'71 F-100 360 4V

I installed an Edelbrock Performer-Plus cam & lifter kit. Started engine and followed directions for break-in. Drove to work and back (46 miles) for two days and the truck ran great. The third day on the way home, I stopped at a light and when I went to take off, the engine popped through the carb and exhaust and then sputtered like a broken valve spring. Towed home and pulled the valve covers to find two springs that looked as if they were broken. But when I removed the rocker rail, they came right up and looked fine- not broken or even distorted.

Then- I pulled the lifters to bleed the oil out to check for proper valve lash and two lifters- different from the ones that had caused the valves to stay open- were beat to death by the cam (LITERALLY). One even had a hole that broke out of the bottom.

What do you guys think happened to cause the cam to eat two lifters and cause two different valves to hang open?

THANKS-

Joe

 

I'm afraid the worst may have happened my friend. From what you are saying I think your valves have hit the pistons. Definitely time to pull the heads at a minimum. Wait a sec... did the valve all of a sudden pop up when the rocker shafts were removed or did they come up with the rocker. Some springs will be slightly compressed when the engine just setting there.

 

The valves weren't stuck- as I unbolted the rocker rail, they came right up as the pressure was being relieved. I don't have a clue as to why the lifters would pump up that far under normal driving. What bothers me the most is the lifters that got chewed up. Are Edelbrock lifters that soft?

Joe

 

Edelbrock cams have a bad rep for lobes going flat. I would go with cranes 343901 cam. It should make you happy if you like the edel cam before it went. How exactly did you break it in? Are your heads milled? Do you have adjustable rockers? I don't know if the base circle on the edel cam is the same as stock.

 

Their directions stated not to allow the engine to run under 1500 rpm for the first hour. The neighbors threw rocks at me while I did this!
Everything else is stock except for the 4bbl, of course (iron Ford intake- nothing fancy with a Holley 600cfm).

I did in fact inspect the cam and all the lobes looked (and felt) just as rough (slightly rough) as the lobes that ate the lifters. I figured the cam wasn't through polishing out so I installed new Sealed Power lifters from O'Reilly's and away we went for another hour. It runs great- the two lobes that ate the lifters were in fact for the exhaust valves so I'm not concerned with a small amount of wear since they are a higher lift that the intake.

So you think that after only a few days of run time that the Edelbrock cam is turning to pudding? The cost of the cam doesn't concern me as much as the amount of time it takes to pull it. But DAMN, I'm getting good at it. (I need some more aspirin!!!)

Joe

 

One thing we should really know is how much lift does the cam produce? How much spring seat pressure. I found that when I put a good lift cam in I was bending push rods. My valve seat pressure was at approx. 200 pounds which is too much for a hyd cam. So I had my springs reset up. I also added adj. rockers.

 

Lift at cam: intake- .265" exhaust- .280"
Lift at valve: intake- .460" exhaust- .480"

Edelbrock recommended the use of stock springs or their Sure Seat Valve Springs with a stock ratio rocker arm, so I opted to keep my stock springs and rocker arms.

Joe

 

Mine were stock springs also. Still a good IDEA to check the seat pressure. High spring pressure is very hard on a cam. It cheap Insurance.

 

>Mine were stock springs also. Still a good IDEA to check the
>seat pressure. High spring pressure is very hard on a cam.
>It cheap Insurance.

Is that something that can be figured out through a mathematical formula or is that something that requires a trip to the machine shop?

Joe

 

Thats something you can do with the heads on the engine. What you need to do is get ahold of a valve spring pressure tool. Remove rocker arms and check the spring pressure on each spring. I some has rebuilt the heads and installed too much spring shims it will cause high seat pressure.

 

Hopefully I won't have any more problems but if I do, I'll look at getting my hands on one of those tools. At any rate, I still have my stock cam so if the Edelbrock finishes it's self-destruct mode, the stock cam will be going back in until I can get my hands on a Crane.

Thanks fellas for all your insight.

Joe

 

Little more info on cams. Once a cam has wiped a lifter the lobe is going to be wiped too. This doesn't just mean that the lift on that lobe will be smaller. When you engine is running the properly broken in lifters are spinning on top of the cam because the cam is ground to make them do this. You're flattened cam will have to be replaced or you will just continue to get metal shavings into your other parts. Sorry man the cam is shot. Your old cam should work fine if you had the lifters organized when you pulled it out. If you start mixing the lifters up it is almost certain that the same thing will happen to your stock cam.

 

Darn the bad luck- I guess I better go to the store and get some more aspirin.

Joe

 

Hey guys-

You've been a great help on this one. Just have one more question.

I'll be installing my original cam until I can lay hands on a Crane (why didn't I do this before?!?!?!). Any way, do you guys think it would be a good idea to advance the stock cam or just set it straight up. I didn't have this option before as I now have a 3 key crank gear.

Thanks again-

Joe