Engine: 289 core plug replacement

[Palantirion]

Hello all. I fired up my Avanti after it sat a long while and got the gift of coolant leaking out of the middle two core plugs on the sides of the block. No corrosion or holes, the leaks are at the seams. These were put in a couple years ago (appx. 25-50 miles driven since) by a mechanic I no longer use (for many reasons, like this issue). Before embarking on what looks to be a very straightforward procedure I thought it prudent to ask the braintrust here:
1) Is there is anything particular or special about changing core plugs on a Studebaker 289 vs. most other engines?
2) What size plugs are used on block sides? IE: Is it something I'll have to mail order, or is it common and I can get them at Autozone?
3) Is RTV or another thin sealant (like Pioneer Core Plug Sealant) recommended, or is dry better for some reason?
4) Installation depth? Seems that some prefer to hammer flush with the block, others to the depth of the bevel.
5) Do I need to drain the coolant before removing the plugs, or is there only a bit of coolant in the block at these areas?

[RadioRoy]

There are two designs of core plugs, depending on the design of the hole in the block.

You might have an easier time of it by removing the exhaust manifolds first.

[PackardV8]

The later blocks use the cup type plugs driven in flush.

Clean the edges of the holes with sandpaper.

The Pioneer sealant is good, but so is old brown Permatex.

While you're in there, flush out the block, especially behind the rear core plug holes.

jack vines

[Milaca]

I'm about to replace the core/freeze plugs due to corrosion on my Lark 259, however I am removing the engine to do so as it is otherwise very difficult to drive the new plugs in straight. I'm not a fan of the RTV silicone for most applications, so I will apply a thin amount of the old-school brown Permatex.

As for the coolant, I would drain the radiator and make sure that the bores in the block are clean and dry prior to plug reinstallation. As for the plugs, any auto supply store should have them on hand (typically Dorman brand). Are they 1.375" diameter?? I don't recall.

[StudeRich]

The Stude. V8 Core Plugs in a correct Avanti Block will be Cup Type Standard 1 1/2 Inch BUT, the Depth MUST be Very Shallow to not protrude Too Deep into the Block, the Ford 289, SHALLOW 1 1/2" Brass Core Plugs come in a set of 6 with a seating/sealing thickness of about 3/16" these work MUCH better than the commonly sold by Stude. Vendors and Parts Stores type with a Wide sealing surface almost 1/2".

And, are Factory Correct, identical to OEM Studebaker Steel Plug Size, but Brass are better..

The problem is, almost all late '62 to '64 Blocks still have remnants of the Ledge used for the Flat Disc Type '51 to early '62 Core Plugs, when you Hit that with the deep Core Plug it will not be deep enough to seat the outer edge of the Cup Plug where it would be the tightest and properly seal.

Normally if you do not grind away the "Flange" in the Block, the deep plugs will not seat flush. If these Deep Core Plugs are driven in Flush, they will restrict the capacity a tiny bit also.

If your Avanti Core Plugs are Not flush in the block, incorrect depth Core Plugs ARE your problem!

[1inxs]

Good information Rich. I only hope that I can remember where I saw this information when my plugs fail. Another sign of getting old!

[StudeRich]

THAT would be a really GOOD reason for this to be a "Sticky" !
OR, at least copy and paste it into a Word Doc. and save it in your "Stude. File"

[bensherb]

Yes, drain the engine block ! If you don't, the first core plug you remove will do it for you and you'll have a mess to contend with as well.

[altair]

Dorman makes a good plug, I am somewhat adventurous and made my own style with lead. o ring and some various stainless steel parts. My block is a 63 259 and the inner lip was rusted away so there was no seat for a conventional plug. The lead plugs bolt in tight and won't rust. The expanding Dorman plugs are good but they have to be in square.

[Palantirion]

Guys, thanks for all the helpful info. After some delays I'm now circling back to this project. Hope to buy plugs tomorrow. I haven't removed any from the block yet but measured them today and their OD is appx. 1 3/8"

I should mention that the guy (who no longer gets my business!) who swapped my Avanti's engine after it threw a rod and bent the old block, was not a Studebaker specialist. His work focused more on brass era car restoration. I discovered only after the new engine's break-in period that he mistakenly got an R2 (he capped the blower oil ports) not an R1 block. Since it ran like crap with the low compression he then tore the engine apart again and put in (as far as I could tell) the right pistons and had my R1's existing heads resurfaced and rebuilt. I have not driven the car more than maybe 100 miles since then, not even through the break-in period, because literally every time I would drive it something new would leak. He always had excuses for why, and would say he'd fix it if I'd bring it in but I stopped trusting him and figured it would be better if I just did the work myself as an amateur.

Most of the leaks I have stopped....because I can read a shop manual and know how to operate a torque wrench. In hindsight this guy was a hack and I wish I had never trusted him. For example: He never bothered to connect the upper and lower dipstick tubes, the dipstick was just hanging in midair! Also, I guess he felt like not reinstalling a hose clamp on the fuel line because it blew the line off when I was giving it a tune up and sprayed gas everywhere! There was no clamp to be found, spent an hour figuring out how to get a new clamp onto the line with only my left hand (couldn't reach any other way) and then how to tighten it without being able to use both hands. PITA. My Avanti is also now missing the flange under the expansion tank after I had him rebuild it. Every time I work on the car I find something new that he did wrong. I'm going to guess that these leaking plugs are because he either used the wrong ones or didn't prep the holes...we'll see.

