Dads 306 TD engine woes

jgra1 · Post by **jgra1** » 23 Sep 2008, 15:51

Hi all.

not sure if I have posted about this before so apologies...

Dads 306 broke recently..

From memory it was recovered home and wouldn't start...
It went to a garage who did some tests and suggested that low turbo pressure and some fault with the EGR were to blame.. they either disconnected or cleaned the EGR. seemed better but no real go..

it now continued to fail to start on the key, if I remember correctly..

Later, Dad did manage to tow start it, it ran ok,

next day wouldnt start, towed again and said it ran rough and only just got him home..

It then went to another nearby garage to see what they thought.

Their diagnosis is , after 5 weeks and no charge ! that the timing is out 2 teeth and the compression has gone and there is certain damage.. they can tell compression is gone by the sound.

Finally:
Car has lucas pump :O and has some SVO in

Now because dad is 300 miles from me, it's tricky for me to know what the best course of action is.

but I have unanswered questions...

How can a garage expect compression if the timing is 2 out ?
what would cause the initial low turbo pressure? I can only think a siezed turbo.

anyway, I am happy to go there , haul the head off and see whats going on.. I have spare valves and between Jim and I we have a bosch fuel system, also I have a spare turbo...

My suggestion to dad was first to check camshaft for breakage and then get timing correct and see what happens, only then can he be sure there is or isn't compression...

any thoughts, especially, what would you do before tacking (another) head job, to try and avoid it ?

If timing is 2 out, could some valves never contact pistons, i.e. could the car run, even slightly ? on 2 cylinders maybe
John

Xaccers · Post by **Xaccers** » 23 Sep 2008, 16:59

Tow starting may have caused the timing issue.
With a bit of luck, no damage has occured to the cam

So definitely get the timing sorted and check the cam.
After they worked on the EGR, was the starter turning the engine over quickly?
Just wondering what the battery is like.

Ed · Post by Ed » 23 Sep 2008, 17:49

I have had a cambelt snap on an XUD9 engine. The valves were undamaged because the camshaft absorbed all the force and snapped in half, breaking a bearing cap with it.

Get your old man to whip the rocker cover off first and it will be obvious.

Oh hang on, if he has had it running but badly, then I would guess the camshaft is still in one piece.

Incidentally, in this instance I just changed the camshaft and bearing cap, and the car ran fine. Very tough engines these.

jgra1 · Post by **jgra1** » 24 Sep 2008, 09:12

thanks both..

yep I still think it's worth the 5 minutes to check cam and , say, less that an hour to retime it..

Maybe after that a compression check and if all good a fueling swap..

Xac, think battery fine, what's your thinking on EGR and engine spinning fast?

jgra1 · Post by **jgra1** » 24 Sep 2008, 20:35

chaps, my dad tried to get the rear cambelt cover off, and thought he may have had to get under car to find the rear-facing allen bolt.

he jacked the car using the sump as a jacking point

anyway, the main LH mounting has pulled apart.. how does the whole mounting attach to car? A great big nut under the wing/chassis I shouldnt wonder .....

He will need a whole mouting from a scrapper asap...
J

jgra1 · Post by **jgra1** » 16 Oct 2008, 15:52

ok

update...

Dad checked timing, all bolts went in all holes, TDC on flywheel fine.. seems timing is spot on..

He brought a compression tester, we think ok quality..

around 80psi on all 4 ... at least they are similar..

Engine was cold (no option) and no oil poured down bores...

its very low ?

any thoughts?

Post by **CitroJim** » 16 Oct 2008, 16:02

That would be considered dangerously low on a petrol engine John. On a diesel, just far too low.

Check the valve clearances before anything else, just to be sure but as all are low and fairly equal, it is looking more and more like the head will have to be lifted before long

I'm interested in more details of the compression tester. Normally diesels are subject to a leak-down test where each cylinder is blown up to around 100psi and leakage over time measured (i.e. see how long it can retain the pressure).

jgra1 · Post by **jgra1** » 16 Oct 2008, 16:10

hi Jim..

Laser compression tester,.. adaptor screws into injector hole, then there is a quick release pipe from the gauge..

Appreciate a leak down would show more, but just 350 psi in the first place would have been nice

what could cause all 4 to go? A crack or HG fail would do one or two.. but all of them ?

Wondering how to prove the gauge is faulty now, all i can think of is 4 carrots stuffed down the holes, if they all fly to the same height then its ok?

Post by **CitroJim** » 16 Oct 2008, 19:01

I love the idea of four carrots John

Mind, to be valid they'd all have to be the same size...

If this tester has an adaptor for a spark plug sized hole, simplest would be to "borrow" a known good petrol car and do a quick compression test on it. A good engine will read about 140-180 psi.

Laser tools are usually good. Nothing to go wrong in them really.

I'm trying to think what would have killed all four compressions like that. A duff HG might account for 2 adjacent perhaps but a crack would have to be enormous to kill all four. A cambelt going in an engine with inclined valves would do all four but not in an XUD. Last time I looked at a (petrol) engine with near-zero compressions on every pot, the cause was holes in the pistons. Never heard of that on a diesel but Xac and I once spent hours pulling a head off a 1.9TD to find it literally melted with bigh holes in it, almost as if the moths had been nibbling at it. It was practically skeletal! The valve seats were there but no metal around them at all.

jgra1 · Post by **jgra1** » 16 Oct 2008, 20:37

valves have clearances......

jgra1 · Post by **jgra1** » 27 Oct 2008, 15:07

update,,,

As some of you saw, compression on dads 306TD is 90psi across the board, and we have run out of speculative ideas...

so we brought another engine.... :O

I havent the time (or the reserves of WVO) to go 300 miles to Newcastle and bring the head home, and repeat the following weekend...

It seems the easiest thing to do is a straight swap, filters and belts changing ..

if anyone wants to come up and point and laugh, the deed should be happening Sat/Sun

Will post mortem the low compression engine if poss...