lifter tap after cam install.......need help

First off my trucks got 150000 miles on it and i just installed a new tsp224r cam, 7.4 pushrods, comp 918 springs, new factory timing chain, and factory oil pump. I ve put about 400 miles on the new cam.

It started a few days ago a started my truck in the morning, cranked fine just a little tap from the stiffer springs like normal, let it warm up for about 5 to 10 minutes then headed off to work(about 8 miles) just befor i got to work it started tap pretty good, pulled in the parking lot at work let it sit and idle for a few minutes and it never quit tapping. let it sit till i drove it back home for lunch didnt have any problems, then let it sit till i had to go to school at 5:30, cranked it after class, everything was fine, but on my way home i stopped and got somethin from the hamburger joint and it started again, sitting in the parking lot it never quit for like 5 minutes pulled back on the hwy got going and it quit.

im thinking my lifters might be getting clogged up due to the miles on the truck and with the new srpings and the cam they just cant keep up
i going to run some bg cleaner through the motor and change my oil tomorrow and see if that helps.

im interested to know the answer to this...

The LS motors seem to have a tapping noise with aftermarket cams due to the fast ramp rates of the cam. I've heard people say they have the sewing machine type noise to them after a cam install. It seems to be normal.

Hopefully someone will chime in that can give you a better answer but that's what I have heard.

I installed a GM p/n 12561721 camshaft in my 4.8L a while bad to replace the factory camshaft. The original one ended up chewing a lifter and a lobe all to pieces. That being said, after installing it, the valve train was making plenty of noise. Unfortunately, i later found that the company that did the valve job on my cylinder heads did not grind the valve stems back down after cutting the seats which resulted in a greater installed height at the rocker tip. and this turned into a higher preload on my lifters. And it was tapping...a lot. So i went with shorter pushrods. That pretty much took care of the problem. I did replace all of the lifters though.

I can tell you that with 150k miles, those lifters probably have a whole lot of wear in them and they are probably full of carbon deposits from old oil. And therefore they are probably sticking. If that werent bad enough, the base circle on that cam shaft may be different from the stock profile which will make all sorts of noise of clearance issues. You can have too much or not enough.

I don't know the problem, but i'm offering what i have found that can cause this. At any rate. you ought to check the tip clearance on the rockers by rolling the engine around until each set of valves is completely closed and make sure each rocker tip will slide side to side on the valve tip. If you get one that doesn't move, you don't have enough clearance.

Did you center the oil pump correctly? Could be low pressure, or inadequate flow.

so i ran some bg engine cleaner through the motor tonight and i changed my oil and it still does the same thing. the thing thats confusing is it starts fine but after u drive it for a few miles it starts then after a few more miles it quits, but the engine runs fine when it does make the tapping noise, and my oil pressure is still good, 45psi at idle and 60psi crusin, i also run synthetic oil.

i just dont know what to do, i guess im going to be workin on it this weekend

so i went ahead with what molitor said a put new ls6 lifters in it and everything was goin good she wasent tapping anymore and the motor was even quieter but this past friday it started again and it did it yesterday too.

anymore thoughts on that?

Live with it bro. its pretty normal on a LS engine with a big cam.

no its not normal!!

pull the valve covers a spring could have broke, just to be on the safe side... yeah the sewing machine sound is usually there, reason being not set up correctly, BUT the tapping isnt, and never will be normal..



so a 224 isa big cam? and i thought a 25x/26x was a big cam ;) without any sewing machine issues or tapping :)

It still sounds like you have too much Pre-Load on your lifters. When that happens, the piston inside the lifter is too close to the bottom of the lifter pump bore and it ends up hitting because there isn't enough oil inside the lifter to overcome the force of the valve spring. The lifters are like really small hydraulic pumps with a really bad leak. Shorted pushrods may be the way to go in this case. -.025'' would probably be safe. Just be sure and check the contact of the rocker arm tips on the valve stems.