But back to the topic at-hand: Because my core plugs are 1 3/8", does this mean I have a non-Avanti R2 block? And if so then what depth plugs should I get? And when I go to tap them out, does it matter if I tap on the top or bottom of the plug because of the possible block "flange".

[Dwight FitzSimons]

Guys, thanks for all the helpful info. After some delays I'm now circling back to this project. Hope to buy plugs tomorrow. I haven't removed any from the block yet but measured them today and their OD is appx. 1 3/8"

I should mention that the guy (who no longer gets my business!) who swapped my Avanti's engine after it threw a rod and bent the old block, was not a Studebaker specialist. His work focused more on brass era car restoration. I discovered only after the new engine's break-in period that he mistakenly got an R2 (he capped the blower oil ports) not an R1 block. Since it ran like crap with the low compression he then tore the engine apart again and put in (as far as I could tell) the right pistons and had my R1's existing heads resurfaced and rebuilt. I have not driven the car more than maybe 100 miles since then, not even through the break-in period, because literally every time I would drive it something new would leak. He always had excuses for why, and would say he'd fix it if I'd bring it in but I stopped trusting him and figured it would be better if I just did the work myself as an amateur.

Most of the leaks I have stopped....because I can read a shop manual and know how to operate a torque wrench. In hindsight this guy was a hack and I wish I had never trusted him. For example: He never bothered to connect the upper and lower dipstick tubes, the dipstick was just hanging in midair! Also, I guess he felt like not reinstalling a hose clamp on the fuel line because it blew the line off when I was giving it a tune up and sprayed gas everywhere! There was no clamp to be found, spent an hour figuring out how to get a new clamp onto the line with only my left hand (couldn't reach any other way) and then how to tighten it without being able to use both hands. PITA. My Avanti is also now missing the flange under the expansion tank after I had him rebuild it. Every time I work on the car I find something new that he did wrong. I'm going to guess that these leaking plugs are because he either used the wrong ones or didn't prep the holes...we'll see.

But back to the topic at-hand: Because my core plugs are 1 3/8", does this mean I have a non-Avanti R2 block? And if so then what depth plugs should I get? And when I go to tap them out, does it matter if I tap on the top or bottom of the plug because of the possible block "flange".

R1 and R2 short blocks are identical (except for the number stamped on the top front of the block). The difference in the compression ratios between R1 and R2 engines is in the heads. If you have an oil filter mounted down low on the block at the right (passenger's side) rear of the block then you have a "full flow" block. That's what you are supposed to have in an Avanti. As far as the bare block itself all 259, 289, R1, & R2 engine blocks are the same.

I don't know what you mean by "blower oil ports." The blower is lubricated by its internal lubricant, not by the engine oil.
--Dwight

[Palantirion]

Dwight, I was referring to what the mechanic told me when he started the car for the first time after the rebuild: That oil shot out through a hole in the block that he didn't expect, and after research he discovered that it had to do with being an R2 block. He told me the oil hole had something to do with the blower, and he plugged it as it was irrelevant to an R1. But I wasn't there, so I don't know firsthand. For all I know he might have been lying the whole time. I never saw the plug he mentioned, as the car was off his lift at the time of pickup.

p.s. The R2 has different pistons too, it's not just a difference in the heads.

[64studeavanti]

Dwight is 100% correct. All Stude V8 full flow blocks are identical it does not matter 259, 289, R1, R2.

R1 and R2 use the same flat top pistons. the difference is in the heads. Non R 289s have dished pistons for lower compression. 259s have shorter stroke with flat top pistons.

Post a picture of the engine number. That way we can identify how the donor engine was originally built.

Do you have spin on oil filter on lower passenger side? If not, you could have older block.

[Dwight FitzSimons]

Dwight, I was referring to what the mechanic told me when he started the car for the first time after the rebuild: That oil shot out through a hole in the block that he didn't expect, and after research he discovered that it had to do with being an R2 block. He told me the oil hole had something to do with the blower, and he plugged it as it was irrelevant to an R1. But I wasn't there, so I don't know firsthand. For all I know he might have been lying the whole time. I never saw the plug he mentioned, as the car was off his lift at the time of pickup.

p.s. The R2 has different pistons too, it's not just a difference in the heads.

Your "mechanic" was giving you a bunch of BS. I have been a Studebaker & Avanti fan since they were new and currently own three Avantis, three '64 Hawks (both with R1 engines), and a '63 Hawk with an R2 engine. They are all originals (no transplants). I have owned Avantis & Hawks since the late 1960s. I do my own mechanical work, with a couple exceptions.

If you will look at page 12 in the Avanti Chassis & Body Parts Catalog you will find that R1 & R2 pistons carry the same part number.

A declarative sentence like "The R2 has different pistons too, it's not just a difference in the heads." should be backed up with facts, not just speculation or assumptions.
--Dwight FitzSimons, Editor, Greater Virginia Chapter of SDC

[Palantirion]

The replacement engine in 2016.

2017, heads pulled after about 500 miles.

2018, one of the pistons that were removed, presumably replaced with flat top but I can't find pics to confirm this.

Same day, pic of one of the old block's pistons.

[64studeavanti]

Did you intend to post pictures?