[hurryinhoosier62]

Originally Posted by 1969GTO

He's the builder with over 30yrs experience....not me and no issues with engine, also my engine is a street/strip only, not a race engine.....if that matters?

I've seen street Pontiacs with clogged RH oil galleries because particulate matter fell out of suspension. I NEVER build a street Pontiac WITHOUT this provision.

[Tom Vaught]

I have used the drilled plug for about 40 years. A WW-II mechanic that worked for my Uncle's Pontiac dealership put me on to the mod, even for a factory gear.

He thought the sludge removal and the removal of trapped air on the passenger side oil gallery was as important as the oil lubing the distributor gear.

He said at some point the last two hydraulic lifters would see air (if there was no bleed) and get noisy. Smart Man.

So the Engine builder was giving you good info even though you had never heard of the mod. There are several little engine mods that can make a pontiac engine a lot more durable. Thrust bearing mods for one (as related to oil flow).

Tom V.

ps Some people restrict the oil lifter galleries to the top end. Hardened set screws. Hard to drill. EASY to drill if you hit the set screw with a torch first and remove the case hardening. The restrictor is there to either add some oil or restrict some oil. No real load on the part so no need for a case hardened surface.

[KEN CROCIE]

Super Duty and maybe RA5 (Tom S confirm)had a .030" drilled hole from the factory. Where do you think H-O got the idea from?? We-H-O-made up a DIY kit.
.030" is not a magic #. 1/32"(.03125") is close enough. I had Kevin(crocie jr) drill one @ .020" and test via an oil pump priming tool. Oil barely trickled out @ 60 psi. He tested one @ .060" and had a gusher. .030" to .035" was goldilocks. You don't have to drill the stock plug-it's too hard anyway. use Al., Brass, stainless, or iron-(water pipe dept.)

Same with lifter restrictors. Use softer material. H-O used Stainless 1/4-20 set screws with a nylon patch.

[tom s]

Ken,I really dont remember!It would make sense with the 80 lb pump.If they did I guess I would have assumed a builder did it at sometime and not the factory.I know the factory large dist gear was a diff material.Looked way dif from a stock small one.Had somekind of coating on it.Tom

[KEN CROCIE]

The SD gear and the 60 psi gears were cadmium plated.

[61-63]

Originally Posted by Tom Vaught

I have used the drilled plug for about 40 years. A WW-II mechanic that worked for my Uncle's Pontiac dealership put me on to the mod, even for a factory gear.

He thought the sludge removal and the removal of trapped air on the passenger side oil gallery was as important as the oil lubing the distributor gear.

He said at some point the last two hydraulic lifters would see air (if there was no bleed) and get noisy. Smart Man.

So the Engine builder was giving you good info even though you had never heard of the mod. There are several little engine mods that can make a pontiac engine a lot more durable. Thrust bearing mods for one (as related to oil flow).

Tom V.

ps Some people restrict the oil lifter galleries to the top end. Hardened set screws. Hard to drill. EASY to drill if you hit the set screw with a torch first and remove the case hardening. The restrictor is there to either add some oil or restrict some oil. No real load on the part so no need for a case hardened surface.

What are the other mods Tom?

[meanone]

Why don't people ever talk about or use the oiling system that Pontiac built into their engine? I've been messing with Pontiacs for 24 years and all I've ever heard about is the drilled plug when it comes to distributor gear oiling. Earlier this year I was working on my distributor and looking at the machined flat spot on the distributor housing. I realized that when the distributor is installed like Pontiac wanted it with the vacuum canister on driver side that flat spot is directly above the cam/distributor gears. The oil hole feeding the distributor bore is a lot bigger than .030" so the gears must be getting showered when set up right. Early Chevy's used a similar system too. I don't know why aftermarket distributors like MSD doesn't come machined with the flat and instructions to use this oiling feature.

[Sun Tuned]

You can take that one step further.

Look at what they were doing with a cast iron housing distributor versus what ended up happening with the aluminum housings up to the end.
Fwiw.

[steve25]

x2 with Suntune !
Unfortunately many guys get around to drilling this hole thing on a Saturday, or Sunday nite and then they are stuck trying to drill the stock plug, or even a harder metal plug like a steel Allen set type!
If you take either type plug and heat it up until it glows orange in a dark room and then keep heat on it and cool it down slow you will then be able to drill it with non high speed bits.
Drill most of the way thru it but for .020" and then use the bit of .030" or so, job done in 15 minutes!

Also a roller timing chain does not even need the amount of oil that comes out if that stock size front lube hole unless the motor never see's over 2500 rpm!

