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Discussion Starter · #1 · (Edited)
I am doing a stock rebuild on a FE 390
using stock non-adjustable rockers 1.76 ratio
using original pushrod length 9.62"
Using hyd. lifters
installed a new cam .507 valve lift INT. + EXH.
I primed the motor - the lifters pumped up
I rolled it over and bam there went 10 pushrods.....
yes they were all seated properly when I installed the rocker assembly...


What did I do wrong?
 

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Discussion Starter · #2 ·
I just read this on another fourm....

Any thoughts on this pros / cons ???

Push rods

A couple of things to keep in mind
Typically hyd lifters have a compression distance of .030 to .060 inch's when the preload is set.
Now if you have adjustable rockers this is not a problem you just bring the rocker down to the rod and then give the adjuster one full turn. That will set the preload at about .040 which is good.
If you have nonadjustable rockers then you need to measure the distance when the whole rocker assembly is bolted down. Using a checker rod and then add .040 inch's to the length of the rod and that will set the pre load.
There is a factory way of checking the lifter preload that involves a special tool. (which I made one day) and then you collapse the lifter and measure the distance between the rocker and valve tip. I think it's something like .200" for a Ford lifter from back in the day. Or you could just order the rods and hope for the best.
But seriously it is very easy to make a checker rod. Take one of your rods you have now and saw it in half. Then saw an extra half or inch off one of the pieces. Get a 1/4" 20 tap and tap the two ends of the rod. Cut the head off a 1/4 20 bolt and screw them together. I've heard tell of solid rods in FE's but I have never actually had some and if I did I would toss them in the metal pile and get some light weight hollow ones which by the way are much stronger than a solid bar.
 

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That cam has more lift (and probably far different timing) than stock. Did you check for piston-to-valve clearance? Pushrods don't generally bend unless the valve hits something, whether your preload is set right or not.

The next issue is that you may have also damaged your valves. Remove your rocker shafts and pushrods, and do a leak-down test to verify your valves are all OK and sealing properly.

If all is fine, then start at the beginning, and verify the entire cam installation, using a degree wheel to check. If you're "lucky", you simply set the timing chain wrong, and you'll be fine. If it was all set-up correctly, you have interference, and either a different cam is required, or mods to your pistons for clearance.

Good luck!

David

PS: you can verify your lifter preload is correct during rocker shaft installation. The pushrods should have end-play between the lifters and rockers of closed cylinders until the rocker shaft bolts are 1/2 to 1-turn from seated.
 

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You may have installed your timing chain 180* out.... :( You may have it 50* out... :( You could have even forgot to put it in, but then nothing would turn :) :)

Something is definitely wrong. a 600 lift will not bend your FE pushrod unless the valve hit's something or the valve springs bind before max lift is reached....
 

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Discussion Starter · #6 ·
That cam has more lift (and probably far different timing) than stock. Did you check for piston-to-valve clearance? Pushrods don't generally bend unless the valve hits something, whether your preload is set right or not.

The next issue is that you may have also damaged your valves. Remove your rocker shafts and pushrods, and do a leak-down test to verify your valves are all OK and sealing properly.

If all is fine, then start at the beginning, and verify the entire cam installation, using a degree wheel to check. If you're "lucky", you simply set the timing chain wrong, and you'll be fine. If it was all set-up correctly, you have interference, and either a different cam is required, or mods to your pistons for clearance.

Good luck!

David

PS: you can verify your lifter preload is correct during rocker shaft installation. The pushrods should have end-play between the lifters and rockers of closed cylinders until the rocker shaft bolts are 1/2 to 1-turn from seated.
Timing chain was installed - dot to dot - I did not degree the cam...
Maybe I need to ?

prior to priming the motor for the first time, I had rolled the crank prob 30 times 360 deg's. with the valve train installed and had no problems of binding or anything.

I primed the motor and noticed I was not getting oil to the tips of the rockers but I was getting a boat load of oil up to the rocker shaft stand.
So I removed the rocker assemblies and disassembled them again and cleaned them again.

I re installed them and rolled the crank and that's when I bent the rods. The only thing that was different was that the lifters were now primed and I had little to no play in them. I took a pushrod and pushed it into the lifter and I could not get the lifter to budge.

I removed the rocker assemblies last night and I was going to make a pushrod checker, install the rocker shaft assemblies without the p rods and check each one with the rocker assemblies torqued down. I did not check valve to piston clearance as I assumed it would be fine running hyd lifters. error #1 im sure.

Do I need to buy a gauge for the leak down test? And instead of modifying the pistons cant I go with shorter p rods?

Here are the cam specs in the pic....
 

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Timing chain was installed - dot to dot - I did not degree the cam...
Maybe I need to ?

prior to priming the motor for the first time, I had rolled the crank prob 30 times 360 deg's. with the valve train installed and had no problems of binding or anything.

I primed the motor and noticed I was not getting oil to the tips of the rockers but I was getting a boat load of oil up to the rocker shaft stand.
So I removed the rocker assemblies and disassembled them again and cleaned them again.

