change lifters and rods with rockers?

[Numax]

Looking for some insight here. I have a 318 that had a purple cam in when I got it and 360 heads. But stock lifters, rods and rockers. I'm getting adjustable roller rockers to make up for the cam but my question is should I get new lifters and rods. The engine only has 29,000 miles on it and everything seems brand new so I thought just rods would be fine but I'm no pro. It has hydraulic flat tappet lifters if it makes a difference. Also the guy said it is a 408 lift cam but he didn't seem very knowledgeable :bs: and I couldn't find anything about a 408 lift. Ill be pulling it tomorrow to see what I'm really working with. Thanks!!

 

[70aarcuda]

check your adjusters on your new roller rockers......see if they are a ball or cup...

if you are going from stock non adjustable rockers to adjustable rockers...you will probably need new pushrods....dont need to mess with the lifters..

you will need lifter with a cup on the top and ball on the bottom ...the cup will fit into the adjuster.....

make sure you get pushrods for adjustable rocker with hydraulic lifter...there is a difference in length ...

dont mean to confuse ya...lol

 

[Mopar Sam]

You may already know this, but if you remove the cam , you must keep the lifters in order. Are you sure he didn't say .508 lift ?

 

[krazykuda]

You may not need new lifters if you are staying with a flat tappet cam. You should be able to change the rocker arms and get the proper push rods to fit and be done....

 

[nm9stheham]

check your adjusters on your new roller rockers......see if they are a ball or cup...

if you are going from stock non adjustable rockers to adjustable rockers...you will probably need new pushrods....dont need to mess with the lifters..

you will need lifter with a cup on the top and ball on the bottom ...the cup will fit into the adjuster.....

make sure you get pushrods for adjustable rocker with hydraulic lifter...there is a difference in length ...

This is where the OP needs to focus. New pushrods with a different top end and different length are a given. The new pushrod length will be determined by the new rockers and by something called lifter preload; read up on that.

OP, what roller rockers are you looking at? Some come with adjustable measuring pushrod kits that are used to determine your new pushrod length. Or you can buy these separately.

And by the statement 'stock lifters', do you mean actual OEM lifters, or stock type lifters, i.e., hydraulic lifters?

 

[Numax]

You may already know this, but if you remove the cam , you must keep the lifters in order. Are you sure he didn't say .508 lift ?

well i measured it today and I got around .3?? lobe lift and .5?? valve lift with 1.5 rockers. havnt sifted through the chrysler purple cam sizes yet to see what it probably is. they advertise the lobe lift not the valve lift right? because the valve lift would be dependent on what the rocker ratio is.

And yes i have all the lifters and rods bagged and labeled by firing order and intake or exhaust.

Edit: got my sheet from the garage

Max lobe lift = 0.302 / 0.345

Max valve lift = 0.453 / 0.5175 (1.5 Rocker Ratio)

 

[Numax]

This is where the OP needs to focus. New pushrods with a different top end and different length are a given. The new pushrod length will be determined by the new rockers and by something called lifter preload; read up on that.

OP, what roller rockers are you looking at? Some come with adjustable measuring pushrod kits that are used to determine your new pushrod length. Or you can buy these separately.

And by the statement 'stock lifters', do you mean actual OEM lifters, or stock type lifters, i.e., hydraulic lifters?

Ill read on preload tonight, thanks. These are the rockers I'm looking at I would like Harland Sharp rockers but I'm pretty low on cash

As for the lifters I'm not entirely sure if they are oem or if they were purchased with the cam. The wear marks on the cam from the lifters don't look very even so I'm assuming they were not bought with this cam but this might just be a normal thing that i don't know about. They are hydraulic lifters and I figured it is a hydraulic cam but I may be overestimating the aptitude of the previous owner.

Edit: I read up a bit on preload, so from my understanding it would be easiest to get the rockers and use the pushrods I have to see what my preload is with those and then order new ones accordingly? Or since I would need rods with a cup with those rockers, find a used pushrod on ebay that I think it about the right length with a ball end and cup end then use that to see if I need longer or shorter rods? Seems like there should be an easier way to figure the length haha

 

[Numax]

check your adjusters on your new roller rockers......see if they are a ball or cup...

if you are going from stock non adjustable rockers to adjustable rockers...you will probably need new pushrods....dont need to mess with the lifters..

you will need lifter with a cup on the top and ball on the bottom ...the cup will fit into the adjuster.....

make sure you get pushrods for adjustable rocker with hydraulic lifter...there is a difference in length ...

dont mean to confuse ya...lol

I didn't know there were different pushrod end types but I was wondering how it stayed on the rocker adjuster pin if they both were rounded, glad I posted before buying anything! Thanks.

