SBC 350 top end noise
 

I have a top end tick that I can't find the cause of. Brand new Lunati cam (10120701), lifters and matching springs installed two weeks ago. No retainer/guide clearance issues, no coil bind, no retainer/rocker arm interference no rocker arm/valve cover contact, no collapsed lifters. Pulling 30 psi oil pressure at idle and 45-50 at cruise.

Valves have been adjusted 1/2 turn past zero lash, both static and while running with no difference. Replaced old stamped rocker arms with brand new OEM replacements and that took only a slight bit of the noise away...at least for a little while. I'm running Vortec heads on an older block. The same noise was there with the old stock heads, thought changing things out would quiet it down. Eliminated all belt driven accessories (alternator, water pump and power steering).

I'm at a loss and it's driving me nuts. Been turning wrenches on SBCs for 25+ years and have never had one stump me like this. Any ideas?

Here is a short video of what it sounds like.
http://youtu.be/B99cClzos1c

Re: SBC 350 top end noise
 

Sounds like you've covered the majority of possible causes.
Is it both sides? Seemed louder on the passenger side in the vid.

Wiped cam lobe? Bad cam break in? Something in the distributor? 30 psi seems low to me for oil pressure but its well within the safe range. Maybe connection between distributor and oil pump?

Unfortunately sounds like you might have to really do some digging. That would drive me nuckin futs.

Re: SBC 350 top end noise
 

Did you install the self aligning style rockers?

Re: SBC 350 top end noise
 

It seems slightly louder on the passenger side to me as well. Break in went perfect, no issues at all. Truck runs like a scalded dog. All the rocker arms have been measured for travel and match the lift specs of the cam.

No metal particles in the oil, that was the first thing I checked. The reason for the new cam was 6 wiped lobes on the original because of the oil I was using. Found out the hard way that these old flat tappet cams don't like the lack of ZDDP in their bath.

I was thinking possibly distributor too, (it is an Accel after all) but nothing indicating that as the cause when I put the stethoscope to it. As a matter of fact, neither the stethoscope or a length of hose to the ear has helped pinpoint the source. Even replaced the header gaskets to eliminate that as a possibility.

I hate not being able to solve this problem, but may have to start collecting the pieces to put the 355 block on the engine stand together to have a little more peace of mind. This old 84 K10 is going to be my daily driver soon and don't want to have to concern myself with reliability issues. The engine is the only thing that I have not completely rebuilt on this truck. Everything but the rods and pistons have been replaced at some point in the last year as I got parts together.

Re: SBC 350 top end noise
 

If hes running guides he shouldn't need the self aligning rockers arms. As long as there is adequate pushrod clearance.

Re: SBC 350 top end noise
 

I did. It took few tries at Advance Auto to get a complete set that were all self aligning. It seemed to help for a short while, but the underlying tick is still there.

Re: SBC 350 top end noise
 

My bet is the noise is the nature of the beast with the aggressive lobe designs of the VooDoo/Extreme/etc.

Some aluminum valve covers amplify this.

Re: SBC 350 top end noise
 

Did you make sure the pushrods were the correct length? If you reused the old ones the tips of the rockers might be sliding off the valvestem?

Im trying to think outside the box here, I know its not likely but stranger things have happened.

I just got done tightening one rocker arm on my buddies vortec crate engine we installed a couple years ago. It was number 8 exhaust. We didnt touch the rockers during installation and everything looked perfect under the cover. Just that one rocker was loose, the nut just decided to back off that day. ???

Re: SBC 350 top end noise
 

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Re: SBC 350 top end noise
 

I dont think you're supposed to run self aligners and guide plates together. Just one or the other.

Re: SBC 350 top end noise
 

Forgot to add pushrods to the list of brand new items with the cam swap. Everything I read said 7.8" pushrods when using Vortec heads with non-roller blocks. If I'm mistaken, please point me in the right direction. I would love for it to be that simple a fix.

