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low power output
Posted: Sun Nov 04, 2007 9:53 pm
by moggybloke
i have a 4.6 with a set of skimmed heads on it when i set the the lifter preload i never drained the lifters would this have an effect on power also because the heads have been skimmed quite a lot will this have an affect on tthe rockers ie needing adjustable push rods
Posted: Sun Nov 04, 2007 10:00 pm
by Coops
your preloads will be all wrong, they will now be to great and you run a risk off either cam or lifter damage,
this will also effect your power.
Posted: Fri Nov 09, 2007 11:15 am
by jefferybond
thev8kid wrote:your preloads will be all wrong, they will now be to great and you run a risk off either cam or lifter damage,
this will also effect your power.
I can see the potential for damage, either by valves hitting pistons or valve caps hitting the valve guides, but I think you'll only get a drop in power if the valves are being held off their seats, and then it'd run pretty badly.
Does it sound and run OK, apart from being down in power?
Jeff
Posted: Fri Nov 09, 2007 1:34 pm
by CastleMGBV8
Moggybloke.
How much was skimmed off the heads.
If say it was 20thou then divide that by the rocker ratio of 1.6 to arrive at a figure of 12.5thou and fit the nearest shim size from a shim kit under all the rocker pillars, it wont be perfect but should get the preload back to roughly where it was before the heads were skimmed.
The only right way of doing it is to remove and number the lifters to match them to the cam lobes so that they go back in the same lifter bores, squeeze out the oil and refit and measure properly as per the cam specs.
Shim kits available from Real Steel or RPI
Kevin.[/quote]