The $500 Allis Chalmers Two Ten Tractor Strikes Back

Well, nearly a year ago we made a video about rebuilding the engine in my dad's Allis Chalmers Two Ten tractor that he picked up for $500. What we've been waiting to tell you is... that rebuilt engine lasted a matter of hours...
• This Is Why You Don't ...
We've finally gotten around to tearing back into it to see what happened...
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[@TheJohndeere466]

You can see on your pistons where the fuel is spraying a little out of the bowl. This is a big no no. It indicates that the timing is too far advanced or your injector tips have the wrong angle for that piston. On our pulling tractor we only have piston problems when the timing makes the spray of the injector come out of the bowl. On those roosamaster pumps they are known for the governor cage falling apart so this cage is always replaced when rebuilding the pump but this cage is where the timing mark is. A new cage comes without a timing mark and the guy rebuilding the pump puts the timing mark on the new cage. Its possible someone put the mark in the wrong place. Do you have access to a diesel timing light to check the timing when you get it rebuilt?

[@jaket9854]

You nailed it that was just what i was going to say. And this will cause heat which will show on rear cylinders that have the least cooling

[@JAMSIONLINE]

Hey, this is the cleaning guy. I think you have nailed our problem. The injection pump and nozzles were rebuilt by a reputable shop 2 years ago when I first got the tractor. I'm not a pump guy but if I understood correctly, we were seeing signs of the cage failing and small pieces of material plugging the return line. When I installed the pump after the injection shop worked it over, I could not get the engine to start. After some diagnostics, I determined they had inadvertently marked the pump to be timed from the window on the engine side of the pump, not the side you see. Since this was my own tractor and did not want to wait 2+ more weeks to get the pump set up correctly, the pump shop and I agreed I would just time this engine off of number 6 cylinder. Do you suppose the stationary mark in the windows of that pump are not exactly 180 degrees apart? Maybe in reality my static timing is nowhere close to the 24 degrees I think I have. Was the pump shop having an off day and there is more wrong than just the pump marked 180 degrees out? We sent the pump and nozzles out for a second opinion. There will be much more discussion about this and we will post our findings in the coming videos of our repair. I would be very interested in any more information you can provide us. Thanks!

[@airwalwer]

A question from a non -diesel (gas) mechanic. With all the oil draining out of the filters overnight, are you concerned with dry starting? It must take a long time to refill the filters and build oil pressure.

[@josepsoler1118]

After looking the cilinder and piston heads, plus knowing the issues you had on the pump when installed, pretty sure the advance timing is in wrong spot and is injecting out of timing, only time will tell

[@TheJohndeere466]

@@JAMSIONLINE Also I am familiar with this pump but not this engine. 24 degrees seems like a lot for stock engine. I know a john deere 4020 which uses the same pump, you only time them at tdc if I remember right. It could be a difference with the cam ring inside the pump though. The cam ring is just a ring with 6 ramps on it that causes the plungers to compress at the right time. The cam ring is what you see looking in the window of the pump. It has the timing mark on it and the other mark is on the governor cage. Also it is possible to put the cam ring in the pump backwards which would really through off the timing.

[@Tshade67]

It's so nice of you to let the cleaning guy work on his $500 tractor in his new shop.

[@JAMSIONLINE]

I’m learning he’s kinda cool to hang out with 😂

[@laleyendadejesus94]

😂😂

[@mauryfeskanich4523]

@@JAMSIONLINE The older you get, the cooler he’ll be!

[@oldsguy354]

​@@mauryfeskanich4523 You ain't never lied. :)

[@albertomoniz9051]

If that engine has piston cooler nozzles i would be looking at them carefully, and that oil galley and nozzel alignment

[@theoldbigmoose]

My Dad went home 43 years ago... watching you two work together I miss him all the more. I never had a mentor, friend, and colleague like him... Your video is a testament to your relationship and values.

[@10868940ih]

My coworker did an engine overhaul that when breaking in on the dyno it kept locking up when it got to operating temp and freed back up after cooling down. Took a while to find the o-ring grooves in the cylinder liners were machined wrong so that it left no room for proper expansion and caused the pistons to lock up until it cooled down. The next set of sleeves were made the same way so they sent them out to have the grooves cut like the original sleeves and never had a problem after that. That's the trouble with some of the aftermarket parts, proper tolerance isn't always figured in.

