Hydraulic Tappets

[kevtherev]

great stuff

[gasman78]

Sorry to jump in on the tread, but as a 'green' mechanic and t25 owner, wanted some advice from someone who has clearly had some experience in these matters. I just allowed a mechanic (and family friend) to replace all the hydraulic tappets on my 1.9dg as at least two of them were knackered and collapsed every time you stopped, making a foul racket for 20mins+. Seemed like it would be a definitive job so went ahead (?regret?!). It now runs well and they are all clearly working 'ok' but the general tappet noise is now always there, so while I haven't got any that are sounding like a hammer on a dustbin, they all sound 'tappety' all the time. I thought that once adjusted, there should be very little tappet noise? If i want to check them, what is the procedure? Hot, warm or cold? I am assuming that there should be zero clearance when set correctly? Should I try a different oil first? What is the worst that can happen?!

[kevtherev]

OK
You can read the lifter bible according Richard Atwell, he has a lot of information and good advice regarding hydraulic lifters

http://www.ratwell.com/technical/HydraulicLifters.html" onclick="window.open(this.href);return false;

I always use 15w/40 mineral oil in the winter and 20w/50 mineral in the summer.

[Fully Loaded Cali']

I've got problems!!

So, van running well after my last post, setting the hyd tappets but hadn't took it on a good run.

Took the van out Good Friday for a short run, got 5 miles out and it started mis-firing and wouldn't tick-over.

Pulled over, left for 5 mins. Started, it coughed then ran ok again, managed to get the 5 mls back.

Wondered if it was fuel as it was in the red....so filled up with fresh.

Got in van to go to Bus types and struggled the last 2 miles with the van juddering, and stalling.

Left engine to cool, started it up, wouldn't tick over.

So re adjusted the tappets to 1/4 turn compression, van fired up and ran well all the way home (20ish miles).

Got in it yesterday, now misfiring won't idle......

Could it be a failed tappet? A Bent push rod? Or possibly I've disturbed something on the dizzy as I remove the cap during adjustments?

What are the symptoms of a failed tappet - it does tick like a beetle but not as bad as a tappet that's pumping up.

At a loss at the moment - all this after I replaced a push rod tube and re-set the tappets. Before this was done the van did a 60 mile trip with no issues at all.

Any ideas??

[kevtherev]

Eliminate the obvious now
When you get the mis-fire pull the lead of each cyl to see if there is any change or no change.
is the carb getting fuel, like is the filter blocked.

it should sound like four grannys knitting socks

[blacky]

Eliminate the obvious now
When you get the mis-fire pull the lead of each cyl to see if there is any change or no change.
is the carb getting fuel, like is the filter blocked.

it should sound like four grannys knitting socks

Class !!

[blacky]

pulling lead off is a good idea, also would be tempted to check compressions when its playing up to see if tappets are "jacking up" and holding valves open ( seeing as you said adjustment cured the problem for a while.)

[Fully Loaded Cali']

Eliminate the obvious now
When you get the mis-fire pull the lead of each cyl to see if there is any change or no change.
is the carb getting fuel, like is the filter blocked.

it should sound like four grannys knitting socks

Class !!

Been through all that....

Ok, when engine was cold it would tick over, 3 mins into it it ran very rough and cut out, it wouldn't tick over and would only run if I held down accelerator to give it a bit of extra fuel. So, now I've wound the rocker off the tappets incase they are not pumped up on adjustment. No different, engine sounds rough as sit and will not idle. I'm running out of ideas.....

[kevtherev]

I think this is a fuel issue Ian
It may well be a bizarre coincidence

you have the leads on right..right?

[kevtherev]

Ok, when engine was cold it would tick over, 3 mins into it it ran very rough and cut out, it wouldn't tick over and would only run if I held down accelerator to give it a bit of extra fuel.....

This is why I think it's fuel.
On cold start mixture is enriched, after 3 mins the choke is coming off.. and the mixture is leaning out.
Holding the acc is then using the main jet + the idle

So I would take a look at the idle jet for blockages.

[Fully Loaded Cali']

Ok, when engine was cold it would tick over, 3 mins into it it ran very rough and cut out, it wouldn't tick over and would only run if I held down accelerator to give it a bit of extra fuel.....

This is why I think it's fuel.
On cold start mixture is enriched, after 3 mins the choke is coming off.. and the mixture is leaning out.
Holding the acc is then using the main jet + the idle

So I would take a look at the idle jet for blockages.

Ok, try that now before it gets dark.

[CJH]

I had a blocked jet just recently, which I cleared by taking the carb apart and blowing my airline through each jet. Just wondering if there's an easier way. Would it be enough to just remove the plastic pancake and squirt WD40 down each jet using the little plastic pipe? Would it give enough pressure to clear the jets? Is WD40 OK in the fuel?

[kevtherev]

Ok, when engine was cold it would tick over, 3 mins into it it ran very rough and cut out, it wouldn't tick over and would only run if I held down accelerator to give it a bit of extra fuel.....

This is why I think it's fuel.
On cold start mixture is enriched, after 3 mins the choke is coming off.. and the mixture is leaning out.
Holding the acc is then using the main jet + the idle

So I would take a look at the idle jet for blockages.

Ok, try that now before it gets dark.

A vac pipe off would be a similar scenario

[Fully Loaded Cali']

Been through the vac pipes. I've checked fuel coming from idle jet but possibly a bit erratic? I'll try some carb cleaner tomorrow after work. Thanks kev.

Ps just noticed a big split in the air box to carb pipe, could have sucked in some crap.?

[kevtherev]

I might clear if you rev the knackers off it and clamp your hand over the top of the carb throat (duct off) briefly or until the engine stalls.