Is it a mechanical fuel pump?

 

Are the rockers hitting the valve cover or maybe even the belly of the rockers hitting the hex nut portion of the stud or the stud boss?

 

It is a mechanical fuel pump. It is new and so is the rod. But I will check it. The tapping continues without the valve covers on so I dont think it is an interference issue there. I will check the studs, but they are identical to the drivers side and they are not making any noise. I'm going to get a stethoscope today and see if I can narrow it down a bit more.

 

1st do the check with the 'steth' and see what you find or where the sound signal is highest.

One other thing.
Was the crank 'line-bored'?
If so did you use a stock timing chain or a 'bore' chain set ...

 

Thanks for the inputs so far. It was line bored but I'm not sure how much. I'll have to ask the shop. I used a standard double roller chain. But I thought the new bearings were sized to compensate for the boring. Not the case? Would that somehow cause the tapping on just one side?

 

A line bore generally moves the crankshaft centerline closer to the camshaft centerline by 0.010", thus requiring a 'shorter chain'.

Easiest way to find out if it is the fuel pump rod is remove the fuel pump and let the rod slide down away from the cam lobe. Noise gone, then either the rod is too short, the pump arm is not strong enough, or bad cam lobe.

Be sure to push up on the rod and screw in a longer on the front of the engine and HAND tighten to hold it in place while installing the pump. Install pump, then remove long bolt and apply sealant on original bolt removed, and install same bolt.

 

Are they roller rockers and or aluminum heads?

 

would chek and see if rocker arms are hitting valve spring from under rocker arm--did you chek push rod length to see if rocker arm tips are riding in center of valve stem-is oil coming thru push rods

 

Not sure about roller lifters but on a big block with regular hydraulic lifters the oil gallery plugs in the front on the lifter oil gallery would get a small hole drilled in them by many builders. If it's too big you will have issues. I think drilling the holes came from what GM did to marine engines that had gear drives in them. On a street engine and reg timing chain you don't need the holes. Can't remember the size of the hole but I am thinking it should not be much larger than .020 or your lifters will be noisy.

 

Not sure about roller lifters but on a big block with regular hydraulic lifters the oil gallery plugs in the front on the lifter oil gallery would get a small hole drilled in them.

If I cant narrow it down today, I'll have to pull the intake and look at the lifters. I'll check for the hole and talk to the machine shop that did the bore, etc. Thanks!

 

They are roller rockers and edelbrock aluminum heads. the push rods seem to be the right length and the roller is in the center of the valve stem and oil is coming through the push rods. I'll double check the spring to rocker clearance.

 

So I checked the fuel pump...not it. still ticked with it disconnected. Using the Steth I really couldnt narrow it down except that it is on the passenger side near the rear. Guess i have to start pulling stuff apart and see what I can figure out.

 

if you can put oil deflector clips on the rockers and let it idle maybe you can check for the lifters by sticking it down the openings near the push rods with the valve covers off??

 

Joe, stick what down the openings? Not sure what you mean.

I took the intake off and pulled off all of the rockers on the passenger side and checked the lifters, rods and rocker clearances. Could not see anything obviously wrong. No wear marks on any of the rollers, all of the rods were clear. No wear marks anywhere on the rockers either. I am quickly running out of ideas here.

 

Stethoscope... is what I was thinking while running. Not even sure if you could do it though. You have, this far down might want to check those oil gallery plug holes.

 

Joe, are those only visible inside the timing cover or can I see those with just the intake off? Not sure where to look for them.

 

Only with the timing cover off. Might want to ask your builder about them and how big the holes are if they did install them. The plugs are an easy change out out if your going to get in there though.

 

Ok. I think I may have found my issue but let me know what you think. When I was putting in the distributor originally, I cut the rubber O-ring that seals the oil galley. Reading the instructions for the distributor it says that if the block wasnt champfered by the builder, the block could cut the O-ring, and you should run without it. I didnt know whether it was chamfered or not so I assumed it wasnt (I know). Well it was. Today with the intake off, I ran the oil primer and oil was pouring out around the primer in the hole in the block. I am going to guess that it is doing the same thing when the distributor is in and not letting enough oil get to the lifters. The trouble now is to find an O-ring for the distributor. Guess a call to MSD is in order. Any thoughts on this guess?

 

... Any thoughts on this guess?

My 'thought's' would be - that the annular groove of the cam/lifter oiling path at the rear bearing should distribute oil to both sides - if there is a distributor properly in place.
GM didn't require an o-ring at the transfer groove of the distributor - so I don't know why any other distributor would need it if it is properly machined and the oil system is properly sized. (dry sump system excluded ...)
And I've never had to install o-rings to control or provide the proper oil flow to the upper end.
And :yes: there is a lot of 'bypass' oil routed around the lower distributor groove that routes oil to the passenger side. It oils the cam gear and returns excess upper flow to the sump.
BBC's are 'Priority Main' oiled, with the bearing oil distribution to the mains and then to the cam bearings via a transfer hole - lifters are via a galley for each side at top of block. (SBC's are via a common center galley(s) and distribute to cam first and then mains ...)

* Is the manifold and head combo a 'stock' height?
* Or have there been cuts/modifications that have changed the mount height of the distributor allowing it to not seal this transfer groove properly?
* Is the base adjustable on the distributor you have and was it measured and set correctly?
* If you remove the rear lifter and 'oil' the system do you get major flow out of the oil galley from the rear of the block?
* No one installed 'restrictors' in your block did they?

