1974 Daimler Double-Six VDP (higher axle stands)

Not sure if I said but the success in removing the stuck screws from the block the other night (the ones for coolant castings) with acetone/brake-fluid mix lead me over to another project which has plagued me for a year or so...

I'm in the unfortunate position of having someone else's Yamaha XJR1300 taking up a huge amount of space in the barn. I can't get rid of it till I get the old corroded exhaust-studs out and put in some new stainless ones I've had for months. Have tried everything under the sun to get them out.

Anyway I waved some of the new fluid at one of them and stuck a pair of mole-grips on and it wound out no problem. Moved over to the other side and got another out. Just needed to tackle the harder-to-reach, more-corroded ones further in

So last night I got back on it, using plenty of the fluid, plus MIG welder and achieved nothing apart from carnage

It was only moving back to the VDP and getting the studs out cleanly that made the baltic spell at barn worthwhile.

So I got home and started checking the Haynes manual for the XJR with a view to taking the cylinder-head off to drill the studs out.

I was struck by how similar the process was to the V12. Before you laugh/mock at that observation bear in mind that my other bikes are 2-strokes apart from SS50 and only other car engine I've rebuilt was VW Polo.

None of the manuals for these engine carry warnings about breaking the camshafts and cam-caps. The XJR book really labours the issue and it made me think of my reluctance to put the cams back in the HE heads the other night. The Jaguar manual doesn't give any special instructions but the XJR book says if you break a cap the cylinder-head has to be replaced. I'm guessing this is because they are line-bored, like the V12 ones. It also explains (badly) how you need to tighten the caps over the valves which will be open once the cam is in place before the ones which will be above closed valves.

The reasoning will be that if you tighten down the 'relaxed' sections first the camshaft above 'unrelaxed' sections will be under great strain with no support from the cap. Makes sense I guess but am glad I noticed this as it's probably a good idea to do same when I re-install the Jag cams.

I've also had some thoughts about getting the remaining V12 head-studs out... wondering if it would be possible to lock just one nut on a stud by staking the top of it. If the studs aren't in tight it may give enough bite to get the stud turning. I don't need to worry about damaging any studs as have a full set available from the HE.



this bike is taking up about same amount of room that the V12 and transmission would





utter c&*nts



hey what was all the fuss about? two out, 6 to go






utter c&*nts

Forgive me here but why are you removing the studs when it's proving difficult

Leave them in until the head is off and then use a suitable one of these (Picture is a clickable link)

So. Back on it tonight. Plan was to tackle thin (3/8") inner studs by thinning-down a correct-sized ring-spanner (9/16" AF). I thought they'd definitely come out but not so.

First problem I hadn't anticipated is that there isn't enough clearance round the nut to get the ring-spanner on without it sitting on a lip in the casting. This wouldn't be a real problem if you were just removing the nut but I needed the spanner to sit below the top of the nut so it didn't interfere with the nut above.

Good thing was the thinner spanner allowed me to get the rest of the outers off. It gave me a bit more purchase than the open-ended 1/4W that I was bodging with. I found a knack for getting the studs to budge that seemed to work well: I'd lock the nuts together then squeeze the two spanners a twist back and forward and you'd fell and hear them let go. Quite satisfying.

I then altered the spanner further by grinding some metal off the front bottom edge so it would clear the casting but I still wasn't getting any joy and figured might need to leave them in and focus on the 7/16" ones as they are likely to be the ones stopping head coming up.

On seeing my pictures after I got home tho I'm thinking I didn't quite remove enough from the spanner at the part it needs it. Might have one more try.

Last night I did quite a bit of reading about other ppl's efforts to get Jag heads off and Coca Cola was mentioned more than once as a successful penetrant so I bought some en route to the barn today.

Rather than wrestle further with the 7/16" studs I filled the wells round the inner row on both heads and will see if it loosens even one of them. I think just seeing one of the water-jacket studs will really help in deciding best way forward here.



inner 3/8" studs not easy to reach



with correct nut on there is very little thread for locking another nut on top...



...and ring-spanner will foul casting



Coca Cola may help free studs from cylinder-heads



inner 7/16" studs have handy wells round them for the fluid to do its stuff

worth welding the nut to the stud ?

Daft question - with half nuts so cheap, why not get some?

So tonight's job was to see if the Cola had done anything. I didn't really expect anything but upon arrival it did look like, perhaps, there was was less of it in the wells of the casting. I tried wiggling the studs but couldn't say they were actually moving. Thought I mb saw a bubbles or two when I flexed them.

I went back to locking two nuts on them but it felt like I was just stripping the threads of the domed nuts if I put them on top and the thin half-nut was starting to get worn and I only have one 11/16" spanner so was using an 18mm on the top nut. Not ideal and felt like all I was going to do was strip threads.

