Drummer Boy

I recently got my block back from the machine shop. Assembly was straight forward however, There is a threaded opening on the drivers side of the engine, just above where the clutch pedal bracket bolts onto the block. It needs to be plugged and I can not prime the engine until it is but I can not fine anything that fits this opening.
There were two hex head screw in plugs left over from my freeze plug kit but they will not "start." I can not find anything that will screw into that opening.
It is clearly threaded and I suspect a pipe thread of some sort.
1/8 pipe is too small---1/4 pipe is too big. The closes thing that does go in is a 7/16 coarse thread bolt BUT even though it turns in it is far too loose and clearly not right.

I am sorry that I do not post a photo but that spot is ALMOST inaccessible now that the engine is in place. I CAN get a hand in there to screw something in but "exactly WHAT" is the problem.
Anyone have any idea what fits?
Eddie

66jack

Is this the area you're looking at?

mike mccagh

i believe that the hole was originally sealed with a freeze(soft) plug. i recently had a small block chevy engine rebuilt. the machine shop installed a freeze plug that leaked significantly. i then drilled and tapped the hole to accept a pipe plug. problem solved. mike mccagh

Robert61

If it's factory tapped it's a 1/4" npt. Some times they have a pressing plug which is an odd size and prone to leak as Mike said.

leif.anderson93

Eddie,
The area you're asking about, are you talking about where the ball stud screws into the block...where the clutch cross shaft is inserted? If so, could you possibly be looking at the hole where the spark plug heat shield bolts to? That's the only hole I can think of in that area. Except, the oil fill tube hole (but it's not threaded).

Drummer Boy

Yes, it appears so but yourphoto shows a predded in plug where mine is clearly threaded. I just can not find anything that will thread into it---one size is too large, the other too small.
Eddie

Drummer Boy

It is directly above and sligtly forward of where the clutcj clutch arm PLATE is attached to the block. I cant believe that something so simple and relatively non essential like the spark plug shield bolt would enter the oil stream.
When we went to prime the engine we pumped an astonishing amount of break in oil onto the floor.
At least I know that my oil pump works REALLY WELL.
Eddie

vark_wso

Drummer -- Here's 3 photos of LH side, '66, "8174" casting, 327. Please identify the threaded hole in question from these photos. All should be blind hole with no access to oil/lubrication.

leif.anderson93

Jeff,
Your pictures are always fantastic. And, I agree, there are no holes in that area that go through to an oil galley. I still think it's the bolt hole for the boomerang...we'll see.

Robert61

The 2 holes with black marks are clutch holes. The yellow high light is the hole that goes into oil. As I said if it’s tapped from the factory it’s 1/4” npt. If it’s a pressed in plug which many were it’s 1/2”. I won’t use the press in plug as they leak. If it was a press in plug from the factory it was 1/2” which is too big to be threaded for 1/4” npt.

67:72

Are you sure you're using a tapered-thread plug (npt) and not straight-thread (nps)?

Robert61

This is one with the 1/2” press in plug.







This is after I drilled it to 9/16” to tap for a 3/8” npt

smacota1

I recognize that block😋

Robert61

Why have you got it at a shop somewhere?

smacota1

No sir my friend. That was the pic you took when you built the engine. It is running perfectly after you laid your healing hands on it. Hope you are doing well. Cruising the Coast is on the radar this year........OP, sorry for the high jack. Hope you find the right plug.

See post #73......
https://www.corvetteforum.com/forums...-solved-4.html

Drummer Boy

Here is MY block. You will notice the slight difference in that the clutch plate holes are on the bell housing NOT the block.
I must have been seriously distracted to have MISSED addressing these two OBVIOUS openings BEFORE dropping the engine back into the car. The SIMPLEST and BEST way to deal with this is to pull the engine and get thongs to where I can SEE clearly and make the proper moved. In other words, do it right.
Who was it that said "if you dont take the time to do it right the first time you WILL find the time to do it right the second time."

The question still remains---just what WAS in there before the machine shop removed everything?

OR--"In the end, the longest way becomes the shortest way!"
Eddie
Lesson learned.

Drummer Boy

Right now I am not using anything because I could not get anything to "start" on the threads. It is simply too tight in there to be certain about anything.
Unfortunately I had to "cry Uncle" and give up on the project for the moment.
I began this rebuild back in FEBRUARY. It was to be tear it down, give it new rings and bearing ---fix those horrible Edelbrock valve seals and put it all back together.
The problem was--that ALL of the machine shops in the phoenix area are so backed up, many would not even take the job--they had "too much work". I gave it one guy and after twomonths he never even got close to doint it so I found someone who said he could turn it around in a week. ONE MONTH LATER I had to really press him to get to it.
I finally got everything back but now I was up against a deadline as I have work commitments out of town from June to Sept and only had two weeks to reassemble the engine.
The sad part is that one thing I specified was to have them install the cam bearings AND the plugs. They did the cam but never did the plugs.
So, the race was on and though I was careful, as time went on I began to hurry.
I SHOULD have primed the engine while on the bench, BEFORE reinstalling but I was so close to my deadline that I took the chance-AND came up short.
Yesterday I decided that since my name had not changed to Bubba-- I said---look--lets take a breather and do this the right way.
I labeled and catalogued everything, towed the car home and will simly hit it again when I get home and do it right--
pull the engine---deal with the plugs properly-whatever that means---do the prime on the bench and even fill the bock with water just to see if I missed anything there as well. THEN reinstall and start her up.
It will have to wait until Sept.
Now, I gotta go to work and pay for all this.
Thanks all
Eddie

Robert61

Now I can better see your situation. A is NOT an oil hole, there should be no oil coming from this hole. That Hole is 1/2 13 thread size. It is a clutch hole period. B is the main oil passage from the oil pump to the filter. Yours is not threaded. You should be able to clean it thoroughly, use some red Loctite, and install a 1/2” press in plug. As I said I tap it for a larger plug but you have it in the car. No way I would pull the engine to fix this problem. Your biggest problem is figuring out how to install the plug. I’m not guessing at any of this I’ve done it a zillion times.


I see a way to install the plug but I’ll wait until you try it.



I dont know if they removed it or not. There’s a plug that goes under the rear main cap. IT MUST BE THERE. If it’s left out will by pass the filter entirely. The only way to check is stick a 1/4” rod down the oil pressure sending unit hole by the distributor and measure how far it goes into the block

Drummer Boy

The hole you refer to as "B" is indeed threaded like the one labeled "A". Probably it a tapered pipe thread fitting but--it will have to wait until I return in Sept. I have simply run out of time.

Thanks to everyone for all of your advice.

Will update you all in the fall.
Eddie

Robert61

When you get back to it post a better pic of B. If it's threaded it would only be 1/4" npt and many did come that way. Also post a pic of the plug you are trying to screw in.