I re installed them and rolled the crank and that's when I bent the rods. The only thing that was different was that the lifters were now primed and I had little to no play in them. I took a pushrod and pushed it into the lifter and I could not get the lifter to budge.

I removed the rocker assemblies last night and I was going to make a pushrod checker, install the rocker shaft assemblies without the p rods and check each one with the rocker assemblies torqued down. I did not check valve to piston clearance as I assumed it would be fine running hyd lifters. error #1 im sure.

Do I need to buy a gauge for the leak down test? And instead of modifying the pistons cant I go with shorter p rods?

Here are the cam specs in the pic....
cam and rocker ratio and valve reliefs/valve drop set the piston to valve clearence . push rod lenght does have an effect on lift.

changing p/r length if Not the fix
 

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cam and rocker ratio and valve reliefs/valve drop set the piston to valve clearence . push rod lenght does have an effect on lift.

changing p/r length if Not the fix
Thanks Dan, This area is not my forte at all but taking a stab in the dark. I learned something though. So now i have a question. What happens when all is correct and the PR is too long, just the valves don't open far enough or the valves hit the pistons or?

Sorry for butting in Krazn8.
 

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with adjustable rockers-stud or shaft to long of a push rod doesnt effect piston to valve clearance.

way to long of a push rod that moves/bottoms out the plunger on hyd's
when/if valve float- most likely piston contac. the same if hyd. lifters are pump up before being installed.
the problem is more on aftermarket cam's with greater duration

today hyd. lifters have the lifter seats about the same height. But Ford did have two oem different seat heights for the FE's
back in the 60's
 

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Discussion Starter · #12 ·
IMO it has to be timing .... or some wrong length pushrods..
There has to be a way to check my timing without taking the ballancer and front cover off. If I am at TDC on the compression stroke in #1 cylinder both valves are closed. So it would stand to reason that this places other valves in a certain location as well. Would it not?

Also, what if I primed the lifters so much that they have hydro lock since I did not rotate the crank as I primed. This put the lifters in a position that does not allow them to relax. then I rotated the system and that's when they bent.

1- Valve springs are not binding
2- Valves are not hitting the pistons
3- this motor is completely stock - nothing is different - other than the cam
 

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Discussion Starter · #14 ·
Even with hydro lock, your FE valves being open in the .060 area with the piston at tdc, it's not likely going to hit unless your piston ins up into your chamber too far...

good point - im learning
 

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Even with hydro lock, your FE valves being open in the .060 area with the piston at tdc, it's not likely going to hit unless your piston ins up into your chamber too far...
FE,what do you mean by- "your piston ins up into your chamber too far" ?
 

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Discussion Starter · #16 ·
IMO it has to be timing .... or some wrong length pushrods..
You had a good point on my other thread---

"What is the lift limit on FE non adjustable rockers"

Does anyone know?
 

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kranz IMO your at the point of needing to back up.

something is wrong.. you bent pushrods and 90% chance you bent valves.

pull the heads pull the front and start investigating.

measure the piston deck height, measure the cam(sure it wasnt miss boxed)
have the heads looked at (do it your self if your able)

measure lifters to be sure you got the right stuff

get a pushrod checker and recheck size.

something has to be wrong inside .... there is no easy way out from were your at ... al this is IMO
 

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Discussion Starter · #18 ·
kranz IMO your at the point of needing to back up.

something is wrong.. you bent pushrods and 90% chance you bent valves.

pull the heads pull the front and start investigating.

measure the piston deck height, measure the cam(sure it wasnt miss boxed)
have the heads looked at (do it your self if your able)

measure lifters to be sure you got the right stuff

get a pushrod checker and recheck size.

something has to be wrong inside .... there is no easy way out from were your at ... al this is IMO
10-4 - I'm on it....
 

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Discussion Starter · #19 ·
kranz IMO your at the point of needing to back up.

something is wrong.. you bent pushrods and 90% chance you bent valves.

pull the heads pull the front and start investigating.

measure the piston deck height, measure the cam(sure it wasnt miss boxed)
have the heads looked at (do it your self if your able)

measure lifters to be sure you got the right stuff

get a pushrod checker and recheck size.

something has to be wrong inside .... there is no easy way out from were your at ... al this is IMO
I will get the data and post my results on this thread when I am done..


Thanks again...

Nate
 

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There has to be a way to check my timing without taking the ballancer and front cover off. If I am at TDC on the compression stroke in #1 cylinder both valves are closed. So it would stand to reason that this places other valves in a certain location as well. Would it not?

Also, what if I primed the lifters so much that they have hydro lock since I did not rotate the crank as I primed. This put the lifters in a position that does not allow them to relax. then I rotated the system and that's when they bent.

1- Valve springs are not binding
2- Valves are not hitting the pistons
3- this motor is completely stock - nothing is different - other than the cam
for an idea where the cam timing is , with the rocker shaft off / push rod in place. turn engine over till the intake p/r just moves. read timing mark at damper.
spark plugs removed , makes it easy to turn over plus a long bar on socket.
got a dial gage on p/r , can check the .050" lift to damper reading .
find pub. spec's to cam.
can do the check also by exhaust closing foor a closer idea
 
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