RPM mods

[ScotiaFE]

So I was in town today and found the best looking air filter for a round 14".



And I was doing some mods on a RPM. Hacking away at the ports. Elongating the push rod holes
and opening up the oil drain back.
But the air filter is GREAT! Love the red.

[KMcCullah]

I see it's a Spectre. Is it washable/reusable? Like a K&N?

[ScotiaFE]

.

I see it's a Spectre. Is it washable/reusable? Like a K&N?

It is a cotton washable type. Although I would imagine the very Kool red will not last for ever.
I like the bold colours and pretty much stop using them when they start to look raggedy.
SPECTRE is also my fav evil company. Looking forward to the new flick.
Hey, he's a navy salt, what can I say.

[ScotiaFE]

So I did so more hacking on the RPM.
Here is a better pic of the pushrod hole work. This is an important step.
Especially for us home builders. You need to pay close attention to the pushrod to intake clearance.
Those rollers have some long ramps.



I'm lucky to have a big ass drill in my shed, but all this can be done with a small compressor and a cheap die grinder.
It just takes longer. 

The ports pretty close to finish. I should dress a couple of sides again.
The port tapers down for about 2 inches so you need to use some dividers to gauge the port as you work in.



Here is a stock RPM.



And a stock Ed head intake port.



It probably took me 10 hours to whittle this out.

[jayb]

Looking good, Howie.  That extra pushrod clearance will come in handy...

[Joe-JDC]

Measure those Victor gasket openings.  They are different widths on the sets I have checked.  Joe-JDC

[ScotiaFE]

Measure those Victor gasket openings.  They are different widths on the sets I have checked.  Joe-JDC

I may actually may reuse them. I have a couple of spares of them also. From the before time. lol

[ScotiaFE]

The oil drain back issue.
Here is a pic of a Cobra Jet head oil drain hole.
The large hole is 0.700" and the step hole is 0.610".



Here is pic of the Ed head oil drain hole.
The large hole is 9/16" and the step hole is 7/16".



So after the oil slot mods this is what the oil drain back looks like.



Staying with the "you can do this in the shed" I drilled the holes out to 1/2" with a hand drill.



Of course the batt was out of gas. That's why robots will loose. They run out of gas.



I also roughed out the exh ports.

[ScotiaFE]

This next part is a "may" require. If your using the stock Edelbrock springs the helicoil is fine.
These heads are going to receive a pretty good spring so I will be changing out the wire
for a more robust thread insert. Everyone one of these steps is completely doable in the shed
with basic hand tools. I used the lathe to drill out the bolts and the mill for accuracy but it can be done on the work bench.
You will need a big pile of patience though.

The basic pile of junk you will need.



Pull out a wire.



Pull out all eight.



So then I was looking at the head and thought, now is the time to address the oil feed issue.
I drilled it out to #7 for a 1/4 20 thread.



Tapping. Brownie points if you know who made the tap.



Using a set screw you can easily adjust the orifice size as needed.



The home made thread inserts



Drilling the rocker pads.



The thread inserts, still a tad long.



Almost to size.



The finished thread insert.



Only seven more to do. I'll finish them up in the morning.

I know you can buy different types, but the kind I wanted where not on the shelf and would have been a
special order and outside the time window.

[jayb]

What's the thread size on those inserts you made, Howie?

[Barry_R]

Cool.  We have done similar.  Usually after the helicoil pulled rather than before.  Actually we have gone "full stupid" on this mod before using vise sized 5/8 threads when repairing them..

[ScotiaFE]

What's the thread size on those inserts you made, Howie?

I started with a 9/16 12 grade 8 bolt and tapped it for 3/8 16.

[ScotiaFE]

Cool.  We have done similar.  Usually after the helicoil pulled rather than before.  Actually we have gone "full stupid" on this mod before using vise sized 5/8 threads when repairing them..

Thanks. The 5/8 11 thread in the rocker pad is probably a better call for the home builder also.
It will be easier to locate a 5/8 11 tap set than a 9/16 12 set. 9/16 12 is not a common thread and tooling
will always cost more when the "not common" comes into play. Something like the FE.
Although the Time Sert which is probably the best thread insert is a 9/16 12 for the 3/8 16 internal thread.

[jayb]

I've used E-Z Loks in the past with good results.  They are available from Enco (www.use-enco.com).  Here's a picture out of the catalog, showing the available sizes.  They even come in the "full stupid" 5/8-11 thread size:

[BruceS]

Do you typically use the carbon steel inserts?

Thanks,
Bruce