I have this flat tappet cam in a 454, just got it broken in and adjusted the valves using the eoic method. This is my first solid cam and noticed that when idling they clack pretty loud, if I raise the rpms the noise goes away, is this normal? I have the timing set a 12 degrees initial and it idles around 800 to 900 rpms (tach needle bounces a lot). Also I'm only getting 9 to 10 lbs of vacuum (that needle bounces a lot too) and was wondering if this was normal as well? Thanks.

i have the same cam but havent started my motor, Solid cams usually have a pretty intense ramp, therefore the valves will open and shut fast, this creates the noise you are hearing. Im not pro but thats my opinion. So yes, this should be normal in my opinion. The vacume thing im not sure of. hopefully someone else can chime in

70, if your vacuum guages bounces alot, then something isn't right, either lash, timing or idle mix . You might consider using more intial timing ( are you using vacuum advance?, and then re-adjusting idle mix and rpm and see if the needle holds steadier. If it doesn't, pull a few plugs man, and go and EO-IC it again.

Be prepared to possibly set lash 4-5X before it finally takes a "set" and stays. 69LS1 mentioned that, and I'm glad he did, otherwise I would have flipped out worrying on my new UD cam. It holds the set well now, although #6 intake has been found loose twice now. One more time and the pushrod should be checked.

I have a holley 750 and turned the idle mix screws out 1.5 times just to get a base, I moved them out a little more (.25 turn) but really didn't see much of a difference in the vacuum gauge. I think I need more initial timing as well, I'm getting about 3 to 4 lbs of vacuum from the top port of the carb. What about the noise though...does it sound normal to you guys?

Did you re-adjust the valves after the break in? Do you have sufficient clearance between the rocker and the retainer? Can you get a measurement while it's hot and running?
It should sound like a sewing machine rather than a bad lifter. ( goofy analogy ) graemlins/clonk.gif

To answer your questions I'am using vacuum advance (currently blocked), I re-adjusted the valves and found 4 that were out (not by much they measured .020 instead of .016). I made it a real tight .016 lash hoping it would quiet down. Any down side making it a real close .016? It looks like I have sufficient clearance between the rocker and retainer. I know what you mean about sounding like a sewing machine, but mine thumps/clacks pretty loud but it DOESN'T smoke or miss.

RN,

If you have not checked/re adjusted the valves since the initial break in, you want to do that first. Warm the engine first, pull all the plugs, disable the ignition, and check/adjust using EOIC. If you set the lash correctly before you fired the engine then they should all still be pretty close. Make note of any that are way outta spec.

Yes, solid lifter cams do make a clacking sound. Cams requiring a lot of lash (clearance) will make more noise than cams that require less. TJC's analogy is good.

Once you've got the rockers adjusted, you probably want to dial in some more timing, 14 or 15 degrees should be good at idle with the vacuum advance disconnected. As you increase you timing you'll note that the RPM's rise - just back the idle down using the idle speed screw (not the mixture screws). Re check your timing. Fiddle with it until you have 14 or 15 at your desired idle speed (try to get it as low as possible but still smooth). Note that once you re-connect your vacuum advance the idle speed will may rise. Just reset it with the idle speed screw.

Once your timing is set move onto adjusting the carb. Connect your vacuum gauge to a manifold vacuum port (either a port on the manifold itself, or a port that is below the throttle blades on the carb). Set your idle mixture screws to about 1.5 turns out. Start it and note the gauge reading. Work one screw at a time. First slowly turn it in, if the engine starts to stumble and the idle becomes erratic slowly turn it out. Keep an eye on the gauge as you manipulate the mixture screw - you're looking for the highest vacuum reading you can obtain. If you back the screw too far out the engine idle should change for the worse. Once you have one side done repeat on the other side. You may have to go back and forth a couple of times to get it just right. Note, if adjusting the mixture screw has NO effect on the idle, you've got some other issues.

Hope this helps,

Dan

They should not clack,they should be more like soft ticks.One tip is to buy a remote starter button this will make useing the EO/IC method much easier,you won't be as likely to forget where you were.It only takes missing one to get the sound you are talking about.Exhaust starts to open adjust intake,intake opens and starts to close adjust exhaust. graemlins/waving.gif

Yeah, I'm thinking my mechanic should look at this thing before it gets driven on the street. I re-adjusted the valves after break in and wrote down each one as I did it to make sure no mistakes were made. My only question now is should I drive it to the shop or have it towed?

Rn, for the record 4 thou IS HUGE when it come to lashing valves. How you measure the lash is important. The feeler has to go in TIGHT. I end up using a feeler one thou OVER (.019) as a no-go guage. So the 18 goes in, but the 19 does, that one is set.

If you haven't done it before it does take some feel. I was setting the valves way too loose on the old cam, just becuase I didn't have the right feel to it.

Don't freak out, once you get some time on the motor, they'll settle down adn hold.

Using posi-locks? What you want to do is to set the lash so your feeler somewhat easily goes in, set screw locked down. Then , the last thou or so, horse on the nut. Man, it really cinches them down.

I have to agree with Gene here..004 is alot to be out of adj. If you are not useing poly locks and are useing the stock type crimped nuts , then you always want to make sure that your last movement on the adjuster is in a clockwise direction. This allows for a somewhat less amount of slop in the threads between the stud and adj nut.That is basically what Gene is saying with respect to the poly locks as you load the set screw against the stud it pulls the adjuster tight against the threads and then moving the adjuster in a clockwise direction helps eliminate the clearence in the threads and helps lock everything up more solidly.... With the poly locks there is only so much you can move the adjuster and still maintain the correct lash so it takes a certin " feel " just like it does on the feeler gage.

As far as tappet noise goes a .016 lash should be fairly quiet.My old 097 Duntov when lashed at .012 and .018 could barely be heard.My Crane cold lashed at .024 was just a whirling sort of sound.
My BBC set @ .020 is nearly as quiet as my old 097 was with just the slightest detectable tappet noise.I dont have headers on my BBC and if I did have headers I'd bet I couldnt hear the tappets at all. A 30-30 Duntov can normally be heard from 3 blocks away. tongue.gif

It should sound like a muffled screw machine at work.

Al, have you ever used Crane's Kool-nuts? Posi-locks for stamped rockers?

Originally posted by 427L88:
It should sound like a muffled screw machine at work.

Al, have you ever used Crane's Kool-nuts? Posi-locks for stamped rockers? Yes Gene I have.... In my moment of insanity when I used that Comp XE hyd cam ... The entire valve train was brand new.... After breaking in the cam I had to readjust the valves... Drove it around and the very next day had to readjust them again...Ok somethings wrong here for a hyd to do this...So I bought some Crane Kool Nuts and replace the stock style crimped adjusters with the Crane's.... The Crane unit's worked great and they stayed adjusted after that.

When I decided enough was enough and put a solid cam in to replace the XE I bought Crane gold race rockers for it.They work fantastically.

Thanks everyone, I'll re-re-adjust the valves with my new knowledge and see what happens.