Has anyone ajusted the valves on a gu 2.8 i have done 230000 kms and still going strong . I was wondering if they close up.

curly,
Can't see how they would "close up", now if you were talkin about "OPENING UP" I'd reckon you may have a point.
Whatever, I have not personaly come across any Nissan Mech who looks upon such a job with pleasure, in fact all my discussions with them, usually reveal contempt and replies such as," don't need to be done, she'll be fine" ect.
Yet the workshop manual clearly states they need to be done regularly.
Maybe the factory's got it WRONG ?
I do know, you need special tools to do the job and it would also appear, some knowledge and know how of how to do it properly, that leaves out every Nissan Techi I know of, and a host of other Mech's I know as well.
In fact I have not yet come across one that's capable of doing the job as described in the manual.
Even the cases wherein people have their 2.8's rebuilt, NEVER is mention made of the tappet adjustment and shimes replaced. Funny that.

 

When I got the T/bel done at 190 I had the valves checked, they were 1 thou tight, or almost in perfect condition. Ill check them again at 280.

 

curly,
Can't see how they would "close up", now if you were talkin about "OPENING UP" I'd reckon you may have a point.
Whatever, I have not personaly come across any Nissan Mech who looks upon such a job with pleasure, in fact all my discussions with them, usually reveal contempt and replies such as," don't need to be done, she'll be fine" ect.
Yet the workshop manual clearly states they need to be done regularly.
Maybe the factory's got it WRONG ?
I do know, you need special tools to do the job and it would also appear, some knowledge and know how of how to do it properly, that leaves out every Nissan Techi I know of, and a host of other Mech's I know as well.
In fact I have not yet come across one that's capable of doing the job as described in the manual.
Even the cases wherein people have their 2.8's rebuilt, NEVER is mention made of the tappet adjustment and shimes replaced. Funny that.

Valve clearances normally get tighter not looser over time & with the correct tool to depress the lifter & a selection of shims shim ajustable valves are fairly simple (on toyota's anyway) as long as long as the cam doesn't have to be removed

Regards Don

 

I think the problem is the shims, you need a boat load covering the different sizes and they are like £$€ each. If you dont have them to hand then it makes it difficult to do the job without running to and fro between the disabled car and Nissan. and no doubt, Nissan wont have the one you want in stock so it'll have to be ordered !

The early RD28 just had the hydraulic tappet, no shim. I think the shim is there to put the hydraulic tappet into its operating range and no doubt Nissan had problems with the early - no shim - set-up. Maybe the shim also acts as a wear face because the tappets on my RD28 were well worn - expensive.

So, in answer to the q, yes they should be checked, but adjusted ?? I'd be tempted to leave well alone if its not rattely. But, check them (procedure is in the book) because as Don says, the clearance will CLOSE up with wear and not increase as suggested in one post above. Give me a OHV push rod set up anyday (for a diesel !).

 

One small point, my experience with combustion engines I've found the tighter tappets get, the less noise they make, and conversly, the looser they get, the more they rattle.

Yet I'm being told exactly the opposite here.
And seeings as my 2.8 rattles like buggery, I take it the clearances are tops ?
Sorry fellas but something simply does not add up with this reasoning.

 

One small point, my experience with combustion engines I've found the tighter tappets get, the less noise they make, and conversly, the looser they get, the more they rattle.

Tis true, to a point.

Yet I'm being told exactly the opposite here.

Where's that then ?

And seeings as my 2.8 rattles like buggery, I take it the clearances are tops ?

Rattles as a diesel should or rattles as in tappety ?
Check the valve clearances as said. The reason the clearances close up is due to the valve slowly sinking into the head. This is balanced with the tappet/cam gear wearing. So you can find the gaps closing up or increasing. With a OHV set up the adjusters tend to work loose, there is also more (compared to OHC) interfaces to wear so the gaps increase. With a OHC with hydraulic tappets the gaps tend to tighten up - a broad generalisation, you must understand !

 

Tis true, to a point.



Where's that then ?




Rattles as a diesel should or rattles as in tappety ?
Check the valve clearances as said. The reason the clearances close up is due to the valve slowly sinking into the head. This is balanced with the tappet/cam gear wearing. So you can find the gaps closing up or increasing. With a OHV set up the adjusters tend to work loose, there is also more (compared to OHC) interfaces to wear so the gaps increase. With a OHC with hydraulic tappets the gaps tend to tighten up - a broad generalisation, you must understand !

Tom

The only explanation I wil give consideration too, is the bit about the valve slowly sinking into the head.
I can accept this, however the time taken for this to become an issue I suspect, would be far in excess of what the average owner would ever face. Let's face it, how many burnt out valve seats do we read of on here ? Also, with the materials used these days for manufacture of valves AND seats, such events are basicaly unheard of these days.
The rest I can't accept at all, especially the reference to hydraulic operation, can't see this applying with the 2.8.