G

Giles Clayton

Member
Hi everyone....
Well it's friday night and I'm scratching my head...
Just put a new head on my TDI300 having melted two of my 'pots' together last weekend.
Very slight scratching on number two cylinder bore and the injector for the same pot has one hole closed due to heat damage (not enough I'd have thought to stop it working)
Bolted everything together and now I'm buggered if I can get it to murmer into life!

Have bled it (but perhaps not correctly?) theres fuel at the top of the injectors, have even taken the plunger out of the stop soleniod just in case that was U/S....

There's good oil pressure too.

So... any ideas why a 300 with new head, valves, springs, oil, water and bits of my knuckle skin wont fire?

Giles...
 
As no-one else seems to be offering any help, I'll throw my tuppence in.

I'm far from an expert in diesels but just going through very basic stuff is all the following sorted;

Valve timing (even one tooth out can stop it dead, maybe)
injection pump timing (was it locked off when the head came off, had it moved when the engine blew?)
Could that injector be causing back pressure? Should still fire on 3 though.
Head is flat i.e. not warped?
Also remember reading somewhere about the head gasket being a particulary thickness depending on the engine block.

I could be wrong on every count on this but at least it may give you a start. Apologies if I'm teaching you how to suck eggs.
 
Just had another thought. Again could be totally wrong but....

If you crank it and fuel is getting to the top of the injectors, if you whip a glowplug out, wouldn't that be wet if fuel was going into the pot?
 
Hi Sticky,

Everything in your first mail has been checked and as the head was new (from Paddocks) I'd take it for granted that it'sa good'n.
But good point on the second tip, I'll give that a go in the morning

Giles
 
Take extreme care now as you may have pumped a fair bit of fuel into the engine, and it will be sitting in the piston crown bowls.

When you were cranking it over on the starter YES or NO, was there white-ish smoke puffing from the exhaust?

If YES, some of the injectors are working, but you don't quite have ignition. That could be glow plugs not working (wire off!) or valve clearances wrong, or whatever.

If NO, there is almost surely no injection taking place.

Who do you know has a running 300tdi that would let you borrow his 4 injectors to try?

CharlesY
 
Giles Clayton said:
Hi everyone....
Well it's friday night and I'm scratching my head...
Just put a new head on my TDI300 having melted two of my 'pots' together last weekend.
Very slight scratching on number two cylinder bore and the injector for the same pot has one hole closed due to heat damage (not enough I'd have thought to stop it working)
Bolted everything together and now I'm buggered if I can get it to murmer into life!

Have bled it (but perhaps not correctly?) theres fuel at the top of the injectors, have even taken the plunger out of the stop soleniod just in case that was U/S....

There's good oil pressure too.

So... any ideas why a 300 with new head, valves, springs, oil, water and bits of my knuckle skin wont fire?

Giles...
Click to expand...

Dont under estimate diesel bleeding, open all pipes to injectors and turn her over until you are getting diesel out of each one.

I've had the same problem after just changing the filter on some Audi's (yeh filled filter before hand) can be a right barstewd if you've got air in there!
 
As Charles says, you have to be careful of pumping diesel into the engine that sits in the piston crowns. A 300tdi WILL bend its con rods on the starter, even if the engine doesn't start. It rather sounds as if your timing is out, though removing and replacing a 300tdi head does not alter the timing at all. A bit of a mystery, so far.
 
Consider overtight valve clearances as well.......oops sorry charlesy just read your reply properly.

regards

Dave
 
If you have a propane, or LPG tank around you might try firing it off on propane. I would check the compression about now. is the engine cranking over fast? faster or slower than normal? I would then try and find out how much pressure your getting out of your injection pump to the injectors. I have heard of engines not firing back up if injectors are installed too tight or with improper shimming as they become distorted or bound up if you will and don't pass fuel. Just some thoughts, the nice thing about running it off bottled gas is it takes the fuel system out of the equation
 
Hi guys,

My local garage has suggested that my piston rings may have siezed during the engine BBQ....
I've been soaking them over night with some WD40 in the pots and will be giving it another go today...! fingers crossed
 
ah dunt really think thats an option but then it depends on how much heat there was ... i'd have thought if there was enough heat to do that there would be other damage aswell that you'd be able to see..

this injector with the blocked hole int gonna work well as they are designed to produce a certain spray if you have one hole blocked it will fook that up, not enough to stop it from running but it will affect the running of it.

also if the heat was so hot it has melted bits on one injector there is a chance that the damage that is causing yer problem is inside the injectors.

all of the above is pure speculation and while not nessesarily true seems to be logical..
 
Cheers Slob,
I think you're right it's a bit of a long shot (the rings that is)
If this doesn't work though I'm going to have to bite the bullet and hand it over to a proffessional garage. Haven't EVER paid anyone to work on any of my vehicles before so I'm now totally paranoid that I'm going to get ripped off, but can't think of what else to do other than stripping it down totally which isn't really an option on the street in central London...doh!
 
why not change the injectors before going to a garage or atleast try and borrow some to try
 
Not the same problem, but im currently helping my neighbour whos water pump sprung a leak and consequently overheated his 300tdi, it got so hot it did the headgasket and burnt out 2 pistons. The head was a mess on that all the injectors closed up and anything connected to the head was burnt out or melted beyond repair.

I agree wiv slob, and plus my recent findings, if its closed an injector up, id suspect heat damage to numerous other items!!

That reminds me, i ave to post some pics of the burnt out pistins, ive never seen any so bad!
 
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