Technical Tappet Adjustment

[Jon]

Hi There,

Anybody got any idea why my 900 sx ( n '96 ) hasn't got adjustable tappets ? The Haynes manual for this car depicts an adjuster that can be used to pre-load the valve spring. My rockers don't have this. Also how do I remove the hydraulic tappet itself, there isn't a circlip I can remove. It was a tappet that sounded like it needed changing you see. How do I refit the rocker shaft if I can't releave the tension on the pushrod ?

Any answers gratefully received....TA !

 

[trev m]

The tappets are hydraulic, aren't they.
No need for adjustment it is done by engine oil pressure.
So low oil in the sump will starve the tappets of oil first, they will start to become noisy....tapping etc.
If the car has not had a service for a long time the oil becomes thick
and makes it hard to flow through the oil way's and may block them.
A change of oil and filter may help.

If it gone too far....the cam lobes will wear,
So the camshaft and followers should to be renewed as will the hydraulic tappets .

hope this helps.


RED HGT

 

[Jon]

Cheers Trev I'll explain further,

The Manual clearly shows an hydraulic tappet and a preload adjuster on the rocker. Mine just has an hydraulic tappet that doesn't appear to be removable from the rocker.

Yeah, I know what you mean about the oil but it sounds like just one tappet is losing it's oil overnight ( probably when the corresponding valve is open ) and the engine requires some revving for a minute or so for the noise to disappear. I really don't want the cam / followers to become worn.

Do I just torque the rocker shaft down against the valve spring tension ? or do I have to remove the oil from all the tappets to refit the shaft ( sounds dodgy ) ?

Cheers !

 

[HP]

According to the Haynes and Porter manuals, you just loosen the rocker pedestal bolts gradually one at a time - e.g. don't take them right off from one end to the other in order. This is the same instructions they give for the type with the adjuster screw / locknut arrangement, I assume yours must be a later type that needs no preloading. I wouldn't drain the tappets down when you remove them, it will cause problems and possible wear / damage when you come to restart the engine. New tappets should be filled with oil prior to installing.

This is only what I have read / heard from others, I haven't worked on an 899 myself.

Pete.
Cinq sporting 1242cc
http://mysite.freeserve.com/close_to_cracking_up/

 

[Whitterz]

ive got tappet noise on mine !!! is it a dear thing to fix ?

 

[mrf94]

When i did my head gasket i got a full head
gasket set and there was a set of tappets
in there oh and mines an 899cc

hope this helps

mrf94

 

[Whitterz]

Mines a 899cc too, gonna goto the garage asap, and see what he says in there

 

[Jon]

Right then,

As it happened there was a circlip that allowed the removal of the tappet but it was a swine to remove as it didn't have eyelets to get the pliers on ( lots of cursing ! ! ).

I refitted the shaft gradually tightening against the valve springs, moving outwards / inwards. Span the engine by hand a few times and double checked etc. Seems to run pretty well anyway.

The Hydraulic tappet are priced at £10 or £13 each depending on what type are fitted ( FIAT determine by chassis No ).

Hope that's of some use to someone.

Jon