Adjusting Tappets

[GrowingLad]

Morning All,

Quick question to make sure I`m thinking straight.

I want to adjust the tappets on my VP AQ115. I was reading the manual at the weekend and just want to check that I´ve understood it correctly.

It states that valve 8 should be open to adjust valve 1 and carries on so, changing valve numbers.

Firstly, is there anything special about getting the valves in the position you need. Should I just turn the engine over by hand, until say valve 8 spring is fully compressed which means the valve is fully open?

Also, when it numbers the valves how do I know which one is 1 and which one is 8. As far as I can tell in this instance it doesn´t matter as long as I decide which end to start from, ie. adjust 1 when 8 is fully open, then when 1 is fully open adjust 8..etc..etc

Anything else I need to bear in mind?

Hopefully I´ve made sense with the above.

Many thanks,

Simon.

 

[Cliveshep]

For an 8-valve 4-cyl engine the principle is "rule of nine". If no. 1 is down, i.e valve open, adjust 8, if 2 is down adjust 7, and so on. In all circumstances there will be two valves open at any one time, turn the engine by fan belt, spanner on crankshaft nut, or jabs of the starter. For a 6-cyl engine, same principle but rule of 13.

 

[GrowingLad]

Rule of nine...ah that makes things easier and saves having to keep looking at the manual.

From what you´ve said it seems to me that I have everything in my head correct.

It´s one of those jobs that´s not difficult but if you´ve never done it before you just want to check you´ve got it straight.

Thanks Clive!!

 

[JustMelfort]

Normally 1 is the front of the engine (the end with the pulleys) and 8 is the back - the end with gearbox. But it doesn't really matter.

Just make sure the engine won't start if using the starter. I fend it easiest to use a socket set to turn the crankshaft from the pulley. It means you can turn backwards if you overshoot top dead centre.

 

[boguing]

and mark each one with chalk once you've adjusted it.

 

[GrowingLad]

As a matter of interest does this go for cylinders too. 4 being the one next to the gear box end?

 

[alan17]

The rule of 9 usually applies to a 4 cylinder engine but there are exceptions. It depends on the inlet/exhaust valve layout.

 

[alan17]

Generally yes but it is upto the manufacturer as to which end they decide to count from. In the "car world" most number from the crankshaft pullet end but some from the gearbox.

 

[JustMelfort]

Re Numbering, yes runs from front to back for cylinders.

 

[pvb]

There's a much easier way, described in this Volvo operator's manual...

 

[GrowingLad]

That does seem to make things a bit easier.

Silly question but I´m going to have to ask.

Top dead centre on compression...how will I find this, both valves 1 and 2 are going to be closed ??

Thanks, Simon.

 

[pvb]

[ QUOTE ]
Top dead centre on compression...how will I find this,

[/ QUOTE ]Read it again, where it says "This corresponds to the 0deg marking on the crankshaft pulley".

 

[GrowingLad]

Engage brain before typing....doh...

I take it there will be a 0 deg mark on the pulley? Not sure I´ve seen one, but then again, i´ve not looked so closely yet.

 

[GrowingLad]

Aye, I shall wear the pointy hat and stand in the corner /forums/images/graemlins/ooo.gif

I did spot the errrr or should that be derrrr in my ways after I hit submit....

Thank again for the info.

Cheers,
Simon.

 

[VicS]

FWIW the method given in the Haynes Manual for the engine fitted in Volvo cars is the rule of 9 method. Dont have to refer to the manual at all and dont have to worry about where TDC is.
Used it for years on 4 cylinder OHV car engines.

Does not apply to all as it depends upon the valve sequence but it does apply to these.

 

[pvb]

Yes, it'll work, Vic, but the Volvo manual method cuts down a lot of the fiddling about turning the engine for every valve. I used to have an AQ115 in a Birchwood 25 in my baby-mobo days! /forums/images/graemlins/grin.gif

 

[vyv_cox]

Your question was a perfectly reasonable one. In a four stroke engine there are two top dead centres in the cycle and in each case the 0 mark on the crankshaft pulley will be at the top mark. The first one occurs at the completion of the exhaust stroke / start of the suction stroke. The second occurs at the top of the compression stroke/ start of the power stroke. At the first one the valves will both be slightly open. At the second both will be closed.

I assume that the Volvo method requires cylinder one to be at TDC for the firing stroke, i.e. with both valves closed and clearance at the tappets.

 

[Malish]

a slight thread drift:

It is possible to buy a tappet adjuster tool from Halfords / Frost, it is particularly useful for the more mature engine as it takes into account the wear on the rocker arms where they strike the valve head, something that feeler guages cannot do. Result = optimum valve gap setting and a quieter engine.

 

[Marsupial]

A "clock dial indicator" is the most accurate way of doing it but expensive some mechanics have set of feeler gauges ground away so they are about 2.5mm wide just for setting tappets.

 

[matelot]

[ QUOTE ]
For an 8-valve 4-cyl engine the principle is "rule of nine".

[/ QUOTE ]

some 4 cyl engines have a different firing order. most are 1342 but some are 1243 so the rule of 9 isnt universal.