Form-A-Gasket is neither red nor black. It’s sort of a puke green, IIRC. It’s a
good product for those who intend to never be back in that engine again, if
there’s any more trouble with it it’s getting sold or junked.
Permatex and Loctite joined forces somewhere along the line. The Loctite
518 is red, and it’s great stuff. There’s also something called Ultra Black, I
think, and it’s supposed to be the cat’s meow as well.
– Kirbert
Clearly, my “Goop” drawer is out dated…
Carl
Another 20 minutes of grunt with the 5/8 studs got the liner out.
The coating of tar seemed to be 2 or 3 thou thick on the liner.
I cleaned up the liner on the bench grinder’s wire brush, and washed the tar off the block bore.
Dropping the liner into the bore it sure was a slip fit, my guess is at least 2 or 3 thou diametrical clearance although it is not easy to judge accurately. Later I can see if feeler gauges will give a better idea.
The scale on the liner area in the water jacket is as hard as the hobs of hell, the wire brush just does not get every little bit off the liner. The scale was quite thick too, usually an indication of using water from a limestone area if I remember my chemistry. Melbourne’s water is not from such an area, but no idea where this engine was used.
The liner bore has spotting on it, looking like rust. It does not clean up entirely with a wire brush, but it is not at all deep. I do not think it is a problem, more of a surface discouloration. The outside of the liner has also been discoulored by the tar and no amount of wire brushing gets rid of it. A finger nail test of the ridge at the top of the liner bore suggests no more than 1 or 2 thou wear which is remarkable. Seems like if the engine is properly looked after it would get you to the moon and back.
Just stripping and cleaning up this engine and its components is going to take well over 100 man hours. I must have spent 50 hours to date and there is still lots to do. Changing studs from the old heads to the new ones could easily take 8 hours even if none of them are a pain to extract.
Even with a fairly clean engine you take far more time to strip and clean than you do for assembing it once again.
The crankshaft is in the machine shop for linishing, and the liners for a light hone.
I have given the block 2 sessions with degreaser and high pressure water to clean out the sludge in the water jacket and as much tar as possible elsewhere. Not looking as sorry as it did when it was first opened up, but I will take it to the machine shop for tanking to get the rest of the tar out.
The tank may be a bit small to get the whole tank in, so might need the front half done, then the rear half.
Something puzzles me in the block design. In the jackshaft valley there are drain holes, except for the rear cavity. That has no drain and traps oil. This engine had 10mm of oil sludge in that cavity.
Last V12 I rebuilt I just drilled a 8mm hole for draining. The other drains are just part of the casting so maybe it was an oversight or maybe a strength of casting mould issue to not give it a drain.
Just does not seem right to have a sludge trap there.
Liners back after honing.
Good news is 11 are o.k.
One has a score mark down the length of it.
Probably related to the piston with an M4 screw head embedded in the crown.
The score is about 1 to 2mm wide and 10 thou deep.
In the scheme of things it would just double the blow by in that bore, not a killer.
Nobody would ever know, but it goes against the grain to use it.
I have ordered all the wearable parts for a rebuild from Prestige Jag in Melbourne.
Luckily they also have 2nd hand parts I need: A liner, 2 pistons, a timing cover and the missing gudgeon pin circlip. Should be good to go and start rebuilding over the Xmas holidays.
Is the replacement liner size A or B? You should ensure that the pistons match the liners at least, if not making sure the whole engine is a matched set.
The 2nd hand pistons are “A” to match.
The pistons have “A” stamped on the crown of course, so you know it.
I have not noticed any letter stamped on the liners, so how do you know ?
It would not be difficult for Jaguar or its contractor to turn all piston ODs to within a thou.
I can see boring or grinding all liner IDs to a thou down the whole length wold be more tricky.
In general it is easier to get the OD of a turned or ground item to size than to get the ID to a size.
So did Jaguar measure the liners first for A and B grade, then turn the OD of pistons sets to match ?
Then which is which ? Is A the bigger bore ? I can turn pistons down in my lathe if they are too big.
There is no way I can rebore the liners on my lathe, I could get it done in a machine shop on a boring rig which is made for the job and it takes only minutes.
The V12 design goes back to the late 1960s. Manufacturing techniques have changed since then and I wonder if that engine was still in production would you need to grade bores and pistons ?
I have no idea what grade the 2nd hand liner is, I do not get it until next week.
I can try the pistons in the liner and make a comparison.
My suspicion is for an old engine like this one it is no big deal, if it looks and feels right, if the ring gap is correct, then it is O.K.
If you plan to go racing then be more fussy.
Ahhh…not unless you can cam grind them: pistons ARE not round.
No, can’t cam grind them.
Now you mention it I have heard they are not round.
I do not have a micrometer to measure these ones.
They do look as if they are turned on the OD, not ground.
