**
The point here is that the starter and ring gear is dimensioned to take the strain of a stalled engine, Foxy - the crankshaft bolt is principally dimensioned to prevent the damper and pulleys to fall off…
And how do you know that the starter is stuck if you haven’t tried…?
I certainly agree that care must be taken when reviving a long dormant engine, but sooner or later the engine must be turned - and the starter is the most powerful item to do it. Liberal amounts of oil in the bores with the plugs removed, and brief repeats with the starter may loosen the b…rd
If the engine turns; just spin it on the starter for some time to ease up the pistons - binding pistons is the only thing that can prevent the starter from turning the engine.
Frank
xj6 85 Sov Europe (UK/NZ)
**
Pouring hot water into the block has no effect in freeing stuck pistons - but is harmless. It is cold water in an overheated block that may crack a block
Thank you for the update, which provides a clearer view of what you’re attempting to achieve. Things to consider if you move forward with the water routine.
Water + Air + Steel = Rust. The head studs are in the water jacket to the block so by adding water to the water jackets you’ll be introducing rust / corrosion to the head studs.
If you do decide to add water to “free it up”, I’d make sure the thermostats are out, and figure out some way to circulate the warm water through the engine. I do like the idea of some sort of heater; like a block heater could prove to be useful.
If your thought is the moisture and degraded diesel is the cause of the seizure and the warm water will expand the metal enough free the pistons; here’s some numbers to give you an idea on what level of expansion you’re looking at.
a. The expansion of a piece of steel 30.5 CM (12 inches) from 0 to 100 C (freezing to boiling) is .3654 mm or.0143 inches
b. The expansion rate of a piece of aluminum 30.5cm (12 inch) from 0 to 100 C (freezing to boiling) is .7004 mm or .0275 inches
c. The expansion rate isn’t linear, meaning if 30.5 cm expands .3656 then 61cm will expand .7308cm its actually a bit more than that but not much. Seriously side tracked. Sorry
If you do the warm water routine, I’d be interested in the outcome; Frankly I don’t think you’re going to accomplish anything; but I hate to be Debbie downer; and I have been known to be wrong – a lot according to my future ex (wife).
If it were me, I’d look down the sparkplug hole with a borescope. Look at the condition of the CYL walls. I’d also take a gander at the Cam and dipstick for signs of moisture / rust. Better yet, pop a cam cover off and look inside. Look at the cam gear & chain for signs of corrosion.
Not as likely as a stuck ring and piston or more, but within the realm of possibles is a bearing. Main, rod, at each end or even a cam bearing.
Decades ago, a pal and I went from El Paso to Carlsbad to consider a joint purchase of a circa 30 RR!! Dirt cheap in present day terms. Just at the reach in $'s of two young guys, 20, or so.
The owner told of freeing the big six that was stuck when he got it. He attacked by dropping the sump and loosening the bearing caps, whil trying to turn it. I forgot how. But, he won. It ran
nicely. But, it rode, drove and steered like a truck compared to my then 47 Ford that took us there.
Lionel and I concluded that if I sold my Ford and he sold his 50 GMC pickup, we could buy it and have enough left for one lessor car. Who got which was not decided. So, we passed.
Oh, me.
A Brewster LHD RR would have been a prize, indeed.
No the Daimler is safe indoors. Hasn’t been outside since the mid eighties.
Thanks for taking the time to post a detailed reply.
Just thinking we’re all talking here about the expansion rates of alloy v steel. Some are saying boiling water will damage the block. Others are saying it won’t do anything but the two items in contact (rings and liner) aren’t even aluminium (both steel?).
It does beg the question that when the engine is up to full operating temp is the block ‘disconnected’ from the liners? Like the block is expanding away from them. Seems unlikely.
But on that subject… since the V12 has liners in the block (manual advises tool should be used to stop them coming up out black when dismantling engine) am thinking if you take the engine apart you could withdraw each stuck piston with its liner and separate them ‘on the bench’ so to speak
Never tried this on a 12, did try it on an XK block.
