73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Longshot379 on April 01, 2010, 07:56:53 pm
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I have a 74 c15 with a stock 454/TH400 that keeps eating camshafts. Number 8 both lobes are gone along with 3 or 4 others. This cam has app. 10,000 miles on it over 10 years. Is there anything particular to these engines to cause this? What do I need to look for before I put it back together?
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BB can eat cams I dont know of any way to solve this but have heard of it often. Hopefully someone has a solution like reboring the cam hole in the block with new bearings.
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You using good oil?
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Valvoline 30HD
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Has the engine wiped more than 1 cam?
Maybe the cam was not broken in properly?
There are many things that can wipe a cam. Most common are oiling problems. But it could also be a valve spring problem. When you put it back together make sure you are getting oil out of the push rods. You can get an adapter to run the oil pump off of a drill motor to check that.
You might also want to check you spring pressure and make sure it is with in spec of what your cam requires.
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As far as I know Stock cam with stock springs. When I replaced the cam 10 years ago it was with a stock replacement cam. If anything the springs are probably weak. Up until I changed the intake about a month ago it ran as smooth as glass(never took the valve covers off), then valves started to rattle and started popping back thru carb. Adjusted valves(Oil coming out of push rods) and noticed some were not moving as far as others. I would get valves to be quiet and then almost immediately they start to rattle again. Pulled the engine down today and could find nothing out of place. Bearings all appear to be in place and have normal even wear.
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when you did the engien the first time. were the oil galley for the lifter bore throughly cleaned prior to assemble?
were the plugs for the galleys pulled and cleaned out?
there are also plugs for the mains as well.
one thing you could try is get a oil pump driver pull al lthe lifters and run the drill. then slowly install the lifters as you flush the galleys
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All of that metal particulate will plug up the oil galleries. The GEN IV BB engines love to eat cams if they sit for long periods of time too. A good solution is a prelube system if it does sit for long periods of time to avoid those dry starts. The other is a good high zinc multi viscosity oil. As far as your current situation make sure the oil galleries are all clear and the cam bearings are properly aligned. A roller cam retrofit is another great option but very pricey.
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Just as Vile mentioned its getting tough to run flat tappets these days. There are just not enough Zinc in them. I have heard that Valvoline VR racing oil and the 15W40 diesel oils still have zinc in them.
You can also have your machine shop groove the lifters to supply additional oil to the cam. Hard faced lifters are another option but pricey.
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I think Vile has gotten it. The truck sat for a while before the first cam went and then it sat for almost 8 yrs the second time. I have just gotten it back out on the road in the last couple of months. As far as oil is concerned, I was looking at Valvoline's Fleet Guard oil today and on the label it said it protected cams and lifters. I was also wondering about synthetics. Would they be a possible solution.
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Do your motor oils contain zinc and phosphorous?
Yes. All Royal Purple engine oils contain the zinc/phosphorous compound zinc dialkyl dithiophosphate (ZDDP) and are suitable for both roller and flat tappet valve trains.
http://www.royalpurple.com/index.php
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Now it does sound like your problem is from sitting. Like Vile said, get a pre lube system. This will pre lube your engine after is has sat for a long time. Most likely your problem is that the cam isn't getting enough oil at start up after sitting for years. Or maybe next time the truck sits for an extended period just unplug your distributor and turn the engine over for a minute to prime the engine before you start it.