Pushrod oiling - do I need it?

[rmchrgr]

I am in the process of finishing up my 416" and have been checking the pushrod length and geometry. Reading up on all this stuff made a light go off in my head. Do I need to convert to pushrod oiling? The reason I'm asking is because I am considering getting a set of cup adjuster screws which have a choice of an oil hole or not.

I've never dealt with pushrod oiling so I'm not sure what I'd need to do to convert to that style. The oil system is standard, basically just an HV72 oil pump (slightly enlarged/smoothed inlet passage). Block is not tubed, no crossover line in the lifter galley. Bearing clearances are .0025". Half groove main and rod bearings.

The lifters I am using (Comp 8043) have a provision for pushrod oiling. The roller wheels are pressure fed on these. Problem is, the rocker arms (Hughes ) do not have pushrod oiling provisions as far as I can tell. There is an oil hole in the top for the shaft and the shaft bore is half-grooved.

With the previous combo from several years ago, (SFT, same rockers though) going up to about 6,500 there was no issue. The pushrods were solid, at least on the bottom. Don't remember exactly what the oil pressures were. I have a solid roller now which will rev higher, maybe 7,000 or more. This will be a street car that will see drag strip duty when time allows. I am aware I'm not supposed to idle the thing for long periods of time or run it wide open for hours on end. I kno the pushrod geometry cn be hard on the tips if the angles get crazy but I think I'm actually OK in that regard.

Honestly, I'd rather not have to deal with converting it and most likely will just let it fly with the standard shaft oiling. The short block is together and I'm not real keen on taking it back apart to drill into the galleys and/or spend another $1,300 on rockers that pushrod oil. Now would be the time to do it though before I button it up for good so if there is a 100% consensus I will consider it.

Thanks,

Greg

 

[OldmanRick]

If i'm reading this correctly, the shaft oiling should be fine. I am curious about the thinking on the 7k plus rpm's with the stroker. Unless you have some serious heads and big tubes, i'd think shift points in the 6 to 6,500 range would be plenty for a street setup.

 

[Oldmanmopar]

Our small block has seen up to and over 9000 rpm's We shift tit a 8000 consistently. We use standard shaft oiling, But. This mod must be done if using studs and not the tapered bolt that allows oil up through and around the bolt. Simple fix if studs are in the engine already, The stud must be clocked and marked for that hole and installed to the same position to allow oil up the passage. One stud on each side.

 

[rmchrgr]

Cylinder heads are fairly serious, I'd say they flow at least 300cfm. Headers are 1 7/8" primary tubes. Cam is a solid roller, 263/268 @.050".

In general, I'd agree there's no reason to rev a stroker that high. In fact, the previous configuration of this motor stopped making power at 6,000 rpm. It's a totally different setup now though and it should still be making power at 6,500+.

I did a little more research on what needs to change to pushrod oil. Basically what this boils down to is that it's probably not worth taking the whole engine apart again to convert it. Even if I had thought about it before I put the short block together at a minimum I would need to get new cam bearings installed since the timed cam journal oiling holes in #2 and #4 that feed the heads get rotated/blocked to prevent too much oil from going to the heads. Can't really have both methods at the same time because you wind up with excess oil up top.

There are are other methods to do it such as installing threaded plugs in the deck oil feed holes but I would have to clean the block after tapping it and I'd still need pushrod oil rockers. The only ones I'm sure that do are the T&D which other than pushrod oiling I have no need for.

Next build I'll think about it ahead of time and if it makes sense I'll have the machine shop take care of all these passageway mods. I still think it's a reasonable consideration at my current level but probably not a necessity. Guess I'll find out the hard way if the stock oiling isn't up to the task but I'm not real worried about it now that I have a little better grasp of it.

Are small block has seen up to and over 9000 rpm's We shift tit a 8000 consistently. We use standard shaft oiling, But. This mod must be done if using studs and not the tapered bolt that allows oil up through and around the bolt. Simple fix if studs are in the engine already, The stud must be clocked and marked for that hole and installed to the same position to allow oil up the passage. One stud on each side.

View attachment 1716165709

View attachment 1716165710

This is the first time I've ever seen that modification and I'm not sure I understand how it works. Is that bolt hole connected to the head oil gallery somehow?

 

[67Dart273]

Cylinder heads are fairly serious, I'd say they flow at least 300cfm. Headers are 1 7/8" primary tubes. Cam is a solid roller, 263/268 @.050".

In general, I'd agree there's no reason to rev a stroker that high. In fact, the previous configuration of this motor stopped making power at 6,000 rpm. It's a totally different setup now though and it should still be making power at 6,500+.

