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Discussion Starter · #1 ·
So im installing an isky 264 mega cam in my 350, and this is my first install. So i have a few questions. Preciate any advice you guys might have.

1. should i go ahead and put the motor at tdc before pulling the cam?

2. I understand (0) lash is where it wont spin between your fingers and then you preload a half a turn. Should i preload them, then after cam break in, check them and put them back to (0) or will they stay where they were?

3. how does the process work to get all the rockers preloaded on the motor. is it in order, 18436572? and if yes how to i go about doing that?

any help would be great thanks guys
 

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So im installing an isky 264 mega cam in my 350, and this is my first install. So i have a few questions. Preciate any advice you guys might have.

1. should i go ahead and put the motor at tdc before pulling the cam?

2. I understand (0) lash is where it wont spin between your fingers and then you preload a half a turn. Should i preload them, then after cam break in, check them and put them back to (0) or will they stay where they were?

3. how does the process work to get all the rockers preloaded on the motor. is it in order, 18436572? and if yes how to i go about doing that?

any help would be great thanks guys

1. Yes. Make sure it is TDC for #1. If the heads are still on, you will feel a poof of air come out of #1 spark plug hole when it is on compression for #1.

2. Zero lash is when there is no slop in the rocker arm pushrod connection. If the pushrod doesn't spin, you're past zero lash.

3. Follow the firing order.


Take a look at the other boxwrench videos on youtube while you're at it.

:beers::beers:

Good luck Josh.
 

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When you line up the dots on the timing gears, you'll be at 6 in the firing order. You might want to line up the dots before you pull the old cam. Then you can turn the crank a full turn (crank gear and cam gear dots should both be at 12 o'clock), and you'll be at 1 in the firing order. You can also leave it at 6 and start from there (65721843)

You'll be fine doing the adjustment in the firing order, doing both intake and exhaust before going to the next cylinder. I like jiggling the pushrod up and down, since it's a little trickier to get a feel by spinning it. You'll get lots of different recommendations for how much to preload it, from 1/2 to 1 1/2 turns. I'd give it 3/4 turn and don't think you'll need to check it again (it should not significantly change).
 

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Mark's right. In order to install the cam, you'll need to have the dot on the cam gear at 6 oclock and the dot on the crank gear at 12 oclock. This orientation is TDC for #6, or one full crank rotation from TDC #1.

TDC #1 is a good reference point to start from though...

 

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1. should i go ahead and put the motor at tdc before pulling the cam?

It won't really matter, but it does make it easier to line up the timing marks on the gears if you do it before disassembly.

2. I understand (0) lash is where it wont spin between your fingers and then you preload a half a turn. Should i preload them, then after cam break in, check them and put them back to (0) or will they stay where they were?

zero lash is where there is no clearance between the roller tip and the valve tip, AND the lifter is not compressed. It isn't rocket science, because the valves will be tightened from a 1/4 turn to 1 1/4 turns past zero lash anyhow. What is important is that all of them are relatively close to the same. What you do on cylinder number one, should be done to all the cylinders. Some roll the pushrods, some wiggle, I do both, while I slowly tighten the nut until I cannot jiggle the rod, then loosen till it moves, then tighten just enough to stop that movement.

3. how does the process work to get all the rockers preloaded on the motor. is it in order, 18436572? and if yes how to i go about doing that?

Use the firing order, to keep it simple. What matters most is that the lifter is on the base circle of the cam lobe, and not going up or down, when you find zero lash. TDC on compression stroke is the most accurate way to do this.

Additional pointers that have not been mentioned, lots and lots and lots of cam lube. I personally use GM EOS on cams during assembly, and have not yet wiped one out. Yet being the operative word, because there will thousands of people who scream foul at this.

I always made it a practice to run the oil pump with a drill to pre-fill the galleries with oil. What kills a cam is lack of lubrication during the break in.

Break in procedure is important. many different opinions on this, mine is greater than 2000 rpms, for no less than 15 minutes, varying the speed every two minutes by either changing the idle set screw, or giving the throttle a little blip. I've not wiped out a new cam yet. Opinions vary.

Motor oil also effects cam break in, because after the first few seconds, most of the cam lube is going to be gone. One of the reasons I use GM EOS, is it mixes with the oil very well, and provides additional protection. Some call for other additives.

Are you replacing the cam bearings?

Are you using new lifters and a new cam? or mixing parts?

Did you inspect the pushrods or using new ones?

Did you inspect the rocker arms?
 

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Discussion Starter · #7 ·
wow thanks for the info guys, and to you sostan... im going to use the stock bearings, i really dont feel like pulling the motor for machine shop duty, im using the isky lifters that came with my isky cam, and i bought isky springs (310) i think. The springs were reccommended by summit for my cam. Stock pushrods (will inspect for warpage this weekend) and im going to use the stock rockers. Whats a good way to see if the rockers are still in good working order?
 

