectors were reset, and the timing was reset too. The latter was blamed on a tow start.

The injectors kept leaking, but the engine ran ok. McDonald refused to even consider accepting responsibility for the timing problem, but given that it seemed to have caused no damage (engine has now done 1000 miles without trouble), it's not much of an ongoing issue.

Mark at McD was distressed about the faulty injectors (2 seriously leaking, 1 far too high a pressure, the last an improper fit), and sent me a cheque for 150 pounds and asked his supplier to ship 4 new injectors directly to me. Mark had asked them to be to double checked so as to avoid trouble.

They arrived yesterday. With 2 injectors still leaking heavily (from the copper ring below the hexagonal head), we decided that the 4 new, tested injectors would polish things up nicely and solve the last outstanding issue. 1 had rust stains along the bottom head (part which sits just above the piston), and the plastic cap was near impossible to remove. So much for 'recently tested injectors'.

Once put in, the engine started, but an immediate knocking sound became apparent, one not heard before. To check whether it was indeed engine speed related, we raised the revs slightly, and the knocking increased. Just before immediately releasing the gas, a single louder knock was heard which then died down with the revs.

We had the injectors checked this morning. 3 were ok. The slightly rusty one gave out the correct amount, but rather than spraying the diesle out properly, it would spray some out and then dribble the rest out on the test bank. This was corrected. The garage who fixed them this morning are the same who tested and fixed the injectors with which the engine ran 1000miles trouble free, so i'm assuming they're not at fault.

When bleeding the fuel system, rusty particulates came out of the injection pump air-release screw. ???

We put the injectors back into the engine, but again, the knocking sound, (now louder) remains. We reset the tappets (for lack of other thigns to test!), but found them to be well within spec. We are now about to check the injectors...again. We'll release them one by one and see what happens.

Any suggestions? Given that when we left the garage, the injectors were ok, is it possible that some slight dirt ingress could cause such troubles? More importantly, could having run the engine before the injectors were checked (therefore with one dribbling one) for all of 20seconds caused any subsequent damage, now responsible for the knocking? Or is it more likely down to a improbable (but not impossible) leak or other injector malfunction?

Called McD. Mark was annoyed at me, for 6 of the 8 injectors he and his supplier had sent were faulty, which was against all odds, espcially since he'd fitted twenty this morning without trouble. Simply fitting an injector without running the engine however obviously wouldn't show any faults with them!

As always, any comments at all welcome. This is now well past frustrating!

Many thanks,

Martin.

[martin.beek]

have taken the injectors out. One was completely seized. Once dismantled, the pin inside would not budge. Replaced it with another which seemed to fix the problem, only to for another injector to seize 300yards further along. Could this just be one large batch of faulty BM Injectors? Called McD, they put it down to the latter, and offered to send us yet another set from another supplier. L:K#%Y(*&DFJH!!!!!!!