Oiling -vs- non-oiling pushrods

[68ChargerAG]

Can someone please explain oiling -vs- non-oiling pushrods? I am thinking the difference is the holes in the ends of oiling pushrods, but just want to confirm.:confused:

Also, can oiling pushrods be used in non-oiling application such as BB Mopar?

Thanks,

 

[68ChargerAG]

Here is the reason for the question...

Many years ago I built this engine and installed Comp Cams high(er) lift cam and hydraulic lifters. I also replaced the pushrods, and valves etc with full valve job. The rocker assembly was still stock with plans to replace with roller tiped rockers someday when I had the money.

Just recently when I finally got the car together and was able to start the engine for the first time. All was good, but lots of valve noise. Original stamped rockers felt loose as well so I figured no lash was problem (hydraulic lifters, so should have positive lash and no noise). So I sprung for adjustable roller rockers from Comp Cams thinking that I would then be able to adjust the proper lash for the hydraulic tappets.

Now there is way too much lash (tappets being pushed in too far), and the rockers are adjusted to there extreme. Lash is 0.135". I don't understand how I went from excessive valve noise which I assumed to be due improper lash... to too much lash. I used an adjustable pushrod and found that the pushrods that I have are about 1/8" longer than what I need for proper lash adjustment.

Maybe I mis-diagnosed the problem, and the valve noise was from something else, but I can't imagine what. Tappets not pumping up???

Now, I can't find pushrods of correct (or even close enough to work) length without being oiling style pushrods... well, I guess I can, but they will cost 10 times as much.

So, is it OK to use oiling pushrods in shaft oiling system, or will they cause excessive wear or fill up with oil or something like that?

Thanks for any advice on this.

 

[Meep-Meep]

The difference is really a decision by the engine designer in how he chose to get oil to the top end and what would make the most sense with the given valve train layout.

I don't THINK you would have an issue using the oiling push rods but there's no reason to. Rocker geometry is very important so you better make sure it's spot on. One clue is to not have a bunch of thread sticking out of the push rod side of the rocker. Check your spring height too. If you need a custom push rod made check these guys out http://www.pushrods.net/

 

[68ChargerAG]

Thanks for the feedback Meep.

I am not considering converting over to oiling through the pushrods, I was just wondering if it would be OK to use the pushrods with the holes in them on a BB Mopar that oils from the rocker shaft. The price difference for getting the size of pushrod that I need is very big. $25 as apposed to close to $200.

The more I think about it the more I think that it would just be a bad idea to use oiling pushrods in a non-oiling application. I think that they will just fill up with oil and it would stay in there with nowhere to go. I will just have to bite the bullet again and do what is right because I just don't know enough to make substitutions.

Thanks for the link, I will check those guys out... but am guessing they will be $$$.

 

[69 Runner]

I'm surprised the adjustable pushrods can't be made the proper length. I've run them before in applications where stamped rockers were required, but the heads (and maybe block) had been cut. I know for a fact they will adjust to .110" SHORTER than stock (what I needed) and will also go longer......although I don't know how much.

 

[68ChargerAG]

I'm surprised the adjustable pushrods can't be made the proper length. I've run them before in applications where stamped rockers were required, but the heads (and maybe block) had been cut. I know for a fact they will adjust to .110" SHORTER than stock (what I needed) and will also go longer......although I don't know how much.

I have some adjustable pushrods that can be adjusted to the correct length, but my understanding is that they are just for finding the correct length, and not for running with them in the engine. Right?

I have done some more measuring and found that the pushrods that I had were too long for the stock stamped rockers as well, but even worse with the Comp Cams roller rockers. I had purchased them FOR A 383 engine, and I have double checked this with other 383 pushrods for sale, and they are 8.555" which is correct... but they are too long. I actually need 8.406". To the best of my knowledge the block or heads have never been trimmed, only shaved for flatness. Hmmmm...

I am pretty much under the assumption now that the pushrods were too long and were not allowing the lifters to pump up. They were probably just squirting the oil back out when lifting. They were about 0.155" too long on the tallest valve stem which is quite a bit... about 5/32"

I have ordered some pushrods of the correct length and will see if this solves the problem when I install them and calibrate the lash (now that I have adjustable rockers... yey!)

I still don't know exactly what caused this problem in the first place. Maybe the Comp Cams tappets that I ordered with the cam are taller than stock??? Could this be the case if they were perhaps for a 440 instead of a 383? Maybe something like that is what happened (about 13 years ago, too late to send them back now).

Just another note... I have found that the Comp Cams High Engergy hydraulic lifters are designed for pushrod oiling type valvetrains (which is annoying because it is wrong for these engines), but I am going to go ahead with oiling type pushrods (because they are the only ones that I can find in the length that I need) and the rockers will just get oil from both sides which doesn't seem like a problem to me.

 

[69 Runner]

I ran the hell out of them. When I first set them up they were a tad short (zero lash), and made the motor sound like it had a solid stick in it. So I gave them .020" preload and all was fine. Motor made power to 7000.

 

[68ChargerAG]

Wow... that is good to know. I was thinking that they would be just like adjustable rockers, and have some nice heavy duty ones from Comp Cams, but everything I read said to never run them so I didn't.

I guess as long as they are strong enough and don't bend or break, the worse they could do is be sort of heavy.