I did a little more research on what needs to change to pushrod oil. Basically what this boils down to is that it's probably not worth taking the whole engine apart again to convert it. Even if I had thought about it before I put the short block together at a minimum I would need to get new cam bearings installed since the timed cam journal oiling holes in #2 and #4 that feed the heads get rotated/blocked to prevent too much oil from going to the heads. Can't really have both methods at the same time because you wind up with excess oil up top.

There are are other methods to do it such as installing threaded plugs in the deck oil feed holes but I would have to clean the block after tapping it and I'd still need pushrod oil rockers. The only ones I'm sure that do are the T&D which other than pushrod oiling I have no need for.

Next build I'll think about it ahead of time and if it makes sense I'll have the machine shop take care of all these passageway mods. I still think it's a reasonable consideration at my current level but probably not a necessity. Guess I'll find out the hard way if the stock oiling isn't up to the task but I'm not real worried about it now that I have a little better grasp of it.


This is the first time I've ever seen that modification and I'm not sure I understand how it works. Is that bolt hole connected to the head oil gallery somehow?

^^It is what communicates oil from the passage in the block, from the block deck to the rocker shaft

 

[rmchrgr]

^^It is what communicates oil from the passage in the block, from the block deck to the rocker shaft

Not trying to be argumentative here but I looked down that bolt hole in my block with a light and could not see any oiling provision in it. I don't see how any oil can get up the stud. Maybe it would drain down but to where? What am I missing?

if there is an oil hole in the bolt threads connected to that passageway from the cam tunnel I can't see it. The smaller hole above it in the picture is obviously what mates up to the head and the oil is fed there from the timed #2 cam bearing hole but as far as I can tell that particular bolt hole with the modified stud in it seems isolated from any pressure-fed oil.

 

[Rocket]

If you want to block the oil to the shaft, you can also put a set screw into the oil passage in the head pedestal oil passage right under the shaft or reduce
The oil with a small jet.

Nothing wrong with shaft oiling.

If running pushrod oiling, you need to be sure your rockers are designed for it. If your rockers are similar to this picture and have to pushrod cup oiling hole below the adjuster threads, these can’t be used for pushrod oiling. Picture is an older Hughes rocker.

For pushrods oiling to work the oil passage in the rocker needs to be drilled into the adjuster threads so it can be fed oil from the pushrod, through the adjuster,
Intersect the oil hole drilled in the threads and get into the rocker and shaft. A special drilled adjuster with a cutaway in the threads to intersect with the oil hole is also needed.

 

[rmchrgr]

Yes, thanks, I had figured that out. Understand about blocking the passage in the deck is an option and that the proper pushrod oiling rocker arms are needed when the passage is blocked.

Like your picture, the oil hole in the Hughes rockers is in the back of the shaft bore and goes through the adjuster screw relief area, not the threads. It’s better than nothing but it’s not direct, pressurized oil.

I’ve decided against pushrod oiling but am glad I asked, I learned a few things.

 

[Oldmanmopar]

Look at the top right picture in the diagram and you will see how the oil reaches the rockers. If studs are used they are the same diameter as the hole for the bolt in the head. So putting a passage in the stud is a must. The factory bolt for this hole is longer then the rest of the bolts and has a tapered shank

 

[rmchrgr]

I looked down the cylinder head bolt hole next to the rocker shaft stand with the oil feed and I see the two holes in the stud bore. I did not realize that bolt hole was exposed to pressurized oil from the gallery, my apologies.

Regardless - what exactly does the trough do? Is it just to allow a little extra oil? It's not a lot of oil but does it affect pressure? What happens when the engine is not running, that little bit of extra oil has to go somewhere?

 

[Oldmanmopar]

I looked down the cylinder head bolt hole next to the rocker shaft stand with the oil feed and I see the two holes in the stud bore. I did not realize that bolt hole was exposed to pressurized oil from the gallery, my apologies.

Regardless - what exactly does the trough do? Is it just to allow a little extra oil? It's not a lot of oil but does it affect pressure? What happens when the engine is not running, that little bit of extra oil has to go somewhere?

The recess cut into the stud lines up with the oil holes in the block and head. That is the reason for indexing the stud then marking it for the recess. When reinstalling the stud the recess should be put in the correct location.

If the stud is 1/2 inch in Diameter and the hole is 1/2 inch in Diameter , There is not room for oil to travel up to the head for rocker shaft oiling between the stud and the hole. And " No " the stud does not weaken with the recess,

We over torqued it when first doing this and no torque issues or stretching were seen. Oil at the rockers was greatly improved. Make sure you do this recess with a Ball end mill on a mill so not to deform the stud while keeping a consistent depth, width, and transition

My son builds a lot of LA small blocks and this is done to everyone he assembles with head studs

 

[rmchrgr]

Thanks. I had to go back and re-read your statement about the factory head bolt. I didn't realize that position has a tapered shank so this all makes sense now. You're essentially putting the oiling system capacity back to the stock configuration. Since the stud is a consistent diameter, it eliminates the gap inside the bolt hole that the tapered shank would normally provide. One day I will get myself a milling machine for things like this but there is a shop in my town that could probably do it pretty easily.

