2.5 diesel breathing heavy

[alfmech]

hi guys i thought i would ask here before taking drastic measures with the old beast

my IIa has a land rover 2.5 naturally asthmatic diesel lump in it which has done good service untill recently, now it has become determined to spew oil everywhere no matter what i try, i have cleaned the rocker cover breather, fitted a catch tank to it to save some of the mess no servo and the servo pump is blanked off but now its started popping the dipstick out when the engine is labored and spitting oil everywhere

the engine seems to run sweet enough and always starts first time no excessive smoking water loss so no issues there just the oil ejection is becoming a major problem no apparant spewing of vital fluid on tick over

is this likely to be a ring issue or something more major?

then i have to address the biggest issue rebuild or replace? i know the non turbo lump is a little ummm how shall we say ummm gutless! but tdi lumps are somewhat expensive and hard to find decent ones and the series isnt a hard working car (general bumbling about and occasional dragging people out of ditches or water) so i think the non turbo is sufficient for my needs i make up for the lack of power with gears and overdrive to get to ramming speed anyway lol

if i could get my hand on a known good 2.5l non turbo engine cheap enough and local ish i would think about swapping it for convienience sake just a one for one swap with no more modding to fit

[Team Idris]

No smoke is odd? Could be a bad injector done for one pistons rings. Or amybe even a holed piston. It still starts on the other 3 then, so appears okay.

The usual test is to drop the injector pipe nuts to see which one is down on tickever. But this is very dangerous, as high pressure oil can get under you skin.

If no one single cylinder drops the engine speed it must just wear, which may be just a re-bore or hone if your lucky

[ejparrott]

Don't give up on a TDi engine, I saw one go on the 'bay recently for 99p, I kid you not!

[alfmech]

Yeah I doubt anything will turn up that dosnt need a ton of money worth of bits to make it work though, I think I will have to stick with the 2.5l n.a lump

[Les Henson]

Your problem is excessive pressure in the engine. The 2.5 N/A engine is very good and generally lasts a long time. Few things can cause this, such as worn bores, head gasket leak (to the camshaft), or perhaps a cracked or holed piston.

Cracked pistons are a problem with the TD engine, so I doubt that would be your problem, and I would guess that it may be just a head gasket blow, which is no big deal to fix on your engine. Your problem will require removal of the head anyway in order to inspect head, bores, etc, so no waste of time anyway.

Les.

[Gazzar]

Perhaps a stupid suggestion, but how sure are you of the oil level? Could be that the oil level is too high?

G.

[alfmech]

Thanks for the input I will try and investigate at the weekend, yes I am positive about the oil level as I am having to check it so frequently not a stupid suggestion at all it's always worth a try lol thanks anyway.

[secondjeremy]

Had the dipstick problem on my 2.25diesel engine - which seemed to go quite well but kept popping the dipstick up in its tube and blowing oil out.

I removed the gauze from the vent - as it seemed to lift when I blew compressed air down the outlet, but the main improvement came when I changed the injectors for a less bad set. I think the uneven combustion was forcing gas past the rings. I did replace the O ring at the top of the tube (think its got 2 now.)

[alfmech]

i called our local motor factors and the guy on the phone is adamant that the engine i have must be a 12h or 17h engine, i was under the impression the diesel engines were all J numbered and petrols were the H ones.

i have searched all over and can find no numbers that i would class as engine numbers,there is a large letter J on the block towards the rear kinda below cyl 3-4 and under that much smaller are the digits 815 or 81s cant really tell clearly but the look more like casting numbers rather than engine codes,

i have taken a couple of pics in the hope one of the oracles here can give me accurate info so i can at least find the right parts when i need them

[Snagger]

It looks like you are using a Series exhaust, and that will have been the underlying trigger for your problems. Pound to a penny you pistons have cracked. The 12J needs a 2" exhaust, and using a Series' much smaller exhaust caused the engine to run hot on climbs, even if at speed with a perfect Series cooling system with 4-row rad. The temperature will creep up to about a needle's width below the red arc on the gauge and stay there for some considerable time unless you use high revs in a low gear (ie reduce the load on the engine while spinning the water pump fast to increase water flow through the system). While the needle might never go into the red, frequent elevated temperatures take their toll and eventually crack the pistons. I had exactly this problem on my rebuilt 12J with AE pistons. The cooling system was all new but didn't seem to cope until the 2" exhaust was fitted, from which point the needle never rose above half way again no matter how hard I pushed the engine in hot ambient conditions.

That is definitely a 12J engine with 10J manifolds.

[alfmech]

oh that is bad news indeed

i will pull the head off over the weekend and have a looksee,

can you tell me if the 12j manifold is even remotly similar or is it a completly different setup? i ask because the exhaust hasnt long been replaced and i would like if possible to retain some of the original look of the old girl without bolting on too many 90 bits

anyone got a gwo 12j they wanna part with for beer tokens?

