SMOOTH idle camshaft ?? - Team Camaro Tech
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post #1 of 13 (permalink) Old Apr 12th, 08, 09:01 PM Thread Starter
 
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SMOOTH idle camshaft ??

I'm starting to suspect my new Comp HE260h has wiped a lobe. It runs great....idles smooth but it has a TICK TICK that will not adjust out. I will measure the lift on the rockers to decide. If I can't locate a bad lifter, I may go ahead and do a ROLLER cam. $$$

Any specefic suggestions for a SMOOTH idle camshaft....max rpm 5200...8.5/1 compression LS4 454 ?

Someone had told me to not exceed 260 duration with the low compression...frankly, I don't know the difference. That's why I am asking for the advice.

Thanks for any help or suggestions ...

Last edited by 74LS454; Apr 13th, 08 at 07:26 AM.
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post #2 of 13 (permalink) Old Apr 12th, 08, 11:36 PM
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Re: SMOOTH idle camshaft ??

I might be a little messy or you can use an old Valve Cover with the top cut out to contain Oil Splash and adjust the Hydraulic Tappets while the engine is idling. At Idle simply loosen the Rocker nut until you hear it clack then tighten until it stops then add another 1/4 turn.

If after adjustment you still hear the TICK TICK as you describe look at the push rods. They all should be rotating or spinning. If one is not then suspect that you may have problems with that particular component - Collapsed lifter - perhaps a wiped lobe. You can use a piece of wood to push down on the rocker arm of the suspected bad lifter or lobe to see if it will change the sound or use a solid bar against the block to you ear to help determine location. You might have a bad rocker or broken spring. If you find something not right with a particular lifter and it's not evident I would put a dial indicator on the push rod end of the rocker and compare lobe profiles.

If you find all looks well and the tappets seems to adjust normally without slack then I would look somewhere else - fuel pump rod, timing chain slap, or perhaps a cracked flywheel if automatic - perhaps an exhaust manifold leak.

That 260H should be very torquey with an 8.5:1 compression and give you a descent DCR. I might have gone a little bigger to 266 or even a 268 and it would still push 3.08 gears very well.

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post #3 of 13 (permalink) Old Apr 13th, 08, 01:29 AM
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Re: SMOOTH idle camshaft ??

You shouldn't ever have to do the engine running valve adjustment. Your cam lobe could be worn. The best thing to do is make sure your exhausts don't have leaks. Then check that your pushrod geometry is correct.

If you want a smoother idle camshaft with a decent duration get a wider lobe sep cam. A 114o lobe will keep vacuum high and maintain street manners. Combine it with a 220o to 230o duration lobe @.050" with as much lift as you can get and you will have a good combo.

Lots of initial will help too. Vacuum advance can help the cruise mellow out. If you want to smooth it down some more get an AF gauge and change the idle fuel and air bleed restrictors to the right combo.
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post #4 of 13 (permalink) Old Apr 13th, 08, 04:07 AM
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Re: SMOOTH idle camshaft ??

Adjusting Hydraulic Flat tappets on an engine that has been run after initial setting of tappets during assembly is best performed while the engine is idling. You can feel the pump up action and condition of a lifter and compare one to the other especially if you suspect a valve train problem. You also have the opportunity to observe, listen, feel and recognize something abnormal during the procedure such as poor oil flow, a collapsed lifter, low lobe profile, no spin or bent push rod, crooked rocker, broken spring ... etc. I've been building and servicing engines too long to argue this point with anyone that says different.

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Last edited by Z15CAM; Apr 13th, 08 at 04:20 AM.
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post #5 of 13 (permalink) Old Apr 13th, 08, 05:46 AM
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Re: SMOOTH idle camshaft ??

I chased a Tick Tick on an engine years ago to the point of changing out the lifters, but that didn't fix it. Turned out a new set of plug wires eliminated the tick because the old wires were arching. Lesson learned... check your basics before you take the engine apart.

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post #6 of 13 (permalink) Old Apr 13th, 08, 07:39 AM
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Re: SMOOTH idle camshaft ??

could also be a little exhaust leak.

Nuthin wrong with running valves running on a hycam except it makes a ****ing mess. A good mess is fun every once in awhile.