[@Kenny-1958]

There are alot of ford tractors in my aera. When a 6 cyl. Ford tractor block would come into the shop, I would always be reminded, don't forget to put .002 extra clearance in back two cylinders. Runs a little hotter due to circulation.

[@bigbelconut]

Make sure you get expansion controlled pistons. Number 5&6 are hot cylinders. I had one on the dyno that had non expansion controlled pistons it stuck as soon as I put the load on it. Same situation as yours let it sit and it started right back up with a ton of blowby. Got expansion controlled pistons, it still running today with 350 thousand miles on it.

[@161Sheriff]

Fun to watch a father and son work together.

[@dougderby9454]

Grew up on a farm. Neighbors farm had a 190 and a 200. From new. We’re great tractors.

[@JAMSIONLINE]

Dad has 3 (I think? Maybe more?) 200s lol but he’s so excited about this 210 😂. Just keeps kicking his butt

[@hershbagelstein545]

DAD is a terrific teacher. Loved his thought process as he went through his mental check list.

[@r.j.sworkshop7883]

Watched it a second time to help with the cleaning guys allowance. Looking forward to the next video when you find the ring problems.

[@brianwalshire2706]

I know you boys like to kid each other, but it's great to see father and son working so well together. I lost my father last month at age 87. A farmer all his life and I learned so much from him! Cherish each other!

[@RJ1999x]

210 had no cooling issues, you wouldn't have an air lock either. Anti freeze on top of the cylinder head is probably from the pipe sealant being cooked out of the pipe plugs on top of the head, they seep around the threads. The balancer has 2 marks stamped in it, one on each side of the rubber, look for them to line up, if they don't line up the balancer is bad and your timing marks are off, as is the balance on the crankshaft.

[@Mrcaffinebean]

Been there done that. Nothing is tougher than tearing apart something you just put together. Kudos to you for showing the rebuild of the rebuild, a lot of people wouldn’t.

[@Adam_Poirier]

Look closely at your injection pump. I was in a very similar scenario like this a few years back. I did a Minneapolis Moline G 1000 Vista engine. (Twice) I ran into very similar issues. I actually had the engine lock up on me and was looking at my measurements and the rings and the bearings the oil pump everything. I checked the timing five or six times just as you have done here. Turns out the Stanadyne pump was damaged internally and the timing advance was stuck all the way one way

[@Adam_Poirier]

Also, I think it's hilarious all of the comment mechanics telling a couple of very talented machinists all the things that could be wrong with this engine haha... that's not my intention with my comment above, just wanted to share my experience. This reminds me so much of a scenario that I have personally been through. Although it was hard for me to not leave a comment saying "maybe you didn't have enough gas in it?" 😂

[@skylinefever]

I heard the same thing would happen to some of the Olds 5.7 diesels. The Stanadyne IP had cheap plastic internals that caused the timing to advance incorrectly. Well, pretty much anything happened to the Olds 5.7 diesel. It may have been the worst thing GM ever built.

[@patcoder7308]

@@Adam_Poirier that's what made olds diesels great when they blow you install a 425 or 455

[@thesearcherman6652]

That looks like classic ring or piston seizure due to improper clearance. My experience is if the piston is fit to tight the rings that came with them will also have to little end gap also unless they are filed to clearance separately. I find in my little world, Chinese replacement pistons/wrist pins will not have OEM weight, which can create balance problems, and their material and design may require a different clearance than OEM pistons. I’d really like to know how you guys deal with piston clearance with Communist replacement pistons at your machine shop? But, you guys already know all this! 😂 Best Wishes?

[@victoramato4692]

Did seats like this for years. Quick and easy. 60, 30, 45 degrees. 44 degrees on the valves. No lapping. Interference angle seats immediately. A minute a seat. Done in 16 minutes. Worked great.

[@shanevids4644]

Sadly a lot of us have been there, rebuilt my 165 Massey and it made a solid day in the field before the mains decided they no longer wanted to stay true...put another set in and got another year out of it before they went again and finished off the crank

[@BruceBoschek]

Sorry to hear this. These things do happen and we just have to face them. Looking forward to hear what went wrong. Thanks for sharing this sad event.

[@mikemaccracken3112]

I agree with your Dad on the ring end gap is too tight. Looking forward to the next video.

[@stevenmarsden2257]

Would that not break the rings?