 

[nm9stheham]

Edit: I read up a bit on preload, so from my understanding it would be easiest to get the rockers and use the pushrods I have to see what my preload is with those and then order new ones accordingly? Or since I would need rods with a cup with those rockers, find a used pushrod on ebay that I think it about the right length with a ball end and cup end then use that to see if I need longer or shorter rods? Seems like there should be an easier way to figure the length haha

Good you are getting there.... as said, there are measuring pushrods that you can buy (typically as a pair) and that are put in temporarily and then adjusted to set the desired preload with new rockers and the lifters. Then you pull them out, measure the length, and order that. You need to have precision calipers that will go to the 7-8" range to measure them accurately; so plan on borrowing some.

As for your lift measurements.... well..... you need to borrow a dial indicator and measure is much more accurately..... you need 2 more digits! .3xx does not say much of anything. Advertised lift is at the valve BTW.

You may find that the setup of the new rockers is pretty tedious: setting side clearance for oiling flow is pretty critical to them. And it may require some minor mods for fitment. So be patient. You don't just bolt them down... and then there is geometry checking. Be ready for some learning... but it can all be done.

 

[Numax]

Good you are getting there.... as said, there are measuring pushrods that you can buy (typically as a pair) and that are put in temporarily and then adjusted to set the desired preload with new rockers and the lifters. Then you pull them out, measure the length, and order that. You need to have precision calipers that will go to the 7-8" range to measure them accurately; so plan on borrowing some.

As for your lift measurements.... well..... you need to borrow a dial indicator and measure is much more accurately..... you need 2 more digits! .3xx does not say much of anything. Advertised lift is at the valve BTW.

You may find that the setup of the new rockers is pretty tedious: setting side clearance for oiling flow is pretty critical to them. And it may require some minor mods for fitment. So be patient. You don't just bolt them down... and then there is geometry checking. Be ready for some learning... but it can all be done.

Sorry, my actual measurements were in the garage but I have them now

Max lobe lift = 0.302 / 0.345

Max valve lift = 0.453 / 0.5175 (1.5 Rocker Ratio)

So assuming my measurements are dead on, I'm sure their not but just pretend, this would be advertised as a 453/5175 lift cam? I thought it would have been 302/345 because the rocker ratio determines the valve lift and they cant predict what ratio will be used with the cam.

 

[nm9stheham]

It would be advertised as a 453/517 cam; the listings assume the standard rocker ratio. What you ultimately care about is the lift at the valve.

BTW, that difference in lift between intake/exhaust is out of line and is abnormally large. So there must be something going on with your measurement. It may be that a lifter has leaked off a bit and that is some give in the lifter piston that is giving you too little lift on the intake side, but that is just a guess. The best way is to measure the lift of the lifter body, not at the pushrod. But you have to get down into the valley to do that.

 

[Numax]

ok, I'll remeasure it once more with less haste. I measured the cam itself so it couldn't have been the lifters or anything but I'll break out the digital calipers this time.

 

[Numax]

Put this together to show what I've been measuring

 

[Numax]

So I Measured a few times and got a Max valve lift of 0.498 and 0.5115. Ive noticed that it varies about 0.003, I remember reading somewhere that hydraulic cams are ground at an angle to rotate the lifters, could this be why I'm not getting dead on measurements? Should I measure each side of a lobe and take the median? It seems this could be a 508 cam and I just cant measure it accurately?

 

[nm9stheham]

The intake and exhaust spread is making a lot more sense. But, I sometimes wonder if measuring across the width may or may not be accurate; it might lose accuracy for long duration cams (like this one appears to be). This is due to the fact that the ramps of the cam may be starting near to the sides where you are measuring.

And as I recall, most modern cams do indeed use a taper for lifter rotation as you say.

 

[AJ/FormS]

Chrysler used to sell just one adjustable pushrod.
When doing the measuring for geometry, you need to swap off the valve springs and install checking springs; and the accompanying-lifter has to be,and remain, fully pumped up for the duration of the test. Then you add the preload last.I suppose you could take a lifter apart and shim the cup just right, and then you wouldn't have to remove the springs; but I wouldn't return that lifter to service.
Check all 4 corners in case somebody messed up the machineworks. It's a real drag finding that out, after all your brand new p-rods are installed and some are too short...

 

[mderoy340]

So I Measured a few times and got a Max valve lift of 0.498 and 0.5115. Ive noticed that it varies about 0.003, I remember reading somewhere that hydraulic cams are ground at an angle to rotate the lifters, could this be why I'm not getting dead on measurements? Should I measure each side of a lobe and take the median? It seems this could be a 508 cam and I just cant measure it accurately?