[kpbrown31]

After searching on here, it seems the consensus is to just drill the rear, passenger side plug? And NOT the front plug to lubricate the timing chain. I had some plugs that came with a block and the rear one seems like it was drilled to .030 with an eyeball test, but the front plugs almost look like a 1/16". I just planned to throw the front ones away and replace with standard, non-drilled plugs. Also being mindful of plug depth to avoid oil starvation.

[steve25]

The timing chain gets plenty of oil from the passage feeding the fuel pump excentric, so no need to bleed off any more oil pressure with front galley holes.

If you drill & tap the front galley for plugs make note that there's a cross feed oil oil on one side so you can't tap that hole to deep otherwise you will partly block that oil passage off before the plug gets tight enough to both seal itself and hold .

[Bruce Meyer]

Originally Posted by kpbrown31

After searching on here, it seems the consensus is to just drill the rear, passenger side plug? And NOT the front plug to lubricate the timing chain. I had some plugs that came with a block and the rear one seems like it was drilled to .030 with an eyeball test, but the front plugs almost look like a 1/16". I just planned to throw the front ones away and replace with standard, non-drilled plugs. Also being mindful of plug depth to avoid oil starvation.

I put a hole in the front driver side plug in my motors. I noticed no difference in oil pressure. More oil on the chain is a good thing.

[Schurkey]

Originally Posted by kpbrown31

After searching on here, it seems the consensus is to just drill the rear, passenger side plug? And NOT the front plug to lubricate the timing chain.

Originally Posted by steve25

The timing chain gets plenty of oil from the passage feeding the fuel pump excentric, so no need to bleed off any more oil pressure with front galley holes.

Originally Posted by Bruce Meyer

I put a hole in the front driver side plug in my motors. I noticed no difference in oil pressure. More oil on the chain is a good thing.

The spurt-hole in the FRONT plugs has NOTHING to do with oiling the timing chain. The chain may get more oil, but it's adequately lubed without the oil gallery plugs getting drilled. Any additional oil on the chain is INCIDENTAL, but not the primary purpose.

The primary purpose of drilling the plugs in the FRONT is to BLEED AIR FROM THE OIL GALLERIES AT STARTUP, so the air in the oil galleries doesn't have to go through the lifters in order to escape. Therefore, the lifters get less air and don't clatter--or at least there's less clatter at startup.

[charlie66]

I drill the plug with a 1/8" bit like 7/8" of the way then finish it with a .030 bit . It makes it much easier and faster..

[Dragncar]

I have a .030 hole in front of the distributor gear and a .023 hole in the driver side front plug. Less air, more oil, better.
I found the factory square plugs are easier to drill than a steel Allen plug. Like others have said, drill a 1/8" more of the way and finish with the smaller bit.
I have lots of time and effort int modifying the oiling system on my engine and I feel its well worth it.
Currently pondering ditching my K&P screen filter for a full flow remote.

[steve25]

The problem with drilling anything ( but especially steel) that most folks just don’t realize is that I drill bit really does not even begin to cut well unless it’s full face is in contact with what you want to drill.
This is because it’s the flute / OD of the bit that does the cutting.

If you can’t center punch the metal your drilling to make a depression at least the same OD as the drill bit then you need to start off with a series of smaller size bits.

[Schurkey]

Originally Posted by steve25

...it’s the flute / OD of the bit that does the cutting.

If you can’t center punch the metal your drilling to make a depression at least the same OD as the drill bit then you need to start off with a series of smaller size bits.

I'd disagree with this.

The center-punch mark can be significantly smaller than the OD of the bit. You wouldn't center punch a half-inch mark to drill a half-inch hole. Might be nice if the center-punch mark was as large or slightly larger than the web of the drill bit; and if that's excessively large then a pilot drill the same diameter as the width of the final drill bit's web is suggested.

Similarly, I do not recommend using multiple drill bits so as to "sneak up" on the final hole size. It's a great way to tear-up the OD of the cutting lips of the bit. Pilot drill about the same diameter as the final drill's web, and then drill with the final size bit.

The web is called the "chisel edge" in this diagram from Viking.
https://www.vikingdrill.com/viking-DrillBitTerms.php

[mrennie]

Schurkey for the win, as always.

Never yet read a post that wasn't educational. Appreciate you sharing your knowledge.

[Schurkey]

Originally Posted by mrennie

Schurkey for the win, as always.

Never yet read a post that wasn't educational. Appreciate you sharing your knowledge.

Gonna make me blush. You are very welcome. One of the many services I offer...

[Dragncar]

If you know how to sharpen a drill bit you can punch a 1" drill through a 1" mild steel plate with nothing more than a center punch mark.