What's this hole for???

[80convertible]

Zies8,

You and I are looking at the same hole. The hole to the right is for some type of clutch linkage. I do have a manual, but no linkage at that hole to the right. Its empty. I'm trying to unplug the hole to the left which is cast into the block. Funny someone else would be wondering the same thing.

Regards,

Jim

 

[69MyWay]

Jim,

That hole that goes into the flywheel area is just for a bolt to hold a ground strap, plug wire loom, etc. etc.

Believe me, if the plug was open just above the filter you would not make it 25 feet at 800 RPM before all the oil was on the ground.

 

[vigman]

Uh Oh

So the info I saw was a Hi-Po modified block,

Looks like it's time to T the oil pressure line
Short of pullling the block, drilling ,tapping etc.

Mike

 

[vigman]

Live from the boneyard!

So after inspecting about 12 small block motors

You have the hole for the clutch support
At a 45 degree angle
Down by the Oil filter
In the side of the block
There is the magic hole of OIL FLOW

10 of the blocks had the temp sender
the other 2 had female square threaded plugs


Most of the blocks were blue
2 were orange

But they ALL had the connection point you seek!

Mike

 

[80convertible]

Thanks Mike,

Now that my cold has begun to fade, I can get back into the garage and look for the mystical plug in the hole. Part of owning a vette is being a good detective eh?

Regards,

Jim

 

[vigman]

Holy Oiley oil

So did you have the hole?

You have a 73 block right?

I went and bought MORE BOOKS
and everyone showed the picture of the MAGIC OIL HOLE!

Mike

 

[80convertible]

I've been very sick for the last week and have not been able to work on the car. I hope to get out in the garage over the weekend if this darn cold will go away. I actually have a 1970 Camaro/Nova 350 in my vette. Almost no part of my car is from the original 73 my car started as. Thats why my wife calls it Frankenvette

Regards,

Jim

 

[vigman]

Sorry about you being sick

I have some good pix's in the new books that might help for location.

The Camaro/Nova might not have it..
all the blocks I looked at were Vettes and I haven't seen mine ( which is not a Vette engine as well)

I'm getting the car back tonight ( If all goes to plan) Yeah right!

Sooooooo. There ya have it!

Mike

 

[80convertible]

Well,

I was finally able to get a good view of the mystical hole and concluded that its a blind hole. I could see no plug just flat metal about an inch into the hole. Go figure

Regards,

Jim

 

[Drummer72]

Sensor thread

Can anyone tell me what the thread is of this oil pressure port?
I've got some oil leaking out of the plug that's screwed in and holds the gauge hose.
Anyone know a solution to finish this leaking?

Jeroen

 

[Jack]

1/8" NPT (tapered pipe thread)

Can anyone tell me what the thread is of this oil pressure port?
I've got some oil leaking out of the plug that's screwed in and holds the gauge hose.
Anyone know a solution to finish this leaking?

Jeroen

1/8" NPT ... aka pipe thread ... it is a tapered thread ... commonly used throughout USA & elsewhere. I know it seems much larger than 1/8" but that is what it is ... 1/8" NPT.

The plastic tube gets brittle with age & will crack. Also, on my 71, the brass part that screws into block failed ... it had a very tiny integral ferrule that slipped inside the ID of plastic tube .. the ferrule broke off allowing tube to come loose ... all oil left engine VERY quickly ... engine did not survive. Suggest replace tubing from engine to gage ... inspect all fittings for stress/cracking ... replace if any are questionable.
JACK:gap

 

[vmrod]

The hole ontop of the block (near the distributor) is 1/8"NPT.

The hole that is right above the oil filter is larger than this. I recently went through a crazy project myself, because I wanted to put my oil pressure sending unit there. (to have it hidden from view and not ontop of the block)

Do a search in the C3 TECH forum for "oil pressure sending unit location". If you read this, you will see the trials and tribulations that I went through. In the end, I went to auto-zone with the sending unit, and the plug that went in the hole. I told them that I need a bushing to make this (the sending unit) fit into the hole that this (the plug) went into. I got the part and all is fine now!

 

[Jack]

clarification

I have a leaking oil pressure sensor on my '71. The fitting that is screwed into the manifold and holds that little hose is the culprit. It seems to be leaking where the hose comes out of the plug. Jeroen

I apologize, I should have described more clearly. The brass fitting & plastic hose/tube I refer to are common to both 71 & 72. It supplies oil pressure through tube to mechanical oil pressure gage. Neither 71 nor 72 had "oil pressure sending unit" as used in later C3s with electrical op gage. The 71 & 72 brass fitting screws into top-rear of block, very near the back of intake manifold, near distributor base ... that brass fitting and its hole in block are both 1/8" NPT.
JACK:gap