Eddy rpm heads with arp studs question

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Pushrod26

Pushrod26

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Hey everyone. I hope yall are doing well and staying healthy. I have done a lot of searching and can not find an answer on this. I have a question for the small block pros out there. I have a small block LA 360/408 stroker that I’m finishing up, and I have come across something that I’m not sure of. I have edelbrock rpm LA heads going on this motor, and I bought a set of arp head studs specifically for the eddy rpm LA heads. The heads were bought brand new and came with one skinny head bolt that oil will flow around to lube the rockers. The arp head stud kit did not come with any studs that are skinnier then the rest. All of the studs fit inside the mounting holes with little room to spare. Is this going to be an issue? I don’t want to get the heads on and torqued down and find out I’m not getting oil to the rockers. Any info on the situation would greatly appreciated.
 
You will be fine. I tube my oiling hole on each head when I bore them so mine are even a little smaller. And I installed a drilled brass set screw in my rocker stand to restrict my oiling to the rocker even more.
 
The reason the heads come with a bolt is because they use two of the long bolts that go between the intake ports, unlike the stock heads which only use one long bolt.
The bolt is supplied for if you’re swapping from stock heads and plan on reusing the bolts over.
Without that one additional long bolt...... you couldn’t finish the job.
 
The bolt/stud to head hole clearance is just one more in about 3 or 4 restrictions in the flow path to the rockers, and is not smaller than any of the others. Realize that there is not constant flow up that passage... just 'spurts' of oil about 5% of the time. So the average flow and pressure are very low.
 
I called edelbrock and they said the bolt that is supplied with the heads is a skinnier bolt then the rest of the head fastener bolts/studs should be, so oil can flow around it freely. If people are running arp head studs without a skinnier stud for the oiling to the rockers location, I will give it a shot and see what happens when I prime the motor.

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The bolt you are referring to is a rocker shaft hold down bolt. All it does is hold the rocker shafts down in the saddles, they do not affect the head bolts or head studs themselves.
 
Demonracer said:
The bolt you are referring to is a rocker shaft hold down bolt. All it does is hold the rocker shafts down in the saddles, they do not affect the head bolts or head studs themselves.
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He’s just posting that picture to show the rocker oiling hole that leads to the head bolt he is referring too. He’s afraid the head bolt stud won’t allow enough oil past it to oil the rockers, but it will.
 
Well great day in the mornin'.....It's been so long since I've been in a small block, I forgot all about how oil goes through the head bolt passage first.
On a different note, are those marks on the valvestems really your scrub pattern?:eek:
:poke:
 
beanhead said:
Well great day in the mornin'.....It's been so long since I've been in a small block, I forgot all about how oil goes through the head bolt passage first.
On a different note, are those marks on the valvestems really your scrub pattern?:eek:
:poke:
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These heads have never been ran ever before. They are fresh out of the box from Hughes engines with what looks like sharpie ink on the top of the valve stems. What that’s there for, I have no idea. I also have Hughes engines roller rockers, and they roll perfectly dead center on the valve stems. As Pittsburghracer mentioned, I’m not talking about a rocker shaft hold down bolt or stud. I am talking about the head stud that holds the head to the block. If you guys say the head stud won’t completely block or restrict the oil to the rockers to a point of negative affects on my pricey Hughes roller rockers, I’ll give it a shot and put it all together and see what the oil Flow looks like at the rockers when I prime the motor. If I get oil flow at the top that I’m happy with, then I will run with it. I’ll report back here with a video or at least a link to a YouTube video of the prime for everyone to see before I actually turn the key and get this thing burning fuel. I do feel better knowing there are people out there running small block LA engines in the same situation I am in right now.
 
I think the bottom line is that those who have done this before you have not ever reported any issues. I was concerned over it at first, but computed all the flow areas at the restrictions in the path and this one is no smaller than the others when you put in the stud. There is a restriction between the rocker hold down bolt and the hole in the rocker shaft over that head passage that is just as small or smaller. Again, there is not real 'flow' in this passage it is just 'spurts' over and over. If you are running 7-8k RPM a lot, like in circle track racing, then every restrictions has to be looked at, as the 'spurts' get 'leaner'.

BTW, the roller pattern being centered on the valve stem is not the indicator that you look for, for best geometry. It does not have to be centered, regardless of what the Comp site says LOL. But that is another can o' worms.
 
"I also have Hughes engines roller rockers, and they roll perfectly dead center on the valve stems."
so what?
 
You want enough oil to lubricate the rocker and cool the springs. A decent flow is required, but not Niagara Falls type flow. Not a drip, nor a fire hose.

