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Old 04-12-2003, 10:48 AM
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Post 351M Cam Problem

My buddy had a 351M sitting in his back shed for a long time, and finally instead of selling it, he gave up and gave it to me.
I love rebuilding engines, so i was happy in another project to work on.
So i tore it completely down, and heres the puzzling part.
Ive never seen this before, and i just wanted to know how it happened, or couldve happened. When i pulled out the camshaft, i only pulled out 3/4 of it, the other half was stil inside!!
How does a camshaft snap directly in half, twist the camshaft at such an angle that it took some prying and pulling to get out, and spin all the cam bearings????

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Old 04-12-2003, 03:46 PM
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Sounds like somebody ran this baby with a bad oil pump or drive,plugged filter or no oil for a while, NO LUBE, thats what spins cam bearings, they weld to the cam, then after spinning,they do a friction weld to the block, the cam breaks at the weakest point and the engine gets real sick, fast!
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Old 04-13-2003, 07:30 AM
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yeah cams do break on occation, ive seen it on an aluminum buick 215 as to why it heppens... i guess its just one of the joys of toying with 30 year old Detriot iron.

Gut bobcrman hit one of the cleveland/modified block´s problems right on. namely a weak oiling system. the fix is Cheap easy and VERY important, installing oil restrictors limiting the flow of oil to the heads and giveing priority oiling to the bottom end, the restrictors are 14$ from jegs and take 2 minutes to install in a disassembled engine.
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Old 04-13-2003, 12:53 PM
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I WOULD LIKE THANK DEUCE 454(2532)FOR THE INFO. ON 351C OILING SYSTEMS-I WAS WONDERING IF YOU WOULD BE WILLING TO ELABORATE ON THIS A LITTLE SUCH AS WHATS INVOLVED IN INSTALLING THESE RESTRICTORS-I CURRANT HAVE TWO OF THESE ENGINES THAT SHOW SINES OF THIS PROBLEM.OIL PRESS LOOKS FAIRLY GOOD AT HIGHWAY SPEEDS BUT DROPS TO NEAR "0"AT IDLE.THANKS.
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Old 04-13-2003, 01:00 PM
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COMING HOME FROM oklamoha i heard a funny noise in my dodge colt's engine. kept running but it just had a little extra noise goin on. some months later the engine let go outside of oakland. looked at the engine and only the first half of the rockers were moving, the rest were just sittin there. so, to answer your first question: yes. i figure it fractured when i heard the funny noise and it held together pretty long before cracking in half. i could be wrong, but that's my take of it. could be the funny noise was something else cam related tho. took my aunt 2 hours to come 20 miles to pick us up.

btw, imho, the 351 is the biggest pile of **** engine ever built. use it for a boat anchor only. signed: former owner of a 351M and a 400M. phhooeey!

[ April 13, 2003: Message edited by: bullheimer ]</p>
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Old 04-19-2003, 10:16 AM
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The 351m-400 engines have gobs of potential. When the 400 was first introduced in '71 it had 9:1 compression and a 4bbl and produced 271hp. In '72, it had 8.2:1 and a 2bbl with 160hp. With the 4in stroke it had gobs of torque, even when they dropped the comp. ratio. It doesn't take much to bring it back to '71 specs or better. The result is a very powerful motor that is very durable. The 351M is the same motor with a 3.5in stroke and taller pistons. It is more difficult to get horsepower out of it because of a lack of shelf parts due to lack of demand. However, with a little research, either engine has the potential to be a great engine. Keep in mind, both engines came into production amidst a horde of government regulations. Also, everybody knows the power of the cleveland heads, and with stroking becoming more commonplace, the 400 seems the natural choice since it is already stroked and already has cleveland heads.
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Old 04-19-2003, 11:56 AM
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For Skyraider, the restrictors are easy to install....after the engine is down, you tap out the oil passages and screw the restrictors in, do extensive cleaning afterward. I don't think your problem is that though, it's primarily for high rpm racing applications and is just extra insurance on a street car. I've run these engines since the early seventies and have never had an oiling system problem, I did once have a name brand oil filter that had a bad bypass or was restricted and after changing the filter and oil noticed that the pressure was extremely low. Since it had been fine prior to the change I decided to try another filter (at first I thought because it was a high mileage engine that some crap had dislodged and was plugging the pick-up) and all returned to normal, and the engine still lives with someone else.

[ April 20, 2003: Message edited by: woodz428 ]</p>
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