[@evankibbe590]

@@stevenmarsden2257 not necessarily !!!

[@mikemaccracken3112]

@@stevenmarsden2257 only if the ring ends touch and micro weld themselves. If the ring ends micro weld themselves you will see the top of the piston broke in the top ring land area.

[@TheJohndeere466]

If the ring gap is too tight, the ends of the rings will be shiny from rubbing against each other.

[@EightiesTV]

Did you watch the same video? He swears he got it to spec, but it would still bind up if the top of the piston overheated. He flat out said that's not the cause - it's just a secondary symptom.

[@sidallen685]

I always pull the oil pan first whenever I see coolant in the top side, then pressurize the cooling system and check the liners for leaks.

[@needleonthevinyl]

Fun to see the troubleshooting process! Looking forward to the next video. "Why is there antifreeze in it?" is a question you NEVER want to hear...

[@brandonkarpel6521]

Always a good idea to check pump and injectors on overhaul. Dont think it is timing related. We have ran 40 degrees on 426 pulling motors with no problems. Check block counter bores. It is always good insurance to install repair sleeve to prevent coolant leaking. Don't think it was coolant or oil related. Just remember you bought a 210 grill and got a tractor!

[@Hotwire454]

Fold up your oil filter pleats, put in a vise, and squeeze the oil out. Makes a mess but makes it so much easier to see what's been captured in them. Thanks for the great vids!

[@kylenobes1]

I really enjoy seeing you and your dad work together. My dad passed away when I was 25 and I miss doing projects with him.

[@bikerktmktm21x]

I feel the pain. I put a 383 in my rig and it just smoked two cylinders out of it within 3 months. Looking at all the data logging, it shows there should be no reason for the damage but its there clear as day. I need to start a YT channel to pay for repairs...

[@michaelreynolds1904]

Nice to see the cleaning guy in the comments! Don't take this as a failure, it is a learning experience. And I subscribed to help the poor guy out!

[@chrissatterwhite711]

It’s actually really cool seeing the injector tester and seeing how the fuel sprays into the combustion chamber.

[@mikeyd5969]

I grew up in a 210 . I don’t know about your dads but ours had the loudest turbo of any tractor I’ve driven, and it was a muffler not straight pipe .

[@sfeather7088]

Your Dad is such an absolute Pro........I'm In awe of his level of Knowledge , and skill.

[@bcbloc02]

You could spill port time it and verify the start of injection. It is possible the pump was marked with the factory timing advance and you are supposed to install it at TDC thus doing it the way you have you have double advance. That would have put it in the range though that it should have had starting issues particularly when cold. That one spot on the cylinder does look like it is firing on the liner and that makes me wonder if it isn't a turn out of time and it just happens to have a small enough cam that there is no overlap so it will run like that. 24deg+ pump advance seems like an excessive amount for that engine. I feel certain the 24 is the full advance and timing should actually be less the advance when mounting the pump. Also might as well check ring gap and piston clearance as a too tight bore will of course cause this issue as well. It is common for people to get the liner o-rings mixed up on the Deere engines and the o-ring will swell enough to cause the piston to seize. A bore gauge check will tell the tale. Also be sure your injection lines are on the pump correct for the firing order and direction of rotation. you could easily get fouled up there too.

[@joshblubaugh6050]

I like the way the parts cleaner communicates. Really cool to see your father and son team working so effectively. Hopefully I can do something like this with my boys when they’re older.

[@honestabe7349]

I always drill a small air relief hole in every thermostat on a new rebuild. Never have to worry about air pockets and the tiny amount of coolant that flows past a closed tstat is negligible

[@petermolnar8667]

Saw a blog post once where someone compared different thermostats, and only found maybe one that did not leak. Could have something to do with this (or just manufacturing costs haha).

[@JohnSmith-yv6eq]

They used to have "jiggle pins" in the OEM small hole in new thermostats... The jiggling pin meant bubbles could not bridge the hole....so the bubbles travelled on through the system.

[@petermolnar8667]

@@JohnSmith-yv6eq that was new for me, thanks!

[@larrypostma2866]

I have to say the plastic on the block was hilarious. Just reminds me of working with my dad. All good fun

[@robinwatts7079]

Had a very similar issue on a Perkins engine I rebuilt some years ago, that would bind up on full power and stop. It would run light load no problem and would restart when cooled. it turned out to be chromium rings, running in chromium liners. One or the other should be of a different metal, cast iron etc. I was given non original parts from different suppliers, instead of matched ones. it’s a real bummer when you’ve taken a lot care, like you do.