So lucky we are nowadays - a Google search will reveal just about anything.
Quickly checked info on piston design.
The profile happens to be quite complicated, not only is the piston cross section oval rather than round, it is not uniform down the length of the piston. Modern pistons are turned on NC machines which must be customised for this application. Plenty of hits on You tube for “piston turning” and “piston processing”.
If you are curious about manufacturing and machine tools ( one of my weaknesses ) there is some excellent material on making items for vehicles.
There was a time all this manufacturing to make a car was carried out in Australia. Not any more, we import all cars. The areas in which we have expertise shrink year by year.
No, you can’t. Pistons are not actually round. They are cam ground, slightly oval and a bit wider at the skirt than at the crown. This is so they become round as they heat up.
Re the question regarding grading of bore and pistons, I seem to recall reading about the latest V8s having multiple grades, just need to do some cranial digging to come up with where I saw it.
Apparently the piston shape is designed to also compensates for the gas pressure in the combustion chamber.
Looking at a Youtube video of Merc V8 production the pistons are obviously forged and have about 2/3 of the skirt cut away. It looks like the skirt relief is done to add strength to the gudgeon pin bore and I guess it might cut down on friction of piston in bore. Perhaps is also saves weight and hence material cost.
I am not familiar with modern engines, other than driving cars which have them, so they probably have similar piston design
Looking down the inside of my v12 pistons there is so much undercut I reckon they would have to be cast and not forged.
The Merc pistons look a more sophisticated design than the Jag V12 ones, but we are talking 40 odd years of advances in design and technology. The newer piston designs may be more influenced by the updated CNC methods of machining and cost saving rather than simply the effectiveness of operation in the engine.
" Re the question regarding grading of bore and pistons, I seem to recall reading about the latest V8s having multiple grades, just need to do some cranial digging to come up with where I saw it ".
I can believe it. With modern measuring technology and CNC machining you could totally automate the process. Nobody has to think, measure the bores and record the data. Send data to piston machining centre and match them up. You could even match pistons to individual bores in an engine with no extra effort, except for tracking pistons against bores when final engine assembly takes place.
This is how I like it, clean and ready for rebuild.
Cost A$180 to have it tanked but well worth it.
The bores look scuffed, but a finger nail test shows no metal removed it is just some form of discouloration and on close inspection looks more like an etched surface. Does not pose any threats.
More concerning is the corrosion on the seat area which takes the liner shoulder.
That looks bad in places but with care in fitting and sealing the liners it should work out O.K.
One or two of the main studs show minor necking on the base of the thread which takes the dome nut. This is due to coolant migrating up the stud and no doubt lack of inhibitor. It looks like they will take full torque but I would like to put something on the thread to protect it. Loctite is possible but the popular 243 might make it mighty hard to get the nuts off in future. There is a Loctite grade much lower in release force but so far have not found a source to buy it. Maybe 518 would do the trick even if it is a sealing product.
Was fortunate to not have any of the troubles with the liners when rebuilding my V12. Their condition was great and the honing liners where still clear as day being an even swirl from to bottom on every one. Tried to find picture showing these homing trails but the attached is best found. Suggest you re hone yours. Even though mine looked good I re-honed each liner using a BRM Flex-Hone pat number GB33418. It’s size is 1 & 3/4" (95mm) 180SC. Wish you where closer so I
could loan it to you.“It’s size is 1 & 3/4” (95mm) 180SC. Wish you where closer so I loan it to you."
Typing error. The hone is of course a 3 & 3/4 " (95mm) size.
Thanks for the offer of a hone Don, but too late.
I had them honed by the same shop that linished the crank and tanked the block.
The spare 2nd hand liner to replace the damaged one i will probably hone on my lathe, not worth the trouble of getting one done by the shop and they will close for 4 weeks over Xmas.
Your block condition looks much better than mine, see the difference in finish on the edge of the block.
Apply 518 to both sides of the flat washers that go under the dome nuts. That will seal them up so that air that rises into the area will stay there. What you should apply to the threads is anti-seize compound.
Well, I always put 518 both sides of those thick washers.
Actually it might also seal the dome nut threads from ingress of coolant wicking up around the stud.
That needs enough 518 in the right place to also seal off the stud.
A spanner in the works is that as you tighten down the dome nut the air trapped in the nut will try to push any type of liquid out of the threads.
I am not too sure about putting ant-seize on the stud threads. I would rather put 518 on them.
The torque figures for the studs are based on lightly oiled threads. Anything more slippery will put more strain on the stud to reach the torque figure.
Whatever, it is possible to do a better job than the original factory assembly because we are not up against a time limit.
Today I received all the wearable rebuild parts, plus two second hand liners + pistons + conrods.
Also a second hand timing cover.
Good to go over the Xmas holidays.
