What is wrong with me, and how do I fit this in my Plymouth?

[FarmerJon]

Around a month ago I was doing my regular search of Craigslist  for old Mopar stuff. I stumbled onto a flathead 6 core "dodge" engine, for way to much money. 

But it was only a couple hours from me, and I still had a few minutes of my lunch break to kill.

 

As I scrolled through the pictures, I realized it also included some pretty expensive new parts, and was actually quite a good deal.

An email and some phone calls,  and the owner kindly agreed to hold it for me till I got time to get it.

I picked it up yesterday. It poured rain on the way home, so I didn't get a chance to look it over very well.

It is a grimy Yellow, with red underneath, industrial 251. I am not sure what it is out of, brass tag has the Chrysler pentastar, so must be '60s.

It does not have the pad for full flow oil filtration.

At a glance, the exhaust valves are standard,  not sodium filled.

Rear sump oil pan.

Turns smoothly 270* then stops hard, has at least 1 stuck (open) valve, but need to pull the tin off to see what's up. A rebuild is planned, so likely no big deal.

 

Head is off, and has been milled an unknown amount. Most likely cut to up compression. 

 

Also included was a new Asche supplied cam regrind, marked 380, split exhaust manifolds, and an unused AOK triple carb setup, linkage and carbs all complete, but linkage is set up for a truck.

 

Anyone know if I can just flip this over and make it work for my passenger car linkage?

 

I belive the cam is their Isky 3/4 race clone, which is their recommendation for trucks and cruisers that want more power, but don't actually want to deal with the hassle of a big cam.

 

I am not sure why I thought this was a good idea, but here I am.

Anyone have a link to a good write-up on how to fit the 25" engine in place of the 23" in '48 Plymouth? 

 

Hey Canadians:

What years did y'all get the 25" 218, and what did the compression get up to?

If they kept up with US improvements, a early to mid '50s head should be around 77-84 cc, which would yield almost 9-1 on this 251. 

 

On industrial engines, how did the crank case get vented? PCV?

How does fresh air come in? The oil fill tube had a sealed cap. 

Will a 23" oil fill tube swap on?

 

If i want to run sodium valves, are the larger diameter valve guides available? Or can the old ones be drilled and reamed?

 

Any reasonable way to convert this block to full flow oil filtration?

 

My 217 runs well, and I have more pressing things to fix, so I am not going to be in a hurry to swap this in.

 

 

ETA: 

Head number is 1327236 (cast number matches stamping)

Anyone able to give me any info on it? Compression ratio? Year?

It is internal bypass type, has large temperature sender threads, and has head mount linkage boss threaded, but plugged with a bolt.

 

Edited August 7, 2023 by FarmerJon
Added Head picture and part number

[D35 Torpedo]

It looks like a gas cap was used to cap off the oil fill tube.

[FarmerJon]

It does look like one, but is a perfect fit. I have seen them capped just like this on other industrial engines. 

[49D-24BusCpe]

FarmerJon,

 

    EXCELLENT SCORE!!!

 

    Do a search on this website for "Don Coatney". Don contributed a LOT of excellent information here on his build/conversion of a 25" engine into a P-15 PLymouth.

 

Walt

[FarmerJon]

I am familiar with the Late Great, Mr. Don Coatney, and have found some scattered pictures of his swap, but not a complete run down. 

He was a prolific contributor, so it is difficult to sift through everything to find what I need.

 

Hoping to get the engine off the trailer tonight. I was able to measure the bore, and it is right at 3.437, with only a slight ridge at the top. May only be .004 to .006 of wear, we will see. 

Glad it isn't already .080 over!

Hopefully the crank is as lightly worn as the cylinders.

[Los_Control]

Good luck with the install ..... I only remember people talking about relocating the radiator.  Needs to be moved to the front side of the radiator support, instead of the rear side a 23" engine is bolted to. ..... You need to gain your 2" in this area.

Obviously the photo is of a truck with a after market radiator & cobbled up mounting brackets  from the original radiator.

 

I'm just saying the brackets & the radiator support are original. .... You just need to figure out what you need to get your radiator moved forward.

 

 

This photo is difficult, in red the mounting bolt is bolted to the outside of the radiator support.

In green the shiny light is a threaded hole for the radiator to mount inside the radiator support. ..... Just saying the factory provided the mounting holes for the swap.

In my case, there is a flat metal piece going across the front of the body to the radiator ..... I suspect it is a early version of a fan shroud.

I would need to use a zip disk to cut it away to make room to move my radiator forward. ..... But it is all doable.

 

I suspect everything from the transmission back stays the same, just need room up front for the longer engine.

Not sure what they did with the motor mounts. Are they also moved forward & need new holes?  My Truck has no extra holes like the radiator support does.

Or does the 25" motor use a different shaped mount that uses the 23" holes on the frame?

 

Throttle linkage I have no idea .... I just suspect you would need to modify something anyways with the setup you have. .... Same with exhaust.