Did not use the water pump.
I used an old 10 gallon water heater in my shop and a zone pump. Brought it up slow and thermocycled the block over almost a week via a water heater timer.
Used a mix of Marvel Mystery oil, Kerosene and tranny fluid. No particular recipe just poured it into the spark plug holes.
It did eventually loosen, persuaded by the big extension bar that did originally didn’t budge anything.
It didn’t work on the one I had to drill out two of the six pistons.
If you are rebuilding a Twelve, good luck and have lots of money, I think I’d buy a running engine before I was to rebuild another Twelve.
The block is a alloy as well as the heads, and pistons. The rings are an alloy I believe chrome molly. The liners are a hardened steel.
Personally, I don’t think your going to be successful with the hot water treatment. But I have been wrong, alot. Haha
Liners being disconnected
It is unlikely for a couple of reasons.
The liners a chilled, and the block is heated and pressed in place.
The liner isn’t going anywhere because of number one above, and are bolted into place by the head, and the lip at the bottom of the cylinder.
Taking the liners out with the piston, Theoretically this does sound plausible. I don’t have any experience to draw from, so I can’t say one way or another
I would like to throw this out there, the pistons being seized, is only one aspect of why the engine won’t turn over. The cams, the timing chain, starter stuck in an engaged state, or a combination of all of the above.
If it were me, I would inspect the bores, and if the bores check out, then I would start on the easy “other” rotating assemblies
Are the cams or dipstick rusted? Milky substance observed in the oil or engine internals?
Reading the Service Manual…
The torque spec on the damper bolt is 150 foot pounds or 20.7 kg m.
Try putting that much torque on it and no more and see what happens.
The manual shows a tool (JD41) to be bolted to the head whenever you remove a piston and conrod. That says to me they are liable to move upwards easily. The manual also mentions when replacing liners ensure they are correct grade (A or B) suggesting they are serviceable items
Wiggles
you are spot on. if the pistons are siezed in the bores, then they will have to come out. there isn’t any amount of magical fluid (oil) that’s going to repair the damage caused by siezed… Well I take part of that back. If the engine is seized because of a chemical to prevent rust, and there isn’t any signs of rust, then some magical fluid that would disolve the no longer viscus fluid. Then I can see Foxy99’s point.
I also just saw the picture, no wonder he hasn’t answered about the dipstick or the cam and /or cam covers.
**
Reminds me of a friend buying an Essex (it’s long ago), cheap as one cylinder seemed to be misfiring.
Got it home and checked the plugs - sure enough; the electrodes were bent together. Aha…gapped the plug and started up - but still misfiring. Let it idle…and there was an almighty bang. Checking closer; the PO had removed a piston and its connecting rod…
**
That’s how pistons are removed and replaced, Foxy; upwards after head removal and disconnecting the big end…
…‘easily’ when the pistons are not stuck - and stuck pistons are a prime reason for a working starter and battery cannot turn the engine. Certainly, if there is corrosion locking up the pistons, forcing them by cranking, wear my result - but with plenty of oil in the bore the risk is bearable.
Point being that other methods to release pistons will do the same - and without getting the engine to turn a major operation, mainly engine out, will be required anyway. Necessary work to be decided based on observations in all cases…
It was only when someone else offered to try that the thin bolt holding the nut thing snapped. I expected this to happen but let the guy find out himself that excessive force wasn’t going to work
I’ve actually got a spare engine which isn’t seized.
Problem is that one is an HE and my car is carbs. I don’t want to convert to fuel injection and afaik you can’t just bolt the carb manifolds etc to the HE heads and expect it to run the same.
Another problem is that the bellhousing on the spare engine is damaged (where it bolts to gearbox)
Rob_Reilly is talking about the more sturdy bold behind the thing that snapped on mine. Sound strange but there is a big bolt holding the damper to the crank and straddling that there is a ‘bolt’ on a flat plate which is connected to the damper by the thin bolts/setscews.
Rob_Reilly is saying I can put that much torque on the big bolt without worrying about shearing the crank threads
