99 cobra

Sup guys,

Me and a couple of my friends just rebuilt a 5.0 mustang. Everything worked fine. We started her up and it worked fine for 20secs and heard a rattling noise. We turned her off and started to pull parts of it. We found out that the push rods are bending. So we thought maybe the old ones were just too old. Bought brand new ones and they did the same. We are trying to look for titianium ones but we can't find them. Can someone tell me why the rods are bending? thanks for the help
By the way he put in new valve springs that are comp. Its has a big spring inside that a medium spring and inside that a small spring. 3 layer springs

99 cobra

99 cobra

or not

99 cobra

nhdungeonracer

Did you check for piston to valve clearance while putting it together?
Did you check the cam timing?

TheGmKiller331

Clay them pistons if this is a radical cam.That rattling noise was most likely the sound of valves kissing the pistons.In fact im almost able to guarantee it.Pull the heads off and im betting you see it.

99 cobra

what do you mean clay them pistons if its a radical cam?



99 cobra

JustinBHR

put clay on the pistons, and rotate the engine. the valves will leave an imprint in the clay.

99 cobra

And that would show what? Sorry but i never heard of this before.

99 cobra

99 cobra

for some reason though the rods are also loose. Even when we torque the rocker arms the rods move side to side. the cam he put in has a .498 lift. any comments


99 cobra

Milky

How much duration? Any reliefs in the pistons? What size valves?

acidman2

Hey dude, did you use a stock camshaft or an aftermarket one??? if you used an aftermarket cam with a higher lift your valves may be hitting your pistons when you turn your engine over.. he said to clay your pistons. this means you put model clay on top of the pistons with the heads on and everything put together and rotate the engine with a socket and ratchet. then remove the heads and see how thick the area is where the valve mashed the clay. if they squish the clay flat you dont have enough piston to valve clearance and will have to correct the problem or you will bust a piston, bend a valve(s), or bend pushrods, or all three. if you used a stock cam, your cam timing may be off and the valves can hit the pistons then too. anyhow, i've rattled off enough now.. later.