70newport

Sorry for asking so many questions lately but I can not ind answers to this stuff.

I am doing a Hydraulic flat tappet cam in my 383 with melling lifters and I have an older set of comp cams 1421 rocker arms that I plan to use. Now with my factory push rod it is depressing the lifter before I even get the rocker arm shaft fully bolted down. I assume I need a shorter push rod but I can not find a ball to ball style shorter than the factory 8.55"

I used a push rod length checker and I am seeing that with the adjuster for my rocker arms backed all the way off I need an 8.375" pushrod (or shorter) to not be depressing my lifters...... Im so confused at what I need or am doing wrong at this point.

Thanks,

Gary

RacerHog

Instruction Vid.... :
AS for the push rods... Any size you need made... From these 2 places...

http://mantonpushrods.com/

Or

http://www.pushrods.net/

Just my 2 cents

70newport

Thanks Hog,

I have actually watched that video before and agree it is good information. I do not have my oil pan on yet so i can not play around with valve train geometry yet but I believe I am setting my lash properly initially and then can adjust geometry with the adjuster on the rocker arm once I have correct length push rods.... please correct me if I am wrong as that is where I am confused.

I also feel like im doubting myself due to not being able to find "mopar specific" pushrods that fit my criteria through summit or similar websites......

RacerHog

Thats the way our Mopar world is....
As for the lifter setting for your Hyd..... This is just me and me only. Use it or dont... The choice is yours....

Spit the difference between compressed and uncompressed.... Give a slight preference to the uncompressed side..

Note: It's Best if you can use a pumped up lifter for the readings.

70newport

I had done my initial test with my lifters after soaking them in oil and bolted down my rockers shaft and then extended the length checker till it had resistance to spin. the adjuster on my rocker arm was all the way out so I assume I could push it down a little with the checker to compress the lifter a bit...

Thanks for all your help!

Myraman

I see Racerhog pointed you in the right direction. I used smith brothers pushrods www.pushrods.net twice now. Both came exactly as I measured and one set is in a 512 stroker and dioing well so far! The can come with just about any end and combo you need. I would use them again in a heartbeat. Good luck

Iowan

I've never heard bad about Smith Brothers.

RacerHog

If the lifter is full and pumped up.... You are correct in your measuring...No reason for the other loaded way...
You will just need a little drag when you spinning the push rod... and then measure the rod... and your good to order....


Not to add confusion.... But also check the rocker tip to valve tip contact... I think you already said you have done this.... It's just a reminder to recheck it....


Keep up posted..... Will Stay Tuned Eh !!!!!

70newport

So I have determined that an 8.3" pushrod is correct for me and the roller tip sits just below the center of the valve. wondering if i should go with an 8.25 " instead and then adjust the rocker arm if needed from there or if this will even make a difference?

Thanks again everyone.

RacerHog

No...No....No...... The way you describe it is...... Roller tip is closer to the exhaust side of the valve stem tip? Or it's closer to the Intake side of the valve stem tip?
That take the confusion out when you ask the question....


Go Perform the felt tip marker instructions on checking the mating of the roller and valve tip if you would need a longer or shorter push rod....

70newport

Sorry Closer to the exhaust side.

when I have the rocker arm adjuster where it should be ( 1 turn in) I need 8.30 to get a little resistance trying to spin the pushrod but I end up with the roller just a little towards the exhaust on the valve.....

I will do the test again tonight to make sure I was not mistaken but I believe I did everything correct

70newport

So I did the felt tip marker test and ended up actually going to an 8.40". Very glad I went through that again.

Is it an issue if it is an"oiling" push rod and has the hole all the way through even though my lifters are not that style?

Also how much it too much gap per pair of rockers? I have .035-.060

Thanks everyone!

RacerHog

Get your part numbers ready and check with Comp Cams...
I am pretty sure your going to need the solid ball and ball?

Iowan

Plus 1 on this one.

70newport

Does this depend on rocker arm or lifter? Only reason I ask is I have melling lifters and comp rockers.

Thanks

Iowan

I believe the Comp rockers take the ball push rods.

70newport

RacerHog

If your oiling threw the rocker shafts... Solid push rod
If your oiling threw the Lifter.............. Hollow push rod


Not sure what route you have taken..... I didn't go look up all the parts, too see what you had purchased...So we have to leave it to you for a little research on your end.


But if those are stock replacement hyd. lifters and oiling threw shaft rockers with ball ends.... That's kind of easy..... it would be a ball to ball solid push rod.


Hope that makes scenes...

70newport

Just talked with Marvin from comp cams and he said although it is oiling through the rocker shaft and not through the lifter that it will not affect anything.

Hopefully he is correct.

RacerHog

.... Never hurts to ask.... MFG all can be different.... Keep us posed on how it runs, and if any issues come up.....

70newport

Will do!

Thanks everyone for your input!