But other than indexing the recess towards the oil holes, is there a specific height/depth/length you use for the recess? What size ball end mill is used, looks like maybe 5/16" or so?

Also, some of my studs don't thread all the way down into the block, there's 1-2 threads proud of the deck surface. I called ARP about it and they said it's normal. I checked this on another 340 block and it's the same thing. It shouldn't affect anything though except for the height where the recess starts. I can measure but just asking since you've done it already.

 

[Oldmanmopar]

Thanks. I had to go back and re-read your statement about the factory head bolt. I didn't realize that position has a tapered shank so this all makes sense now. You're essentially putting the oiling system capacity back to the stock configuration. Since the stud is a consistent diameter, it eliminates the gap inside the bolt hole that the tapered shank would normally provide. One day I will get myself a milling machine for things like this but there is a shop in my town that could probably do it pretty easily.

But other than indexing the recess towards the oil holes, is there a specific height/depth/length you use for the recess? What size ball end mill is used, looks like maybe 5/16" or so?

Also, some of my studs don't thread all the way down into the block, there's 1-2 threads proud of the deck surface. I called ARP about it and they said it's normal. I checked this on another 340 block and it's the same thing. It shouldn't affect anything though except for the height where the recess starts. I can measure but just asking since you've done it already.

I'll ask my son.

 

[Newbomb Turk]

Thanks. I had to go back and re-read your statement about the factory head bolt. I didn't realize that position has a tapered shank so this all makes sense now. You're essentially putting the oiling system capacity back to the stock configuration. Since the stud is a consistent diameter, it eliminates the gap inside the bolt hole that the tapered shank would normally provide. One day I will get myself a milling machine for things like this but there is a shop in my town that could probably do it pretty easily.

But other than indexing the recess towards the oil holes, is there a specific height/depth/length you use for the recess? What size ball end mill is used, looks like maybe 5/16" or so?

Also, some of my studs don't thread all the way down into the block, there's 1-2 threads proud of the deck surface. I called ARP about it and they said it's normal. I checked this on another 340 block and it's the same thing. It shouldn't affect anything though except for the height where the recess starts. I can measure but just asking since you've done it already.

Oversize the two bolt holes in the head a 32nd or if it really bothers you open them up a 1/16 and send it.

 

[pittsburghracer]

We get into this discussion every winter. One guy wants to restrict oil with a .060 drilled set plug and one guy wants to machine a stud. Come on springtime.

 

[rmchrgr]

We get into this discussion every winter. One guy wants to restrict oil with a .060 drilled set plug and one guy wants to machine a stud. Come on springtime.

Come on John, you realize we have to bring things like this up for the eight millionth time or we'd have no forum.

I decided against doing it anyway. I'll be happy if/when I get to a point where I need to be genuinely concerned about it.

 

[pittsburghracer]

Come on John, you realize we have to bring things like this up for the eight millionth time or we'd have no forum.

I decided against doing it anyway. I'll be happy if/when I get to a point where I need to be genuinely concerned about it.

I have a lathe that I don’t use but I’ve given anything I thought needed a little more clearance with a grinder and moved on.

 

[Oldmanmopar]

I have a lathe that I don’t use but I’ve given anything I thought needed a little more clearance with a grinder and moved on.

He don't use a grinder on parts that are not ours to grind on unless its body work. When customers have heads $3500 , rockers $2000, We modify the Head studs they only cost $100.

Drilling the head doesn't guarantee the stud is in the center and not blocking the oil feed holes . Yes if needed you can install a restrictor and know the exact restriction you have once the oil is sure to reach the restrictor under the rocker shaft. Or you can drill and grind and guess at your work.

Like the Edelbrock heads we just got in with the valve seat heights and spring pockets all over the place from doing them by hand with a New way cutter set. Using a precision machine with digital readout duplicates everything that is done to the same consistent measurement on every valve and seat. Steve just got a set of heads dropped off from western Pa. to install new seats to fix the valve heights .

Don't throw stones they may come back.

 

[MOPAROFFICIAL]

Rocker matters, oil holes.. as in.

I hear good thing about having both shaft and pushrod oiling in unison.

Tight cup pushrods could use it with say
.. solid roller spring pressures.

 

[pittsburghracer]

He don't use a grinder on parts that are not ours to grind on unless its body work. When customers have heads $3500 , rockers $2000, We modify the Head studs they only cost $100.

Drilling the head doesn't guarantee the stud is in the center and not blocking the oil feed holes . Yes if needed you can install a restrictor and know the exact restriction you have once the oil is sure to reach the restrictor under the rocker shaft. Or you can drill and grind and guess at your work.

