re hydraulic tappet clearance

[carpmansam]

hello to everyone,
have a vw t25 1600ct engine Aircooled. am renewing push rod tubes very shortly.been reading when you reinstate the push rods the tappets need reajusting. have been looking in the haynes manual and doesnt say the clearancce needed. does anyone know what it is.
many thanks sam

[kevtherev]

no clearance...
you need to read about hydraulic lifters

http://www.ratwell.com/technical/HydraulicLifters.html" onclick="window.open(this.href);return false;

or just google it mate

[toomanytoys]

As long as it has hydraulic followers installed (from the factory they were) then with each cyl at TDC then the adjusting screw should be 1/2 - 1 turn max in from just touching... as long as the lifters are primed and full of oil still.. if not they will be rattly for a while, ideally and soft ones should be removed and refilled before the tubes are reinstalled..

[carpmansam]

think wrotre down wrong.
am renewing push rod tubes and taking pushrodsout.the tappet ajustment is what i mean insde the rocker covers.
cheers sam

[California Dreamin]

I don't think you are understanding peoples replies.......your engine should have hydraulic tappets (self adjusting tappet clearances) so there isn't any clearance just a setup proceedure so the 'automatic' hydraulic tappets work correctly.

Martin

[kevtherev]

we know what you meant but your not thinking VW here..
VW decided that it would use hydraulic cam followers which makes the need for gap adjustment not necessary.

how cool is that?
no more need for feeler gauges
so read up on them

[dugcati]

I dont want to confuse things....

Your replacing the push rod tubes - which kind of tubes are you replacing with as stock ones require the engine out and heads off on CT1600 cc engine, 2.0l engines the tubes can be replaced without a strip down.


Cam followers - these should be hydraulic and look like this once removed from the engine..




*some* CT engines have had tweaks and might have solid lifters instead of the hydraulic ones, they look like this.....





The link that Kevtherev put up has the following statement which might also help...

If a magnet sticks to the push rod shaft you've got hydraulic (steel) push rods. If it only sticks to the tips, you've got solid (aluminum) push rods.

Now you can see the difference once you pull it all apart there are two (well three) setup methods...

1. Hydraulic lifters need preloading with about 2.0 to 2.5 turns pressure on the valve adjuster when the valve is in the closed position (this rule is for all valves inlet and exits)

2. Solid lifters require a feeler gauge with 0.006” clearanceon the valve adjuster when the valve is in the closed position (this rule is for all valves inlet and exits) http://www.youtube.com/watch?v=6S5Uapc8GjE
3. don't risk leaving your van not running and pay someone who knows!

[sarran1955]

Hello,

When you are reseating your pushrods, you will find it a bit tricky to get the pushrod to fit into the depression on the top of the hydraulic tappet.

If you have removed the rocker bar without re adjusting the setting screws, then , when you have all in place, turn the engine over by hand several times to settle in the pushrods. the engine should turn over without any tight spots.

If when you start the motor it runs rough, even with spitting through the carb, this is a sure sign that the pushrods are not properly in place

These videos might help:

http://www.youtube.com/user/sarran1955/videos" onclick="window.open(this.href);return false;

After a rebuild I run the engine for 2 mins, and then drop the oil into a clean container, then set the rocker screws 1 turn more than just touching, refill and recheck. Once its right, you should not have to touch anything again for quite a while.

Cordialement,

[toomanytoys]

As prev said.. and as Sarran1955 has said.. 1 turn in from just touching is all thats required..
IIRC VW changed the setting very late on from the original 2-2.5 turns to 1/2 to 1 turn.. on well used and new lifters this seems to work much better IMHO.. and from the wear I have seen on many heads in my engine collection.. the 2-2.5 is way way too much..