[@BikerHenz]

Farthest cylinders away from the water pump are scored the most . Check your impeller and clearances in the water pump . Make sure the impeller isn’t a spun on shaft

[@jamesriordan3494]

I greatly appreciated the “out of the shop” content; as a fellow farmer, the practical day to day debugging and maintenance is something I can, unfortunately, relate to !

[@jims6323]

I'd give anything to be able to work with my dad again. You don't know how lucky you are!

[@erniezsigo3926]

When I went to school 65 yrs ago tractors were a very special piece of machinery. Our first tractor on the family farm was a 1948 farmall M .I thought I was a big shot when I got to do field work with it .I can not imagine what my dad with think of a John Deere 94 R . Great video enjoyed all those tractors and young future farmers 😀

[@djwilliams4714]

Hey guys, to show the Good with the Bad, and asking your audience opinions on what happened is Awesome! No one person knows it all, the ability to learn is the Key to success. No different than one shop asking another, and sharing info.

[@Dungfly-dc6vg]

I love the tears on the cleaning guy.

[@rickjohnson1632]

Sorry to see that happen. At this point the best outcome ( if there can be one) after something like this is to find the problem. Thanks for taking us along .

[@jayss10]

My thoughts 1. Might be a ring gap issue but I’m banking more on the piston to bore being too tight. If the ring gap was too tight I would think a ring land would be broken off as well. Plus motors don’t lock up super tight from just rings. If this was a non OE rebuild kit I’m gonna bet the pistons aren’t manufactured of the same material or weren’t manufactured to OE spec. 2. Not a bad call to check the pump out. 2a. Know where your pump is set at and where it should be. It might have been “turned up” by somebody in the past and if things are on tight side that’s a good way to hurt it. 3. Not sure on that engine but I’m wondering if some of those head bolts or rocker stand bolts are water jacket bolts and you forgot to use thread sealer.

[@danwhiting4399]

Utmost respect for making this video. Watched start to finish

[@stephenpoe2037]

Nice ! Easier than splitting a John Deer I think . Thanks for sharing .

[@warusweims]

I cut all my oil filters open. It's great indicator of engine longevity.

[@jamesfairchild5349]

Had that happen on an Oliver 1600 one time. Old timer that I talked to about said it probably spun a main bearing and when we tore it down it he was right it spun a main bearing.

[@jeffreykull4676]

sorry to see you engin didn't hold up. hop you find what caused the failure. i have rebuilt a 190xt,185,and a 8030. i did not see where you did anything wrong when i watched you videos from when you put it together. good luck i will keep watching.

[@jix177]

Such a gentleman to work with. Well done lads.

[@rgreen93021]

As a farmer, I feel your pain. Full-length engaged.

[@alamow1]

I have seen a similar outcome due to the piston oil cooling nozzle being blocked. Bearings are usually toast as well.

[@gonesideways6621]

Your Dad is so much like me I was a tool & die maker for 45 years and I wouldn't work in a mess and neither will your Dad!

[@brianreynolds1717]

Back Years ago I overhauled a late 60's cummins 855 that was 250hp. sent the injectors and pump to the shop with the cpl number for the engine. The guy working the injectors used the incorrect cpl# and flowed the injectors for a 400 engine. the pump was set up fro 10% over stock. In later model engines with piston oil sprayers this would not have been an issue. but early 885 engine did not have oil sprayers. the driver on this truck was a very conservative driver. He drove the truck 50-60 miles and loaded it with cows and made it around a hundred miles before he gaulded a piston. we brought the truck back and found the piston and scratched our heads then decided to have the injectors re-flowed. they were dumping so much fuel that it washed down the cylinder and stuck the piston. 3 other holes were also scuffed but not stuck. pump shop paid for the repairs.

[@swayme67]

You guys make it look easy! Can't wait for the next installment.

[@babyfacelmao69]

Y'all put out great content. Thanks for sharing the adventures

[@ptfarina]

love the thumb nail art - Black and blue - hammered again!

[@loupuleff571]

Nice video sure is nice to see you guys working together need more of that these days !

