Discrepancies in information on LA and Magnum series oil gallery plugs

[Kern Dog]

A friend and I are building engines in the shop out back...his is a 5.9/408, mine is a stock stroke 360.
We have both read numerous books and online threads on the cupped plugs that fit into the oil galleries at the front of the block.
My 1990 roller cam 360 did not have them in place but it had been rebuilt before. His 5.9 didn't have them, it was an original 360/380 MP crate engine cast in 2001. They seem redundant given that some thrust plates block off the oil flow there anyway.
I pulled a 1968 casting 318 out of the corner today...

This one looks pretty grungy but I don't know for sure if it is all original. It does have a single row timing chain. It also had no dripper tab for the timing chain.

The plate is off....

I see no plugs in the oil galleries, do you?

The thrust plate:

You can see that the oil galleries dead end right here:

Now here is a thrust plate for the 1990 360 and the 5.9:

Note that the right side dead ends but the left allows an escape path for the oil:

There are some books that describe how one should drill a hole in the gallery plug. There are thrust plate kits that come with a bolt that is drilled through.
The 318 here had no plugs, the 5.9 had none, the 1990 360 had none when I tore it down.
Why the discrepancy?

 

[RustyRatRod]

That's just how they were built. I'm unfamiliar with the Magnum engines, but I've seen the LA engines both with and without the plugs.

 

[TF360]

I have a book on LA's that shows (plugs) in there. I don't see your upper lefthand bolt that has the hole in it either. It says that engines either have the bolt (with hole) or a drip plate (upper left.) Funny that in one pic it shows the plugs and in another they are not there??

 

[Kern Dog]

I have a book on LA's that shows (plugs) in there. I don't see your upper lefthand bolt that has the hole in it either. It says that engines either have the bolt (with hole) or a drip plate (upper left.) Funny that in one pic it shows the plugs and in another they are not there??

I took the pictures. None of the 4 engines I looked at here have plugs in the oil galleries. 318, 340, 360 and the 5.9.
The camshaft thrust plate from my 360 has the same part number as the one in Rich's 5.9/408 so they both have this design:

The 318 had all four thrust plate bolts in place but no drip tab:

The bolts are all the same, none had a hole drilled through them.
The 1990 360 and 5.9 only have three tapped holes in the face of the block.

 

[Newbomb Turk]

A friend and I are building engines in the shop out back...his is a 5.9/408, mine is a stock stroke 360.
We have both read numerous books and online threads on the cupped plugs that fit into the oil galleries at the front of the block.
My 1990 roller cam 360 did not have them in place but it had been rebuilt before. His 5.9 didn't have them, it was an original 360/380 MP crate engine cast in 2001. They seem redundant given that some thrust plates block off the oil flow there anyway.
I pulled a 1968 casting 318 out of the corner today...

View attachment 1716402497

This one looks pretty grungy but I don't know for sure if it is all original. It does have a single row timing chain. It also had no dripper tab for the timing chain.

View attachment 1716402498

The plate is off....

View attachment 1716402499

I see no plugs in the oil galleries, do you?

View attachment 1716402500

The thrust plate:

View attachment 1716402501

You can see that the oil galleries dead end right here:

View attachment 1716402502

Now here is a thrust plate for the 1990 360 and the 5.9:

View attachment 1716402503

Note that the right side dead ends but the left allows an escape path for the oil:

View attachment 1716402504

There are some books that describe how one should drill a hole in the gallery plug. There are thrust plate kits that come with a bolt that is drilled through.
The 318 here had no plugs, the 5.9 had none, the 1990 360 had none when I tore it down.
Why the discrepancy?

They were hit and miss.

I leave them out. They serve no purpose.

 

[Newbomb Turk]

A friend and I are building engines in the shop out back...his is a 5.9/408, mine is a stock stroke 360.
We have both read numerous books and online threads on the cupped plugs that fit into the oil galleries at the front of the block.
My 1990 roller cam 360 did not have them in place but it had been rebuilt before. His 5.9 didn't have them, it was an original 360/380 MP crate engine cast in 2001. They seem redundant given that some thrust plates block off the oil flow there anyway.
I pulled a 1968 casting 318 out of the corner today...

View attachment 1716402497

This one looks pretty grungy but I don't know for sure if it is all original. It does have a single row timing chain. It also had no dripper tab for the timing chain.

View attachment 1716402498

The plate is off....

View attachment 1716402499

I see no plugs in the oil galleries, do you?

View attachment 1716402500

The thrust plate:

View attachment 1716402501

You can see that the oil galleries dead end right here:

View attachment 1716402502

Now here is a thrust plate for the 1990 360 and the 5.9:

View attachment 1716402503

Note that the right side dead ends but the left allows an escape path for the oil:

View attachment 1716402504

There are some books that describe how one should drill a hole in the gallery plug. There are thrust plate kits that come with a bolt that is drilled through.
The 318 here had no plugs, the 5.9 had none, the 1990 360 had none when I tore it down.
Why the discrepancy?

That bottom plate was designed to work with the drip tray. More junk ****.

Also I saw the bolt with the hole in it came up.

That thing is absolutely worthless.

Use a cam plate with no relief on it.

Drill and tap the plate for a Holley air bleed. Use an .042 hole bleed.

Bolt the plate on. Done.

I should be clear. Drill the plate where it covers the oil gallery. That way you get full pressure oil into the timing cover.

Don’t use the cup plugs.