Next minute I was out with the welder and put the thicker half-nut on one of the studs leaving a recess to weld into. I figured it would be easier to salvage the stud if only the top was damaged. I'd soaked up the Coke when I dried the stud prior to welding but as soon as I welded it I could hear a lot of fizzing which sounded promising as it suggested there was some down the length of the stud.

As soon as I turned the spanner the nut came right off so my enthusiasm died a bit but I cut another domed nut and this time put it further down the stud so I could get penetration right round it. Got more fizzing too. Actually took a little video on my camera and you can clearly hear it above Classic FM lol. Will put link up later.

So take #2. Spanner on and twist and yaay it gave way. Wound out no problem untilthe very end wherew the bottom got a bit stuck in the top of the head.

I was surprised to see it was sort of black and oily. Surely not the Cola? Once it was out I gave it a wipe and couldn't believe how lean/etched it looked. Like it had been in acid for days/weeks. I then gave it a wire-brushing and could see bizarrely that the only bit that wouldn't come clean were the threads at top. The stud looks to corroded to use again but am impressed at how good the threads that go into the block are.

Buoyed by that success I cut another nut and tried one of the outer thick studs which had only had a drizzle of Cola as there are no wells there for it to sit in. I figured this would give a good indication of whether or not the Coke was responsible for the cleanliness of the first one out.

Surprisingly I heard the fizzing again and the nut held firm. I could feel the stud twisting but it but it wouldn't yield and I couldn't get any more leverage on it due to the inner wing. I'm going to need to get an 11/16" socket and use it on an extension.

So a bit disappointing not to see the difference between the full-Cola one and the other but still a success. I could've carried on cutting nuts and welding them on I guess but it struck me that I better make sure I could actually get the studs out the HE block first.

So over to the HE block and put grips on the un-threaded part of a couple of the studs but they didn't budge which surprised me a little. Next was cutting another domed nut and locking two etc and still the stud wouldn't budge. Was getting worried and tried some other studs. 3rd one came no probs and before I knew it was an expert and got them all out including the first ones that wouldn't budge. Best technique was to lock the nuts then hold spanners at 180 degrees from each other and twist back and forward and they'd crack. Theses studs are in much better nick so I can now mutilate the VDP originals without concern.

However.... am thinking the problem may not really be corrosion. Am just not getting enough leverage/purchase on the stud/nuts unit to crack them. Think I'll just need to buy a bag of sacrificial nuts and carry on with the welding-trick.

Then again mb I should focus on getting Coke down the studs and I can lift the head off conventionally then take out the studs.


1st welding of nut to 7/16" stud


nut just came off so 2nd nut wound down stud further prior to welding



take #2



and out it came. didn't expect it to be black & oily



wipe with cloth reveals it to be thinned by corrosion but strangely clean



close-up



threads at bottom are perfect



threads at top didn't come clean even after wire-brushing. strange



stud from same area on HE, not cleaned



HE stud shows very minor corrosion and good bottom threads



all 7/16" studs came out RHS of HE block with no drama



my first view of liners


So there we have it. Good spare set of studs to replace likely all corroded originals from car. Knowledge that the studs will come out and perhaps Coca Cola sufficient to clean them enough for block to slide off conventionally. Back on it tomorrow

The Coke can't hurt, let's put it this way. It isn't a miracle liquid but makes a positive difference from experience and in the case of the environment those studs are in, every little helps.

Welding a nut to them helps as well (heat frees most things - depends how much you can apply!) but so does giving them a good whack. With the domed nuts you have, assuming access, then a good tap with a lump hammer on the domed nuts can't hurt either (and is good for cracking corrosion free).

Add up all the little bits (Coke, heat, shock) and it will make the difference between a stud relenting and it not.

Yip. At end of day tho it's hard to tell what's worked and what hasn't. I've been at the XJR studs for over a year now. Tried everything: oxy-acetylene torch on them; nuts MIG welded on, freeze-sprays, penetrating fluids, nut locked together, shocking with chisels and centre-punches, vise grips. Everything and no real outcome - apart from 2 moved and one snapped.

With the VDP studs there are two obstacles to overcome (unlike the XJR studs): there's the torque needed to unscrew the threads from the block (no corrosion issues) and any chemical/electrolytic bond between the shafts of the studs and the heads.

So on the HE block there was only one factor to deal with and you needed a good bit of leverage to break the bond. On the VDP there may or may not be the second factor. If there was you'd need to overcome that just to get to the same stage as removing bare studs.

So looking at the one I did get out it's unlikely that the black oily substance was stopping the stud turning. So the question is was that there before the Coke was poured down or after? Maybe any penetrating fluid down there would've achieved same thing. I'm just thinking it was the Coke due to the shiny pickled appearance of a stud that's obviously corroded at some point.

good progress .