5 replies to this topic

[chris1965mk1]

Just after some advise on re-fitting my rocker assembly to head after head gasket change.

The question i have that i can`t seem to get the answer to from the old faithful haynes manual is when pushing the assembly down over the bolts it gets so far before the rockers sit tight on the pushrods and stop it going down all the way ?

I would also really like to know why some of the pushrods sit higher (i don`t mean exhaust to inlet) i mean when adjusted so all are level ish there is always 1 that sits higher !

I will be the first to admit i have got a lot to learn about these old engines and have never really understood how they work, oh yeah should have said its a 1275cc A+ engine.

Are there any issues involved with timing etc after head gasket change ??

 

 As always any help/tips or tricks would be gratefully received 

 

[Ethel]

'because that's what a cam does.

The high rods would be opening valves. Back off the tappet screw to unload the rocker posts.

[Batmini]

As above, good practice to back off all tappet screws (wind out) then set your tappets up as per the haynes manual. On these old engines the cam is set lower than the valves. The cam pushes on a cam follower (basically a cup that sits over each cam lobe that the rod sits in), these followers are pushed up by the cam lobes and move the rods up and down. The rods push the tappets (or rockers) up and down on a pivot (rocker shaft), these tappets push the valves open.
On a more modern (overhead valve engine), the cam is sat above the valves so can be used to directly push the valves open without the need for rods or rockers

[Ethel]

Moot point but the A Series is an overhead valve engine. The alternative is a side valve engine, where the combustion chamber extends over the side of the cylinder so the valves can be mounted head uppermost & pushed directly by the cam, like an overhead cam version of an overhead valve engine. It's an interesting sort of mechanical evolution how we got to ohc via the somewhat less obvious ohv 'n pushrods.

[Ethel]

Moot point but the A Series is an overhead valve engine. The alternative is a side valve engine, where the combustion chamber extends over the side of the cylinder so the valves can be mounted head uppermost & pushed directly by the cam, like an overhead cam version of an overhead valve engine. It's an interesting sort of mechanical evolution how we got to ohc via the somewhat less obvious ohv 'n pushrods.

[chris1965mk1]

Perfect thanks guys  !

 

I will back off the rockers to allow the assembly to sit flush on the head then consult the Haynes for head bolt torque settings .

Setting up the tappets/rockers correctly should be fun as well