Its been a while since i have posted, and worked on the 55 3600. I have recently pulled the 235 out of the truck and have it on the stand for inspection, with the intention of resealing and replacing whats only necessary. The rear "petcock" which i believe is a water/coolant drain has been removed and is plugged so i will need to work on cleaning the passage ways which seems to be common. The thing that has me perplexed is the large pipe plug that is above it, which appears to be an 1 1/2" pipe plug with the square head on it. I have searched around and cant seem to find any info on this. The attached picture shows the plug at the rear of the engine (you may have to zoom in on this) keeping in mind the engine is upside down on the stand. Ive tried to remove this but it is seized solid. My question is what is behind the plug, and if i remove it would it assist me in cleaning the water passages?
Can't zoom in on your pic enough to see what you're talking about. Can you post a closeup of the area where the plug is? Possibly someone removed a freeze plug and threaded it for a pipe plug, but can't tell from your pic.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
I was afraid you couldn't see it, although when i hold control key and scroll with the mouse it does zoom in to see it, that is if you know where your looking (meaning i should describe better lol ). I will try and post another picture tonight, but it is to the left and up slightly from the most rear freeze plug. I am describing the picture of course, and i have posted with a circle drawn around the plug in question until i can get a better picture posted.
I was able to zoom in and see the plug, but am not familiar with where the freeze plugs are on that engine. Someone who is familiar can verify if that's a freeze plug location. ( I think Martin did that.)
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
It is most likely a freeze plug, but have never heard of one being tapped and plugged this way, and the fact that it isn't inline with the others has me scratching my head a bit as well.
There are 2 freeze plugs on that side (manifold side) of the engine block. This isn't one of those, however. I've not actually seen this before...which I find odd. There are 2 freeze plugs on the manifold side of the block (which I can see) and there is a freeze plug on the back side of the engine (something like 1 7/8 inches in diameter as I recall). This rear (back side) plug when removed will indeed help you clean out some of the gunk at the back of #6 cylinder. Drill a small hole in it, thread a screw in and pry it out using a claw hammer.
As for this plug, you could heat this up and probably remove it.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
My ‘59 235 does not have that plug nor is there a freeze plug in that location. Maybe the ‘57 is different?
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1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
Maybe this is a very rare unicorn engine that i will be able to sell and retire early with the proceeds, i will double check my casting numbers but early this year i determined it to be a 1958 235.
Judging by the high mount water pump, 1954 and earlier side mount provision, and the oil pump pickup design, I would say you have a 1953, 54, or first series 55 engine. I have seen one other engine that had a similar plug, but I didn’t get to work on it.
My Canadian 216 has a large threaded hole near the front on the same side. It used to have an original block heater there. Does your block have a raised area for that opening?
Core holes (for freeze plugs) are typically between cylinders, and that one seems to be inline with the cylinder, which would leave little room behind it for a block heater. My 216 has a block heater in the freeze plug opening just forward of #1 cylinder. It's not threaded in, but is an expansion plug type thing.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
I'm a bit late to the conversation, but I've not seen a plug at that location on a 235 before. It is not a typical freeze plug location (as Jon pointed out). Here's a '53 passenger service, full-pressure 235 that I recently picked up (engine serial number prefix LAQ). There are two freeze plugs on that side of the block, but the "standard" one farthest to the rear is over the throttle linkage stud, well forward of the plug on that block, and similar to images others have posted.
The plug has a definite casted boss that is threaded, and it is a Canadian truck so the block heater theory is reasonable. I have attached a close up of it, and you’ll notice something below it that I can’t explain either. It was covered in rust crystals which I assumed was from the plug leaking but on closer inspection it has almost little holes embedded in it. I will need to clean it out better to determine what it is. I added some pictures of the casting numbers and serial numbers in case I have given this 1958 235 a mistaken identity.
Hmmm, it’s in a 55 but the serial number doesn’t match the cab, I can’t remember why I identified it as a 58. I pulled the mains and rod bearing and they look new, so plastigauge this weekend possibly, clean the water passages and then reassemble and paint. Need to remove some carbon on the heads but for sitting for 25 years this engine seems decent.