I restrict the oil in the pedestal quite often depending on the build. If you have a grooved magnum cam in an LA normally uses a cross drilled cam, it can be quite the issue on some builds.
 
nm9stheham said:
I think the bottom line is that those who have done this before you have not ever reported any issues. I was concerned over it at first, but computed all the flow areas at the restrictions in the path and this one is no smaller than the others when you put in the stud. There is a restriction between the rocker hold down bolt and the hole in the rocker shaft over that head passage that is just as small or smaller. Again, there is not real 'flow' in this passage it is just 'spurts' over and over. If you are running 7-8k RPM a lot, like in circle track racing, then every restrictions has to be looked at, as the 'spurts' get 'leaner'.

BTW, the roller pattern being centered on the valve stem is not the indicator that you look for, for best geometry. It does not have to be centered, regardless of what the Comp site says LOL. But that is another can o' worms.
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I’m just going off of what the guys at Hughes engines is telling me for rocker roller contact on the valve stem. Hughes website says in a tech article, for best valve train geometry, the roller should be centers on the valve stem. Everything about my motors valve train is Hughes engines. This motor will spend a good amount of time up in the 7k+ rpm range, so I guess I will have to figure something out for the rocker oiling situation. I don’t think it will get enough oil up top. Also, the eddy rpm heads are only temporary, and will be for sale soon. I will be ditching the eddy heads for a set of trickflow power port 190 heads and intake manifold in the near future. When I bought the eddy heads, trickflow hadn’t released there power port heads yet and I thought I’d have this motor in the car and running before trickflow released the power port heads, so I went with the eddys just to get it up and running while I wait for the trickflow’s. I also had my tremec tko 5 speed transmission that this motor will be bolted too, built to handle 6500+ rpm shifts.

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^^ That B3 site is a much better source of knowledge. OK if that info of centering is on the Hughes site.... but it's still not the parameter you look at. Roller tipped rockers simply don't have to be centered on the valve stems.. just not too near either edge.

They might be at best geometry be when centered, but then again they just as well can have a wider scrub pattern than they should and so that is not optimum. My son's 340 has the Hughes rockers on Edlebrock heads, and the pattern is near center, but not nearly the minimum scrub width that it could have. So that combination is not optimized, despite being near center.

But hey, if your heads are changing, then not any real issue for now.

Nice trannie!
 
Pushrod26 said:
I called edelbrock and they said the bolt that is supplied with the heads is a skinnier bolt then the rest of the head fastener bolts/studs should be, so oil can flow around it freely. If people are running arp head studs without a skinnier stud for the oiling to the rockers location, I will give it a shot and see what happens when I prime the motor.

View attachment 1715529270

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If that’s how wide the pattern really is, I’d fix it. Centering the swipe at the cost of width is wrong. The fix is simple. Don’t skimp. You need to correct that geometry.
 
Pushrod26 said:
I’m just going off of what the guys at Hughes engines is telling me for rocker roller contact on the valve stem. Hughes website says in a tech article, for best valve train geometry, the roller should be centers on the valve stem. Everything about my motors valve train is Hughes engines. This motor will spend a good amount of time up in the 7k+ rpm range, so I guess I will have to figure something out for the rocker oiling situation. I don’t think it will get enough oil up top. Also, the eddy rpm heads are only temporary, and will be for sale soon. I will be ditching the eddy heads for a set of trickflow power port 190 heads and intake manifold in the near future. When I bought the eddy heads, trickflow hadn’t released there power port heads yet and I thought I’d have this motor in the car and running before trickflow released the power port heads, so I went with the eddys just to get it up and running while I wait for the trickflow’s. I also had my tremec tko 5 speed transmission that this motor will be bolted too, built to handle 6500+ rpm shifts.

View attachment 1715530844

View attachment 1715530845
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You could drill and tap the heads for external rocker oil supply and/or run oil-through pushrods. I had to do that on my Eddy heads because I put them on a late Magnum block that didn't have the rocker shaft oil hole drilled. Oil flows into the back of the head and up through a hollow rocker shaft hold-down bolt; nice thing about doing it that way is you can drill the rocker bolt to a specific size for the right amount of flow. Mine were way too big initially so I welded the end of the bolt shut then drilled a smaller .040" hole, now my hot oil pressure is where it should be. I like the peace of mind knowing the rockers are getting constant oil flow not just momentary spurts like the factory system. I only rev it to about 6000 RPM but I am running stock LA stamped rockers with a custom-grind hydraulic roller cam at just under .550" lift so it's kind of at the limits of the stock rockers. I definitely plan to upgrade to roller rockers and a B3 geometry kit but it already runs great I'm having a hard time justifying the cost for little to no performance increase.

For real though check out B3 Racing Engines website, he basically disproves the "conventional" understanding of rocker geometry you see perpetuated by all the big cam companies. There are very complex physics going on with pushrod valvetrains I had no idea about until I read the articles on his site which nobody else (COMP, Hughes, etc.) even mentions.
 
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