Technical Hydraulic tappet adjustment

[Maddadfixemotor]

Mistake made some were down the line as lack of power and no go

Spoken fiat garage about tappet adjustment, said yes that how to do it i.e. 1 1/2 turn for peload on tappet as per haynes man

Then spoke to x fiat mechanic and he said that whey to much pre load should be about 3/4 of a turn

and i take it that after you have taken all the slack off the hydraulic tappet first??

still running as if valves are to tight, no go!!!!!!!!!!!!!!!!!!! :bang:

Also forgot that compression on 3 pot is very low but engine running fine just tappie, now know that this was not the way to go.

 

[multipete]

slacken then tighten tappet so it just touches the valve,you may have to start engine and adjust again till quiet,better that than too tight...............

 

[Maddadfixemotor]

So you mean no pre-load, also do you take slack from hydraulic tappet with ya hand first

 

[multipete]

get cyl 1 rocking, and work on cyl 4,slacken the adjuster so the push rod turns,then tighten adjuster finger tight on to push rod,so rod still turns and lock adjuster............do all tappets like this,if when you start the car they are noisey,do it again,till you take all the play out,BUT do not over tighten them or the car has no compression and will not start.............................

 

[multipete]

hope this is clear and helps...................................mp

 

[Maddadfixemotor]

Many thanks been adjusting them in firing order, this will do same thing yes/no.
Also you say run the engine ,but i've taken carb off with rocker cover etc, so did ya mean crank it over or put it back together and run it

 

[Maddadfixemotor]

:chin: Right going have another go and redcue adjustment perload to 1/4 of a turn ill let you all know how it goes

This is a really great forum and iam glad i found it

 

[Maddadfixemotor]

All sorted and pumped up and thank you for ya help me daugher is back in her Cento and very happy she can go back home now

 

[Maddadfixemotor]

I've read in one of the threads that you can replace the hydraulic tappets with the rocker shaft Assembly from a Panda, Then set the tappets as for a Panda and hay pesto no more type writer sounds.

As I've had a problem with the Hydraulic ones and am still not happy with the net results this must be a cheaper way to go.

can any one who has made this mod give me some feed back

 

[atsoft]

Hi,
I've been trying to follow this procedure from the fiat manal and it also says about preload and 1 1/4 turns after taking the slack out.

When i have tried this procedure, the push rods tighten slightly (rotating them helps to judge) as the slack is taken out, then if you keep turning, the hydraulic adjuster hardens up and the valve starts opening. The distance between the slack being removed and the valve starting moving is only about 3/4 turn.

Does this stack up with your experience of this?

I'd say it was quite difficult to judge where the exact point of slackness removed, but i think the best thing to do is pick a point somewhere between the slack being removed and the adjuster tightening up and pushing the valve down. I cant imagine they want the valve to be open after you have preloaded ( or maybe you should and then when the engine runs the adjuster corrects it ?)

Any advise would be gratefully received

Regards
Andy T

 

[rallycinq]

Are you sure you have hydraulics?

Without the engine running the pressure of the valve spring will be greater than the pressure remaining in the tappet.

I find that finding the point of contact is easy if you do it by finger. The oil usually means that you fingers slip on the tappet at meeting point.

Cheers

PD

 

[atsoft]

Yes, as i have had to replace one of them because the return spring was broken

should i put oil inside the bottom chamber of the tappet when reaasembling? or just in the top part. If i don't put oil in the bottom part the tappet doesn't stay together as the return spring pushes them apart. procedure for reassembly of Tappet is not described anywhere ....

 

[rallycinq]

Replace the tappet if its coming apart.

Cheers

PD

 

[atsoft]

The tappets behave much the same way as the replacement one i bought direct from fiat, and they weren't noisy b4 so i'm guessing that they are all ok.

I've been filling the bottom chamber of the tappet with oil before assembly, so i'm guess ing thats the problem. The Tappet is solid like that which probably explains the problem i've been having. I'll take them apart and squidge the oil out. Then hopefully the preload should work !

Does this make sense ?

 

[rallycinq]

Tappets should be filled with oil before fitting. I've never had them push the valves open.

