I have a 383 shortblock to install, and I'm double checking everything.

I noticed the shop didn't install soft plugs in the 2 holes at the front of the lifter valley. My book says they should get plugged, but I looked at my stock block and it didn't have the plugs either! [pic]

According to "How to Rebuild Smallblock Chevy LT-1/LT-4 Engines", those two plugs are an oddball size, and come with a small hole in the center, possibly to help oil the chain.

I was wondering if anyone here has seen a lot of LT-1 blocks and can tell me how important those plugs are and how common it is to see them missing.

Thanks,
-Mike.

 

The two holes I circled are what I assume you are talking about - they do not get plugged.



The ones the book is talking about are behind the timing gear.

 

You can just put in Gen 1 plugs and drill them, i think the size is .030

 

Here is a pic of the plugs that should have the tiny hole in them for oiling, they are in the oil galley at the end of the lifter oiling channel, with no plugs here you'd be with very little oil pressure.
At least one of the 2 plugs is clearly shown in this pic

 

OK, Thanks for all the replies. So far I have to replace 3 freeze plugs on the outside that are leaking. I think I'm going to start it up and look for all the leaks before I drop the k frame again, then tackle them all at once. Hopefully I'll see oil pressure, cuz I dont really want to tear down the timing gears again to look for the galley plugs!

 

Well, if you are running the gear driven waterpump, it may be a good idea to check it for the appropriate holes, they may have just installed plugs without the little holes to feed oil onto the wp drive gear/cam gear, which has been a cause for some stripped cam gears I would suspect, along with very tight water pumps..be sure your water pump shaft can be turned fairly easily by hand, there was a bad round of Bosch replacement pumps that had overly tight bearings that contributed to some gear stripping also. I know its a pain, but I'd want to be sure or just take the pic above and go ask the builder.

 

Heh, I actually had one of those Bosch pumps, and stripped cam gears. I posted it all here on the board in 2003. That was on my stock block with the little oil holes in the plugs. With the new engine I switched to an electric wp to avoid all that nonsense.

But now I am curious if the new plugs have oil holes

 

I just remembered, I took some pics of my new block when I first got it!!




The front oil galley plugs have been switched to screw in plugs. I hear that's common. But they don't appear to have any holes.

 

I don't worry about those small air bleed holes in the front galley plugs in my LT1 engines. That's all they are, (air bleed holes). They are not for oiling the timing set. The air bleed holes are to help for quick lube of the valve train. It's a start up noise dealie really. The air bleed holes won't help to lube the timing set in other words. Looks like your motor is in good shap as is with the threaded plugs.

Karl Ellwein

 

If you are using an ewp then don't worry about the holes. As far as it oiling the cam gear, it sure doesn't hurt, especially when that seems to be one of the common links in alot of gear failures on the this board over the years. Never heard it to be an air bleed hole as the SBC never had then for 50+ years and it was the same concept just without the wp cam gear.

 

False. Oil drainback has absolutely NOTHING to do with oil pressure unless you are over oiling and causing the pump to cavitate.
There really is no point in plugging and drilling those tiny holes. Just not necessary.

 

Drainback? I was assuming it was pressurized oil coming from the pump.

 

would be just like a lifter was missing in the bore.. and the oil will take the easiest way out..which would be out the hole left by an absent plug and have no oil going up thru the pushrods, and no backpressure to create oil pressure up stream....just like putting your finger over the end of a garden hose raises the pressure all the way to the faucet. You're thinking about the 2 holes circled in the first pic above for drainback not the 2 in the end of the lifter bore.

 

Oh hell I'm an idiot. I was looking at the wrong ****.
Strike my statement alltogether.

 

Pages 135 and 136 in the How to rebuild LT1/LT4 has a pictures, and talks about the 3 oil gallery holes.....

As stated earlier by MachinistOne, the big holes do not get plugged...