Junkyard 5.9L Magnum + Edelbrock LA heads build

-
So I talked to my machinist today and the heads have been drilled for the external rocker oiling, I'm going down this Wednesday to pick them up. When I go there I'll ask him about the head gaskets vs. factory deck finish issue, I don't mind spending the money on Cometics I just don't want them to leak or I'll be piiiiissed!

Stay tuned for some cylinder head **** you're gonna want to see these...
 
Got the heads back... unfortunately he wasn't able to drill the oil passages at an angle, i'm thinking of cutting a groove up the side of the rocker shaft bolt because the oil has to get past that somehow. He did that and re-tapped the threads on the side where it will feed for 1/8" NPT for free so can't really blame him.

Curious what y'all experienced porters think of the port job i'll get some more pics with better lighting...

20181219_155109.jpg


20181219_155035.jpg


20181219_155027.jpg


20181219_155049.jpg
 
nm9stheham said:
IIRC, the Edelbrocks do have a groove up the side of that one rocker stand.
Click to expand...

True but that's one of the middle stands (second from the front/back), this one is on the end closest to the back of the head. I confirmed by threading in a rocker shaft bolt and I couldn't get any air to go through with the bolt in.
 
Ah... so where are you feeding the oil into the head? You got me all perplexed now LOL,,, is this discussed earlier in the thread?
 
nm9stheham said:
Ah... so where are you feeding the oil into the head? You got me all perplexed now LOL,,, is this discussed earlier in the thread?
Click to expand...

Here's a pic I took with the stock LA rockers I cleaned up just now (Simple Green is awesome, mild enough to use indoors), you can see the arrow drawn on the side of the head points to the factory accessory bolt hole which just so happens to line up almost directly with the rocker shaft bolt. I intend to plumb a line with a T (or 4-way if possible) off the oil pressure sender port on the back of the block.

20181220_172702.jpg
 
Seems like a decent solution.... out of the way. Where do you plan to put the restrictions? You're gonna have full pressure so I would think restrictors smaller than those used in an LA blcok would be needed.

If you look at the rocker shafts you will see the 2nd and 4th rocker shaft bolt holes are larger on the lower side of the shaft to accomodate the oil flow up from the stand. So you may need to enlarge that back hole.
 
rumblefish360 said:
Have you seen this done before?
Click to expand...

I haven't seen it but it's been mentioned in past threads. I know it's not OEM reliable but I think if I use proper high-quality fittings and tubing it'll work. Careful planning and routing too.

FWIW I'd rather have an external oil supply outside of the engine as opposed to through the valley, if anything leaks i'll be able to see it instantly...

nm9stheham said:
Seems like a decent solution.... out of the way. Where do you plan to put the restrictions? You're gonna have full pressure so I would think restrictors smaller than those used in an LA blcok would be needed.

If you look at the rocker shafts you will see the 2nd and 4th rocker shaft bolt holes are larger on the lower side of the shaft to accomodate the oil flow up from the stand. So you may need to enlarge that back hole.
Click to expand...

I looked closely at the holes on the rocker shafts, they all seem to be the same oversize. I bet it was easier for manufacturing just to drill them all the same diameter. Besides the oil will be traveling up through the bolt basically.

For oil restriction it'll be a bit of a trial-and-error deal, I think i'll try an orifice at the block outlet. For testing I got the idea to saw the tops off some stock LA valve covers and run the oil pump with a drill while turning the engine by hand, that way I can test it on the stand before it goes in the car and gets fired up.

I'll be going to a local plumbing supply shop and see what advice they might also have, it's basically a hydraulic system.
 
Last edited:
OK, well double check top and bottom. I have 6 shafts; all have the same sized 5 holes on top, and that same sized hole on bottom in positions 1, 3, & 5, but positions 2 and 4 are larger (on the bottom only). (All my shafts are from the late 60's or early 70's.)

Just be aware..... if there is some nebulous difference in the restrictions going into the 2 shafts downstream of a single restriction, you could get most of the flow into one side and end up starving the other. (It's exactly like any other hydraulic system that way.) With 2 restrictors, each side will be separately regulated, and flow into one won't effect the other...... like the factory did with feeding both head separately.

Good on the testing IMHO. You just need them dribbling....We used the same open top cover trick, running with a drill AND running live.
 
Well I got the lifters in and put a head on to mock up the valvetrain and my suspicions were confirmed... I need to clearance the pushrod holes in the heads due to the different angle from the roller lifters. Not a huge deal they just barely touch at max lift.

I looked at the rocker shafts again, the 2 and 4 holes are juuust a hair bigger than the 1, 3 and 5 but all of them are quite a bit bigger than the diameter of the shaft bolt. Plenty of clearance around all of them.

Good point on the dual restrictors I hadn't thought of that issue... I'm sure something will cause it to be unequal side-to-side
 
FWIW, those larger holes around bottom holes 2 or 4, when a bolt is inserted, have a smaller flow area that the rocker oiling passage passage up through the LA head or block, or the oil passage through the cam. I suspect you are right in thinking you are going to use a far smaller flow area with the full oil pressure going into this feed. A .100" diameter restrictor would have an open area about 1/4 of the area of the more open shaft hole with a bolt through it, so the smaller shaft holes will be an even more noticeable added restriction. Just be aware it is there, so that something like the shaft shifting a bit when mounted does not come into the picture.

