14platoon · Jul 26, 2017

Hello
Ex mod 90 defender 2.5N/A Diesel engine

I have smoke (grey) if I blip the throttle having been stood at idle for a time, eg stuck in traffic. The smoke clears after a run. Sometimes the smoke is quite bad.
I initially thought (googled) the issue was valve stem seals. I've since spoken to a respected Lamd Rover garage who state that it's unlikely the stem seals on my engine as they rarely go. They point towards injectors as an educated guess over the phone.
Does anyone have experience of this issue?
Ps they told me to do a thorough service and check valve clearances.

jamesmartin · Jul 26, 2017

14platoon said:
Hello
Ex mod 90 defender 2.5N/A Diesel engine

I have smoke (grey) if I blip the throttle having been stood at idle for a time, eg stuck in traffic. The smoke clears after a run. Sometimes the smoke is quite bad.
I initially thought (googled) the issue was valve stem seals. I've since spoken to a respected Lamd Rover garage who state that it's unlikely the stem seals on my engine as they rarely go. They point towards injectors as an educated guess over the phone.
Does anyone have experience of this issue?
Ps they told me to do a thorough service and check valve clearances.

definitely check valve clearances ,and id get pump and injectors checked ,valve stem seals are very prone on those engines as is valve guide and cylinder bore wear

14platoon · Jul 26, 2017

jamesmartin said:
definitely check valve clearances ,and id get pump and injectors checked ,valve stem seals are very prone on those engines as is valve guide and cylinder bore wear

Thanks for that. Is there a way for me to check the pump and injectors myself or is it too involved? I'm pretty much just a basic DIY home mechanic, skills wise.

jamesmartin · Jul 26, 2017

14platoon said:
Thanks for that. Is there a way for me to check the pump and injectors myself or is it too involved? I'm pretty much just a basic DIY home mechanic, skills wise.

you need an injector tester so you can simulate idle conditions with the injector ,worn injectors can often have a very poor pattern at idle (including dribbling)but are better as revs increase, they are not cheap ,better getting them done professionally

14platoon · Jul 26, 2017

jamesmartin said:
you need an injector tester so you can simulate idle conditions with the injector ,worn injectors can often have a very poor pattern at idle (including dribbling)but are better as revs increase, they are not cheap ,better getting them done professionally

Ok good call. I'll sort a service and a valve clearance out and see if that makes a difference. Ps the idle speed seems too low

jamesmartin · Jul 26, 2017

14platoon said:
Ok good call. I'll sort a service and a valve clearance out and see if that makes a difference. Ps the idle speed seems too low

a poor injector can leak or dribble at low revs ,that will give smoke as fuel will not be fully burned

14platoon · Jul 26, 2017

jamesmartin said:
a poor injector can leak or dribble at low revs ,that will give smoke as fuel will not be fully burned

Thanks I'll have all the above checked (£££££££) once I've done a service.

14platoon · Jul 29, 2017

Is there a good write up for valve stem seal replacement?
Thanks

Oldseadog · Jul 29, 2017

Head off, valve springs compressed, collets removed, valve seals popped off, new ones popped on, springs compressed, collets replaced, head back on, tappets adjusted, job done

14platoon · Jul 29, 2017

Oldseadog said:
Head off, valve springs compressed, collets removed, valve seals popped off, new ones popped on, springs compressed, collets replaced, head back on, tappets adjusted, job done

Simples..

To Be honest I have been reading up on doing the stem seals with the head on. Looks fairly simple but I just need to find the right tool for it. I saw a video with a tool On a rail, looked perfect but I can't find one.

Oldseadog · Jul 30, 2017

Doing it that way is OK ... until you drop a valve!!

Not recommended!!

14platoon · Jul 30, 2017

Oldseadog said:
Doing it that way is OK ... until you drop a valve!!

Not recommended!!

From what I read as long as you rotate the engine to have the particular valve you're working on at TDC, it can't fall far. Of course this is all theoretical so far!

jamesmartin · Jul 30, 2017

Simples..
To Be honest I have been reading up on doing the stem seals with the head on. Looks fairly simple but I just need to find the right tool for it. I saw a video with a tool On a rail, looked perfect but I can't find one.

you want one like this ,i have one as long as pistons at tdc you cant go wrong ,so you can do 1 and 4 at the same time then turn engine over 180 and do 2 and 3

14platoon · Jul 30, 2017

jamesmartin said:
you want one like this ,i have one as long as pistons at tdc you cant go wrong ,so you can do 1 and 4 at the same time then turn engine over 180 and do 2 and 3

Very helpful as usual. The more I read the more confident I am at doing it myself. I've messed around with cars for years although nothing too complicated.

flat · Jul 30, 2017

Oldseadog said:
Doing it that way is OK ... until you drop a valve!!

Not recommended!!

In a pinch I did some valve stem seals on an overhead cam engine by feeding some cord through the spark plug hole then rotating the engine to jam the valve then was able to replace the bits. Bit of a dodgy short cut tbh and I wouldn't do it now but I used to run my cars on a complete shoe string and that included tools

14platoon · Jul 30, 2017

flat said:
In a pinch I did some valve stem seals on an overhead cam engine by feeding some cord through the spark plug hole then rotating the engine to jam the valve then was able to replace the bits. Bit of a dodgy short cut tbh and I wouldn't do it now but I used to run my cars on a complete shoe string and that included tools

Did it work out well when you did it that way.

Magicgrotto · Jul 30, 2017

Or make your own !

julianf · Jul 30, 2017

Ive got one of those compressors like photographed above.

Ive only ever used it in testing on a head that was already off, but it certainly works.

As stated, if the pistons are up, then the valve wont fall. And, if you stuff it up, and it does fall, youre in no worse state than you would have been if you tried to do them by taking the head off... Just plan for failure, and you have little to loose.

julianf · Jul 30, 2017

Ps.

I would think that, if you have the injectors out anyhow, putting a rigid wire (somthing like a TIG rod, etc) down the injector hole to check the position of the piston will eliminate any chance of mis-calculation.

flat · Jul 30, 2017

14platoon said:
Did it work out well when you did it that way.

It was okay, It got the job done but I would do it properly if I had to do it again.

IIRC I used climbing accessory cord.

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