Diesel Disaster

The message from "Stuffed" contains these words:

Not a lot. It'll need the tank emptying and nice fresh petrol putting in

- then just drive it.

Tank's emptied, proper (well, decaff) petrol now back in it, new cap and arm means it'll see the red line in low gears (instead of half way there in first, down a hill). Still doesn't fire on number three though, spark look OK though.

Seeing as there's a spark, fuel (or 4 wouldn't run), and the valves appear to go up and down, should I start thinking valve gone? And presumably from the above, it went before the PO filled with derv.

The damage can vary. Typically diesel burns at a higher temperature, so it has similar effects to pre-ignition. It can lead to damaged spark plugs, burnt valves, holed pistons, and even damage the bottom end. As it's an A-series, these are a good bit more robust than you're modern petrol, so damage is likely to be far less severe. The cause of the misfire, might or might not be related to the diesel.

One last thing, if it had dropped a valve, you'd know. The banging off the valve head rattling about in the cylinder would be very noticeable.

The message from "Stuffed" contains these words:

Is the engine of the right age to take decaff petrol?

Although I haven't felt much like scraping the crud off the engine number, it's a 1990, so certainly should be. I can't remember quite when the A series change over was, but it was around 88/89 IIRC.

That's part of the reason why I want to try and figure out (with much appreciated help on here) what the liekly cause of the miss is - Don't much fancy trawling through the breakers trying to locate another decaff friendly head if a new valve will most likely cure it. Going to try and find my comp tester tomorrow, or at least offer a backstreet place a couple of quid to do a quickie.

It felt and smelled very very hot when it turned up last night. But of course, one of the minor problems was the temp sender connector had rotted off..

I'm guessing I'd notice something like a holed piston, with crankcase pressure, or major Red Arrows trials, or suchlike occurring? Plugs haver all been changed (for the wrong type, thanks to the local motor factors trying to know more than me, changed back once I knew the old ones were OK).

Bugger :(

I know there's no real way of tell, just have that awful feeling I've been ripped off here.

lol

There's no massive contact noises like that going on :) But there's still no go on number three, so if it's getting fuel (will triple check), and spark (quadruple check), then there must be something wrong with the suck or the squash, surely? And assuming a holed piston would show itself in some way, I'm right in thinking I'm looking top end, aren't I?

Normally I'd have noticed these things when they started going wrong, but in this instance I've basically got all manner of faults in various stages of knackeredness all in one go, and it's slightly beffulding :(

Diesel will have that affect in a petrol. Petrols are quite frankly not designed to withstand the heat + pressure of having diesel in them

Holed pistons are sometimes not that obvious. All depends on how badly holed it is. I've seen a piston where the ring groves had melted, resulting in the piston ring breaking up. Everything looked good with the head off, absolutley zero compression, and not really any noticeable sump pressure whenit was running.

Easiest way to find out is either get a leakage test done, or as it's an A-series, just take the head off (head gasket would likely be cheaper than paying a garage to do a leakage test). Could be something as simple as a sticky valve.

Seconded. Although I haven't worked on Metros the old Moggie engine was a doddle to work on and hopefully you'd have more space than on a Mini.

-- Malc

I got quite adept at doing things like this on Minis, but have been spoiled recently by having a workshop and a sturdy bench. Last A series I touched was on a Moggie pickup that's being assembled completely from parts, so access was no problem at all :)

Keeping my fingers crossed it is something simple, but as I've said, I'm also trying to be armed with replacements for the most likely suspects.

The diesel wont have caused any damage- infact, if it had been more than about 50% it wouldnt have run anyhow- you need more than a spark to light it- how did they start it from cold?

Anyhow, do a compression test- sounds like you have a burnt valve on 3- which is pretty common on the A+ engine- this pot seems to run alittle hotter than the others.

A series and A+ valves are not the same, even if they're both from a 1275 engine- AFAIK. :(

Tim..

Actually, when I first started it yesterday morning, it was a bitch. When it did finally get going, it blew out a cloud of whiteish smoke, very much like a diesel with tired glow plugs...

I'm only going by sense of smell of course, but there was none of that petrol twang to the air, so there must have been a fair old amount of diesel in it, maybe not quite 50% though, going by what you've said :)

The Marina head I can cannibalise is an A+, but I know the inlet valves could be different on different spec 1275 heads, just can't find out about the exhausts. It'd be nice if I could either find out or pick up the right valves on my way in to fix it today, cause there's plenty of other work to do on the resto, without sorting this blasted Metro out. I'll have a laugh at the Rover dealership en route I think.

You mean you actually paid money for it? ;-)

Yep :(

I know, I should stick to the freebies - My last classic cost me absolutely nothing, with 10 months tax and test, and to get it on the road was less than 20 quid.

Still, I got a few quids worth of diesel and leather seats out of this one, so if I give up, it's not so bad. Leather seats in one of my classics would be kind of nice :)

It was somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Stuffed" saying something like:

Just the internal design of the head. Less coolant flow around no3 exhaust valve.

I can't tell you for sure if the Marina ones are the same. If you've got it apart and they look the same (length, width, angles, etc), there's every chance it'll do.

"or at least offer a backstreet place a couple of quid to do

Where do you live?! You can't get quickie's for a couple of quid here!!!

Matthew