Re: SBC 350 top end noise
 

Maybe I missed it but, I don't see where he said he is using guide plates.

Re: SBC 350 top end noise
 

I've almost resigned to that possibility, but I've seen far more radical cams that don't make half this noise. And this isn't but one step up from their baseline in the VooDoo line; .454 lift/213 duration intake, .468 lift and 220 duration exhaust.

Using some old stamped valve covers I picked up at the bone yard.

Re: SBC 350 top end noise
 

No guide plates, just self-aligning rockers.

Re: SBC 350 top end noise
 

Is it oiling up top? 6 flat lobes can leave ALOT of debris in an engine.

Re: SBC 350 top end noise
 

Lots of oil to the top. All of the remnants of the six wiped lobes were on the big donut magnet I had in the bottom of the oil pan. I'm sure the filter was pretty well filled with it too, but surprisingly, the oil didn't look like metallic paint as I've seen it before. I gave everything I could see a good bath in brake cleaner before putting any of the new parts in. I replaced the oil pan as well.

Re: SBC 350 top end noise
 

My bad, I saw guides and thought guide plates. Didn't think about valve guides.

Re: SBC 350 top end noise
 

Well they would have to be pretty damn long or short to actually be sliding off the edges of the valvespring. But with no other solid leads it wouldn't hurt to check. You can clean off the tip of the valve stem and rocker. Put a good coat of Sharpie ink on the valvestem and reinstall the rocker. Turn it over a few times and see where the rocker tip is making contact.

Re: SBC 350 top end noise
 

What lifters? I rarely use flat tappets anymore but, when I do, I use the GM hard face lifters from Chevrolet Performance.

You are going to have valvetrain noise with the VooDoo line of cams, yours does seem extreme on the video.

Re: SBC 350 top end noise
 

Hadn't tried that yet. They appear to be centered laterally, at least visually. I'll try that out tomorrow or Wednesday when I get a chance just to verify.

Re: SBC 350 top end noise
 

Lunati p/n 71817PR-16...they came as part of the cam kit. I would prefer to be using rollers myself and I think I might bite the bullet and pick up a retrofit roller kit and save myself the worry.

Re: SBC 350 top end noise
 

Try changing your oil, use a good Wix 51061 oil filter (NAPA 1061) and some Valvoline VR1 30wt racing oil in silver bottle (plenty of ZINC)

http://www.valvoline.com/products/co...ng-motor-oil/6

Re: SBC 350 top end noise
 

I've found some SAE 30 in stock at a local Napa. Temps are warming up enough here I could probably get away with a straight weight oil for the next few months. Using Quaker State Defy 10W30 and a Mobile 1 filter presently. The QS oil had a pretty high ZDDP content, was cheap and readily available. Did the break-in with Shell Rotella 10W30 and the Lunati break-in additive. Rotella was another one recommended throughout several forums as suitable for flat tappet cams. I love my Amsoil, but at over $10 a quart for their high ZDDP content oil, Valvoline is looking pretty good.

Re: SBC 350 top end noise
 

Good Morning, I'll chime in on this a bit. Have you determined if it is cam or crank rpm based. If cam rpm... have you listened to the fuel pump yet? They have been known to make sounds like this. If it's crank rpm based... When does the ticking start, cold, hot, when revving up or winding down? This should lead to whether it maybe a piston or rod sound. Well just trying to help. Seems to me if it was there before all the work was done and it's still there, the fix would be something entirely separate not yet addressed.

All have a great day, God bless, Terry

Re: SBC 350 top end noise
 

Changed filter and oil to VR1 10W30...no change in the noise. Not much of anything to speak of as far as metal particles in the oil. Just a few speckles here and there; about what you'd expect in the first 800 miles after break-in (changed the oil immediately after break-in, final valve adjustment and timing dialed in). Certainly nothing indicating wiped cam lobes.