If you're going to prime again, try pulling the front-most lifter on this side not getting oil and see if you get any flow out of that location - if not trace back to where you do have flow ...

 

posibility but i would think the front lifters would be ticking because oil travels from back to front which means the furtherest away would loose the most oil

 

GM's dizzy isn't machined for O-rings, it's a bit larger in diameter than the aftermarket and fits more snugly into the holes in the block. The aftermarket dizzy was built for O-rings, will hemorrhage/leak oil back down into the pan if you don't have a good O-ring fit.

 

Ok...I put the O-rings on the distributor and put the motor back together. No change. I did notice that the intake and exhaust pushrods for #2 and #4 and the intake for #6 could be depressed with my thumb about a 1/16th to 1/8th of an inch. #8 and exhaust on 6 were solid and all on driver's side were solid. Figure it's got to be an oil issue not getting oil to the front of the passenger side lifters. Next option is to call the engine guy on Monday and see about the galley plugs and if they have holes in them, change them. The other thing I am thinking is changing the oil from the break-in oil to 30 wt. Any other thoughts?

 

An update for those that are interested... Work kept me from digging into it the way I wanted and I thought I had exceeded my capabilities, so I took it to a shop that was recommended to me. When I took the vert there, he had a 51 Ford F100 rodded out in his garage so Ithought I was in the right place. Not so much. After several weeks of tweeking, putting the car aside for other jobs, and swapping rockers, some more tweaking, etc, ect... it was determined he had no idea why it was doing what it is doing. At that point I took it back to the guy that did the machine work on it as he builds motors for several of the racers in the area. He still thinks it's a lifter that's not pumping up. Since I replaced the lifters, he thinks it may be a problem with the oiling system bypassing the lifter somehow. He is coming to house this week to help me tear into it. We'll see what comes out of it. More to follow.

 

More than likely, lifter(s) are notpumping up, they could be stuck. If you pull the intake manifoild to look, look at the plunger cup inside, the cup the pushrod sits in. If the plunger is sunk into the lifter body, good chance the lifter is stuck. Replace it or them.

 

Thanks so much for keeping your post active and letting us know how things are evolving... makes this website all that much better!

I was going to suggest something simple on this... exhaust leak on that side... however, seems to reason that you might have a lifter issue. A collapsed lifter would be very obvious from the valves though? Let us know what you find.

 

In addition to above observation I don't see how a lifter failing to pump up causes a "knock" without the rocker indicating excessive lash no matter how much you adjust it. Lastly should cause typical tapping sound vs knocking sound.

 

Yes,dont they usually leave loose adjuster nuts,that never stay tight?

 

The sound of a loose CLACKING Hydraulic Lifter is distinctive and different then from most other tapping sounds an Engine can make. When adjusting Hydraulic Tappets with the Engine at Idle you loosen each on separately until it CLACKS and let be for the Lifter to Pump Up, then you tighten slowly to 1/8th or 1/4 or 1/2 turn whatever and you can feel the engine load up as you do - This is a sign that the lifter is probably OK.

If you can adjust a Hydraulic lifter while the engine is idling I would believe the lifter has pumped up; however a bad lifter can collapse after adjustment while the engine has run for awhile but then the following scenarios can case similar symptoms:

If you have used the STK OEM Rocker Studs the Rocker Shaft Bores can ride the Threads of the OEM Studs causing noise and you are unlikely able to properly tighten the Poly-Locks as there is not enough thread height and the surface not machined to make a clinch. Proper 1.9" to 2" ARP Rocker Studs ensure the Rocker Shaft Bores don't ride threads, they have machined heads and enough thread on top to properly clinch Poly Locks. You really should no need more then 1/8th turn to keep a Hydraulic lifter from Clacking.

Ensure your Rocker Arm to Valve Spring Retainer Clearance is OK.

Your Anti-Cam-Walk Devices should lock that Roller cam in at .004" to a max of .008". Never use the STK OEM or cheap after market Timing Clover as a Positive Stop for a Cam Button without some sort of bracing to the Water Pump housing as the Timing Cover will Flex.

What kind of Anti-Cam-Walk Wear Plate to Block are you using?

It is possible the Fuel Pump Rod is too short, have the wrong Angle on the Fuel Pump Arm or the Fuel Pump Rod is being jammed by Too Long a Bolt that runs into the Fuel Pump Rod Cavity from the front of the Engine Block.

Another thing: Lining up the Push Rod Guides is the most time consuming part of assembling a BBC. If they're not properly aligned or clearance too big the Rocker will flutter Side to Side and you will never achieve descent Lash or Hydraulic Lifter adjustment in your case. It is common to cut the link Bar of the Push Rod Guide in two or use a Solid Bar and Hammer to align the Guides while Torquing the Rocker Studs plus File or Squeeze the Forks for proper Push Rod clearance. Proper Push Rod Guide alignment is also easy on the Rocker Needles and Valve Guides.

Windage-Tray ticking Crank or possible Timing Chain ticking Timing Cover?

What can be really bad is that during assembly some small peace of metal, say something like a 1/16th" square piece broken lock washer found it's way into the intake runner of either your #2 or #4 Cylinder and is mashing about the top of one of a Piston - I've had that happen and to this day will NEVER use a Lock Washer anywhere near the Top Side of an Engine. To check this scenario: Remove all plugs and rotate engine by hand and feel for a Rub - Something I always do now after a Rebuild and before Firing Up.

What kind of Oil are you running?