I've been having problems with an engine. The previous owner installed a bigger cam in it, it ran good when first purchased, hard and fast. The car has like 170,000 miles on it and the only thing rebuilt is the engine, I'm pretty sure the tranny has not. I'll be honest I drove it hard and after a while of doing that it seemed like it started loosing power more and more, it wouldn't accelerate as fast as it originaly did when the gas was nailed. Now it seems like it's missing too, and when taken above 65 like when I've had it on the freeway it starts to backfire, and loud, scared the hell out of me once. When it started running crappy once I had it on the freeway and it didn't feel right and then all of a sudden the engine seemed to just give out and a loud knock could be heard from the engine compartment, didn't know what it was at the time. Had it towed back home pulled the valve covers off and noticed that one of the rocker arms had shattered to pieces and on another the pushrod was bent. After replacing all rocker arms and push rods with new the same problem seemed to remain. I have no idea why it is running like crap, it ran hard when I first bought it but now it's not even worth riding in it.

By the way this is a ford 351 cleavland, I hate fords don't ask me why I even bought the damn thing it's been sitting like this for about 2 yrs. I just want to get it running good so I can get rid of it and put the money in my Camaro. I'm tempted to just scrap the thing but want to try and fix it first. There's no better place for a Ford then the car compacter! Do you guys have any ideas why it might be running like this?

Mark

 

So is there still a knock or just the sluggish feeling and the backfiring? The backfiring may just mean you need a tune up. Have you replaced the wires/plugs lately?

-Matt

 

Sounds to me like the guy who rebuilt it overtightened the valve lash and wore some of the cam lobes off. Your timing would have been all wacko at this point and some pushrods, rockers, valves etc... could get mashed.

Is it really worth resusitating another Ford?

 

Yes it still misses and backfires and all that. And yes it's had a tune up new plugs and wires also.

I really don't want to bring it back to life but could use the money on my Camaro.

 

judging by the sound of what you have with the miles and larger cam, you may be having a problem with the valve springs. i'm assuming the knocking noise you were referring too was the broken rocker arm. you may be experiencing valve float which would be the loss of power and what could have caused the broken rocker arm.

 

yes the knock was from the pushrod hitting the underside of the valve cover. I'm almost positive all the springs are new.

 

If it has SOLID LIFTERS they need to be re-adjusted all the damn time, especially with a radical cam. Check your valve lash, the rockers shouldnt be TIGHT AT ALL if they are SOLID LIFTERS in fact there should be a small space between the rocker and the spring... but how small? CHECK WITH A FEELER GUAGE dont try Doing it by eye it will get worse. if your not sure how to lash the valves using the feeler then call comp cams or crane or somthing and ask or check their website. if your not sure, SOLID or HYDROULIC, it cant hurt to give them LASH like SOLIDS and see how it runs, if it still run like crap, try adjusting them like hydroulics, if it still runs like crap, pull a lifter out see if they are dead or messed up if they are then your cam has died as well from neglect....
the problems you described can be attributed to a SOLID CAM with BAD VALVE LASH exactly.

 

the rocker arms in it are the pedestal style mounts, I've heard that these are not adjustable, is this true?

 

i have an idea.... Dig a big pit in you back yard an burry it. No realy it does sound like the valve lash was tightened to much.