Finally, after 15 years my '69 is back on the road. That was the good news. The bad news is I have a noise in my new engine and I'm starting to think it's a lifter.

The engine is a .060 over 454 with all the good stuff in it including a solid roller cam. This is my first roller cam motor, but from the beginning I thought it was noisier than it should be. After break in, I readjusted the valves and found several that were a little loose and one that had been touching the valve cover. After doing this, it developed a louder, more distinct noise that while it still sounds like a loose rocker, it seems to be coming from under the intake and not from the valve cover areas.

My question is, what breaks on the lifter? Will the valve lash greatly increase when it happens? Apparantly nothing has fallen apart since the motor still runs fine, except for this noise. I really just want some opinions before I pull the intake off, just in case it may be something else.

 

What kind of cam - specs could be nice - and whose lifters? Increasing lash generally indicates a cam or lifter problem, decreasing can be a valve about to drop.

 

Have you considered a bent or mushroomed rod? Pretty tough to break a lifter.

Do you get valve chatter (like a rattling) when accelerating?

Jim

 

Comp Cams part #11-711-9
Grind #CB 306C-R8
Duration @ .050 Intake 272, Exhaust 280
Gross Lift Intake 680, Exhaust 680
Lobe Separation 108
Lifters are Comp cams

 

No rattling. Pushrods all look fine.

 

Weird. I've heard of them collapsing. Never heard of one breaking. Or are they solid lifters? Pull the plugs on the side you think the noise is coming from. Anything noticable in the burn pattern?

I've heard that the piston for the fuel pump could also cause this type of noise.

Jim

 

exhaust leak will sound like a lifter gone south...check your exhaust for leaks

Another possibility, your valve adjustment may be way too loose...how did you adjust your valves?

 

They are solid roller lifters, and I can't distinguish which side it's coming from. It sounds like it's coming from under the intake.

 

No exhaust leaks. valves shouldn't be too loose, I even set them .002" tighter than Comp says.

 

it's best to set them .001-.002 on the loose side...how did you adjust the valves?

 

I brought #1 up to TDC on compression, set those and went through the firing order by turning the crank 90* each time. Is there another way?

After thinking about this, the fuel pump pushrod seems to be the easiest thing to check first. It has a bronze tipped pushrod which I wasn't thrilled about anyway, but didn't really have a choice.

 

With the cam that size the proper way to adjust is by the valve openings...when the intake starts to open, adjust the exhaust and when the exhaust just starts to close, adjust the intake...I think that's the sequence...

 

What heads are on it?


JIM

 

Thats backwards here is 427Hotrods way and is the way I have done it forever.



First you have to roll the motor around to set each valve right? The cam has to be on the base circle. Easiest way for me is to set them as follows:

1) When the exhaust on a cylinder is just starting to OPEN...set the intake valve on that cylinder.
2) When the intake is almost CLOSED..set the exhaust on that cylinder.


So back off all the valves until they are loose and then start bumping motor over watching the valves as above.

Once you get it on correct position to set each valve...you want to reach down and pinch the pushrod between your fingertips right below the rocker arm. Lift it up and down with the nut backed off. You want to slowly tighten the adjuster nut just until that up and down slop just barely disappears. You want to just BARELY take all the slack out of the assy. Don't overtighten...you just barely want that up and down wiggle to be gone. It only takes finger tip action...you will likely still be able to spin the pushrod when you have just barely got it to *O* lash.THAT is *O* lash.....the lifter plunger is up and you have no play in the pushrod/rockerarm/valve. THEN you tighten the 1/4-1/2 turn to put the lifter plunger down in the lifter slightly.

Repeat by bumping the motor around for each valve....it will run then just fine.


Good luck! Instructions by 427 HOTROD

 

Yep..that's the way to do it. Same procedure whether it's a solid or a hyd. Just replace all that pushrod jiggling stuff with a feeler gauge and you're all set on the solid cam.

JIM

 

Thanks...been too long since I did that....forgot the sequence...

 

GM Rectangular port.