Diesel VM help..

[Stevo11]

Just wanted to run this by the forum for your opinions (no I'm not selling it Gildo! Constructive comments only please! )

On cylinder #4 the push rods keep popping out of the rockers (only one at a time, sometimes its one, sometimes the other). It can go a month without having one pop out.
I've fixed it again this morning but would like to fix it permanently... I've noticed that when tightened down the rockers can still be moved about 2 mm on this head (the rear one), only one of the other rockers displays the same symthom, the rest are all tight up against the valve springs.
What do you guys think I'll need to fix? Is it a case of worn pushrods? Valve springs? entire rocker assembly? new head?

Is this a common problem?
Any help appreciated!
Steve

[dxj]

Hi,

Just guessing the hydraulic lifters are at fault as they are supposed to take up the slack in the valve train.

Just after engine stopped the lifters should hold the valve train tight. Any slack says something wrong.

Has the engine ever been "fixed". Maybe the lifters/pushrods are wrong/faulty.

Have you checked the leak down of the lifters in question and the travel until they bottom.

Should have roughly the same on all llifters.

Worth checking the push rod lengths are all the same too.

Not trying to be funny.. has the engine got oil, right type, viscosity? Wrong stuff may 'upset' the hydraulic lifters.

Lastly check the lifters are getting oil. No oil, no work!

Is it running really rattly? I mean more than usual diesel.

Maybe you have some stuck valves that never come back fully to the valve seat? check 'at rest' height off head 'deck' of the top of the valve tips. Should be very close on each valve.

Bent/cracked rockers?

Good luck

DXJ

[Stevo11]

Hey DXJ,

Thanks for the reply! I understand most of it

>Has the engine ever been "fixed". Maybe the lifters/pushrods are wrong/faulty.

Yes, someone has definately been in there before...

>Have you checked the leak down of the lifters in question and the travel until they bottom.

No.. how does one go about that?

>Worth checking the push rod lengths are all the same too.

Will do (will prob just replace them actually.. I seem to remember reading something about them not being too expensive?)

>Not trying to be funny.. has the engine got oil, right type, viscosity? Wrong stuff may 'upset' the hydraulic lifters.

Not sure about the previous oil, but its definately correct since its last oil change (6 weeks ago)

> Lastly check the lifters are getting oil. No oil, no work!

Oil appears to be in the central tube.. again.. any help on how I go about checking this would be great too (I don't ask for much do I? )

>Is it running really rattly? I mean more than usual diesel.

A bit rattly when cold.. certainly not as smooth as the old Merc units I'm used to.

>Maybe you have some stuck valves that never come back fully to the valve seat? check 'at rest' height off head 'deck' of the top of the valve tips. >Should be very close on each valve.

Will do!

> Bent/cracked rockers?

No, they seem ok.. might be worth replacing all the same tho..


Really appreciate the suggestions/feedback!

Steve

[dxj]

Hi,

Check leakdown with pressure on the pushrod (can do via the rocker). the pushrod should slowly recede as the lifter leaks down oil. The amount of travel down should be similar on each lifter. Note you have to start each one from the valve shut (relaxed) position. You are just bottoming out the lifters travel and measuring how far down, you need two poeple to do this one to push and one to measure.
lifters are just things that fill with oil and leak slowly. They settle at the right height to suit valve seating. If you rev too hard for too long they can fill to high and hold the valve open ( little chance on a diesel). Yours sound like they are not working and have no spring to take up the slack.

Just a thought... some people think the Jeep VM is the same as the old range rover VM... Not so, one difference is Range rovers had solid lifters with adjustable rockers, Jeep has hydraulic self adjusting valve train. Maybe check someone hasn't used some handy bits from an old rangie in there.

You will know if the lifters are getting oil if they take time to leakdown.

Good Luck

DXJ

[Gildo]

Only way to fix a diesel XJ is to drive it off a cliff, then go buy a petrol XJ

[dxj]

Still slagging off other peoples cars......???

Get over it! People who drive Jeeps......

DXJ

[Stevo11]

Originally Posted by Gildo

Only way to fix a diesel XJ is to drive it off a cliff, then go buy a petrol XJ

*Yawn* v.predictable.

Due to road tax here, a petrol XJ isn't an option :

https://www.motortax.ie/mtoapp/pdf/m...es_2004_en.pdf

2.5lt = 821euro
>3lt = 1343euro