Do the preload SLOW, it allows the hydraulic piston time to bleed and get it's act together. It's also a good time to experiment with different preloads, most of em I've done you can hear it hurt em at 3/4 like the old manuals told you to use. I normally go 1/4 on an engine I will have around that I can keep an eye on. If it's an engine that goes in service for somebody else it gets closer to 1/2 so there is plenty of service.

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post #7 of 13 (permalink) Old Apr 13th, 08, 08:08 AM
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Re: SMOOTH idle camshaft ??

I agree with Ron and Tim.

While it's certainly possible for the more skilled to adjust hydraulics without running the engine, my ear is more sensitive than my feel.

Also, when you loosen a rocker while idling, you WILL be able to tel if / when you get to the one that is ticking.

If you're fast and pay attention, you can do this without making a mess. Jusy don't rev the motor, and watch the oil level in the heads. I'm not sure about BB's, but small blocks can overflow in the back corner, due to where the drainback holes are.

I'm currently chasing a very loud TICK that goes away after warmup. I've run the valves idling twice, and am now convinced it is a header leak where the tube welds to the flange. Will be getting new headers.





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post #8 of 13 (permalink) Old Apr 13th, 08, 08:16 AM
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Re: SMOOTH idle camshaft ??

Parts stores these little "Rocker stoppers" just for this reason but the old half cover works too. As for smooth idle, I agree with a wider LSA. I currently have a 112 and had same cam in 110 , definately a smoother idling cam. Broadens power range too. 114 would probably be smoother.

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post #9 of 13 (permalink) Old Apr 13th, 08, 10:23 AM
 
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Smile Re: SMOOTH idle camshaft ??

These are way old-school cams that still run fine if you want to use them and consider them having a smooth enough idle??From Clevite:Part # 229-2006 Hy. -- 293/214, 114/112, .503 liftor this one.Part # 229-2356 Hy. -- 277/218/287/228, 114/109, .502/.501. Both of these are on 114 LCA.This one from Elgin may be too rough??E-928-P; 308/222/328/235, 115/110, .500/.505.But notice the 115 LCA!And I do figure that the eff. durations on these old cams are shorter by some!!I'd have NO problem running any of these in a low compressioned 454! But I would install .020 thick steel shim headgaskets to close my quench up! And as well as gain a schosh more CR!!In fact, I have a new still in the box Clevite's copy of the above Elgin cam out in my garage now.pdq67




Last edited by pdq67; Apr 13th, 08 at 02:58 PM.
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post #10 of 13 (permalink) Old Apr 13th, 08, 12:05 PM
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Re: SMOOTH idle camshaft ??

Oops _ Boo Boo !

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post #11 of 13 (permalink) Old Apr 13th, 08, 12:12 PM
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Re: SMOOTH idle camshaft ??

pdq67:

I prefer 12 to 14 LCA Marine Cams in my engines when running a manual tranny. I know Cam Mfgr's recommend 108 LCA Cams for 4 spds but think they are referencing the 1/4 mile where upper rpm torque might be advantageous at drag high rpm shift points. They do not consider every day driving where you may have to travel for hours in heavy snow and ice conditions. You simply have a much broader and stronger torque curve with a reliable throttle response for HWY driving running a wider lobe center angle camshaft. Plus you can run a longer duration with less Static Compression with 3.31's or 3.08's and the exhaust note sure sounds sweet with that extra scavaging.

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Last edited by Z15CAM; Apr 13th, 08 at 12:42 PM.
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post #12 of 13 (permalink) Old Apr 13th, 08, 12:43 PM
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Re: SMOOTH idle camshaft ??

You can backk all th rocker off a turn and run the enging to warm everything up and pump the lifters up. Then, while it is still warm and OFF, take the covers off and adjust the valvetrain. This is almost never needed

Sometimes it can be hard to tell when you are compressing spring or lifter plunger. You can mark the pushrod above your pushrod slot to see which the the rod moves.

If you guys like adjusting with engine running continue by all means. I just know for a fact it can be done off in any circumstance on a hyd. cam.
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post #13 of 13 (permalink) Old Apr 13th, 08, 02:59 PM
 
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Re: SMOOTH idle camshaft ??

ol' 'puter going inta the shop shortly!!

Sorry about that...

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