Dauntless Head Removal

Yes............where were the timing marks on the front cover versus the balancer............when you were at TDC #1 where did those marks line up?
No .....................piston should be at or near TDC on the compression / firing stroke so neither of the valves are open.........as I mentioned you can stick your thumb in the spark plug hole and get the same result for finding TDC on the correct stroke........otherwise on the exhaust stroke the exhaust valve will start to open

 

I gotcha now. But yeah, at TDC on #1 the marks lined up. I confirmed it the other way, I lined up the marks and put the borescope in, and as soon as I got past the plug hole the piston was there. I wasn't getting any air leaking from the block that I could tell so I didn't figure it was the rings either.

termin8ed, the leak results from #1 were a few posts back, and I was just hunting down my compression results when you asked. Left bank, #1: 60, #3, 65, #5, 142. Right bank, #2: 111, #4: 136, #6: 121. All done on a cold block as the engine currently isn't running (I hate the diagnosis that say warm the engine to operating temp first, if I have something to diagnose it's probably because I can't warm it up since it doesn't run ). The leakdown on #1 was something like 80% loss. That was at the top of both the compression and exhaust stroke. The 111 concerns me as well, being so far from #5, guessing #2 could use some rings. I'll get more info from a leakdown test on #2 as well I'm sure.

 

Yeah, I'd planned on trying that before the starter crapped out, even bought an oil can for the purpose, and guess I forgot. I'll give that a go too.

 

Back when I rebuilt mine, the factory head gaskets are stamped steel and thin, they were eroded away between cylinders causing backfiring and bad compression.
Pulling a head without pulling the intake separate is a recipe for a disaster, might be able to do it but it's a crap shoot at best.

 

Again, usually, when the rings wear out, they all wear out. An engine with worn rings will have low and variable compression on all cylinders. Just because the numbers are a little beter on some of the cylinders does not mean that the rings there are ok. Not sure what you'd see with a fresh 225, but on the AMC engines they hang in the 150 range, typically. From there, a range of +/- 10 psi is normal. For example, the healthy 258 in my J-10 measures 160/160/160/150/155/152 - pretty sure this was rebuilt not long before I got it. I would expect a 225 to be similar. To me, your numbers are consistent with worn-out rings, except for the two that are around 60... although those could be attributed to the rings. The wet compression test will help to evaluate the rings. You can run an engine a long time with worn rings, although you will likely have problems with smoke, excess oil consumption and oil-fouling of the plugs.

 

I think Mcruff has the answer; I think the head gasket between #1 and #3 is blown, likely from rusting through. It sounds like a good time to pull both heads off to freshen them up (read: valve grind and possible resurface).
When the heads are off, you can check the ridge at the top of the cylinders to determine wear.
-Donny

 

Took some more readings. Since my last readings, I installed a brand new starter, and the battery has been on a Nokio Genius charger so it was reliably topped off. The starter cranks twice as fast it feels like. So the pre-oil numbers went up significantly, but unfortunately I didn't get a pre-oil number for #1. Gonna guess it was similar to #3 based on what I see now.

Pre-oil, old starter: #1 - 60, #3 - 65, #5 - 142, #2 - 111, #4 - 136, #6 - 121
Pre-oil, new starter: #1 - n/a, #3 - 95, #5 - 158, #2 - 152, #4 - 160, #6 - 161
Post-oil, new starter: #1 - 98, #3 - 118, #5 - 175, #2 - 182, #4 - 175, #6 - 176

timgr, 4 of my cylinders are now really close to yours, when my starter cranks at full speed and I let it build up over 3 or 4 compressions. Feeling good that those 4 cylinders are ok. The oil didn't completely solve #1 or #3, but it did seem to make an improvement for #3 at least.

I did leak #3 and #5, it was getting late so I'll save the passenger bank for later. #1 and #3 still came in low at 15/90. #5 came in at about 73/90. Little concerned it's not within 10% but it's at least confirmation my leaktester isn't broken. Both #1 and #3 seem to escape through the carburetor. I couldn't detect any sound or draft from the exhaust on either. I keep forgetting to check the disconnected coolant hose now that I think about it, shoot. Either way, starting to seem more like head gasket to me than a pair of valves.

 

If it was a head gasket..........you should be able to hear the leak between the cylinders, through each spark plug hole........on rings normally the leak is into the crankcase below or pan..........but if you remove your smog plug or valve on the valve cover the noise will also be present there. Leaking to the carburetor is normally and Intake valve and through the exhaust is normally an Exhaust valve.................................make sure your compressor is up to say at least 100 PSI before each cylinder test..........With all things being equal...........I think it looks like it will need to come apart.

 

Yeah it was on automatic recharge, kicked on every cylinder or two depending on how quick I was. I had the gauge set to 90 instead of 100 as the box gave a lookup table for both 90 and 100. I haven't been able to detect anything from the spark plug hole on the adjacent cylinder so wasn't sure. But yeah, gonna prepare to pull this head, although I'm going to leak test the other side for S&Gs first.

Hopefully I can keep myself motivated on this for a while with the weather being nice. I realized I really need better garage lighting though. The wall behind me is dark, so no real reflection of the single CFL bulb I have for lighting at the moment. Ballast seems to be going out on my overhead 4' shop light, blinks and then nothing each time the switch is flipped. I have a couple LED 4' lights, could install one in its place, but thinking about calling my goto electrician to see if I can't get something a little beefier going on. Thinking about lining the side walls of the garage with lighting. Want to make sure I don't overdo my existing circuit. We just put in a 200A box last year for my hot tub install, so I should have the capacity to run a new circuit if need be. Would be nice being able to see clearly in my garage without dangling little shop lights everywhere.

