I picked up a complete 1965 MkX 4.2. It turned out to be stuck. Oh well, I planned on rebuilding it anyway. How bad could it be? Um, kind of bad.
It looks like #1 is going to need a new sleeve and piston. Hopefully it is savable. The other cylinders have surface rust, so I might get away with a hone, but will probably need to be bored out… plus new pistons.
The head at #1 was caked with corrosion, but doesn’t look too bad underneath. The head gasket was intact, but it was stored without the spark plug and the safety wire was gone from the cam gears. The seller may have known more than he let on. It was stored for 30+ years in a Florida (humid!) shed. Fingers crossed the head is in decent shape.
That’s a bad one, and I’ll bet you are looking at a sleeve on #1. Pay close attention to the rust debris in the water ports of the block in the last photo. You might want to pick at those some and see how bad the erosion is. I’ve just gone to a spare engine for my 65 Mk10-out-of-Florida-in-a-shed car that has absolutely the worst corrosion I’ve ever seen in an XK motor. The reason I mention it to you is that it was hard to tell how bad it really was until the block was cleaned, and then the water passages looked like someone was after them with a sugar scoop. We’ve already scrapped the head, pretty much junk (yours looks quite a bit better). If the spare block isn’t usable, we might have to weld.
I just unstuck a piston in that spare Mk10 engine and I’ll share my method as I think you might need it from the looks of it. This was hard stuck and sounded like cast iron when struck. Penetrating oil and coke didn’t work, no surprise. With everything else apart, I put powdered lye (Sodium Hydroxide, caustic soda) down the bore and carefully added water (very caustic - gloves, goggles, no kids, no pets, care!). Do this outside as is makes hydrogen gas and it will kill the s&*^ out of your lawn. I let it sit overnight, still bubbling from the slowly dissolving aluminum the next day. With the engine upside down, I whanged the piston wrist bosses with a long pipe and BFH. Piston moves and soon pops free. I’d continue it for several days if needed. When the cylinder starts to clean up, you might want to run a hone through it before you try to move the piston. I believe there is no way that you will be reusing the pistons from this engine!
Thanks Ron. The last 3 pictures are the same cylinder after sucking out the debris & oil and before. The visible water jackets look nice, I’ll have to find out lower down. The corrosion in #1 may extend through the liner. It’s nasty. A mixture of ATF and kerosene made it past 2 pistons, but the cylinders don’t look TOO bad. I won’t really know until I knock those pistons out and clean everything.
I was going to try EvapoRust or Metal Shield in the cylinders. I’ve had luck with it before and far less caustic than lye… but that may be a last resort. Maybe vinegar through the water passages since it’s a lot cheaper and works almost as well.
I’d like to keep the short stud, 60s block… but 70s and 80s 4.2 blocks (even complete engines!) are really cheap, so I might end up swapping heads. Fingers crossed.
I picked around in the head. There seems to be some deep pits in the exhaust port, but not through into a water jacket. I won’t know for sure until I really clean it. Combustion chamber has a lot of carbon, but otherwise seems to be in OK shape. Valves look bad in the port, but all snapped closed when I removed the cams… which were dry.
I’m wondering about your progress. I personally haven’t had much luck with vinegar, but if you use the concentrated 30% stuff maybe it would work. Probably better on the rust than lye, but less effect on the pistons.
As to the 70s and 80s engines, I know the series 3 XJ6 cars have the engine mounts further back and won’t bolt up to a 60s car. I don’t know when that changed.
I soaked all the cylinders with vinegar for a few days. I figured that vinegar was weak (but effective) I would let it take care of the easy stuff. Most of the cylinders looked pretty good afterwards. Surface rust on the walls and the piston tops look pitted. #1 is bad. I then soaked them all in EvapoRust several days followed by Kroil. Since EvapoRust loses it’s efficacy after it turns black, I had to change it out a few times in #1. I need to post pics later. I can definitely see layers of metal that has been eaten away, probably completely through the liner, but it doesn’t look like it has gone through the interior walls. I probably won’t know for sure until I get the pistons out and have a machine shop look at it. As bad as it is, I may be able to remove the remnants of the liner myself.
