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Discussion Starter · #1 ·
Last spring I did a complete overhaul. The only thing I didn't replace was the pushrods and rockerarms. Engine has compcam 270H cam. Heads are 781 ovals. The block is a 76 454. Heads were reworked at a good shop.
This thing has ticked from the day She first fired up. I just put new lifters pushrods and comp roller tip rockers and still the same ticking.
This is the list of what it is not-
exhaust leaks
valvecover clearance
incorrect valve adjustment (trust me on this one)
BTW it is quiet at cold startup!
Then gets louder as it warms up.
I'm at a loss. The only thing I can think of is the comp lifters don't like 70 pounds of high volume oil pressure. But why would it sound fine when cold, but after about 2to3 minutes you start to hear ticking and the it gets louder and louder.


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MY CAR
Stacey
67 chevelle

At sixteen I got my license. (One of the best days of my life.)
 

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Stacy,

My completely rebuilt 396 (new Comp Cam, lifters, push rods, rockers, springs, pistons, etc-etc) does exactly the same thing. When it's cold it's actually pretty quiet. As it warms up it starts ticking.

Trust me on this, your Comp Cams roller tipped rockers are contributing to the problem. I had them installed on my fresh rebuild. Went back and forth with Comp, as did the engine builder, and Comp basically said that the roller tipped rockers tend to make a little noise.

I still wasn't too comfortable with the noise, seeing as how it's a hydraulic grind - it should be taking up all the slack in the valve train. The fellow that built the engine even came out to my house to listen to it in person. His verdict; although they are a little clacketty, no problem whatsoever. He did leave me with a set of stock replacement rockers to try though.

Bolted on the stockers and the noise was lessened, perhaps by half, but not eliminated.

It seems that the cam may also be a source of the noise due to the aggressive ramps. I'm running a Comp 265DEH-10.

Hope this helps.

Dan

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Awww, fer cyrin out loud, there's that IMPALA guy again.

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I don't think the lifters are bad, they don't have full oil at startup and should not be pushing your valves fully open until they are. I would expect them to tick initially, then stop once they get pumped up. Have you checked for piston-to-valve clearance? As the lifters start properly working the valves, it's possible you've got interference. Pushrods too long?
 

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Just to throw in some info from a non expert.

What kind of lifters are you using? I have Rhoads hydraulic lifters in mine and they are - by design - noisey. Suppose to be the "charm" of solids but convenience of hydraulics. And they clack like hell...and the warmer the engine gets the louder they become. They are actually quieter right after start up (cold engine). I adjusted and readjusted until I read up on them and posted a question here and the result is - that is the nature of the beast. Although sometimes irritating, I did gain some top end performance with these lifters (Stock matching numbers 396 350HP motor in my 67) as was touted by Rhoads. I contacted them and they basically reiterated what the literature that comes with them says...it is their design.

Now having said all that, it is my understanding that Crane also has something similar to these called "fast bleed" lifters. Same noise factor as the Rhoads is my understanding.

Hope some of this helps

Mytmouse


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67 SS396 350HP 4 sp 3:55 Posi Butternut Yellow w/Black Vinyl
68 RS Z/28 302 350+Hp? 4sp 4:10 Posi, Euro Red on Black
70 SS396 350HP 4 sp 3:55 Posi, Black on Black

Mytmouse A.K.A. Robert Stacho
ACES Member # 04359
 

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Does not sound as if you have anything special. I would install ALL CHEVROLET PARTS. Stock oil pump, rockers, pushrods, lifters and a high performance CHEVROLET CAM. You will have no valve noise (unless bad head work) and a very good performing engine. I have never understood why someone would waste their money on roller tip rockers. Good luck Jon
 

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Stacey-understand hydralic lifters-are they roller or flat?

Like I posted to you before-my cousin installed new crane hydralic roller lifters (fast bleed?) with a comp cams cam. He's not using the stock rockers, but I don't know whose they are (they were fairly quiet on his last motor that had a solid cam, using polyloks).
His motor has a tap that comes and goes intermittently in the valvetrain.

According to Crane cams, the extreme spring pressure required by roller cams is causing the lifters to have issues getting and keeping pumped up-and he should just expect to live with it. Their offer to fix it was a lifter by lifter offer IF he bought new lifters first, then sent the old ones (each) in. They would then test them-destructively. If they were, in Crane's opinion, faulty, then they would pay, lifter by lifter, for his replacements. I know who I'm buying my lifters from next engine I build....NOT. Know this didn't really help you-but thought I'd let ya know. Are you running a really high spring pressure?

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MCC #347, TC (Gold) #174
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Stacey, just RE=RAN them again!!!!

This time we only did one side at a time. Ran the car for about a minute, then shut down and immediately started.

Adjusted one side(per instructions) by first loosening them to where there's alot of slop in the rocker, let sit for about 30 seconds. Then tightened by the "spin & tighten" method until we had 0 lash. Then turned 1 complete turn, tightened polylocs, and tightened again to snug them down, approx. 1/8 turn.
Finished driver's side. Buttoned it back up and ran car for about 2 minutes. Shut down and did same for pass. side.
Car still has a faint tick, is somewhat better after following this method. He's taking it on a long cruise tomorrow-I'll hear about it on Sunday. Good luck!

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71 Ragtop, finally under reconstruction!
MCC #347, TC (Gold) #174
[email protected]
 
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