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Josh - I don't mean to be a buzz-wrecker, but my experience with Isky is they like to recommend a lot of seat pressure. Make sure your springs aren't more than 125-130 lbs closed and less than 300 open. If they're stiffer than this, you don't want to use these springs for the break-in. I know this sounds like a major PIA, but too much pressure can take out your cam at break-in, which will take out all the bearings and other stuff. Be as anal as possible with this, since break-ins with flat tappet cams are getting more challenging with the new oils.

There's a couple of good threads explaining the oil stuff. I think I would use every trick someone comes up with. After the break-in, the stiff springs will likely be perfect.

A cam change can often change the ideal push rod length. You might want to use a marker on the valve tip, set up one rocker, and turn over the engine to see what the pattern on the valve tip looks like. You don't want a big sweep and want it sort of close to the center (short sweep is more important). Don't overlook this check. It can cost you some valve lift and hurt longevity of the valve guides if the pushrod length is off.
 

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Josh - I don't mean to be a buzz-wrecker, but my experience with Isky is they like to recommend a lot of seat pressure. Make sure your springs aren't more than 125-130 lbs closed and less than 300 open. If they're stiffer than this, you don't want to use these springs for the break-in. I know this sounds like a major PIA, but too much pressure can take out your cam at break-in, which will take out all the bearings and other stuff. Be as anal as possible with this, since break-ins with flat tappet cams are getting more challenging with the new oils.

There's a couple of good threads explaining the oil stuff. I think I would use every trick someone comes up with. After the break-in, the stiff springs will likely be perfect.

A cam change can often change the ideal push rod length. You might want to use a marker on the valve tip, set up one rocker, and turn over the engine to see what the pattern on the valve tip looks like. You don't want a big sweep and want it sort of close to the center (short sweep is more important). Don't overlook this check. It can cost you some valve lift and hurt longevity of the valve guides if the pushrod length is off.
Madman makes good points, you should do everything possible to reduce the seat pressure on the valves during the break in. It is a PITA, but changing the new cam a second time is much more pain. Changing the springs is not that big of a deal, especially since you'll already have everything you need to do it on hand.

Forgot to mention yesterday, prime the lifters! I usually use the bottom half of a antifreeze jug, clean it out, stand your lifters up in it,, then fill it 50/50 with motor oil and GM EOS, to cover the lifters. Then pump each lifter with an old pushrod to suck the oil into them.

Inspect your rocker arms for any cracks, deformation, and wear in both the pushrod socket and the valve tip. Used rockers will be a touch shiney here, but shouldnt show any signs of wear.

Push rod tips should be clean and shiney, get a piece of plate glass, and roll them across the glass. they should roll very smoothly and the center of the rod should not lift off the glass.

before you stick the cam into the bearings, get a flashlight and a mirror and check those bearings. If you're doing this in the car, you've already got the radiator out. Knocking in and removing the bearings isn't a huge task at this point. All you need is the driver. This isn't machine shop work, if you use the correct tools.
 

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Discussion Starter · #12 · (Edited)
ok thanks every body. I havent seen one thing about priming the lifters, very interesting and i will definately do that. Ill take into effect everything everone said and use that on this install. I really appreciate it guys, alot. Oh and that article jake put up is pretty crazy. I plan on doing the break in first fire up on the first same day, but still good to know in case its not possible. Oh !!

And should I also soak the springs in oil? Whats some of those little things that I should know. Like I didnt know about priming the lifters, kinda stuff.
 

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No need to soak the springs.

Some people do the priming step and others skip it (I like to do it).

I also put a small dab of moly lube on the valve tip and in the rocker cup where the pushrod goes.

Those pics Jake took are pretty alarming, at least regarding the CC lube (which I wouldn't use after seeing the pics).

The most important thing is to get it broken in without breaking. Doing the break-in with 5qts of break-in oil might be smart to do.
 

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M


Forgot to mention yesterday, prime the lifters! I usually use the bottom half of a antifreeze jug, clean it out, stand your lifters up in it,, then fill it 50/50 with motor oil and GM EOS, to cover the lifters. Then pump each lifter with an old pushrod to suck the oil into them.
Not all manufacturers recommend this. I recently installed an Edelbrock cam and lifter set and the directions most definitely said DO NOT pump up the lifters. Check your cam manufacturer instructions.
 

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Not all manufacturers recommend this. I recently installed an Edelbrock cam and lifter set and the directions most definitely said DO NOT pump up the lifters. Check your cam manufacturer instructions.

Who reads the directions!? I can honestly say, today, for the first time, I read the directions that came with a set of headers. HMMM all this time I been fighting down from the top, and they supposed to come up from the bottom. Dammit!

Tribal knowledge is good and is bad. The only reason I can see for them to not recommend priming, would be because they are already primed.
 

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Discussion Starter · #17 ·
haha. you had the same problem sostan! yeah that was fun. I dont think mine are primed yet, just covered in that beautifully disgusting fresh machine work/ packaging grease. Why does that smell so good? maybe im just weird haha. Thanks guys
 
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