Flat tappet cam lobes are ground on an angle to make the lifter rotate. You are dealing with a used cam and have to account for wear, so all lobes are not going to be exactly the same.

 

[Numax]

Chrysler used to sell just one adjustable pushrod.
When doing the measuring for geometry, you need to swap off the valve springs and install checking springs; and the accompanying-lifter has to be,and remain, fully pumped up for the duration of the test. Then you add the preload last.I suppose you could take a lifter apart and shim the cup just right, and then you wouldn't have to remove the springs; but I wouldn't return that lifter to service.
Check all 4 corners in case somebody messed up the machineworks. It's a real drag finding that out, after all your brand new p-rods are installed and some are too short...

awesome thanks for clearing up the process and for the tip

 

[Numax]

The intake and exhaust spread is making a lot more sense. But, I sometimes wonder if measuring across the width may or may not be accurate; it might lose accuracy for long duration cams (like this one appears to be). This is due to the fact that the ramps of the cam may be starting near to the sides where you are measuring.

And as I recall, most modern cams do indeed use a taper for lifter rotation as you say.

Good point, not something I considered. I'm hoping that this cam has a shortish duration because I'm looking for a low rpm power and torque curve but I'll find out when I get everything set up to measure it, thanks!

 

[Numax]

Thanks everyone for the help, I feel like I have a pretty good handle on what needs to be done now. Awesome community!

 

[j par]

Just spitballing here, and it would be more work- but since you spending the time and money on those expensive ajustable rockers and custom made pushrods and I heard talk about springs ? Just an idea, take the cam out and send it to someone (like I did) oregon cam grinding and definitely know what you have and totally have what you want for like $75 ??

 

[nm9stheham]

Chrysler used to sell just one adjustable pushrod.
When doing the measuring for geometry, you need to swap off the valve springs and install checking springs; and the accompanying-lifter has to be,and remain, fully pumped up for the duration of the test. Then you add the preload last.I suppose you could take a lifter apart and shim the cup just right, and then you wouldn't have to remove the springs; but I wouldn't return that lifter to service.
Check all 4 corners in case somebody messed up the machineworks. It's a real drag finding that out, after all your brand new p-rods are installed and some are too short...

Other ways to do it:
1. Keep the stock springs in place and then just look at the amount of preload being put into a non-pumped up lifter and stop when it get to the right amount.
2. Keep the stock springs in place and stop the adjustment when the the measuring pushrod's slack is all taken up at 0 preload. Then add the desired preload amount to the measured length.

Keep in mind that in this case, the OP is going to use adjustable rockers. So the rocker adjustment has to be set at the nominal setting first. Doing all 4 corners in this case is not needed, as any deck height variations will be compensated for with a fraction of a turn of the adjuster. And if no one said it yet and if it is not obvious (which it probably is), the measuring pushrods are set with the lifters on the base circle of the cam.... no lift at all.

 

[j par]

Other ways to do it:
1. Keep the stock springs in place and then just look at the amount of preload being put into a non-pumped up lifter and stop when it get to the right amount.
2. Keep the stock springs in place and stop the adjustment when the the measuring pushrod's slack is all taken up at 0 preload. Then add the desired preload amount to the measured length.

Keep in mind that in this case, the OP is going to use adjustable rockers. So the rocker adjustment has to be set at the nominal setting first. Doing all 4 corners in this case is not needed, as any deck height variations will be compensated for with a fraction of a turn of the adjuster. And if no one said it yet and if it is not obvious (which it probably is), the measuring pushrods are set with the lifters on the base circle of the cam.... no lift at all.

How about skip all this crap and get solid lifters and have the cam regrind ( so he'll actually know what he has and have what he wants ?) for a solid lifter since he's getting adjustable rockers? Harlan sharp rockers he was talking about $600 + and won't spend $200 for a new cam and lifters?
Again just mostly spitballing with the idea and not trying to cyber spend the man's cash But....

 

[nm9stheham]

Ummm..... he WANTS Harland-Sharp rockers but can afford Speedmaters....

 

[krazykuda]

So I Measured a few times and got a Max valve lift of 0.498 and 0.5115. Ive noticed that it varies about 0.003, I remember reading somewhere that hydraulic cams are ground at an angle to rotate the lifters, could this be why I'm not getting dead on measurements? Should I measure each side of a lobe and take the median? It seems this could be a 508 cam and I just cant measure it accurately?

How are you measuring? Calipers? Micrometers? Center of the lobe or ends, and is there a difference?

How many times do you measure it? I like to do 3 repeatable measurements within .001" - .002".

If a measurement is not repeatable, it's not accurate.