Re-buil Issue help please

ZeroG84

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I have a 95 mustang 5.0. Before the rebuild it had a 70mm throttle body, long tube headers, high flow cats and a cold air intake.

I started burning too much coolant so did a rebuild. For the rebuild I added the following mods:
96 explorer gt40 heads (3bar)
96 explorer upper and lower intake manifolds
Comp cams 987-16 valve springs
FRPP F303 cam
Under drive pulleys
Prom-m 75mm MAF
All new engine gaskets

The first time I turned the car over and warmed it up the rockers sounded a little loose after a 5 min drive, which it also had horrible pickup at low rpms. I parked it overnight and started it up in the morning and it had a horrible valve train noise. When I took the top end apart and got the valve covers off, 13/16 rods were bent, 1 rocker broke and 3 had the push rods inside the rocker arm head.

I followed the valve lash procedure for TDC at each cylinder in firing order and thought everything was good.

Any ideas? Please help. I have another set of stock stamped rockers and push rods.....
 

ZeroG84

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I have a 95 mustang 5.0. Before the rebuild it had a 70mm throttle body, long tube headers, high flow cats and a cold air intake.

I started burning too much coolant so did a rebuild. For the rebuild I added the following mods:
96 explorer gt40 heads (3bar)
96 explorer upper and lower intake manifolds
Comp cams 987-16 valve springs
FRPP F303 cam
Under drive pulleys
Prom-m 75mm MAF
All new engine gaskets

The first time I turned the car over and warmed it up the rockers sounded a little loose after a 5 min drive, which it also had horrible pickup at low rpms. I parked it overnight and started it up in the morning and it had a horrible valve train noise. When I took the top end apart and got the valve covers off, 13/16 rods were bent, 1 rocker broke and 3 had the push rods inside the rocker arm head.

I followed the valve lash procedure for TDC at each cylinder in firing order and thought everything was good.

Any ideas? Please help. I have another set of stock stamped rockers and push rods.....
I also installed the cam and balancer at 0 degrees timing eith the cam pin straight down and the crankshaft lip straight up and installed the timing chain (new comp cams one) in that setup....
 

evilcw311

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I’d be curious to take a measurement and see if different length pushrods were needed. Up to the b303 isn’t a big change. But the f303 is a larger cam and I believe it has more lift. Anytime changing heads and cam to a totally different setup it’s best to take a measurement


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evilcw311

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Shorter. I’d have to search to find which one is best.


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50HSN95

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Were the lifters new? Also stock stamped rockers or aftermarket that were in the motor? I seen you had a spare stock set but not sure what was in the motor.

Anytime you are putting a new stick in you should be measuring for push rod length. One never knows if the heads have had material taken off of the surface or what type of machine work they have had. With a new bump stick also (and this is a personal thing) I would look at new lifters as not knowing the age or condition and going with a higher lift cam I just again personally would be replacing them, cheap insurance.

Do you know what the seat closed and open pressure is on the springs? Just a few things to look at that may assist in narrowing down the problem. I know the cam has been around forever but as every motor is slightly different, good to look at everything involved to see where the problem may lie.
 

ZeroG84

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Were the lifters new? Also stock stamped rockers or aftermarket that were in the motor? I seen you had a spare stock set but not sure what was in the motor.

Anytime you are putting a new stick in you should be measuring for push rod length. One never knows if the heads have had material taken off of the surface or what type of machine work they have had. With a new bump stick also (and this is a personal thing) I would look at new lifters as not knowing the age or condition and going with a higher lift cam I just again personally would be replacing them, cheap insurance.

Do you know what the seat closed and open pressure is on the springs? Just a few things to look at that may assist in narrowing down the problem. I know the cam has been around forever but as every motor is slightly different, good to look at everything involved to see where the problem may lie.
Thank you for the reply. The heads I pulled from the junkyard and cleaned up they don't appear to have any machining work at all. I pulled them myself. The lifters are stock originals and the rockers prior and rods prior were stock as well. I didn't check length b/c all i have read before was they will work with stock lifters rods and rockers. That was my first mistake. The springs are 130 seat pressure and 385 open pressure. I checked the installed height and all appear to be within .05 cm of the 4.45 required (1.8 inches) with valves closed... The heads were not milled nor the spring seats or the head itself. The pistons are stock notched piston heads. I'm attaching pictures of the aftermath.
 

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ZeroG84

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Thank you for the reply. The heads I pulled fron the junkyard and cleaned up they dont appear to have any machining work at all. I pulled them myself. The lifters are stock originals and the rockers prior and rods prior were stock as well. I didnt check length bc alk i ahd read before was they will work with stock lifters rods and rockers. That was my first mistake. The springs are 130 seat pressure and 385 open pressure. I checked the ibstalled height and all appear to be within .05 cms of the 4.45 require (1.8 inches) with valves closed... The heads were not milled for the spring seats or the head itself. The pistons are stock notched piston heads. Im attaching pictures of the aftermath.
 

95opal

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I wouldnt run stock spring with that cam. Trick flow makes a set to use with that set up. You'll also have to measure for proper length pushrods.
Comp cams makes a nice checker and grab a solid lifter to use to measure.
 
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ZeroG84

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I wouldnt run stock spring with that cam. Trick flow makes a set to use with that set up. You'll also have to measure for proper length pushrods.
Om cams makes a nice checker and grab a solid lifter to use to measure.
Just got the trick flow springs kit today. Good info for the rod checker
 

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