63dartman
Well-Known Member
Does anyone know if the mopar performance pushrods listed for the magnum swap on an la are hardened pushrods? They are 7.625 in length and part number is p5007477.
mopar performance pushrods?
- Thread starter 63dartman
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63dartman
Well-Known Member
Nevermind....Summit lists them as steel with no heat treatment. Maybe thats why they are not lasting. That and I'm a tad under on preload. I am Going to the hughes adjustable setup as soon as I can Force myself to part with the funds.
What combo do you have? Mike
moper
Well-Known Member
How are they failing?
goldduster318
Overzealous Car Modifier
I had them in my engine. they rubbed a little on casting flash I had to grind away, and two of them bent. They seemed a little flimsy (they are very light for being steel). I ended up buying the Summit Racing brand (Same as Comp) 7.650" length chrome moly pushrods and they are great. VERY high quality. I believe they are $63 for a set of 16.
moper
Well-Known Member
Ok. I thought it was the pushrods' fault. not clearance issues.
63dartman
Well-Known Member
I don't have clearance issues with the clear water castings. I think they may have slightly better clearance than the stock magnum heads. My problem is a combination of weak pushrods, minimal preload on the pushrods, too light of a valve spring.......a great combo for bent pushrods.
GoldDuster, The 7.65 work with stock non adjustable pedestal rockers? Not too much preload?
GoldDuster, The 7.65 work with stock non adjustable pedestal rockers? Not too much preload?
mopar340dave
Well-Known Member
You have magnum heads on a ???
63dartman
Well-Known Member
I have the clear water 360 magnum heads on a la 360 block.
mopar340dave
Well-Known Member
OK, you really need to make sure you buy the right length, regardless of which rockers you run. Do you know how to check pushrod length and rocker arm to valve alignment?
If not, read this**:
** anywhere in these instructions were I talk about adjustment or rocker shafts~~~you are not adjustable...ignore~~~~~~Rocker Shafts....you don't have em...ignore....replace with normal shop practices for rockers
If your engine is assembled already you need to remove all the pushrods (if they are in) and both sets of rockers (obviously) and the spark plugs should be removed.
If you only have one adjustable push-rod length checker, do the intake and then the exhaust (or exhaust then intake, does not matter).
Make sure the cam is on the base circle on the cylinder you are checking and put the adjustable pushrod(s) in place (adjusted shorter than needed) and install your rockers. You only need two on at this time, but you can leave them all on, no matter. Adjust the adjuster screws so they show about 2-3 threads protruding out the bottom of the rocker and lock them in place. If the thread count that the rocker manufacturer suggests is different than what I suggested, go with theirs.
The first thing to look at is the roller tip to valve alignment. The tip should be just inboard of center on the valve at zero lift.( see Valvetrain Geometry sheet below)
If that looks good, you can move on to adjusting the pushrod(s).
Adjust the pushrod(s) to take out all lash. Do not preload the lifter(s).
Have a helper slowly rotate the engine by hand 2 full revs and watch the roller(s) on the valve(s) closely. It should start at just slightly IB of center on the base circle of the cam, roll out to just OB of center at half lift, and end up at just IB of center at full lift.
If this all works out, add .040" to the actual pushrod length. This is the correct length.
If your roller tip is not in the right spot, you either have to shim the rocker shafts up or possibly use lash caps on the valves to get the required geometry. I have never used the lash caps so maybe some of the guys that have could tell you about those, if you require them.
Final adjustment procedure after new pushrod install:
When the intake just starts to open, adjust the exhaust
When the exhaust closes, adjust the intake
also, a quicker method:
This sheet really helps, too:
I hope this helps. It is very important that everything is right on this. Once you have your new pushrods installed and adjusted, take a close look at all the valves for roller tip alignment while a helper slowly turns the engine to make sure you don't have any issues.
Good luck, Dave
If not, read this**:
** anywhere in these instructions were I talk about adjustment or rocker shafts~~~you are not adjustable...ignore~~~~~~Rocker Shafts....you don't have em...ignore....replace with normal shop practices for rockers
If your engine is assembled already you need to remove all the pushrods (if they are in) and both sets of rockers (obviously) and the spark plugs should be removed.
If you only have one adjustable push-rod length checker, do the intake and then the exhaust (or exhaust then intake, does not matter).
Make sure the cam is on the base circle on the cylinder you are checking and put the adjustable pushrod(s) in place (adjusted shorter than needed) and install your rockers. You only need two on at this time, but you can leave them all on, no matter. Adjust the adjuster screws so they show about 2-3 threads protruding out the bottom of the rocker and lock them in place. If the thread count that the rocker manufacturer suggests is different than what I suggested, go with theirs.
The first thing to look at is the roller tip to valve alignment. The tip should be just inboard of center on the valve at zero lift.( see Valvetrain Geometry sheet below)
If that looks good, you can move on to adjusting the pushrod(s).
Adjust the pushrod(s) to take out all lash. Do not preload the lifter(s).
Have a helper slowly rotate the engine by hand 2 full revs and watch the roller(s) on the valve(s) closely. It should start at just slightly IB of center on the base circle of the cam, roll out to just OB of center at half lift, and end up at just IB of center at full lift.
If this all works out, add .040" to the actual pushrod length. This is the correct length.
If your roller tip is not in the right spot, you either have to shim the rocker shafts up or possibly use lash caps on the valves to get the required geometry. I have never used the lash caps so maybe some of the guys that have could tell you about those, if you require them.
