Lost Oil Pressure

[bushwackertn]

My son and I recently installed a new performance cam, valve springs, intake and carb on his jeep. After we ran the engine at 2000 rpm's to break the cam in, and got everything adjusted. He started running the jeep, after about 3 days he came home and said that he had lost all oil pressure. Well the first thing that I thought was the cam bearings had wore out. When we replaced the cam we didn't insall new bearings, so thats why I thought it was the bearings, so we started building a new 360 for his jeep. Well today we pulled the intake off the engine and what we then saw made it clear why there was no oil pressure, 2 broke pushrods and 2 lifters laying in the valley.

Just thought that I would share this with others to keep them from makeing the same mistake that I did.

[tufcj]

It happens. I've had it happen on a V-8 also. Bridged rocker bolt broke, allowed the pushrod to jump out, then the lifter came out. Instant 0 oil pressure.

Bob
tufcj

[bushwackertn]

Yep, this was a 360 that it happened in also. When we had the heads redone we installed new valve springs they were bought from Maddog. The springs were for a performance cam, maybe now we need to get some high performance push rods. 2 of them were broke and 1 is bent. Does anyone think that the stiffer springs is our problem?

[tufcj]

What kind of lift does the cam have? You could be getting a coil bind on the valve springs or the rockers are hitting the end of the slot if the lift is over .500 (at the valve). You could also have valve-piston interference, depending on which pistons, and what cam timing you're running. Pushrods usually don't bend unless something stops the valve from moving.

I usually buy valve springs matched to the cam. That way you know you have the right pressure and travel. I usually replace pushrods in a fresh motor, at $2 each, it's such a small fraction of the rebuild cost that it's just cheap insurance.

Bob
tufcj

[bushwackertn]

The cam is .488 int. and .488 exh. lift w/adv. dur. .287, I bought this cam and springs from Maddog Racing, I also bought new hardened push-rods and installed all of these together. However I did not use guide plates, I don't know really what guide plates are used for, I only know that allot of cams and rocker combo's. recmd. the use of them. As far as their purpose it don't know what they do. I think that they are used for a rad. cam grind they are used to keep the push rod aligned up with the rocker.
As far as pistons they are the fac. dish pistons, However we were running this cam -4 deg. for better low end, yesterday we changed that to 0 deg. or fac. setting. While putting the timing chain back on, the cam is very hard to turn with the push-rods installed, easy with-out them. I'm starting to think that these springs are way to much lb.age. Thinking that if we keep having this problem we will install the fac. springs, or get some that are not as strong such as the springs for the eldel. performer cam.
Unless you know something else to look for, how do I look for spring bind, is this when the spring coil's bottom out, and the push-rod is still coming up? I checked this yesterday and every thing looks O.K. But I could be missing something.

[tufcj]

Shouldn't be any problems with that lift/duration and stock pistons. Guide plates are only used to keep the pushrod and rocker in the correct alignment. With the bridged rockers, you don't need them because the base of the bridge keeps the rocker aligned. The springs may be too strong, but if you bought them all together, I'd think they would match them to the cam. Call Mad-Dog, ask for D.W. at ext. 113, he's their AMC guy. Verify that you have the right springs. Ususally the card that comes with the cam will have a recommended seated (valve closed) pressure and height for the springs. Check with the valve fully open that the spring retainer isn't hitting the valve guide. Don't know what else to suggest, except a set of hardened pushrods, and try again. Not over revving it and floating the valves, are you?

Bob
tufcj

[bushwackertn]

Got the problem fixed, as far as over reving it. No I wasn't, but what I did do was while installing the cam and lifters, was I retarded the timing 4 deg. I had read that this would give me better bottom end, well take my word for it, don't do that. You would be much better off timing it at 0 deg. or degree the cam in as it should be.
I recently timed it up at 0 and it is screaming now, it even runs better like this.