1st time swapping out a cam - input welcomed..

[FullChat289]

'87 or so 5.0L block, hydraulic roller, 13K miles on everything..nothing fancy.  Any lessons learned you can relay from a disassembly/reassembly perspective?  I've searched the internets for some knowledge, but still have questions like:

Does the cam timing gear require a puller? 

Reason I need to do the swap is b/c I run webers (changing to IDA's from IDF's) and found through my IDA source that my present bumpstick has too tight of lobe separation.  (excessive fuel reversion at high engine speeds = lean)

Thanks in advance,

- Allen.

[Wade Chamberlain]

cam sprocket is held on by a single bolt and indexed by a dowel pin.  The crank sprocket simply slides over the nose of the crank and is indexed on the keyway.  Once you remove the bolt in the center of the cam sprocket, the whole works (2 sprockets and chain) should slide off together.

[edit] - no puller required

[FullChat289]

Thanks, Wade.

For Hyd lifters:

Do you set the valvetrain lash by hand (able to rotate, but no up/down movement) then add another 1/2 turn on the rocker nut?  that's how I've read to do it for hyd lifters..  Sound right?

- Allen.

[Wade Chamberlain]

do you have stud-mount or pedestal-mount rockers?

[Scott Harrison]

Lots of things to do wrong....I've probably done them all. Some random thoughts:

Is the engine staying in the car or coming out?

>Might want to drain the coolant from the block as well as the radiator, if you can get to the drain plugs it saves some mess.
>Shouldn't need a puller for the cam gear, but makes it easier. Use a couple of pry bars/screwdrivers and walk it off along with the chain and crank pulley.
>You will need a puller for the damper.
>I assume you're leaving the heads on and will only remove the intake. (Get the right intake gaskets)
>I keep the pushrods and lifters in order, even though you'll be putting in a different cam.
>Lube the lobes and bearing surfaces...don't nick the bearings or the lobes.
> Put a long bolt in end of camshaft to hold cam and ease installation
>Check camshaft endplay.
>Check piston-valve clearance. Even if the lift is the same, the timing events will be different.
>Get a degree wheel, piston stop and dial indicator and use them, don't trust the manufacturer specs.
>Keep the engine a TDC #1 compression stroke-that should have the cam and crank gears lined up.
>Mark the rotor location on the dizzy.
>Get all the correct gaskets together and new front crank seal.

[FullChat289]

Wade - Stud mount.

Scott - Yes, I'm planning to leave the engine in the car.  I appreciate your comments.  Intake is already off, dizzy is pulled, and I'll be removing the radiator.  Should be able to remove the trans tunnel, loosen the trans mount, and jack/twist a bit about the engine mounts to point the cam through the "A" hole in the FIA spring tower crossmember weldment.  I've got pullers and such.  Will have to take my time with the timing for sure.....

- Allen.

[Wade Chamberlain]

the Crane sight has a decent write-up on adjusting preload.

http://www.cranecams.com/faqview.php?s_id=41

The only comment  I would add is be careful when finding your zero-lash point.  A lot of guys say to snug up the rocker until you can't spin the pushrod w/ your fingers.  I'll guarantee the lifter is already starting to collapse well before the pushrod gets that tight.  Instead, just wiggle the pushrod up and down as you start to snug up the adjuster nut.  You can easily feel the point where all play is gone...that's zero preload.  1/2 turn and lock it down.   

I've always been able to turn the polylocks by hand until the point of zero preload...it's even easier to tell when you hit zero that way.

[Fred K]

While you are at it you might consider adding a second dowel pin to the cam pulley. If one breaks you've got a big problem. If you have two they don't break, ever. Plus it's cool.

[Mike Holt]

New Hyd lifters?  Soak them in oil overnight before hand.
Re-measure the pushrod height with a push rod tool.
EO/IC...Exhaust Opening/Intake Closing when adjusting valve lash...tighten the Intake when the Exhaust is just opening and the Exhaust when the Intake is 1/2 to 3/4 closed.  Ensures your'e on the base circle of the cam.


Most importantly don't pay any attention to me!  I'm only on my umpteenth time triple checking mine (I second guess every bolt I turn on that engine!).   Oh and if you want to know what it sounds like when you don't have one rocker torqued down, I can tell ya that too!

[FullChat289]

Thanks for the responses!!

Any good tips for checking piston to valve clearance if I'm not removing the heads?  The lobe separation is a bit wider than my old cam, and the lift is a skoche more...couple hundredeths...  The internets shows lots of examples of folks removing the heads and using clay.  Others say rotate the crank after adjusting things and see if you feel any resistance.  Do hyd lifters come into play here since there is no oil pressure when turning over by hand, or is this purely a cam timing thing?  Lift is in the .58X range for intake and a bit less for exhaust as I remember from the spec card (don't have it here in front of me) and I'm using standard 1.6 ratio rockers and Dart Pro1's. (1.94" intake valve/1.6" exhaust valve)

- Allen.

- Allen.

[zimmy]

Changing the cam for my Weber install on the FE Big Block while still in the car. Have fun! 

[FullChat289]

LOL...I never heard the back story on that photo.  Now I understand!

- Allen.

[czarsmith]

Ditto on Fred's comment regarding the second dowel pin. Several years ago I blew up a 408 with about 1000 miles on it at about 90-100 mph out at Summit Point in a most spectacular way due to the pin shearing - three rods through the block and pan - 9 quarts of oil and a whole bunch of antifreeze all over the track just after the bridge coming up to turn 10 - big bang followed by three 360's right up the middle of the track followed by a red flag and a half-hour to clean up the mess.  (Yes, in a spin, both feet in.)  About the only thing left was the intake manifold.

[Scott Harrison]

To check piston-valve clearance, replace one set of valve springs with some light springs, Place your dial indicator on the top of the valve and as you rotate the crank through TDC, depress the top of valves until they touch the piston. Do this every 2° or so from 15°-20° BTDC to 15°- 20° ATDC. Make sure you have 100 thousandths (0.100") clearance...particularly on the exhaust side. (When swapping out the springs, keep the piston on TDC and try not to drop the valve into the cylinder.)

Although sold at Summit and Jegs, you can get what you need at Home depot.

[Wade Chamberlain]

I would argue there's no need to double pin a cam unless you're running a solid roller with crazy spring pressures and crazy lift, ramp rates, etc.  Even then, it would take a lot to convince me its necessary.  If you need two dowels to keep your cam gear fromspinning on the cam, you have much bigger problems! 

Herb - seriously.....somebody looked at the pile of shrapnel and determined it was a sheared cam dowel that caused it?      If you have big parts flying around punching holes in the block, there's about a 100% chance that one of them will contact the cam, which would THEN shear the dowel.  Much higher chance that the sheared dowel was one of the many results...not the cause.