Just finish getting my car back up and running after a rebuild. The bottom end has all new stock parts and arp bolts all around. The top end is stock 853 with 918 springs (2 yrs old 10k miles) 224 cam, hardened pr, and stock lifters and rockers. Oil pressure is good at 40psi on cold and increases with rpms. The car idles all day long without a problem and drives well. So feeling good I decide to take it on a back road were I give it 70% throttle for first 2 gears. Getting late and decide to do 1 more run from a stop through 3 gears to 90mph.

Slowing down and I start to hear this tapping sound like a rocker has come loose. Pull off the road and remove both side valve covers to check things over. Everything is nice and tight and about 30 mins has passed while I figure out whats wrong. Put everything back together and the car drives fine home. One more look, start it up and let it idle in the driveway for about 15 mins then decide to go get gas......runs fine through the neighborhood get to the intersection and gas it a bit in 1st then second and around 3k the ticking noise comes back. All readings are good on the guages and turn around back to the house. Getting ready for bed and decide to start her again.....idles fine like nothing happened. Leaning towards exhaust leak, but won't rule out collapse lifter.....any other ideas? The tapping definately sounds topend and increases with rpm. Oil and coolant levels are good....so are the sparkplugs. Ran autotap scan but only code is EGR and O2 sensor. Appears one of the header holes is stripped a bit but not sure if that is the issue. Either way I will probably buy new heads and replace the lifters at the sametime.......was hoping not to put more money into the car so early

 

lifters may have bled down during the engines down time, sometimes lifters take a little bit to "come back" or fill with oil and bleed the air. hopefully thats all it is. if the noise comes and goes with out much consistency I would guess that first.

when you had the covers off did you happen to see if there was any free play/excessive push rod to rocker clearence?

 

I checked the rockers but didn't check the pushrods....will do that tonight. Can a lifter uncollapse which is why it doesn't happen at idle?

 

Lifters pump up if they're fed pressurized oil, assuming they're operating properly. With the old flat-tappet lifters you could submerge them in oil and cycle them with an old pushrod to get them pumped before installation, but it's not feasible with rollers.

What oil are you running?

 

Running valvoline 10w 30 fully synthetic....the lifters were sitting in oil while motor was down

 

Valvoline SynPower seems to have a good reputation.

If you're interested in experimenting, I've used Torco MPZ Magnetic Friction Reducer:

http://torcousa.com/products/product...9-2c0fb1b194a5

This stuff added at 1oz per quart of engine oil stood up to plenty of hard road course abuse in my LS1, added to Mobil-1 10W-30. The MPZ supposedly stands for Moly, Phosphorous, Zinc and it has plenty of each.

I stopped using it when I switched to Mobil-1 15W-50 for track use, it already had ~1500ppm zinc and didn't need more.

I'm now experimenting with Mobil-1 High Mileage 10W-40 and my first Blackstone Labs data shows single-digit wear metals...I'm on the fence about adding Torco MPZ.

 

ok....pulled the covers and check each pr, rocker, and spring...all seemed good with no play. So I backed off the screws and retorqued the rocker to 10ft lbs....bumped started the motor a few times and rechecked at 10ft lbs. Then bumped the motor again and retorqued to 15ft lbs. I believe 22ft lbs is recommended by will try and run at 15lbs for a few miles to see if the sounds changes and update tomorrow.

 

So I put everything back together with the rockers torqued to 15ft lbs and the car ran great.......could not duplicate the tapping. Didn't go full throttle at all but got at least 50% and above 3k rpms several times with no problems. So I will let the car cool and retorque to 22ft lbs and test drive. Any ideas if the car runs fine what might have happened and do you think it is safe to go have dyno tuned? If not save yet how many miles or how hard should I get on it without a good tune? TIA

 

Dang it!! Came back after driving for about 20 mins and am leaning more towards bad lifter. The sound seems to be coming from the back center of the intake so I will be pulling the heads tomorrow.

 

never soak your lifters...its impossible to correctly set lifter preload when the lifters are totally pumped up.

 

Update to tapping thread.....finally got everything a part and noticed the #8 lifter would not come out even when using a magnet. It actually took a pair of pliers to loosen it before I could get it out. Looked at the cam lobe and found no damage. However, looking at the #1 cam lobe and I do have some damage.....seems like the lifter was spinning in the tray. This is the only lobe that shows any damage, with new lifters is this cam still usable???

 

That doesn't look reusable. Can you possibly get your finger down there and see if the scratches catch your finger nail? From the pictures I'd have to say not reusable.

 

Can get my finger down and it does catch my nail, but the score seems to run parallel to the lobe. So that being said and roller lifters am I ok?

Didn't want to spend money for another cam, but if I have to can I get a cam spec for one that has the rpm range of tr224 .563 114 (1700-6400),flat torque curve, more lope,and make a little more power?

 

I'd go with a new cam... Personally, I'd rather spend the extra bucks for a new cam and put it in now rather than run the damaged one and have to build a whole new motor later on down the line.

 

man that sucks

 

Used roller cams are USUALLY ok to reuse, but with the looks of yours I would replace or upgrade. I wouldn't take a chance on having to do the work twice. Dean.