[@thorsbyguy5121]

I own an Allis 200. I have a couple observations that may help you troubleshoot this issue. First, the cab heat system is part of the cooling system. I replaced my heater hoses, and found it was very difficult to get the air out of the cooling system afterward, with the heater core being four feet higher than the rad cap. I repeatedly cracked the hose fitting at the heater core with the engine running, and air continued to come out. Bleed, add a little coolant, repeat. You have to drop the ceiling tin in the cab to get at the heater core connections. If your heater doesn't blow hot, you likely have air in the system. I think one of those vacuum coolant fillers might be the way to go on this system. Second, read your oil dipstick. Mine says to check the engine oil level running, which is kind of odd, and the oil level shows way high not running. You have a different engine (301 vs 426), but if your dipstick is calibrated the same and you're checking it with the engine stopped, you may be running it way low on oil. You may want to confirm you have an original, correct dipstick. I enjoy your videos. If you were in my area (Northern Alberta), you'd be my machine shop!

[@RJ1999x]

The hoses on your 200 were plumbed both on either pressure side or both on suction, the water didn't circulate , I ve ran into that on 200's before

[@donbenson5292]

Thanks again for a great video. Interesting to see it run right again.

[@komatsutech1]

After you cut the filter paper out put it in a vice and squeeze all the oil out. It leaves the metal in paper and makes it very easy to see the different colors of metal in the paper

[@rogerwhiting9310]

I admire your patience with this recurring breakdown. Looking forward to the rest of the fun..

[@alansvanes8479]

I would have thought there would be a check valve to keep the oil from running out of the filter every time the tractor is shut down. Sorry this happened to such nice people. Hopefully you will get it running before springs work

[@rickbargar3145]

Good luck !!! You’ll figure it out! Really enjoy the content.

[@dominicbushnell4092]

Agree with the ring gap as the symptom, and +1 that it could be caused by a partial oil blockage, would like to see the con rods to see if there's blueing, but could also be something restricting the exhaust flow at the rear of the engine. Lastly, could there be variable injector pressure distribution meaning that the back two are running weak?

[@trevort4286]

So good would love to see a longer video of the cleaning guy share his knowledge with us

[@codyfinchum890]

Dad super pissed but is remaining calm for the camera

[@jarnailbrar6732]

Excellent video. Learned so much from watching you work and listening to you explanations. Thank you for inviting us into your workshop by taking the time to make these videos. Hope you get this fixed quickly. You two make a great team.

[@3232jrob]

It's amazing watching a master at work...your old man is awesome

[@eliwillis1]

Good luck. Thanks for the videos

[@johndesaavedra1040]

I watched the second rebuild, and it makes sense that some of the injector pattern is on the cylinder walls. The injector timing is so advanced that the piston is two inches from TDC when the injector fired. Hindsight says the injector pump should have been returned at the discovery of the 180 out condition. A good mechanic always questions their own work first--sometimes to their detriment.

[@James-pf9mn]

Awesome video, I love this kinda stuff

[@edsmachine93]

Sorry to see this has happened to you guys. I know that you will figure it out. Thanks for sharing. Take care, Ed.

[@DaVinci0963]

I just found you guys today. Your "Curse Of" videos are must see for tractor owners and mechanics. My nephew is a younger version of Jim. I sent him the trilogy and subscribed to you because you are a hell of a teacher. Thanks Men!

[@SchwachsinnProduzent]

Well, at least this provides good content, which might attract more viewers. At some subscriber amount having a vehicle you own fail, would become a positive event, since the ad revenue would dwarf the repair costs.

[@JAMSIONLINE]

At some point, but we aren’t there yet 😂

[@christopherkise]

This is so excellen! I love your cleanliness, and calmness. I would say 11,5 and i would to.

[@robertquast9684]

The earlier comments on injection timing seems logical. Other thoughts would be a quality control issue with the rebuild parts. Seems every supplier is having issues

[@kimazbell460]

I'm going to guess you'll find a couple broken piston rings. BUT, make sure you check for electrolysis erosion around the cylinder liners. I had a one-ninety XT years ago that was getting water into the oil because of that. As I recall the shop used some JB Weld to build up that eroded area and it ran fine till I traded it off.

[@dwightkeegan4376]

Comment left to help support the rebuild.

[@waynegalvin4639]

Nice work and I feel your pain and frustration!