Cheers

PD

 

[atsoft]

Ok, heres the verdict,

you don't fill the bottom part of the tappet, just the top. This is Definitely the way to do this. I have checked with several experts on this matter, the book says fill the top only and also from my experience which stacks up with what i have been told.

To assemble the tappets, after checking for wear, smear some oil on the lower half of tappet. Assemble the spring loosely on upper half and slide spring and upper half into lower half. Use a small blunt bar in upper chamber to open the one way ball valve as you assemble, so the two half slide together (and should stay together as the oil will seal the tappet and stop any air getting in)

The tappet should feel springy when you squeeze the ends together, if it doesn't compress significantly (3-4mm) there is too much oil in the lower chamber, so take apart and remove the oil. It is important that the tappet is springy like this otherwise you will not be able to do the adjustment! (this is where i think a lot of people in the past have had problems)

To assemble in car, fill the top (open chamber) of Tappet with oil and slide into rocker arm ( I Left the circlips in place and slid the shim and tappet in from below). The tappet should move under gravity in the rocker arm.

bolt and torque up the rocker assembly, after loosening the adjusters.

To adjust, turn engine until piston in question at TDC in firing stroke (inlet open then closed...not at the rocking point as has been mentioned on the forum)

take up the slack with the adjuster (rotating the push rod helps, but i found it better to rock the rocker, then turn the adjuster a further 1.25 turns. The value shouldn't move (see earlier comment about springyness of tappet)

It isn't absolutely essential to get this spot on accurate. The main point of this adjustment is to get the tappet roughly mid travel which is about 1.5-2mm from slack. (The thread on the adjuster is approx 1mm pitch, hence the 1.25 turns)

This procedure worked first time and the car is running silently for the first time in years !

 

[desilva]

Ok, heres the verdict,

you don't fill the bottom part of the tappet, just the top. This is Definitely the way to do this. I have checked with several experts on this matter, the book says fill the top only and also from my experience which stacks up with what i have been told.

To assemble the tappets, after checking for wear, smear some oil on the lower half of tappet. Assemble the spring loosely on upper half and slide spring and upper half into lower half. Use a small blunt bar in upper chamber to open the one way ball valve as you assemble, so the two half slide together (and should stay together as the oil will seal the tappet and stop any air getting in)

The tappet should feel springy when you squeeze the ends together, if it doesn't compress significantly (3-4mm) there is too much oil in the lower chamber, so take apart and remove the oil. It is important that the tappet is springy like this otherwise you will not be able to do the adjustment! (this is where i think a lot of people in the past have had problems)

To assemble in car, fill the top (open chamber) of Tappet with oil and slide into rocker arm ( I Left the circlips in place and slid the shim and tappet in from below). The tappet should move under gravity in the rocker arm.

bolt and torque up the rocker assembly, after loosening the adjusters.

To adjust, turn engine until piston in question at TDC in firing stroke (inlet open then closed...not at the rocking point as has been mentioned on the forum)

take up the slack with the adjuster (rotating the push rod helps, but i found it better to rock the rocker, then turn the adjuster a further 1.25 turns. The value shouldn't move (see earlier comment about springyness of tappet)

It isn't absolutely essential to get this spot on accurate. The main point of this adjustment is to get the tappet roughly mid travel which is about 1.5-2mm from slack. (The thread on the adjuster is approx 1mm pitch, hence the 1.25 turns)

This procedure worked first time and the car is running silently for the first time in years !

Ive just done this job and totally agree with the above procedure.....tappets are now totally silent. Instead of using a small bar to push the valve down on the tappet on reassembling the tappets, I used a tiny jewellers screwdriver.

Please note that yes you can dismantle the tappets and there is no harm in doing so. It is the only way of finding out which tappets have broken springs.

Be warned when removing the rocker cover - the rear allen bolts can easily round off and will require drilling to be removed. Its a real pain. They cannot be replaced with normal 10mm bolts as there is no clearance to get a socket or spanner in, so replace the front bolts with 10mm bolts and use the front allen bolts for the two rear ones if they get damaged.

Also apparently Fiat no longer supply the circlips to hold the tapets in, so to be safe, remove and reinstall the tappets from below. They need a little pushing to remove and reinstall but far safer than losing / breaking a circlip

Also thanks to YCMING and RALLYCINQ for advice.