[Snagger]

They're similar and are interchangeable. Have a look here: http://www.nickslandrover.co.uk/archives/51

The inlet manifold is designed to connect directly to an air filter in the left side of the engine bay and has no vacuum butterfly valve. The exhaust manifold accepts a 2" bore vertically oriented down pipe. You can use the existing 10J inlet manifold with the 12J exhaust, if you wish.

[alfmech]

well i have the head off and still no clarity

the pistons seems good with no visable damage

the bores are for the mostpart un scored/marked the usual lip at the top but nothing unexpected

when the head was removed the water sloshed into the bores and that stayed there for quite some time without dissapearing untill i dried it myself i then turned the engine till all the crowns were halfway down the bores and applied some very thin machine oil to the crowns and bores which as i type is still sat there unmoved so it still has some ring integrity i guess :)head gastket pretty clean no apparent blow marks or splits

now to the head itself:-

number 3 as seen in the picture has suffered previous damage i assume prior to work as there are no corrisponding marks anywhere else to suggest impact

as pictured each of the injector inserts appears to have cracking in it,

is it likely the inserts being cracked could cause this problem?

[Les Henson]

Cracked hotspots is very common, and yours actually look ok to me If the head gasket was blowing to the sump - via the camshaft housing, then you might not be able to see it as the head gasket gets wrecked when the head is removed. pistons look fine, bores look fine - if a little too shiny. Head won't warp with a gasket blow as it's one heavy lump of pig iron Clean the deck and head faces and replace the gasket and tighten down as per the torque figures for the head bolts/nuts.

Les.

[Snagger]

The pattern on the no1 crown looks like you may have had valve contact at some point, though it's more of a wash of the carbon than an imprint in the crown itself. maybe it was just when you wiped away some of the spilled oil or water?

Like Les, I reckon your hotspots are fine - they're just pre-combustion chambers for the fuel injection to create a swirl in the injector mist to improve fuel burn. There is nowhere for any gasses to leak as long as the head has no cracks. The head looks like it has suffered a broken piston or catastrophic head gasket failure in the past, but as long as the edge of the face open to the bore is good, it should seal against the gasket.

Before you reassemble anything, check that the head and block deck are flat - my 12J's block deck had pulled up around each head bolt hole (like a very shallow volcano), though I was lucky that it was shallow enough that the head gasket could compress enough around the holes to seal correctly.

Look carefully at the valves and their seats - it's possible that a bent valve or eroded seat (be particularly thorough inspecting the valves of the bore with the head marking) could be allowing gasses up the valve guide and into the rocker case, from where it is free to pressurise the crank case via the push rod bores and cam gallery.

Your breather system will be aggravating the pressurising issue. The outlet of the cap has to be connected to a low pressure chamber in the induction system, like the inlet manifold or ducting between the manifold and air filter. This is to suck the gasses through the gauze, preventing the pressure from building within the engine voids. Your system relies on positive pressure within the engine to force the gasses through the breather before venting to merely ambient, rather than low pressure. If you consider how the gauze in the cap tends to be oil soaked, you will realise how much back pressure this can create. You may also need a new o-ring on the dipstick tube.

Oil level is important in oil consumption or pressurisation issues. I have recently traced my Tdi's excessive oil use to an erroneous dipstick - the dipstick tube is too tall since straightening it out (Discovery dipsticks were very curved) and the level was being over-filled by about an inch, resulting in the crank shaft and big ends whipping up the surface of the oil and filling the block with oil vapour, much of which was expelled through the breather and some of which was no doubt passing the piston rings and getting burnt in the cylinders. Measuring the length of you dipstick from tip to "bell" and the tube from end to fixing nut and comparing the lengths to others', or draining the oil and refilling with the prescribed amount in pints or litres and then checking the level on the dipstick will tell you if the dipstick is giving false low indications and encouraging you to overfill the sump.

[alfmech]

thanks to everyone for the input so much more food for thought than expected lol

the crown on no 1 is actually me wiping the crud off badly, the pistons after meticulous cleaning are thankfully spotless

i need to strip and clean the head completley and check as snagger quite rightly suggest valves, seats and guides and then stand in a corner and slap myself repetedly for not realising about to breather to manifold (what a prat!) though in my defence just slightly, since i got the car it has been setup like that and only recently has this issue occured

i have to admit today i cheated and was offered another used lump to chuck in her for the VERY short term while i bugger about with the other engine, its a bit of a smoker but will hopefully just about keep me moving in the meantime

the replacement lump comes with manifolds the right size and with relavent connection for low pressure on the inlet manifold, a choice of filler caps one with a valve affair built in and one without, the dipstick is identical to mine so thats fine and i had already replaced the o-ring before getting worried about it keep popping out

at least when i rebuild the current lump to my satisfaction i can at least do it properly then pray no more problems like this

thankyou all again for the helpful advise and information and i am gonna get to the bottom of this and make it work properly even if it kills me

[Snagger]

Glad to help.

