Tappets

B

Beaser

New Member
Hi all. I've just fitted my new heads and the rocker gear. When I bring the number 1 cylinder up to tdc on the firing stroke, there is little to no valve clearance. The heads have been skimmed so I'm wondering if I have to shim the rocker gear?
 
No dave. There's no gap to speak of. I'm wondering if the engine needs to be running to allow the tappets to find their own position?
 
Doesn't the workshop manual go on about preload on camshaft followers ? I've never understood it but seems you have to measure how far part of the hydraulic tappet is depressed
Dave
 
Beaser said:
Hi all. I've just fitted my new heads and the rocker gear. When I bring the number 1 cylinder up to tdc on the firing stroke, there is little to no valve clearance. The heads have been skimmed so I'm wondering if I have to shim the rocker gear?
Click to expand...
are you using standard cam? and stadard valves?

are the tappets new or old ones? Old ones may still be pumped up with oil 0- whch is how they are supposed to be - so there would very be little clearance.

how much were the head skimmed by?
 
The tappets and the cams are the original ones from the engine. I've had approx 10thou" skimmed from them. Do you think I would have to empty them before start up or will they find there own position? Woops I've already asked that.
 
ten thou = less then .3 mm; I'd be very surprised if that will be a problem - there is a fair bit of play in the push rods when brand new followers are fitted.

Have you tried draining the oil out of the followers - (don't ask me how - but there is a ball bearing/spring valve - maybe pressing that down and holding the follower upside will do it? you can remove the spring clip and take it apart but that is more effort).

Maybe worth trying on one or two valves?

Just to recap; everything is the same excpet the heads are different? Are the heads from the same model?

If you are really stuck, then fit composite gasket instead of metal one; this will raise the heads up at a loss in compression ratio.
 
The heads came off an sd1 because I want to run unleaded and keep forgetting about the additive. I've had one of the tappets in bits for a look and don't think they hold any oil although there isn't a big drain hole in them. I'll spin it a couple of times by hand and see if there's any change. Thanks for the input though and I'll keep you posted
 
I put new sd1 heads on my p6 engine, new tappets, cam and push rods and pretty sure there was some slack in the gear; runs ok. It would be pretty obvous if the valves weren't closing.

You may need to take one head off and do some mesuring/comaprison with the p6 head.
 
I've spoken to someone at Land Rover and he has told me that it will be ok as the tappets will only go where they need to. I'm a bit happier now.
 
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