spudz

Ok me an a buddy installed a z303 cam in his 92 5.0. Stock heads, stock bottom end... YEAH YEAH YEAH, I KNOW this is TOO big of a cam for a stock motor.. It doesn't matter... We just want it to run for now... So please don't give me any gripe about it.... ITs just there for now. Anyways... we installed it. And after install, we checked to see if there were any piston to valve probs and there wern't so he cranked it. LOTS of valve train noise. SO it looks like it needs longer push rods???? My question is now.......ONCE we get longer push rods... Is he goin to have a prob with piston to valve??? Becasue its not hitting now, but with longer pushrods we don't know... See we checked the piston to valve with the stock push rods that seem to short now... ANYONE HAVE ANY EXPERIENCE WITH THIS????

Grimace5.0

Just out of curiosity, why do you think it needs different pushrods?

wildcobrar

Given the E303 cam runs very tight with minimal piston to valve clearance with 220 degrees duration @ .050 and 1.7 rockers making it around .530 lift I would say you have big troubles. The Z303 has more duration hanging the valves open longer (228 Degrees @ .050) and more lift .552 you are more than likely hitting the pistons and valves together. You also must consider that the cam is on the same base circle so you should not have push rod length trouble. You may want to investigate a little further as to what to noise is. Not trying to be a bad messenger here but I don't like what I see given I have built a great deal of performance engines.

wildcobrar

If you don't mind me asking. How much piston to valev clearance in Thousands of an inch did you have?

spudz

I read the specs for the z303 cam on a web site that sells them and it even said that it would need longer push rods... SO it MUST not be on the same base circle... Also it has 1.6s on it and not 1.7s... ITS NOT currently hitting the piston.. The valve train noise is just that.. It looks like there is .050 to mush lash in the valve train... My question is IF I get the correct length push rods... is it THEN goin to hit the pistons???

spudz

y are I read the specs for the z303 cam on a web site that sells them and it even said that it would need longer push rods... SO it MUST not be on the same base circle... Also it has 1.6s on it and not 1.7s... ITS NOT currently hitting the piston.. The valve train noise is just that.. It looks like there is .050 to mush lash in the valve train... My question is IF I get the correct length push rods... is it THEN goin to hit the pistons???

tchamber

It's possible that you need to shim your rockers. Cams don't usually require diff rods, it's usually the heads. If they said you needed diff pushrods, it most likely meant hardened, not longer. And the cam IS on the same base circle, as the cam bearings are the same! How long did you run the engine before you turned it off? Did you prime the oil pump? Over/under torque the rocker arms?

spudz

Go here and under NOTES read #5 http://www.fordracingparts.com/parts...tKeyField=2969

wildcobrar

I won't argue the smaller base circle till I look it up. But if your push rods were .050 too short, how did you check the P to V clearance with all that slack?

The E303 cam has .498 lift with 1.6 rockers and .529 with 1.7 rockers. The Z303 has .552 with 1.6 rockers and 8 degrees more duration so it is going to be very very close. I had just enough with 8 degrees less duration with .023 thous less lift. If you have it in there and it works than great!!!! What was you piston to valve clearance in thousands of an inch? Just curious so I know a cam like that may work on a future build for a client.

I have the FRPP catalogue in front of me and it nothing about a smaller base circle on any of the 6 footnotes. I will take a peak at the link though. Yes foot note #5 says requires vale spring pressure of 120# on the seat and 340 open and may require longer push rods. It says nothing of a smaller base circle. I don't think it has because it would not be of any bennefit to do so on that cam. The X303 has lift within .010 thous of the Z303 and it has no mention of base circle or other requirements. Though you never know with Ford.

Grimace5.0

What "stock" pistons are in this thing? The ones with the dish? or ones with valve reliefs?