 

Good Lighting , helps...........Take some pictures as you dissemble it. Keep the parts , head gasket and other Items separated between each head..........

Don't let the head gaskets get damaged or thrown away until after a complete inspection of both sides are made which should also include inspecting the mating surfaces of both the block and heads..........This is important if you suspect head gasket failure which could be loose bolts, or a warped head or block. If compression , or water is migrating between the block , head or cylinders that migration will leave a distinct trail........

 

The water pump developed a leak a while back, most of the fluid that was in the radiator is gone at this point. Some might have migrated into the oil as well. There is kind of a strange web-like oil film under the rocker covers, which feels like something I've seen when water mixed with oil. Just my guess though. Anyway, when I pulled the upper radiator hose, there is a lot of rusted metal bits sitting in the top passageway. I can maybe get some photos. It's not pretty. I don't know if it's from the radiator or the block. The radiator externally doesn't look all that rough, aside from the overflow outlet I mentioned rusted through. Internally it is saturated with sludge but the material itself doesn't seem too rotten.

 

Sludge in Radiators can be several things like *just dirty old contaminated water or a * migration of compression gases from a head gasket leaking that finds it way into the water jackets and eventually the cooling system or *just lubricating oil that finds it's way into the water system..........also sometimes it could be a cold weather issue whereby the motor is collecting condensation from being Hot & then Cold?

If you have a radiator pressure checker available to you I would pressurize the system and see if any leaks show up.

In either case when that motor comes apart the block & heads should be thoroughly checked for any cracks or leaks.

 

This much though? I think the evaporating fluid left behind a sticky corrosive sludge. Gonna have some work cut out for me. Not liking the stuff I see coming out of that heater core line either.





Broken radiator nipple.





Lots of bits I fished out of the radiator passage were like this. Kind of like a really brittle slate material. Not sure what would have corroded into this kind of substance. Falls apart under not much pressure.



Probably what caused the water pump to start leaking was all the corrosion going on, didn't see how bad this was until I got the fan off the other day. The shaft had a lot of play as I was removing the pulley.



Someone had taken a larger hose and just slipped it over the smaller one to fix the hose up to the radiator. I have a feeling this isn't stock? The broken rusted output piece is half in the larger hose section still.

 

if it were me, I would pull the intake manifold, and then the head. For one thing, if the heat riser passage is plugged with carbon you have to have both off in order to clean that passage. And after almost 50 years, that passage can be pretty tightly packed with carbon.

 

Yup, that is the plan it seems. Just got my blown out shop light replaced this weekend, garage is a little brighter and the weather should be nice so I might be able to get a start on it this week I hope. Any tools that will come in handy for cleaning those passages while I have the heads off?

 

I used a long blades flat-head screwdriver as a scraper.

 

I replaced the head gaskets on mine back in Jan. I could actually see water coming out of the front where the head and block meet. I do have a newer 231 (1987). Autozone had some helpful information published on their website. Took a Sat afternoon and 1/2 day Sun.
| Repair Guides | Engine Mechanical | Cylinder Head | AutoZone.com

 

Thanks I'll definitely give that a read as well as going over the other dauntless rebuild threads another time to study the tips and pics.

 

Got partway into this last night. I went in with the mindset that I am trying to interfere with as little as possible - disconnect as little as possible, remove as little as possible, etc. Some of these parts have been stuck together for a long time, and as I am just trying to investigate at this point what it will actually take to get this thing running, I don't want to break more things in the process. So, I ended up only removing one end of hoses, cables, etc, and finding creative ways to tuck the other ends out of the way. I've documented all these for your enjoyment. I don't claim to be a mechanic, just a guy with some free time and a nice phone camera. So, I may not always know what I'm doing. Please tell me if that's the case, only way I'll learn.

Is there a per-post photo limit? We'll find out.

Here's where I started. Got my NOS dashpot in the mail, tested it out, works great. Slid the coil in its general location to see how it fits with the coolant sender behind it. Note that the coil is already unmounted, you may need to figure out its removal earlier in the process than I have it depicted. I also started with the fan shroud, fan, belt, and air cleaner assembly out of my way. Those removals are pretty straightforward and probably documented elsewhere. The shroud has 2-3 screws on each side, the fan has four bolts and pops off with some wiggling (maybe a better way than wiggling if you care about your water pump's shaft, I'm replacing mine), and the belt comes off with a loosening of two alternator bolts. I don't even remember taking the air cleaner off, it's been off for so long. You may also need to drain your block of antifreeze enough to empty the manifold/head passages. Mine had mostly already leaked out the water pump so I didn't have to worry.



Fuel line first - mauled it previously with a line wrench so it's been vise grips to take it on and off since then.



Had already removed this before so went ahead and slipped it out of the other fitting - I'd forgotten to even re-tighten that worm clamp when I reinstalled the carburetor.







Next, this thing. Loosened the top one and slid it back off, and pulled it up out of the valve cover. That method may break the hose if it's brittle.





Dashpot and throttle/choke assemblies next. My spring tab is not bent like some of the photos I've seen here, making it hard to install like those. Anyone have a photo of a tab that isn't bent like mine, and how it should look installed?



Dashpot removed, pieces bolted together so they don't disappear.