BMC 1.5 - Loss of Compression

[21FtFreedom]

Hi Folks

This is my first engine project, so I'm on a steep learning curve.

I have a 1.5BMC. Cranks fine. Injectors are fine (I've replaced one of them). But it's not firing up.

I've done a compression test this week. Results are 75, 25, 50 and 150 PSI.

I've got two questions on this:

Firstly, I was doing my compression test through the glow plug holes, with the injectors screwed into place. Do I need to have the atomising washers in place on the injectors for this to be effective?

You'll see from pg48 of the manual (https://the-norfolk-broads.co.uk/dow...hop-manual.pdf) that the injector has two sealing elements: the copper washer and the atomising washer. My atomising washers came out when I first removed the injectors, and I haven't replaced them yet. Will this affect my compression test, or should the copper washer above it be enough?

Secondly, how should I go about diagnosing where the leak is? I know there's a few places where it's possible - piston rings, gasket head, valves, etc.

What's the best procedure for determining which of these it is? And is there something I can do initially that doesn't involve stripping it down? I've read a lot of forums that mention squirting oil into the cylinder to see if the pressure goes up, but is this the first step?

Many thanks in advance.

 

[QBhoy]

Hi
There are a few variants to be considered with a compression test on a diesel which presumably hasn’t fired for a while and particularity the way you are doing it. Not the ideal way to do it really, but I’d forget that just now and throw some 2 stroke oil down the bores by any way possible. Turn it over then some more and leave over night. Sticking rings and lack of oil in the bores are most likely causing low compression. After that, fire her over to build oil pressure and she should fire. If you are brave fire some easy start or wd 40 in the air intake. Likely find once fired she will be ok....outside precious known mechanical failire