I'm sure you'll get it sorted, but be aware these engines breathe a bit even when perfect. I spent £2k rebuilding mine years ago with a rebore, new crank and cam shafts,oversized pistons, new valves, seats and guides, new cam followers, push rods and rockers, new pumps (all of them) and injectors... basically all of the moving parts and ancillaries. It still had pressure build up if you held your hand over the breather hole, and would weep a small amount of oil out of the breather seal and the rear right corner of the head gasket (probably because of the block deck distortions around the head bolts). With the cracked pistons (which happened a few years after the full rebuild, due to the small exhaust), oil was forced out of the breather, dipstick tube, crank seals, rocker cover gasket, brake servo vacuum pump gaskets and some of the small core plugs. That all disappeared with a second set of new pistons.

The 12J is well suited to a Series vehicle and I was pretty happy with mine. With the roof rack fitted, I got 60 mph on the flat and with it removed could eventually get 80 mph. It would start instantly even after two weeks of inaction in sub-zero temperatures and was comfortably refined in the cab. The Tdi allows me to hold 60 mph up significant hills and makes accelerating much easier, but it's a good deal less pleasant for noise and harshness in the cab. The 12J is a great engine if you don't need sparkling performance, so sorting yours out will be worth the effort.

[ejparrott]

Yeah I doubt anything will turn up that dosnt need a ton of money worth of bits to make it work though, I think I will have to stick with the 2.5l n.a lump

here's one...http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320824136620&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

[alfmech]

finally got the replacement lump alive today after swapping out the injection pump that refused to put any fuel out then about a week of cranking to get the damn thing going, its a bit smokey but sounds a lot healthier expected i think the pump timing is way out due to the smoke but at least it runs i never realised what a pig these engines are to bleed air out of till now

at least i can take my time and sort my engine out properly now and hopefully have a sweet long lasting engine at the end of it, already stripped the head a little carbon behind the valves and tiddle poor valve seating but nothing too scarey yet will clean it all lap the valves back in and reassemble it then take a look at the bottom end,

is it worth going the whole hog with regrinds/rebore etc or just check and replace unservicable components?

[lexi]

<div>

is it worth going the whole hog with regrinds/rebore etc or just check and replace unservicable components?

<

If stuff is half decent then engine will run for a while yet without big expense. Sometimes if you look for wear in an older engine you will find it. Yet these engines can run for a long time even with wear. Good enough is all you need in a truck like 11a IMO. If you are happy with bores you could whip the sump off and check the bearings and shells for condition. It is down to time , money ,long term plans for truck etc etc.

[Snagger]

If the bores are not too bad and the pistons are undamaged, then a hone and new rings could be worthwhile. When I rebuilt my Tdi, I checked the crank and found no significant wear - all the journals looked like new and there was no ovality, so I just put in new standard size main bearings and big ends as they're pretty cheap.

As far as ease of starting is concerned, the big thing is to get air-tight fuel lines and injector pipes. That will prevent air entering the system when the engine is off, allowing the fuel to drain down back to the tank. With a primed fuel system, the engine will not need cranking over to prime before firing. That is why an engine which has just been run will start really easily if you start it again soon after shut down, even if the engine was run for mere seconds and had no time to warm up. You can get away with fairly poor compression if the timing is correct and the fuel system in good order.

You can help engine longevity by using caustic soda to clean a lot of the scale and rust from inside the engine and radiator (it can help with heater matrix efficiency too), but you must be careful to thoroughly flush the lot out before refilling the system with coolant. I'd recommend using 50% antifreeze mix to help with anti-corrosion and anti-rust properties, pump lubrication and specific heat capacity in addition to the frost damage protection, and if possible use soft water (I used the water collected in my condensing tumble drier). As far as oil is concerned, better quality helps, but more important is regular changes and decent filters (not Britpart). As long as you use 10W40 diesel oil, you can use cheap brands as long as you stick to the 6,000 mile schedule - I use Comma oil with a 5,000 schedule and Gen Parts filters with a FilterMag to get the fine steel particles out of the oil and prevent filter clogging.

[alfmech]

sent the head to local engineering company and now feel the need to sulk for their response

8x guides worn excessively

2x inlet valves need replacing

very slighy distortion requiring refacing

recut and reseat alll valves

£225+ the dreaded

they agree the guides were worn more than enough to pressurise the vital fluids out of the engine

sadly insufficient slush fund to afford this rebuild so will have to shelve the idea indefinatly

[Snagger]

The slight warping might be able to be ignored, after all, it wasn't causing trouble before the head was removed. The valves and guides are the issue. You can lap the existing seats by hand with grinding paste and deal with new valves the same way. The valve guides are pressed in and out of the head, so someone might be able to advise you on how to do it yourself. If you have the means to do that, then the costs should be relatively low.