225 sharing parts on 231

[Apple]

FNG here on this forum. I have had a mostly stock 68 CJ5 with 225 V6 for a while now that I am currently swapping over to a 231 so I can take my time and rebuild the 225 and still have my Jeep running while I do it. This week is the first time in years my Jeep is down for repairs. My Jeep is a work horse and not a show queen. I started this swap process about four years ago and life had gotten in the way until now.

What I have is a 1975 231 odd fire that I have rebuilt. It is .030" overbore, crank ground .010", RV cam, stock style pistons, double roller timing chain, .090" shim lift on rocker shaft supports with new length push rods for proper rocker angles on valves. ...nothing special. I don't want to run the 231 intake as I don't have a carburetor for it and it has all the EGR on it. Also the front cover is trash on the 231 and has the wrong oil pump orientation. My plan is to run the like new cover that is currently on my 225 and swap the intake and flywheel as well. The front cover should be a direct swap over. The intake will not be a direct swap as the exhaust cross over ports are different and the 231 heads have a void near those ports at the mating surfaces that will not allow a good seal of the intake gasket around those ports with mismatched parts.

The 231 port gasket surface is a square with a clipped corner and the 225 gaskets are the full square. 225 gaskets leave a hole from that port into the void on the head and out to the air. The 231 gaskets will seal the port on the head side but leave an unsupported gasket into the exhaust port of the 225 intake so a leak will occur there as well.

What I have done to remedy this is block the ports in the head altogether. The 231 ports are a rounded hole about 5/8" diameter cast on an angle to the mating surface. I rounded the edges of the holes and drove freeze plugs into the holes and peened the casting to hold them in place. In my experience those exhaust ports always carbon over and plug up and I have never seen any adverse effects on my engines when they are plugged even with the butterfly valve still in the right side exhaust manifold. My 225 intake had carbon plugged ports and the 231 was plugged on one side.

My plan is to eliminate the butterfly valve in the right side exhaust manifold just to get rid of it as mine has a cracked housing and I'm unsure if it operates correctly anyway.

I want to keep the engine looking as close to a 225 as I can as it might be a while before that old 225 gets rebuilt again. My plan for it is to rebuild it with a cam and better fuel system. The current 225 was rebuilt not that many miles ago but many years ago by a crappy engine builder. It went to be rebuilt again after the oil pump was not changed on the first rebuild and had to go back a third time for the heads to get done again. All the years I have owned it the heads have been an issue as I believe the rocker arm to valve angle is way off pushing sideways on the valves and wearing the guides. I will be tearing into that engine soon and confirming what I am sure is happening. Plus I want to see what else is worn or incorrect from that last rebuild by the idiot shop. In a perfect world the bottom end will still be good and all I will have to do is the heads and update the cam. I run an Overdrive unit and the cam will help me with torque when traveling down the highway.

Has anyone else tried to morph the 225 and 231 together?

Skidding logs a few years ago...

Current 225 about to be pulled out....

231 with 225 intake installed..... I removed it again to swap gaskets and plug those ports. You can see those voids in the heads at the centers where the intake gasket is visible...the holes are now plugged waiting on the new gasket.


When the gasket gets here I will install the intake again and then I will pull the front cover off the 225 and clean it up, rebuild the oil pump, and attach it to the 231. I have a fairly new water pump on the cover already. Once all the easy parts are swapped over I will pull the 225 out of the Jeep and finish the swap. I am also going to rebuild the steering box and apply some ceramic coating on the firewall and floor boards to help slow heat transfer into the cab before setting the 231 in place.

 

[Manic Mechanic]

Welcome. I look forward to watching this build

 

[Belizean]

 

[Apple]

This 231 engine did not originally have a breather on any valve cover. It only has a PCV valve mounted at the back of the intake. The 225 has the PCV on the passenger side cover and a vent into the air cleaner on the drivers side. I drilled the 231's passenger side cover for the PCV and have been holding off drilling the drivers side for the vent. The 225 has a baffle inside to help keep oil out of the vent and the 231 may have a baffle there. I need to pull both covers off as I remember there being a baffle someplace on the rocker shafts. I need to see about that baffle and cutting a hole into the drivers side cover and installing the vent there. There is no embossed area for adding a hole so I will just cut one anyway. I'm not worried about messing up the 231's covers...I want to keep all the 225's parts intact though. Too bad the covers will not interchange.

I'm going to have to research how that 231 vented in the original 1975 Regal as not having a second way for gasses to escape had to make that engine a real oil leaker.

 

[Apple]

Well, the mistakes made rebuilding this engine years ago keep on growing. I took the front cover off today and what did I not find?.....the cam button and spring, the crankshaft oil slinger, and the timing chain tensioner (stock style chain). All missing, gone, forgotten.

The camshaft was free to float whatever amount the fuel pump arm and timing chain would let it move.