 

[junkyardhero]

It says that engines either have the bolt (with hole) or a drip plate (upper left.)

this is not true, sometimes they have neither! sometimes they have both!

 

[Kern Dog]

I've torn down a bunch of 318s, 360s and a few 273s but simply wasn't paying attention to all of the differences.
This '68 318 has a 4 bolt thrust plate with no oil dripper. I don't recall ever seeing any LA engine that had those plugs in the oil gallery ends.
A friend is rebuilding his engine here, his first ever engine build. He put the plugs in his block on the advice of threads he read on this site and what he has read in books.

 

[Kendog 170]

My 68 340 had no plugs and no hole in bolt. My 74 360 had plugs no hole in bolt.

 

[TF360]

So, the million dollar question is, what are you going to do?

 

[66fs]

The older LA engines had exactly what your original 318 had. No plugs, 4 bolts and a thrust plate. Around 69 or 70, 340's and the High Performance 360's that came stock with double roller timing chains came with the upper left bolt with the hole through the middle. No Plugs in any of them. Later, not sure when, the drip plate came on the standard engines. I have not worked on many newer engines, so not sure how the thrust plate works with the open bottom? Just for informational purposes, I'm taking the 273 apart in my brothers 67 Barracuda. Built with just the 4 bolts, no plugs, thrust plate, and a Direct Connection double roller timing set from the 70's. It has over 300,000 miles on it and the chain only has 1 degree of wear/stretch on it.

 

[Tsully]

All the Mid 90’s Magnums I have rebuilt had the plugs and drip plate on top of the cam thrust plate cover.

I’m just wondering if it has something to do with the different cams… short vs. long snout?

Here’s what everyone of mine have had during teardown.

And to add to the mix… I’ve had some with and without the timing chain tensioner!!!

I guess it all goes back to the same old thing, depends on who built it that day and whether it was a Friday or a Monday!!!

 

[Newbomb Turk]

My 68 340 had no plugs and no hole in bolt. My 74 360 had plugs no hole in bolt.

Yup. It’s almost like they used whatever was lying around. That’s the only thing I can think of.

 

[emmett442]

For me, it depends on the thrust plate. It seems some plates are a machined finish, some are as-cast. I'd think that installing plugs with an as-cast plate could be worth a few extra PSI of oil pressure, and that can't hurt. Probably doesn't matter when both surfaces are machined and seal up well.

 

[66fs]

Yup. It’s almost like they used whatever was lying around. That’s the only thing I can think of.

From what I can tell they were running changes over time. I have never seen oil gallery plugs in a virgin LA engine before 1974. They all had machined thrust plates. I have no experience after that.

 

[NC Engine Builder]

I personally install those plugs on every engine I build. Not crazy about depending on that plate to seal. For more serious builds, I drill a hole in the plate and put a .030 hole in pass side plug to provide more oil to the timing set.

 

[Kern Dog]

I’m leaving the plugs out.

 

[NC Engine Builder]

I’m leaving the plugs out.

What's your logic behind that?

 

[Newbomb Turk]

What's your logic behind that?

Chrysler left them out. That’s why I never use them.

I suppose if anyone is worried about a leak around the plate you can use a dab of silicone to seal it.

I’m of the mind the little bit of oil that might leak past the plate is a teaspoon in a river.

That’s why I don’t use them.

I know guys that use them on every build too, and frankly I’ve never seen an issue using them.

So it’s personal preference really.

 

[NC Engine Builder]

My experience has been the majority of original engine I have torn down had them. My theory is nothing lost by installing them, prevents the chance of oil galley leakage without them.

 

[RustyRatRod]

My experience has been the majority of original engine I have torn down had them. My theory is nothing lost by installing them, prevents the chance of oil galley leakage without them.

I'd have to say that's my experience too. I have torn down some that didn't have them, but the majority did.

 

[Kern Dog]

What's your logic behind that?

This engine did not have them. So far, none that I have torn down have had them.

My experience has been the majority of original engine I have torn down had them. My theory is nothing lost by installing them, prevents the chance of oil galley leakage without them.

Explain the reason for this then:

The side on the right dead ends, the side on the left diverts some oil down toward the timing chain. If the galleries had plugs, this diverter would see no oil flow at all.

 

[NC Engine Builder]

This engine did not have them. So far, none that I have torn down have had them.



Explain the reason for this then:

View attachment 1716402778

The side on the right dead ends, the side on the left diverts some oil down toward the timing chain. If the galleries had plugs, this diverter would see no oil flow at all.

Well you got it figured out, leave the plug out. I'm sure that lifter galley will be just fine with a huge hydraulic leak, go for it

 

[Kern Dog]

When confronted with a question that you cannot answer, you respond like this? Have you considered working in politics?
This engine never had the plugs, the bearings were fine when I tore it down a few months back so if there were a problem, it sure didn't show any sign of it. I started the thread to learn why some came with the plugs while others did not.
You clearly don't know.
I don't either but I don't go by the screen name Kern Dog Engine Builder.
For the others here that actually know the answer......If the galleries are blocked off with plugs, why does my thrust plate have this design?

I ask because I don't know. I'm trying to understand the logic. A blocked off gallery passage would flow nothing so what point would there be to the recess on the left side of the plate?

 

[Valman]

I'd have to say that's my experience too. I have torn down some that didn't have them, but the majority did.

Every small block I’ve seen has had the plugs. Including a 1969 318 engine. Chrysler Australia must’ve done it that way, don’t know about the early 273’s.