Camshaft R&R

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Date: Wed, 23 Apr 1997 20:34:35 -0700
From: James Brink 
Subject: Cam power
To: Toy4x4@tlca.org

Call me biased, but I like the DOWNEY cam for overall performance
improvements.

Regardless of what others might say, this is not a simple, wham-bam job.
Consider the mileage on your vehicle first. If the motor is freshly
rebuilt, this is not much of a problem. If high miles, however, consider
removing the cylinder head and replacing the head gasket. 

In order to gain access to the cam, the rocker arm assembly must be
removed, i.e., untorquing the head bolts. If you decide to go this
route, do yourself a favor and disassemble the rocker arm stanchions so
that the head bolts can be reinstalled and torqued while you perform the
cam swap. Not doing so may result in head gasket damage, causing more
problems later on.

Carefully inspect the pads on the rocker arms for wear and consider
replacing them too. Not much sense in installing a new camshaft just to
have old, worn rockers eat it up (some cam mfg's. even require this).

Remove the fuel pump, cam sprocket bolt, fuel pump eccentric and cam
sprocket. Try to wire the cam sprocket up so that it retains it's
tension once it is removed from the cam.

Be sure to use plenty of cam lube and clean and lubricate the cam
bearing surfaces on the head. Do not mix up the cam bearing caps
(usually they are marked with a number and an arrow). Torque the caps to
14 ft.-lbs.

Loosen all of the lash adjusters on the rocker arms before reassembly.
This will make installing the rocker arm assembly much easier. Torque
the head bolts to spec. in sequence and adjust the valves cold.

Upon start-up, I like to run the motor around 2,000 rpm for about 20
minutes. This assures that plenty of oil is flowing to the new cam. This
is a bit like a break-in procedure.

After the break-in, retorque the head bolts, adjust the valves hot and
button everything else up. Another good point would be to change the
engine oil and filter.

If I have left anything out, anyone, let me know (It was one of THOSE
days)!

- -- 
Jim Brink
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Date: Sat, 12 Dec 1998 13:47:08 -0800
From: Michael Czajkowski 
Subject: Re: Cam replacement

Roy Arblaster wrote:

> Has anyone ever replaced their cam without replacing the head gaskets, I
> know (after 3 head gaskets) that the bolts that hold down the rocker
> assembly on top of the cam also hold down the head gasket.  Will removing
> the bolts to replace the cam disturb the head gasket? I have a NWOR cam that
> only has about 300 miles on it and would like to install it in my new head
> (that I installed without thinking of the cam being there)
>
> Thanx in advance

Roy,

    I have replaced a cam before without having to deal with the head gasket.
    First drain the coolant.
    After removing the head bolts and rocker arm assembly, you must remove oil
from the head bolt holes in the block.
    After replacing the camshaft and reinstalling the rocker arms, torque the
head to 57lbs cold in 3 steps:
        1. 30lbs
        2. 45lbs
        3. 57lbs(cold), 63lbs(hot) respectively
    Finally, dont forget to replace the coolant!

- -BigMike

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