15P Cracked head

I thought I would start a thread on fixing my 15P head.

Hopefully there wont be too many surprises along the way!

I also want to share things I come across, good and bad!

As per my previous posts, my 2004 D2 had its engine run away in sunny Scotland a few weeks ago, I stopped it and got relayed back to Bedford, thank you RAC!

Drained more than 12 litres of oil/fuel from the sump, assumed it was injector seals, turned out to be No.1 injector pocket cracked.

Looked at head options, AMC head from UK supplier around £1.5K incl fitting bits a pieces, add to that the good chance that one or more con rods are bent and that the big end bearings are gone, its a good chance the final bill will be around £2K! Im not up for splashing that out without looking at alternatives.

Options were:
Complete 15P engine from scrapyard £1.5K
Complete head from scrap engine £350
Rebuild my head £150 repair, + fitting parts £250 = £400 ish

Im not equipped to remove the whole engine.

So I found what looks like a good place that can repair the head, after a chat with them I got the following feedback:

The pockets on 15P heads still crack.

But its caused by the injector being forced against the side of the pocket by the injector cam putting too much load onto the injector plunger stem.

The clearance adjustment, obtained by backing off the adjusting screw 1 turn is too small, the correct setting is obtained by backing it off 1.5 turns. Note: even the LR manual says rotate the engine 2 complete turns AFTER setting the adjustment to check for bottoming out of plungers, so there is a lot of logic to turning them back 1.5 turns!

The company that do the repairs are on Ebay, they are just outside Newark, they didnt mind if I visit them and drop my head in, which I think is a good sign.

They do a full pressure test after welding and heads very rarely need skimming because they dont get hot enough to warp.

So thats it so far, next steps are:

Strip down and remove head
Poss send injectors for testing at Diesel Bobs
Drop the sump and replace the big ends
Check for any bent rods and replace if required

Wont be doing anything for a couple of weeks but Ill update as things progress.

Mark

Sounds like a plan Mark,will follow your progress.Incidentally I wonder if the 15p is more prone to "injector head cracking" due to higher injection pressure vs the older 10p,if not set up dead right?

Hi Yes that could add to it, I wonder if the manual should have been updated to give a larger "gap" setting?

Might back mine off a bit more in that case. I followed the advice on Ratty's injector thread and backed off one turn, but others are saying 11/2 or 2 so it might be worth a little further adjustment.

Will be interesting to see how this develops. Plenty of pictures please!

Made use of this lovely weekend weather to crack on with the Disco.

Removed the head after a bit of a struggle trying to take the inlet manifold off first, if I had to do it again Id just leave it on, it doesnt save much weight when its off!

Clear from looking at various dates on hoses etc that its never been apart, all standard hose clips present, looks like most of the hoses are original, ok for 70+K miles.

Lots of oily gunk under the right side inter cooler hose, must have been leaking for ages!

I pressure tested the intercooler, looks ok, could have been from the EGR assembly, all cleaned now, Ill renew the hose anyway.

Major find after removing the head was No.1 piston has started to melt! Seems like its poor old no.1 that always gets it! Wonder why?

So new piston going on order with everything else on Monday.

I did a quick check on piston/block heights at TDC, all looked ok, so fingers crossed no bent rods.

Im dropping all the big ends anyway so ill check them properly.

Decided that I will take the block out, its virtually done anyway, just gearbox/engine mounts to go, it will make changing the big ends etc a lot easier. I can also use the hoist to refit the head, I removed the head by myself without a hoist and my back is still aching!

Spent a lot of time bagging up all the bits/bolts etc. Its so much easier to refit things when they are bagged, "Tamiya" model kit style!

Stripped the head, valves out etc, again all bagged, hydraulic tappets stored upright as per the book. Vales look ok, ish, a couple with slight marks on the seats, ill regrind (not recut) them all anyway, valve guides ok, one or two exhaust guides a little slack so I may replace them.

Cam looks great, no bearing surface pick up, all rollers good, so fingers crossed the bottom end is ok and didnt mind getting its diesel "enema"!

Very little build up on any valves, just cleaning with scotchbright will be ok.

Head being shipped off for repair Monday.

I will post up some pics later

Mark

Moving on with it then Mark,sounds good so far

Scary stuff! I was going to see a 15p 2003 defender today, I might go and see the 300 tdi 1998 one instead!!!

For every one with issues how many are running fine?

MJI said:

For every one with issues how many are running fine?

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+1 I think the numbers are 300,000+ Td5s out there.

Despite my woes I still rate it.

As with most things, its a small thing that tripped it up, in my case its probably down to the injector cam clearance, and I can say that I didnt do what the book said and check for the correct clearance after I did the injector seals last year.

Ordered an engine hoist today, £120. Dropping of head Tuesday as Im now passing Newark, other bits on order, plan to put it all back together weekend after next.

Mark

Hi Mark Any news on your progress?
I keep on reading about TD5 head cracks and wondering just how common is it, I also wondered about the cause of the problem, the pressure in the diesel rail is only 4 Bar which should not crack the injector port bore on its own, I also wondered if the copper injector seals failing may allow a shock pulse to blow back and pressurise the rail with a short pulse each time it fires.
I will back off my cam followers a bit more just in case.
I am sure lots of people have seen the add on E-bay and wondered how well it works, even the ones who don't have a problem at the moment keep on wondering just in case.
Hope it went well for you.