Final adjustment procedure after new pushrod install:
When the intake just starts to open, adjust the exhaust
When the exhaust closes, adjust the intake
also, a quicker method:
This sheet really helps, too:
I hope this helps. It is very important that everything is right on this. Once you have your new pushrods installed and adjusted, take a close look at all the valves for roller tip alignment while a helper slowly turns the engine to make sure you don't have any issues.
Good luck, Dave
mopar340dave
Well-Known Member
Yours has a scrub radius on the rocker arm instead of a roller tip. This should line up with the valve the same way the roller does.
63dartman
Well-Known Member
Thanks for that great write up Mopar340dave, Right now I'm not using a roller tip rocker. Just the stock magnum setup. I copied and saved your comments for a later date. Working on frame connectors and a new wiper motor install today and tomorrow. Hopefully I can get to the rocker and springs next week. Thanks again.
mopar340dave
Well-Known Member
Magnum head pushrod length check with non-adjustable rockers:
Remove all spark plugs
Rotate engine until #1 has both valves closed (see above chart)
Remove all rocker arms and pushrods. Keep rockers and parts in order to go back in the same spots.
Adjust a pair of adjustable length checking pushrods to about 7.62 and put one in the lifter for the intake and one in the lifter for the exhaust valve. Leave the adjuster loose.
Install the #1 cylinder rocker arms per factory manual.
Adjust pushrods until they are snug and lock the adjustment.
Have a helper turn the engine over with a socket and breaker bar while you watch the scrub radius ride the valves. They should look sililar to the above geometry sheet.
If all is good, remove rockers and pushrods and measure push rods.
Add .050" to your measurement, this is your correct push rod length.
Remove all spark plugs
Rotate engine until #1 has both valves closed (see above chart)
Remove all rocker arms and pushrods. Keep rockers and parts in order to go back in the same spots.
Adjust a pair of adjustable length checking pushrods to about 7.62 and put one in the lifter for the intake and one in the lifter for the exhaust valve. Leave the adjuster loose.
Install the #1 cylinder rocker arms per factory manual.
Adjust pushrods until they are snug and lock the adjustment.
Have a helper turn the engine over with a socket and breaker bar while you watch the scrub radius ride the valves. They should look sililar to the above geometry sheet.
If all is good, remove rockers and pushrods and measure push rods.
Add .050" to your measurement, this is your correct push rod length.
mopar340dave
Well-Known Member
I rewrote the instructions in Magnum speak.
The valve timing chart and geometry sheet still apply.
goldduster318
Overzealous Car Modifier
I have the stock magnum rocker arms. I believe the preload to be good as they are not bottoming out nor are they loose. The geometry looks good as well. If you look at all the magnum buildups on "LA" blocks that they do in the car mags, they also use 7.650" pushrods, even after using a length checker.
moper
Well-Known Member
With stud mounted rockers you really need to do more than make sure the rocker is on the inside of the center of the stem. Pushrod length affects the geometry on stud rockers. You should be checking the sweep of the rocker over the valve tip at full lift. By just looking at the stationary placement, you could have ones that are too long or too short, both of which will mess up the geometry. The roller or non roller make no difference. The stationary check should be done at 1/2 lift, in order to see if the tip is centered on the valve tip at that point of its' travel. Are your Magnums pedestal or stud mounted?
mopar340dave
Well-Known Member
The car mag guys are there for two reasons:
~~~~~~~~~~To sell magazines
~~~~~~~~~~To sell parts
Technically, it boils down to one reason....money.
If you want to make sure that your pushrod length and rocker arm geometry is correct, follow my instructions.
If you don't believe me, then do whatever you see fit. It's your car.:read2:
P.S. Keep in mind that every time the head and/or block is resurfaced and/or when you change head gaskets, the correct pushrod length can and will change. This will effect both rocker geometry and lifter preload.
You will notice that pushrod manufacturers offer pushrods in increments of .050". They do this because they are a necessity.
63dartman
Well-Known Member
O.K. guys, I got my 7.65 hardened pushrods in and everything looks good. Geometry looks correct, preload is good, only thing I noticed that was "wierd".......When I adjust the preload in my lifters the valves are the part that is moving? Not sure if the spring pressure is suposed to cause the lifter to bleed down and give me the preload or if the oil in the lifter stays there when the engine is sitting still. These are not new lifters. I have had them in for almost two years now. I know when I installed the lifters new they did take up the preload at the pushrod. I hope I'm explaining this clearly. Is this normal for pumped up lifters?
mopar340dave
Well-Known Member
So you bought adjustable rockers and new push rods?
The lifters will at least partially open the valve even if the valve spring is compressing the lifter some. You should rotate the engine over (on a Magnum head) as you do each cylinder so that the cam is on the I/E base circle. It makes it easier because the valve springs are not fighting your install.
Did you go through the engine rotation and adjust each valve to a .050" preload? If you did, and all the rollers are lined up correctly, you should be good to go!
The lifters will at least partially open the valve even if the valve spring is compressing the lifter some. You should rotate the engine over (on a Magnum head) as you do each cylinder so that the cam is on the I/E base circle. It makes it easier because the valve springs are not fighting your install.
Did you go through the engine rotation and adjust each valve to a .050" preload? If you did, and all the rollers are lined up correctly, you should be good to go!
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