I look forward to seeing how this works out!
 
nm9stheham said:
FWIW, those larger holes around bottom holes 2 or 4, when a bolt is inserted, have a smaller flow area that the rocker oiling passage passage up through the LA head or block, or the oil passage through the cam. I suspect you are right in thinking you are going to use a far smaller flow area with the full oil pressure going into this feed. A .100" diameter restrictor would have an open area about 1/4 of the area of the more open shaft hole with a bolt through it, so the smaller shaft holes will be an even more noticeable added restriction. Just be aware it is there, so that something like the shaft shifting a bit when mounted does not come into the picture.

I look forward to seeing how this works out!
Click to expand...

I had to think about that for a minute but I see what you're saying. Something I also have to consider is there will be oil supplied to the top end through the pushrods which might make it tougher to keep from over-filling the rocker space. If that becomes an issue where I "turn down" the oil supply to the rocker shafts but there's still significant flow out of the pushrods I may have to get solid pushrods. I like the idea of having oil pressure directly at the pushrod cups though, isn't that an area that sometimes needs attention on LA builds with big cams and valve springs? Smoking out pushrods and punching holes in rocker arms, etc.
 
Something that would be really helpful... does anyone here happen to have a video of an LA engine running with the rockers visible so I can see what the factory oiling volume looks like? So I have a better idea of how much oil is enough oil?
 
I recall Yellow Rose discussing galled pushrod cups at high RPM's with rockers like the 273's, oiling via the standard LA top-end oiling system. I very much suspect that the stock top end oiling restriction... that of the cam hole lining up to allow oil flow for <10 degrees of cam rotation once per revolution...... is the culprit. When the RPM's get high, the time window of these openings gets so short that the oil's mass in the passages just can't get accelerated adequately during that short time window, and this is made worse by the long length of that oiling path. So the top end starves more and more as RPM's go up.

Seems like the direct oiling via pushrods would solve that. Your approach would also help as there is nothing to limit/stop the flow to the rocker shafts at higher RPM's; it ought to stay constant as long as the pressure is constant.
 
Funny enough, I just did this to my Magnum block/ speedmaster head build. Don't mean to hijack just figured I would show how I did it.

Started with a 1/4NPT tap at the hole, then used a 1/16 drill bit to break through into the rocker stand. Unfortunately I didn't get any pictures of drilling out the mounting bolt but I did use 1/16 up the shaft and slightly smaller for the cross hole in the bolt.
48397026_10210470612840459_4508213036426723328_n.jpg

48412181_10210470612360447_572507303626932224_n.jpg

Connected the 2 using small -3AN brake lines from allstar.
48429002_10210470611880435_2393515218849234944_n.jpg
48385031_10210470612120441_4497650174247567360_n.jpg
 
Last edited:
Toluene56 said:
Funny enough, I just did this to my Magnum block/ speedmaster head build. Don't mean to hijack just figured I would show how I did it.

Started with a 1/4NPT tap at the hole, then used a 1/16 drill bit to break through into the rocker stand. Unfortunately I didn't get any pictures of drilling out the mounting bolt but I did use 1/16 up the shaft and slightly smaller for the cross hole in the bolt.
View attachment 1715264937
View attachment 1715264938
Connected the 2 using small -3AN break lines from allstar
View attachment 1715264939 View attachment 1715264936
Click to expand...
Aaa - HA!

Your the person that I had in my head who did this!
Your pictures are in the back of my head.

Now, the rocker shaft bolt hole has a modification to allow oil up into the shaft? (I think I need a diagram.)
 
rumblefish360 said:
Aaa - HA!

Your the person that I had in my head who did this!
Your pictures are in the back of my head.

Now, the rocker shaft bolt hole has a modification to allow oil up into the shaft?
Click to expand...
actually I just completed this tonight.. the original Idea i got from a moparts post from 2012 I think.
and yes the shaft bolt is drilled down the center and then a connecting hole about where the inside of the shaft would be.
LA heads on Magnum Block??? | Unlawfl's Race & Engine Tech | Moparts Forums
 
HEELLL yeah @Toluene56 that's brilliant! You saved me a lot of time trying to figure this out thanks... I was thinking the whole time I'd be having to use hard lines for some reason. What are the other parts you used like the fittings and Tees, where did you get them? I like how you have the tee coming off the brass block there gives a little more room for the distributor. How's the clearance to the firewall in the car?

Also I don't have a drill press so drilling a hole through a bolt isn't really possible for me but it would be ideal...
 
Last edited:
MOPEkidD-3 said:
HEELLL yeah @Toluene56 that's brilliant! You saved me a lot of time trying to figure this out thanks... I was thinking the whole time I'd be having to use hard lines for some reason. What are the other parts you used like the fittings and Tees, where did you get them? I like how you have the tee coming off the brass block there gives a little more room for the distributor. How's the clearance to the firewall in the car?

Also I don't have a drill press so drilling a hole through a bolt isn't really possible for me but it would be ideal...
Click to expand...
where the engine sits I should have plenty of room, gonna be close but it shouldn't hang up on anything. If i have to modify the tee or change to a different style I will. Maybe take the hold down bolts down to a shop and ask if they can drill the holes for you? Hell, even a cheapo harbor freight drill press would work too.
as far as parts I purchased them from summit, being as I live in Reno and there is one local.
I drilled and tapped the holes at the back of the head for 1/4NPT so those fittings will be that size.
Here is the list of parts I bought - summit part #s:
ALL46300-10 - 10 inch -3an line
ALL46300-6 - 6 inch -3an line
AT982503ERL - 1/8npt to -3an tee
482334-BL x 2 -1/4npt to -3an 45* fitting
16775NOS - 1/8npt male to female tee
 
Honestly.. I would probably get 90* fittings instead of 45s the ones I have stick out a fair amount and I'll probably have to change them later on.
 
You must log in or register to reply here.
-

Back
Top