Hi Funny i was just putting together an update!

Ill do a proper post, but, story so far!

Head back from repair, not sure about it yet, its been tested but the repair guy said it was a bad crack, a lot of metal has gone from the side of the pocket and a quick test fit of the injector showed a high spot which I will have to take down.

Just have to lap valves in and re assemble head.

Valves and guides within limits tested with micrometer and DTI.

Engine now out and fully stripped to component pieces, I work by my self so removal was fun but all done and stripped in a day.

Crankshaft damper U/S along with front oil seal.

All conrods look ok, No1 piston and rod to be replaced anyway.

All bearings being replaced.

Journals look ok, some pick up on No1 journal but not bad.

Injectors tested at Diesel Bobs, 3 were toast, overheated tips and leaking, but Im getting all 5 rebuilt by him at a very reasonable £95 each!

Possibly starting rebuild this weekend, been laid up with bad back etc this week!

The cracking, on later heads is rare, anecdotal evidence is that its caused by the rocker clearance being wrong.

More updates soon with pics!

Mark

markomate2 said:

Hi Funny i was just putting together an update!

Ill do a proper post, but, story so far!

Head back from repair, not sure about it yet, its been tested but the repair guy said it was a bad crack, a lot of metal has gone from the side of the pocket and a quick test fit of the injector showed a high spot which I will have to take down.

Just have to lap valves in and re assemble head.

Valves and guides within limits tested with micrometer and DTI.

Engine now out and fully stripped to component pieces, I work by my self so removal was fun but all done and stripped in a day.

Crankshaft damper U/S along with front oil seal.

All conrods look ok, No1 piston and rod to be replaced anyway.

All bearings being replaced.

Journals look ok, some pick up on No1 journal but not bad.

Injectors tested at Diesel Bobs, 3 were toast, overheated tips and leaking, but Im getting all 5 rebuilt by him at a very reasonable £95 each!

Possibly starting rebuild this weekend, been laid up with bad back etc this week!

The cracking, on later heads is rare, anecdotal evidence is that its caused by the rocker clearance being wrong.

More updates soon with pics!

Mark

Click to expand...

cant go wrong with Diesel Bob, Top bloke

biolandy said:

Sounds like a plan Mark,will follow your progress.Incidentally I wonder if the 15p is more prone to "injector head cracking" due to higher injection pressure vs the older 10p,if not set up dead right?

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The injection pressure is generated within the injector body so will have no effect on the head fuel gallery pressure of about 4bar.
You can open the injector rockers slightly but you may them have issues with follower noise and uneven running. It may also effect engine emissions if full injection pressure is not generated because the tips on the later injectors may not atomise the fuel shot properly at lower pressures.

Shifty1962 said:

You can open the injector rockers slightly but you may them have issues with follower noise and uneven running. It may also effect engine emissions if full injection pressure is not generated because the tips on the later injectors may not atomise the fuel shot properly at lower pressures.

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Im going to have to "suck it and see". One interesting thing about getting the injectors done is that they will all be pretty equal, performance wise, Bob says they are allowed quite a range on the delivery volume between the injectors, hence the need to code them to the ECU.

The codes on them will now have no meaning, i.e. there all the same, Im curious to know if anyone knows how to "decode" the coding?

Its not a big issue, yet, but as Im turning this rebuild into a learning exercise I want to get as much info as possible.

Ive found some very good papers on diesel engine failure modes, including some excellent descriptions on piston and bearing markings post failure.

New anorak on order

PS The markings on three of the piston crowns, star shaped pattern, are indicative of late/prolonged ignition, which is usually caused by leaking injectors (as per Bobs findings), this can also melt piston crowns, as per No1. So Im now thinking the cracked head was just one of the factors that caused the failure.

Give Gary a call at Alive Tuning. He may be able to advise you or point you in the right direction re the injector coding values.

markomate2 said:

Im going to have to "suck it and see". One interesting thing about getting the injectors done is that they will all be pretty equal, performance wise, Bob says they are allowed quite a range on the delivery volume between the injectors, hence the need to code them to the ECU.

The codes on them will now have no meaning, i.e. there all the same, Im curious to know if anyone knows how to "decode" the coding?

Its not a big issue, yet, but as Im turning this rebuild into a learning exercise I want to get as much info as possible.

Ive found some very good papers on diesel engine failure modes, including some excellent descriptions on piston and bearing markings post failure.

New anorak on order

PS The markings on three of the piston crowns, star shaped pattern, are indicative of late/prolonged ignition, which is usually caused by leaking injectors (as per Bobs findings), this can also melt piston crowns, as per No1. So Im now thinking the cracked head was just one of the factors that caused the failure.

Click to expand...

Cheers Shifty!
Ill give him a call.
Injectors should be back soon but apart from the weekend coming, I wont be able able to do a serious work on it until the end of June.

More bits arrived from Turners today, Ill try to get some pics uploaded to Photobucket soon.

Have to say, budget wise, it probably would have been cheaper to pay £1.5k for a 15P engine from a scrapie!

Tools and parts are hitting about £1.7k in total....so far!!