I just traded for this car,it has a 73 340 with a hydraulic cam. When the car arrived and i started it it sounded like it was not pumping oil to the lifters. I went right away and put an oil pressure gauge on it. It has around 20lbs at idle and goes up to 40 with some throttle. I thought the lifters may be bad so i just installed a new set. And it is going the same thing. With the valve covers off it is shooting what seems to be plenty of oil in the rockers. The rockers do seem awful loose on the shaft, could they maybe be worn out and not letting the lifters pump up ? Thanks for any help here.

Did you oil soak and prime the new lifters prior to installing?

i soaked them in oil and stp mixture overnight

i soaked them in oil and stp mixture overnight

Did you prime them too? Typically I'll take a pushrod and prime them until they fill with oil and become solid. You'll see the air bubbles escaping if you do it while they are soaking. Even after I prime them I still let them oil soak for a couple days to make sure all the air has escaped.

if the rockers (both banks) are being fed then the horizontle main galleries & therefore the lifters (which are upstream) are being fed also. I'm assuming you did a cam breakin procedure when you dropped the new lifters (unrelated to the noise tho). Only thing coming to mind is, see what your preload is: get a lifter on base circle. Set a small thin 6" steel scale ruler across on the valve cover rails close to the pushrod. make a sharpie mark on the ruler edge & slide it over fast to make a witness mark on the pushrod. unbolt the rocker shaft evenly so it rises evenly (horizontally) till the pushrod JUST stops moving upward )if it goes sideways it'll skew your test). repeat a witness mark then remove the rocker shaft/rockers all the way off & lift out the pushrod & measure the distance between the two marks. you're sure nothing else is rubbing/touching correct & that it is lifter clatter? I wouldn't think the preload would be borderline not enough then something finally reduced it that last bit/locked it solid (in effect no preload). Holler how it turns out

I can take the rockers and on a few push in the lifters. Not all of them push in. but a few do like they don't pump up, and they are the same ones as the old ones in the same lifer bores. I can also wiggle the rocker arms on the shaft which i think is a way too much play.

I would bet that those rocker arms are a bit wallowed out, or there is possibly a mismatch of parts. (pushrods, lifters wrong etc.)

It`s possible you could have some bad new lifters. You do know that the exhaust and intake rockers are different. They can get them mixed up easily. Rockers are normally somewhat loose on the shaft. If you think they are worn bad, get one new one and compare to see. BTW, i never pump up the lifters prior to installation. I just quickly dip them in oil and put the break in lube on the base. Never had a issue. Also what did the bottoms of the old lifters look like? Worn?

Filling or priming hydraulic lifters is a great way to bend pushrods when installing the rocker assmblies, not so good a way to properly fill them though. If they aren't filling up from engine oil pressure then lack of priming or filling them isn't the problem.

I would take the soft lifters out, disassemble, clean and inspect them.

A lot of lifter suppliers are recommending not soaking new lifters and to install them out of the box. If the top of the engine is getting oil feed then here is what I have learned to do to help get lifters to pump up. It is messy but the vast majority of the time works. Run the engine with the valve cover off and put downward pressure on the pushrod end of the rocker. This helps the lifter bleed the air out and take a prime. Also some times all it takes is to run the engine and then shut it down and let sit for a few minutes, restart and the lifters have bled out and pump up on restart.

Thanks moparforlife i will try that.

Chrysler used some blocks with .008 O.S. lifter bores. They should be stamped with a diamond shaped mark on the lifter boss. If there is a standard diameter lifter in an oversize hole it'll fit like a brick in an ashcan. Check side play on the noisy ones.

I had a customers car 71 roadrunner with a 440 that had the same problem. Car came in with a blown head gasket and clacking away. Replaced the head gasket and reset lifter preload as the owner said he tried adjusting them. Rolling the engine by hand I would have loose lifters by the time I got the bank done. You could push the lifters down like slinkies!!! Finally got the to adjust fired the engine and it was noisy for about one minute and settled down. The customer took the car and ran it about three weeks and came back with same clacking and wanted to change the lifters. Changed the lifters and it ran good for about 5 miles and the ducks were back. Just couldn't get the lifters to hold a prime. The engine had about 500 miles on a complete rebuild that another shop did. Only thing I could come up with was the lifter bores had excessive play but the new lifters felt good in the bores. The owner parked the car and is planning to bring it back when he has the funds to open it back up. This one always puzzled me and I looking forward to getting it back to find the answer.

oh boy lifter bore sizes don,t sound good. thanks for that info

Phil, interesting topic! post what it ends up being

Have not messed with it ,am going out now to start work on it, I will let you know what i find out.

Sorry it has taken so long to get back, Latest thing i did was install new pushrods and adjustable rockers. Same clatter as before, so when I feel like it I am pulling the motor and install all new bearings and oil pump. And new cam and lifters, Hope for the best then.

You really need to determine what the EXACT problem, problems, are before throwing some more parts at it

Parts replacing may not fix it. you already did the lifters once. What is the most oil pressure it will make running?

Hoping will not fix it!

I just went through soomething similar on a 340 a guy brought in and found the caps out of the hole behind the cam thrust plate, it was driving us nuts because it was only one lifter and just at 800 or so idle then it would go away with reving it a bit. It had 12-15 PSI at idle and it has always been enough in other engines I have seen but this one just would not quit the ticking. The pressure would jump right on up to 70 with a few RPMs. After putting in the plugs it now holds 50PSI hot idle and zero ticking.