what caused hydraulic lifters to fail?

[bender235]

I am putting new heads and lifters in my 305. Beacuse of a loud tapping coming from the motor. I asked around and deduced lifter failure is the culprit. Replacing heads because I got it all apart and might as well and to eliminate future problems. So now I am wondering why the lifters failed (about 4-6 so it seems) and what caused their failure. Also how do I tell if it is failed? I am worried about the cam and oil pressure. Is the cam toast?, Is the oil pump that was replaced less than 3000 miles ago faulty? By the way my oil pressure gauge shows 0 until a load is placed on the motor and even then it slowly rises only a qaurter of the way up. The loud tapping started 1/4 tank through a full tank of gas with engine treatment for loosening build up in it. I parked it after driving about 10 miles to get home.

[graymarki]

On all the small block chevy engines that I have rebuilt, Everyone that had lifter problems were caused by dirty oil. Hydraulic lifters are machined so closely that just that smallest amount of dirt will cause them to jam in their cylinders. Everytime I rebuild an engine, the first thing I do is dissasemble the lifters, soak them in a good carb cleaner, or laquer thinner, air dry them, coat the parts with a light oil (3-in one) and reassemble them. I make absolutely certain that I prime the lifters with oil before I insert them back into the engine. Preparation is the key to a successful rebuild. I also take an old gutted distributor and prime the engine before the intial startup. I coat the shit out of every movable part in the engine with lubraplate, or engine assembly lube. I prefer the lubraplate because it seems to stick better and we used it for years in the tank engine rebuilds in the USMC. Don't rely on just engine oil to break in your cam or lifters. Then prior to startup, I disconnect the coil and crank the engine to build up the oil pressure. If your installing a new cam and lifters, let the engine run at least 1000 rpms for 10 or 15 minutes to allow for break in. Don't let it lope at low idle, or the oil won't have a chance to flow up to the heads causing premature failure of the lifters & cam due to lack of lubrication. I recently installed a corvette L82 in my 79 Elky and i had to run the engine for twenty minutes before all the lifters stopped making noise.

graymarki

[graymarki]

Using so called engine treatments is not only a waste of money, but is damaging to your engine. The first thing these treatments do is break down the oil viscosity and flush the crap to circulate thru the engine. They all contain whats called Petroleum distillets. Hope I spelled that right. Anyway they contain components that will destroy your bearings and cause your oil pressure to drop, usually to a point where you will have to rebuild your engine. Let's face it, there are no miracle cures, all this crap they sell whether it's for your engine or transmission simply just don't work. If your oil pressure is low, it's usually caused by worn bearings, a clogged oil pump screen, worn oil pump, etc. If your tranny is slipping, then it's the bands that are worn, none of this stuff is going to improve the condition, regardless of the claims by the company producing this crap. I had the opportunity to work with a company a few years back that did extensive research on "DuraLube" and found that it did nothing more than just using regular oil in your engine. After that, the Feds made the company remove all the claims on their bottles and their sales went down the drain. You can use 20w50 oil, Motor Honey, or STP to raise your oil pressure, but it's simply a temporary cure.
Just change your oil and filter frequently and you won't have these problems.

graymarki

[bender235]

my block is shot. cam valley and heads full of sludge. worn main and rod bearings causing low oil pressure. looking for a shor block. thanks for the info