 

I honestly think getting the radiator moved forward is your biggest problem fitting the motor.

 

file:///home/genfool/hound dog/new.jpg

 

 

[Los_Control]

9 hours ago, FarmerJon said:

Turns smoothly 270* then stops hard, has at least 1 stuck (open) valve, but need to pull the tin off to see what's up.

I dunno about it being a valve. .... I thought the valves are located to the side of the piston?

Piston not going to hit the valve.

 

I had one 218 engine .... was in "flower pot" the engine was loose & could turn it by hand using the fan & one finger .... zero compression.

It would only turn 90% one way & stop with a loud metallic clunk ....  spin it the other direction ... loud metallic clunk.

I just always assumed it was something in the rotating assembly .... broken rod is my first choice ... could be several thing maybe even a cam .... I did not suspect stuck valves though.

[Jerry Roberts]

On Don Coatney's 25 inch engine , he had to cut a section out of his front cross member and ad a patch to it for clearance . 

[FarmerJon]

5 hours ago, Los_Control said:

I dunno about it being a valve. .... I thought the valves are located to the side of the piston?

Piston not going to hit the valve.

 

I had one 218 engine .... was in "flower pot" the engine was loose & could turn it by hand using the fan & one finger .... zero compression.

It would only turn 90% one way & stop with a loud metallic clunk ....  spin it the other direction ... loud metallic clunk.

I just always assumed it was something in the rotating assembly .... broken rod is my first choice ... could be several thing maybe even a cam .... I did not suspect stuck valves though.

Got the engine dropped off at work and was able to take a look at it.

Head is off, but lifter can't push a couple valves the rest of the way up. I am just turning the crank pulley by hand, so I dont really have the leverage to push the valve open. 

I soaked it all in Kroil, and pushed it into the corner. I will start tearing it down soon.

Bore measures 3.4448 at the top of the ring wear.

 

Anyone know when this tag is from?

It seems the star started being used around '63

Edited August 8, 2023 by FarmerJon

[Sniper]

I tried using Kroil for that, the valve laughed.  Use brake fluid and a plastic faced hammer. I used a Precision Oiler to get the fluid on the valve stem from above and some From Below then tap them close with the plastic faced hammer crank the engine over to pop them up worked it a couple of times that way and 2 years later they're still free.

Edited August 8, 2023 by Sniper

[FarmerJon]

Kroil, a little plastic deadblow and a pair of channel locks got the valves all going up and mostly down, pistons all move as they should, can make complete rotation now. 

This motor is reasonably clean, likely just oil residue, carbon and time making things sticky.

Good enough to tear it down. 

Going to get it apart, clean, magnuflux and measure before making a plan with my machine shop. 

I will definitely be putting a lot of weight on the suggestions laid out in Tony Smith's engine build tech article.

The 380 cam has 242* of duration, and makes peak power around 4500rpm, so I am going to be giving a good bit of attention to the health and safety of the rods and crank.

 

 

[D35 Torpedo]

10 hours ago, FarmerJon said:

Kroil, a little plastic deadblow and a pair of channel locks got the valves all going up and mostly down, pistons all move as they should, can make complete rotation now. 

This motor is reasonably clean, likely just oil residue, carbon and time making things sticky.

Good enough to tear it down. 

Going to get it apart, clean, magnuflux and measure before making a plan with my machine shop. 

I will definitely be putting a lot of weight on the suggestions laid out in Tony Smith's engine build tech article.

The 380 cam has 242* of duration, and makes peak power around 4500rpm, so I am going to be giving a good bit of attention to the health and safety of the rods and crank.

 

 

Good stuff. There isn't many things more fun and rewarding than building an engine. Those speed parts make me jealous. I wouldn't be able to wait before I started porting on the head! Good luck and have fun.

[QEC]

Will be interesting to follow along. Good luck.

[FarmerJon]

It's going to take a while. I can usually take 15-40 minutes a day to work on stuff like this at work. 

Yesterday I got the head cleaned up a little and took some measurements.

Deck is nice and flat.

Chamber is .420" over intake valves, and .408 over exhaust.

Rough Chamber volume was 84cc. Need to drill the hole in my measuring plate bigger. Spark plug I had handy sat a good ways down in the head. 

I will work to find a plug that sits more flush. 

Piston tops are around .012-.015 below deck.

With current bore size this combo would yield around 7.7-1 compression. 

With likely machine work needed ( .040 overbore, pistons .020 above deck) this will yield 8.4-1.

 

I am surprised, as this is originally a 6.8-1

Industrial head, best I can tell. 

 

I am getting head sandblasted now, going to check it for cracks before doing more work to it.

I belive there is flow to be had at the back and roof of the chamber, as well as in the transfer area. I am thinking about making a shop vac powered flow meter to research this. 

Edited August 11, 2023 by FarmerJon

[OUTFXD]

My father would say.  If it doesnt fit, Force it,  If you cant force it, get a bigger hammer.  If it breaks *shrug*  it needed to be replaced anyways.