Like the Edelbrock heads we just got in with the valve seat heights and spring pockets all over the place from doing them by hand with a New way cutter set. Using a precision machine with digital readout duplicates everything that is done to the same consistent measurement on every valve and seat. Steve just got a set of heads dropped off from western Pa. to install new seats to fix the valve heights .

Don't throw stones they may come back.

What you have to remember is most of us don’t have 50,000.00 plus to put into a state of art head machine. Nor have the money or desire to pay for someone else’s machine. I and most of my customers race for fun and do so on a budget. Edelbrock and many other don’t have consistent spring heights from the factory so to get them right you would be sinking valves. As crude as stones are many many racers used them to go fast for many years. What’s the going rate for a 5 angle valve job??? 300-350.00 I’m guessing. I do my junk exactly like I do my customers and it runs pretty good and hold up well. We all have options on how much we want to spend but I have noticed one thing. Most of the guys that have engine shops no longer race or do so on a very limited schedule. Hmmmmm

 

[rmchrgr]

I hear good thing about having both shaft and pushrod oiling in unison.

I could be wrong but after reading about pushrod oiling until my head was going to explode, I'm of the opinion that too much oil up top is not a good thing. If there's excess oil just sitting there in the head trough you end up starving the bottom end where the oil is needed the most. Wives tale? I dunno but oil surely does not drain back into the crank case a fast as it gets pushed through the galleries or orifices.

I thought about that dual oiling scenario myself but concluded it's not a good idea. I'd say either one or the other but not both since pushrod oiling (generally) requires blocking the feed to the heads because the oil is now coming through the pushrods. Besides, you'd need rocker arms that pushrod oil (basically T&D = $$$). But eithr way, the main drawback to that idea is that you'd have pretty low oil pressure if you're feeding oil to the top through two separate circuits instead of just one. The less leaks the better, right?

Just as an example, I used to shift my old W2 340 at 7,200 with the standard shaft oiling system and a HV oil pump with no observable issues. I didn't know as much then as I know now but I definitey would have known if things were getting burned up due to a lack of oil or what have you and for sure they weren't. General wear from use/heat cycling etc. is a different story.

 

[Newbomb Turk]

He don't use a grinder on parts that are not ours to grind on unless its body work. When customers have heads $3500 , rockers $2000, We modify the Head studs they only cost $100.

Drilling the head doesn't guarantee the stud is in the center and not blocking the oil feed holes . Yes if needed you can install a restrictor and know the exact restriction you have once the oil is sure to reach the restrictor under the rocker shaft. Or you can drill and grind and guess at your work.

Like the Edelbrock heads we just got in with the valve seat heights and spring pockets all over the place from doing them by hand with a New way cutter set. Using a precision machine with digital readout duplicates everything that is done to the same consistent measurement on every valve and seat. Steve just got a set of heads dropped off from western Pa. to install new seats to fix the valve heights .

Don't throw stones they may come back.

The guy that taught me 10 years ago to just oversize the hole has been doing it since the 60’s.

The oil will get around the stud even if the stud isn’t quite centered in the hole. If you use a mill, the hole will be in the exact same place as the bolt was, so if it’s off it would have been off with the bolt as well.

Im not sure what ARP would say about milling a stress riser in the stud. Maybe I will call them and see what they say.

 

[Newbomb Turk]

I just got off the phone with ARP. They said any time you have a stud (or bolt) in tension like that if you get a nick in it you should replace the stud (or bolt).

ARP said do not kill a trench in the stud.

Not my words, that came from ARP.

 

[rmchrgr]

Yeah, I tend to agree with the above. Sorry Oldmanmopar, even though I sort of understand the concept, I'm really not seeing the benefit of the recess in a real-world situation. Besides, reason says that if cutting a relief in that particular stud is 100% necessary, ARP would provide a modifed stud intheir kits. Studs are simple things. ARP would never sell them if there was a need for the end user to modify them after the initial purchase.

In my heads, there are two oil holes in the intake side of that bolt hole. As we're all aware, the oil passage that goes up the rocker stand right next to that bolt hole is pressure fed so the oil is forced up to the rockers through it. Frankly, I'm not even sure why those holes are there but my guess is they act as a bleed to slow down the oil just enough so it doesn't gush out the top.

Either way, cutting that recess in the stud would effectively reduce the oil pressure by some amount because you're adding volume to the oil path by whatever amount is represented by the area of the recess. How much is presure is lost is probably not worth debating but Boyle's law states adding more volume always reduces pressure. Always.

Plus, if you run a high volume oil pump, you're already creating a slight loss of pressure so the recess would add to it.

 

[pittsburghracer]

The 100.00 fee to have it done is enough for me. I hope that’s at least for the set.