4.6 litre noisy tappets

[MoodyBlue]

I recently rebuilt my 4.6 litre motor from my 96 HSE.

Top end stuff included skimming the heads, new valves, new rockers and shafts, new lifters, new cam, new timing cover and oil pump.

When it warms up the left bank has a couple of tappets clicking and I don't know what I've done wrong?

Any experienced Guru's know where I can look to to solve it?

Thanks
jeff
moodyblue933@hotmail.com

[PhilipA]

Join the club! LOL

The most common reason for noisy tappets in a new rebuild is that the lifter preload is insufficient, caused by many possibilities including the tappets not being to spec, the cam not to spec, the lifters not to spec.
They all have to be correct.
The only real way to check is to pull off the valley cover and measure the preload on each lifter at the heel of the cam. You can do this by making a gauge from an old hanger , bending about 4MM of the end to 90 degrees, then filing it to 20 thou at one end and 50 thou at the other. The gauge fits between the plunger that the pushrod fits in and the spring circlip and should be between 20 and 50 thou.
If it is less, like nil then the tappets/lifters will be noisy and the only way to remedy is to take a little off the rocker pedestals.
You may be able to shift the lifters around if the clearances are all over the place but this should only be done if the engine has done very few ks.
Regards Philip A

[Rupert Prior]

i agree, the preload should be checked. also, are the lifters the correct type, some push rods have a large burr where the ball end has been formed (it is better for this end should go to the lifter), some rockers look genuine but are chinese fakes (the steel pad and cup are lose from new).

[benji]

Jeff, did you go through Bendigo yesterday? I saw one like your's go up Mc Ivor road.

So many people i've spoken to (including a few mechanics in Bendigo) say to use holden lifters, but they've apparently different bleed characteristics.

[MacMan]

I would also look at lifter preload. I spent ages checking mine in my recent rebuild and needed substantial shimming on both sides to get ALL preloads within spec. PhilipA explained it well. Critically, you're looking to ensure you have a minimum of 0.020" so that the follower remains in contact with the cam at all times and stops the valve gear clattering in and out of contact. I did a quick google images search - this is where you need to measure:



While you're checking that, verify that all the finished heights of the valve stems are as close as possible. With the rocker gear off you can run a straight edge ruler across the valve tops. The peanuts who did my heads finished one side beautifully and the other side not so well, so the LH bank has more variation in the preloads.

I used Delphi lifters and when I found my variation on the 1-3-5-7 bank I did a number of different measurements with the lifters swapped around to see if I could find a favourable arrangement, but as best as I could tell the lifters all measured up the same regardless of position.

[MoodyBlue]

I did check the preload, by the book with a welding wire gauge. I don't believe the shims under the pedestals is a good idea.

Now ONLY the left bank clicks which is really annoying.

This week end I fitted a set of adjustable pushrods and increased the preload but still have the same level of click.

Next plan is to fit a set of solid lifters and use the adjustable pushrods to get close clearances like the old days pre hydraulics.

Thanks for the quick replies.

Jeff

PS, No I played with the pushrods on Saturday, and today was too cold to bother going out.

[PhilipA]

Then you have crook lifters that are leaking down.

Regards Philip A

[Rupert Prior]

i'm not certain but, i think that with solid lifters you are supposed to use a different camshaft, as the profile of a standard cam includes lift lost within the valving of the hydraulic lifter.

[MacMan]

Correct, and perhaps more importantly Rupert a solid lifter cam must be more progressive in lift.

[RR P38]

Pretty sure with solid lifters you will need fully adjustable pushrods or rocker arms.
Anti pump up lifters account for the wear that you normally get over the life of the engine.
So with solid lifters you will need to adjust as things wear.
In my experience solid lifter cams are noisy.

I would be looking to see what sort of oil flow you are getting up top.
Pull a rocker cover off and run the engine.
Just make sure you get some cover over the headers for any oil drips.
You might have a blocked oil gallery on one of the posts.