TAPPET PRE-LOAD

[Patrick M]

Hi Blokes I am in the process of having my heads done up on VILET and was wondering if anybody has experienced doing the tappet pre-loads, is there an easy way of doing it without taking any shortcuts?
I would be interested to hear from anyone who has accomplished this tedious (from what I have been told) chore.

Regards:-
Patrick M.

[PhilipA]

You fill the lifters with oil before inserting them either by soaking for a day or pushing oil into the hole.
You get a coathanger or similar.
You cut a bit about 200MM long.
You bend over the end to a right angle for about 5MM
You file the end to AFAIR 20thou thick.( that is the outside of the 90degrees to the inside of the 90degrees)
You turn the engine so that the lifter is on the heel of the cam with heads on and pushrods in place..
you then try to insert the filed end between the plunger of the lifter and the circlip.
Do that 16 times and you are done.
Don't worry if they are over 20 thou too much as they can be up to 50 thou .

If one is well under 20 thou then you have to shim under the rocker post on that side of the engine so that the smallest gap is over 20 thou. If over 50-60 thou you should machine the rocker pedestals.
There are no real shortcuts that I know of anyway.
To be sure I checked with "Tuning Rover V8s by David Hardcastle" and the above is correct although he states 60 thou max but 40 thou ideal.
Regards PhilipA

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[Patrick M]

Hi Philip.
How did I know you would reply first?
I remembered years ago you doing it and if memory serves me correctly think you were suggesting back then that it was a very tedious job but needed to be done.
I have done a few head rebuilds and never bothered checking the pre-loads, but now I am older and thinking I may be stretching my luck a bit so I'd better do it this time around.

Thanks very much Philip.
Always appreciate your inputs.

[Blknight.aus]

before you start any of that....

make sure the head is flat and true, esp if you're installing a reman head, often a warped head will simply be machined flat on one side and the warp will be apparent on the cover side of the head. if you know the deviation you can normally shim them up pretty close before you start.

make 2 of the gauges a Go and no go gauge set. one you make to 20 thou the other 50 and when doing the checks if one fits and the other doesnt you're good to go. The pair I made had the words shim up on the 20 and file down on the 50.

now the fun starts.

if you have to shim up....

have 2 sets of feeler gauges on hand, start unclamping the pedestal until the no go gauge fits, then using a set of feeler gauges on both sides of the bolt in the pedestal measure up the gap between the head and the pedstal and thats the shim size you need.

IF you're under and have to file down....

good luck.....

or.

using a small pry bar, lift the rocker off the valve and start inserting feeler gauges until the go/no go gauges fit appropriately. Remembering its a seesaw, calculate out the difference between the movement on the arm and the movement of the pivot point and thats the amount of filing you have to do to get it down to spec.

from vague memory you need to remove about half the feeler gauge stack height. Theres a formula for it which I can never remember so I usually wind up drawing the thing and then gonkulating out the fractions.