I have a 4.7 with 100,000 miles and the valve train starts rattling like the lifters are losing prime, and will throw off a rocker arm. I have replaced all the lifters, valve springs, rocker arms, and oil pump with the regulator. The engine is clean and free of sludge. The parts used in the replacement are all OEM. About every 300 miles its throwing a rocker, and rattles on start up about 1 in 10 starts. Any idea's? The truck is a 2002 2wd Ram 1500.

Terry
whop86@yahoo.com

 

Sounds like your cam lobes are shot. How does the truck run otherwise?

If the lobes aren't within spec, they don't retain proper tension on the rocker arms, however, you say you replaced them so that would mean you had them tightened to spec again????hhmmmm...
You check all your push rods and make sure they are not bent at all?

 

If you replaced the followers and lash adjusters then the only other thing I can think of would be the cams... are they worn? I find it hard to beleive they would be... but hey something is clearly wrong.

What weight oil are you useing?

I would have the spring compression height checked to make sure its giving enough seat pressure when closed.

Im sure stepping up to a stiffer spring may help eliminate your issue as well.

What cams are you running? Are they stock? Are they an aftermarket cam? If they are a regrind then you should have lash caps on top of the valves. They are used to make up for the meterial removed from the cams when re-ground.

Keep us posted.

SPEED SAFE, AIR RAM






The 4.7L does not have push rods. The Followers ride the cams so when installed everything is fixed... non adjustable.

SPEED SAFE, AIR RAM

 

The cams are stock and good condition, I replaced the valve springs also. I have a manual oil pressure gage at the sender port next to the oil pump, and have been starting while watching what the oil pressure does. I happened again this morning. The oil pressure is fine, but all the valve train started rattling. Sounds like all the lifters loose oil pressure for about 15 seconds, and with the valve train loose, the rocker arms pop off the lifter. I even replaced the lifters a second time with OEM which didn't help.
One of the posts asked if the pushrods are bent, this engine has no push rods, it has overhead cams and the rockers ride right on the cam with the lifters holding tension on the rocker arm keeping them in place. I am using conventional 10w30 motor oil.

 

You are losing pressure. Is this briefly or consistent? Maybe your pick-up screen is getting clogged?

 

what type oil filter are you using? If a filter has a bad anti drain back valve in it it will allow all the oil in the oil passages to drain back into the pan. The net result would be a "dry start" and valve train gear are the last to get oil, so they rattle when this happens.

 

I was thinking the same thing

 

sniff...sniff....FRAM??...lol

 

I have been running the FRAM HP-1 for over 120,000 Wide Open Throttle miles... I have never had an issue... Some people get caught up in the hype, if FRAM was really such a crappy filter, then they would have gone out of business long ago.

This last oil change I went with a cleanable / re-useable PURE POWER filter. Hands down the best oil filter money can buy.

SPEED SAFE, AIR RAM

 

have you looked into the fact that your valves might be sticking (in the guides) on cold starts?

you can't answer this because we can't see the valves, but is their lots of carbon build up and olefins on the valve stems? olefins are present in cheap gas. cheap gas is defined as: having the epa required minimum detergent. olefins are sticky when cold.

have you owned this truck since new? and what is the history? short trips etc????