I got the front cover and water pump all cleaned up and will have to tackle the oil pump and all the cover bolts next. Everything is covered in a 1/4" of oil and sludge. The water pump and fuel pump are fairly new so I will reuse those. I have a rebuild kit for the oil pump.

I need to get the intake manifold on and button up that top end before I put the front cover on the 231. My gaskets should be here today for the intake.

 

[Apple]

I ran into a fitment issue with the front cover. The 225 and 231 share the same front cover, zero differences on the cover itself.

My 225 has an aftermarket front cover that I am putting on the 231. The 231 has an original cover that is wore out in the water pump area. I was able to confirm all key measurements are the same between them.

I upgraded my timing chain set to a double roller for longevity and deleting the tensioner. Both the 225 and the 231 had stock style timing sets. The front cover has an area the cam button rides on to keep the cam pushed into the block. Above that area is a small post that is there to act as a safety of sorts (I'm guessing) that will ride on the front face of the upper timing gear if the cam button were not there and possibly keep a loose chain from jumping off and getting between the gear and cover. The 231 original cover shows zero contact between the cam gear and this post.

The double roller timing set has a top gear that is wider than stock. Wide enough contact is happening between that post and the cam gear not allowing the cover to seat by at least 1/8". I was test fitting the parts when I discovered this. This double roller set was advertised to go into a 231.

My plan is to machine down that post until I have the same clearance as it would with a stock set of gears. I am going to machine it down until the cover fits flat without the gasket and take another .002" off the post. That post was keeping my cam in place on the 225 and has wear on the post so I have no idea how close it should be and it will be impossible to figure it out based on what is left of the gasket on the 225 to measure off of. What I do know is that post was untouched on the 231 with stock timing set.

Big takeaway is a double roller timing set will need modifications to the front cover to fit.

 

[Apple]

A little more progress today. I machined that cover and installed it. I got the fuel pump on, coil, alternator, intake, oil pan, carburetor, bypass water hose, and spark plugs all installed. I debated about painting the front cover as it was raw aluminum...paint won out. It feels good to finally have this block buttoned up after nearly four years since I assembled it.

I need to go shopping and get some oil and a few other odds and ends so I can prime the oil pump and prime the entire engine with oil. Once that is done I will drop the distributor in and put the front dampener and pulley on. I'm leaving the front dampener off until I get the distributer in place as the 231 engine is sitting at TDC on number one and I marked and pulled the distributor on number one in the 225. I should be dead on for timing when I stab it back in. Once that is done I don't care if the engine rolls over when I put that dampener and pulley on, until then it's not getting moved.



I need to keep this pace going and not stall out. I'm trying not to burn myself out and only working on it a little each day. I'm going to keep swapping parts off the 225 until I have everything off I can before I have to pull the engine out of the Jeep.

I did not have the original oil pan bolts and bought 14 bolts a few day ago.....14 of the wrong bolts!!! So, I dug through my nuts and bolts bins and found 14 bolts and washers that were perfect for it...they are not all the same bolt but I don't care about that on this build.

 

[Apple]

More progress today. I went and got oil and zinc additive and a few other supplies. I put on a new oil filter and filled it with oil. I built an oil pump drive that attached to my drill and primed the oil system until it was oiling all the rockers. I punched a hole in the drivers side valve cover and put a grommet in to attach to the original 225 vent with an adapter as I could not get the same sized (without paying $16 dollars shipping on a $3 part) grommet as the 225 has. I still need to pick up some matching hose clamps for that breather hose.

I stabbed the distributor and clocked it where I have room to move it both ways. I repaired a broken bolt on the front dampener and installed it with the pulley. I also installed the alternator and fan. I swapped out the plug wire holders and put the cap and wires on.

Next I need to try and get the dipstick and tube out of the 225. I may have to wait until I pull the engine to do that. I am at the point where I will need to pull the 225 out. I don't want to try and get the exhaust manifolds off in the Jeep and I need the motor mounts, flywheel, and starter too.

I want to get the 231 dressed as much as I can before it goes in the Jeep. I have had the engine out of the Jeep twice before for clutch work and I can pull the engine complete, minus only the starter and air cleaner. I plan on leaving the starter, air filter, fuel filter, and fuel lines off when it goes back in.

I did have to decide where I would quit painting things. I stopped painting at the pulleys, fan, dampener, fuel pump, air cleaner, and vent on valve cover. The rest of the Jeep is old and greasy and I had to stop someplace

My original plan was to not paint anything and let it all be raw and ugly and I talked myself out of that idea. I just could not talk myself into painting any more though.

 

[Apple]

I tried to not work on the engine today but I snuck in an hour pulling the drivers side exhaust manifold and dip stick. I found another issue with the 225, there was at least one heli-coil on the manifold to head bolts as the coil pulled out with the bolt. I know broken manifold bolts are common so not a big deal but still an issue to deal with when I rebuild those heads. I might just pop a new coil in it right away so I don't forget.