[@paulerenberger1286]

Keep uploading and I’ll keep watching to help pay for that 2nd rebuild!

[@verdantacres4460]

Awesome video thank you.

[@PRRGG1]

Hello, I just found your channel and really enjoyed the attention to detail of diagnosis. Guessing sometimes makes a bad situation worse, and not going down that path is the sign of a true craftsman. I'm not sure where you guys are, but I'm in Ohio and just started following.

[@djosbun]

I really feel sorry for your dad. Nothing worse than completing a personal project and something going wrong afterwards.

[@stephenbridges2791]

Back during the early 80's I had the great misfortune of working on a fleet that included the Detroit Fuel Pincher in some of it's first iterations. Those things would do totally inexplicable things, sometimes. Unsupported cylinder walls were it's particular plague.

[@CraigLYoung]

Thanks for sharing 👍

[@c2133jb]

I'm in a similar boat. Bought a new, to me tractor and first test drive in the field she threw a rod. I''m working on the new engine right now. Got just a few weeks before planting!

[@dmcdow]

I love your videos. I look forward to the next video!

[@markh2860]

Jus watched last week your video of rebuilding this engine. Noticed you mic'd sleeves and pistons etc. This guy is very thorough and meticulous. Great job! Now this, that sucks! Is this a Reliance kit?

[@jasonmead6760]

Love watching your videos and I’m subscribed

[@martinbeukes4773]

NOOOOOOOO, why stop!?! lol. Good luck with repairs. Looking forward to seeing the next one

[@jamesdavis8021]

It will be interesting to see what the problem is. I am looking forward to watching the tear down

[@benjaminzabriskie5729]

When you first posted the teaser on this, my first response was that it was fuel related; primarily based upon the video from your initial cold start. At that time I was thinking over fueling washing down the a cylinder but a timing seems more probable given the damage

[@markwallace5274]

I really enjoy this channel you guys do amazing work !!! My first thought was pistons and or ring gap since everything else in a engine as far as bearing clearances usually gain clearance with heat not so much with cast iron blocks but when pistons get hot they expand and if your P2W clearance is to tight they will seize in the bore. I’m sure the piston to wall clearance was within spec so it seems like something is overheating those pistons like detonation and or afr being to lean. Either way I know you guys will figure it out !!!

[@alwayssearching1882]

You guys have a blessed relationship.

[@dannop2562]

Noooooo!!! The Orange Ghost is on the haunt…

[@JAMSIONLINE]

👻

[@TheOffsetter]

I have a 1952 Allis Chambers model B that I use for farming pumpkins and sunflowers. I have a lot of classic tractors in my fleet, but the allis Chambers starts the easiest. Best of luck with yours!

[@andylampe2036]

That new crane is going to make life easier for you guys. Wonder if the guys who rebuilt it will stand behind their work.

[@bobbygetsbanned6049]

I'm no diesel guy but scored cylinders, massive crankcase pressure and dry oil filters screams oil starvation to me. On a gas engine detonation will damage your pistons not score the cylinder walls. Usually it's small dents and/or melting on the top of the cylinder. If your piston ring gap is too tight it will cause serious damage to the ring lands. If the ring lands aren't damaged I seriously doubt that's the problem. Lots of people are talking about the fuel system and timing, which I don't know anything about. I don't know if that could cause all this damage on a diesel. But I'd be checking the oil pump and oil pressure before running it for more than a few seconds, especially if the bottom end bearings are shot and/or showing heat. If it did overheat iron heads can warp or crack and need to be be magnafluxed and checked for flatness.

[@JackdeDuCoeur]

Nice work

[@BBQandStreetCars]

Since I first seen your videos I subbed and hit the bell for all your content. I honestly wish I lived closer to your shop, it's hard to find a good reliable honest machine shop around here

[@internet_internet]

Love y’alls videos. If y’all ever end up wanting to expand any parts of your operation to the Austin area, I’m in.

[@greatnorthernn-3154]

For what it's worth my view is that the antifreeze that migrated out of the cooling system is where the source of the problem lies. With the block full of coolant there is no way the lower sleeve o-rings could be damaged by heat. I'd be looking for a combustion side coolant leak that could affect both #5 and #6....perhaps a coolant port in the block or head that is in the close proximity of both cylinders. The cylinder scoring may be caused by the piston skirts melting due to the ingestion of antifreeze on those two cylinders.