I have no clue as the purpose of the plug but there's a long unused synapse firing that is telling me the circle with the indents next to the plug was a line code identifying some aspect of the casting process. Possibly a date "stamp" or batch identifier? I could be completely wrong but that synapse won't shut up. You see there's another in your second picture.
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Layback... I have no idea how much coolant would be in there, I assume its all drained now as the engine was turned upside down and lots of dirty water came out. I will try and get that plug out and clean the passages the best I can, I will let you know how it goes. I tried heating the plug but ran out of acetylene after a couple minutes..... always the way, might be time to switch to propane as i can get it at the gas station anytime.
Tiny, I think your right, I noticed a couple more of those casting marks last night when I was cleaning the block.
Dads50, yes that plug is pretty soft, the corner came off after trying 24" pipe wrench and 230 lbs of lean lol.... hoping a bit more heat will get it out.
Heat the plug until it's almost red, and apply some candle wax or some other type of paraffin such as the jelly-sealing stuff that's available in blocks at most grocery stores. Hot wax seems to penetrate seized threads much better than most types of oil. I do that when trying to remove oil gallery plugs for a pass with gun cleaning brushes during engine rebuilds.
It takes a lot more Propane than acetyline to make enough heat for loosening threads. My "weed burner" wand and a 5 gallon Propane cylinder comes in handy for that little chore, if the area to be heated doesn't need to be precise. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry, i was thinking oxy acetylene, I recently used that set up at a buddy's machine shop, he switched years ago and said he wouldn't go back just because of the convenience. The preheat takes a touch longer when cutting, especially on the 1 1/2" mill slab, but for the home shop i think its do-able. I have never heard of, or tried the wax method, but I will for sure.... I love your tips Jerry, thank you.
Gord, I was wanting to get that opened up to hopefully help with the water jacket cleaning, fingers crossed it will give me some better access. I did notice that there was some crystals just below the plug so i believe it was leaking at some point, but I am a BIG fan of the ain't broke don't fix principle.
Maybe you were thinking "Oxy-Propane"? It's good for cutting but it requires a different cutting head for the torch if you want it to work right. Welding with Propane, even if you use oxygen with it, is almost impossible- - - -no way to get the flame pointy enough to run a bead with it! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I have a 261 block that has a threaded insert that threads into an expansion/freeze plug hole. It has a machined screw in steel adapter plug that accepts a long block heater sensor with plug in wire. Will take picture tomorrow and post. Tom
Very well could be the screw in for a military Korean Era head. I have a new in box military heater that was designed to fil in the bed with a covered canvas top. Just sayin. Doc.
Currently making 1954 3100 better than new and Genetics
Jerry, you are correct, I meant "Oxy-Propane" and I havent gas welded in a long time, I am lucky enough to have a mig and tig in my shop. I have read that the savings on fuel may not outway the extra Oxy burnt with the propane set up, so we shall see, thanks for the info.
Hoping to get back to this on the coming weekend and pop that plug out, I have no intention of adding a block heater as I doubt this thing will see much winter driving. Now if my boys fall in love with driving this thing, and want to run it year round, we may add something down the road.
Here are some pics of a block heater or temperature gauge that threads into a freeze plug hole on the side of the block. The photos are disorienting and show the block upside down on a stand (I guess I could have held the camera upside down).
Absent better explanation, I would venture that this plugs a hole for a pipe nipple that was the return line for a personnel heater on a military application or possibly a rear heater for a school bus. It's not a core plug nor suitable for a block heater in that location. If it ain't leaking I'd leave it alone.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
I got the plug out this weekend with some heat, and failing attempts with a pipe wrench. Digging around in my 3/4 drive socket drawer i found an BUDD wheel socket that fit the plug perfectly, and she came out! As expected it was full of crud so i spent some time cleaning and scraping the water jackets and sucked out lots of debris with the shop vac. I was able to get a clear passage around the back of #6 which i understand to be the problem area, so fingers crossed we are in business.
The pics below show the crud and socket.
The last pic is me showing off my photography skills lol, I moved the front clip out the back to make some room, and with the fall leaves and my dogs colours it looks almost like art.....lol
Probably a good idea that you got it out to clean the crud out of there. Persistence pays off.
That front clip looks like a twin of what mine was. Omaha Orange originally that someone painted blue.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