I got everything cleaned up and installed on the 231. The dipstick and tube fit perfectly. With 4.5 quarts in a dry engine it reads almost a quart low.

The passenger side manifold will be next if it does not fight me. I had two bolts fight me on the drivers side that required flexing back and forth before they started to move, and tiny back and forth motions to get them out without breaking them. I would rather spend an hour wiggling a bolt than removing a broken one. When I used to rebuild Model A Ford engines I would spend hours wiggling head studs out of blocks to not break them.

If I can get the other manifold off in the Jeep it will be the last item I can pull before getting under the Jeep to start removing the engine.

 

[Apple]

Today I pulled the passenger side exhaust manifold and that cast butterfly valve. I kept having exhaust leaks at that valve and lo and behold it was broken in two. I was going to delete it anyway but did want to use the casting as it mates between the flat flange and the flared pipe.

I ordered a new exhaust flange and machined myself a flared spacer that I will weld into the new flange. I may have to machine the part a little more once the flange gets here to insure a nice fit.

The machined part will slip inside the new flange and get welded inside and out. In the photo you can see the broken casting and my old gasket sitting under the machined part. The new flange will take the spot of the gasket to mimic the cast part.


Here is the 231 all complete except for the flywheel...

 

[Apple]

Here is my machined part and the flange I purchased. All I have to do is weld it up now. I'm really hoping I can bolt the new part on separately and then add the nuts for the exhaust pipe flare flange. I think that would be more secure than just letting the exhaust pipe flair flange sandwich it all together.

 

[Apple]

Butterfly valve delete finished. I welded the inside, placed two tacks on the opposite side, and machined it flat....that should do it...I should now be able to clamp the pipe on separately from the valve delete. That will help with losing that gasket over time with the exhaust pipe twisting on the seat and loosening things.

Pay no attention to my 120 year old lathe...it gets these types of jobs done.

 

[Apple]

I spent some time in the shop today and got the oil drained in the 225, pulled the Transmission covers from inside the cab, and cut a few bolts out that were stuck on the transmission covers. I ordered new cage nuts for those covers to help get it sealed back up tighter when it goes back together. I will unwire the starter and pull it, pull the flywheel cover, remove the motor mount bolts and get those six bell housing bolts out next and get that engine ready to lift out. I have spent less than five minutes on my back so far and I think maybe ten minutes tomorrow on my back and that will be it. All. the bell housing bolts will come out from the top now that I finally got those covers all the way off. The last two times I pulled the engine I did. not take those covers out all the way.

And FYI, I can pull the engine twice as fast as the transmission for working on the clutch so that is how I have done it in the past. Air cleaner and starter are the only things on the engine I take off to pull it...makes if pretty fast.

 

[Apple]

I spent some time today and harvested the last of the 225 parts to go on the 231. I pulled the 225 out of the Jeep and took off the motor mounts, starter, and flywheel+clutch.

I am going to replace the whole clutch assembly while I am in there. My old clutch is like new but the pressure plate fingers looked a little wonky so I bought all new to be safe.

I also popped the steering box apart to see about fixing the play and stiffness in the box. I found out the box had been rebuilt but the bearing cage was broken on the bottom of the worm and the pieces were interfering with the ball bearings. It's all working correctly now, minus the bearing cage.

I have some wiring to clean up and fuel hoses to swap out next. I need to adjust the flare on the right side exhaust pipe and I need to clean the starter up and clean and remount the motor mounts onto the 231. Once hanging on the cherry picker I will install the flywheel and clutch and stab the 231 in the Jeep.

 

[Apple]

I made a big push today and got the engine stabbed in. I buttoned up the steering, fixed the exhaust, cleaned up the wiring, and put on the throwout bearing before assembling the flywheel and clutch on the engine and finally setting it in place. There is a definite system to getting the engine stabbed back on.
Raise Transmission until it is bending back on firewall,
Lower engine until you get it started on input shaft,
Push engine back until valve covers hit firewall,
Lower transmission,
Lower engine,
Start bell housing bolts and suck it all together,
Set it down over front motor mounts.

In between each step is a lot of wiggling and cussing!

I have the 225 on the engine stand and need to pull it outside and dump the remaining water out of it, re-drain the oil pan, and seal it up for storage.

