Valve clearances on a CU

[albertramsbottom]

I have just done my valves. I losened the screw and then wound it in so just touching and then wound in a further 2 turns, as the bentley states. But I have to say the engine sounds real bad now and runs erratically.

Originally the distace between the adjuster and the valve stem was about 5mm

Is two turns inwards correct? and would the erractic running be due to worn valve stems?

I ask as I have noticed that when I wind the screws in there are moments of resistance and then it goes easy again, as if the valve stem has worn and each time i wind the screw in it is slipping off the stem. This would make sense as the adjusters (tappets?), would have been hammering the valve stems.

Cant belive that the guys that fitted my new head forgot to do the initail valve settings at all

[kevtherev]

Have you got hydraulic tappets then?

[albertramsbottom]

Intresting question

I thought all CU engines had hydralic tappets

According to the bentley and the haynes I have

Do you mean hydrualic lifters
Cheers

[kevtherev]

yes
if it's a recon it may well have them.

[albertramsbottom]

yes
if it's a recon it may well have them.

What does that mean, your scaring me now. Its not a recon, just had a top end rebuild.

Now Im under the understanding that all type 4 engines from 1978 had hydralic lifters

What are you getting at?

[kevtherev]

In the long history of your engine has anyone replaced the hydro lifters with solid lifters?

[albertramsbottom]

Just confimed that I have hydralic lifters becuase I have wavy spacers between the rocker arms rather than springs

So back to my original question, and I think that ratwell has answered this by suggesting that it should 1.5 turns rather than two.

Cheers

[kevtherev]

good news..

I turn mine in 1.5 then ran it for five miles
went quiet after 20 mins

what do the stem tops look like?

[gsmoke]

With all your engine troubles I'd check for sure that you don't have solid lifters in your van. There are a few reasons that someone might have put in solid ones, one is price.
Solid valves can be used with the standard rocker arms if shorter aluminium pushrods are used. You can tell easily as they are much fatter than the steel pushrods.
To be extra sure, If you pull the pushrod tube out, you can use a magnet to fish out the valve (providing that they aern't mushroomed)
It might explain the terrible engine noise you had after you adjusted the valves.
When you set top dead centre, are you sure that it was done on the firing stroke not compression stroke?

[albertramsbottom]

With all your engine troubles I'd check for sure that you don't have solid lifters in your van. There are a few reasons that someone might have put in solid ones, one is price.
Solid valves can be used with the standard rocker arms if shorter aluminium pushrods are used. You can tell easily as they are much fatter than the steel pushrods.
To be extra sure, If you pull the pushrod tube out, you can use a magnet to fish out the valve (providing that they aern't mushroomed)
It might explain the terrible engine noise you had after you adjusted the valves.
When you set top dead centre, are you sure that it was done on the firing stroke not compression stroke?

Intresting because all the books I have suggest that it should be TDC on no 1 on compression stroke, which to be fair I thought was the same. As both valves will be closed

But I know what you are getting at, I still could have mechanical lifters, need to do some further checks. Not sure why I am doing this as the van is being picked up on monday for a recon.

Oh and thanks for the very kind offer

[kevtherev]

Intresting because all the books I have suggest that it should be TDC on no 1 on compression stroke, which to be fair I thought was the same. As both valves will be closed

spot on

[toomanytoys]

back them off to just touching at TDC on each cyl.. It should run fine with either lifter/tappet/follower type... although if the hydros are bled down then it will rattle a lot..

What concerns me more is the fact you say the adjuster went off the valve stem.. thats NOT good...

You could of course remove the rockers/shaft, pull the pushrod tube retainer clip out and remove a pushrod tube and then pull out a lifter to see what lifters you might have... at least thats easy on the 2L

Oh and I would only use 1/2 *half" turn in from just touching...

[albertramsbottom]

What concerns me more is the fact you say the adjuster went off the valve stem.. thats NOT good...

By at least 5mm, ive never felt anything like it, they were rattling like hell. Could be the root of all my probs. Anyway, time for a recon

Is that half a turn or one and a half tuns? Not that it matters anymore, but I am enjoying learning about my air cooled CU

[kevtherev]

Simon likes half a turn.... I prefer 1 and a 1/2 turns
1 turn is about a millimetre, what you are doing is pre-loading the return spring.

some good reading about hydro lifters.. here, here, and here