I will finish cleaning up the shop this afternoon and reset everything and finish the install, starter, wiring, hoses, fuel lines, exhaust, radiator, supports, and miscellaneous stuff. I need to adjust the clutch before the floor pans go on as the adjuster is right there in the open. I am waiting on some parts to put the floor pans back in place and I have some work to do getting all that back together before I am ready to fire up the engine. I am just glad I have the big work out of the way. I will finish things up during the week

 

[Apple]

Well poop.....I was taking the afternoon off after stabbing the engine in and something kept telling me to go adjust the clutch. I finally listened to my gut around 9 pm and went out and pushed the pedal. It had 3/4's throw of free play. There was not enough adjustment to take up that slack and the fork was already near the back of travel when the throwout bearing engaged. After using a mirror to confirm the fork and bearing were on correctly I pulled the engine back out. Lucky for me I had only loosely bolted a few bolts in and had not started assembly.

What I discovered was the fingers on the diaphragm were pointed inward and not outward, meaning they were in the release position when the clutch was not engaged by the throwout bearing. That explained the excess free play in the fork.

I unbolted everything and confirmed I had the disc on correctly facing the right way. I then bolted my old clutch to the flywheel and the fingers are pointed outward like they should be. I did take measurements of the pressure plate housing (they matched). I also measured the depth of friction material to the rivets on the new and old disks. The old is .050" and the new is .055". If both disks were made the same my old disk is worn .010" (adding both sides). I then measured the overall thickness of the friction plates. The new plate is approximately .100" thicker overall than the old one (.090" thicker if my disk was new and made similar). That would account for the fingers going down further into the released position when bolting up the pressure plate. I swapped out the throwout bearings but left the pilot bushing in place. I am going to take the clutch back and return it. I am going to just run my old clutch.

I am not returning the pilot bushing as I need it and pulling it out would be useless as nobody is going to reuse that after it was installed into the crank. I also know those bushings go in tight and filling the pilot with grease and pushing them out with a punch has not worked for me in the past. I will let them know it is not being returned.

I'm not very happy with parts quality but I am very happy that my only mistake was not catching the finger position before I stabbed the engine in. It has been a few years since I have worked on my vehicles and I overlooked it or did not realize it was wrong( my gut knew something was not right). I will return the parts before I stab the engine back in just in case they do have the right parts for this kit on hand. Either way I will be fine running my old clutch, it has lots of life left in it.

It seems I end up doing the clutch twice in this Jeep every time I work on it. Ten years ago the throwout bearing was making noise so I pulled the engine and replaced it. I looked over the rest of the parts and they looked fine so I put it back together and the whirring noise went away but the growl was still there. I took it back apart and found the pilot was actually bad and I could not tell until it was pulled out of the crank. Part of the reason I wanted all new parts this time was to avoid having a failure...I'm in there I might as well put in new stuff to save myself the headache later.....and look where it got me!

Now that I remember the combination for getting the engine back in I should have it back in pretty fast in the morning.

 

[Apple]

I took the new clutch back and the parts house said they could get another one by this afternoon so I am going to wait to install the engine again until that new set up arrives. I will measure it at the store and if it looks right I'll bring it home and install it and double check it on the flywheel. If it does not check out I will just give up and run the old set up.
....I need to find something to do in the shop this morning. If the wife finds out I am delayed she might put me to work in the house

 

[Apple]

The parts house got in the second clutch around 3:30 pm and it was the same as the first so I got my money back and just put my old one back in. I spent about two hours getting the engine back in and clutch adjusted to make sure it was good, and I got this far along getting it back together...


I still have fuel lines to pump, R/ exhaust, radiator and shell, grill supports, starter, flywheel cover, throttle linkage, and floor pans to get done. My repair parts for the floor pans arrived today so I can get those sealed and installed as well.

I am going to have to do some research as to why those new clutch disks are so thick. I don't care what flat flywheel you mate them to the fingers will over center and be in the released position when engaged. I have a friend who is high up at O Rileys ..I think I will contact him to see if he has had the same issue come up.

 

[Apple]

I got everything back together today on the floor boards. I took the time to redo all the bad cage nuts and weather strip the Transmission covers. Those pans never go in easy and I had two more cage nuts fail mid install. It would have been too much hassle to start over so I left those two bolts out and will seal over the holes....still better than the six that were missing before. It looks like I sealed it up fairly well. I did find another big air leak on the firewall into the cab and will seal that in the morning.

I do still have the three shifter boots and knobs to install. That is all that is left as far as parts go to put back on. It's full of plain water currently and sitting all night to see if I have a leak anywhere. I have oil in it and will need to put the gas back in the tank. I also put the battery on a trickle charge over night.

If all goes well I will hook up my dwell and tach meter and set it up where I can see it from in the cab. I might hook up a vacuum gauge to dial in the timing too. I'll do one last check of everything, do a quick nut and bolt on key items, and if all goes to plan I will fire it up and take it to 2000 rpm for twenty minutes to break in the camshaft.

I'm crossing my fingers all the bad luck with the clutch is behind me. I have rebuilt a lot of engines in my life and every one makes you a little nervous firing it up for the first time.

 

[CJ]

You have made some excellent headway!
Looking forward to seeing more...