I might try a cheap hone next to help facilitate movement by creating a somewhat smoother path. I might try electrolysis, too. It will, no doubt, be a struggle to get this one out no matter what I do. I think the other 5 will come out with a lot less struggle, but still a struggle.
This is definitely the worst I’ve seen. The lye treatment would be easiest imo, just use a little care and do it outside, let it bubble for a week. If you have a hot tank service in town, it would dissolve those pistons. I do think you will need to spend much $s to recover this engine - might not be worth it. Keep me posted, please, and good luck!
Weeeellll… I was still optimistic about a sleeve… but I’m pretty sure this hole isn’t supposed to be there. This is looking up from below #1 at the back of the block. I noticed light from a water jacket hole at the top, so it’s in a coolant passage. Sooo… unless this is supposed to be there (doubt it), or is an easy fix (doubt it), then that may be the final nail in this block’s coffin.
The head is looking salvageable though. The #1 intake/exhaust ports will need some clean up. There’s one stuck valve (#6) and it looks like the valve guides are various stages of proper seating.
I agree, not reasonable to try to weld this one up. You definitely want to salvage all of the parts from the block though.
The chain guides look unworn from what I can see and new upper guides have a reputation for failure. Likewise the tensioner and possibly the oil pump - more so on the 3.8 oil pumps, but I would reuse an excellent original 4.2 pump over a new one. I think a lip seal conversion is preferred now, but some might still like to add a rope seal carrier to an early block. And, of course, crankshafts don’t grow on trees. Now that you aren’t worried about damaging the block, if you hit the wrist bosses from below with a big enough hammer via a sold bar, they will probably fracture above the skirts and come out.
Thanks all. So a repair isn’t possible, not reliable, or both? Very disappointed.
OTOH, the head, triple carbs, valve covers, oil pan etc seem to be in good shape. How much can transfer over to a later block? Very inexpensive, running 1980s XJ6 engines can often be found. I’m not going for numbers matching or anything like that, but I want it to look original and be reliable when I’m done. I know the 70s-80s blocks have long head studs that go into the water jackets so are prone to corrosion and breaking inside the block, the blocks themselves are prone to cracking, and the engine mounts are in a different place.
Before I would make a final decision, I would take it to a machine shop and see what they have to say. Back in my warranty days, surprisingly we actually repaired porous blocks (crankcase to exterior where there was no pressure) with J B Weld.
Thanks, John. I probably will have it looked at to at least give an assessment/confirmation. I have time. There are 2 machine shops in town and neither have responded to an email (but I didn’t really expect them to). I didn’t identify the engine to avoid Jaguar inflation, but one shop specializes in US racing blocks, so probably not worth his time.
As long as you are talking about a block and not a cylinder head, you may very well find a local shop willing to work on it, as the Jag really isn’t anything very exotic. I’ve had poor results trying to build local expertise with cylinder heads and I would recommend you find a shop experienced with Jag heads.
It’s a lot of money (several thousand dollars) to put into an engine for a risky repair to a water channel that dumps coolant into your crankcase if it fails. Cast iron requires special technique. I had freeze cracks in a series 1 e-type block repaired by an expert, who heated it up in a forge first. He’s an older guy (like me) and says that he’s on his last batch of cast iron rod, that there’s no more good rod out there, and he’s quitting when that runs out. So, if you really want to save this block, I would look for a specialist who knows cast iron, but that won’t be easy.
Personally, I would scrap the block, but it wouldn’t hurt to show it to the locals - maybe they have an idea? Doubt they will respond to an e-mail as every shop I know has been hammered since the pandemic started because of all the guys getting in their shops. If you don’t care about the engine mount location (what would it go in?), you could get a cheap XJ6 block. Or maybe see if someone in your local Jag club has a spare more repairable 4.2 block.
Sorry that this is turning into a disappointment for you.
John, I added more details to my profile, but it’s not much.
Ron, I’ll see what a shop says, but by the time I get the pistons out, I may feel differently. Probably not worth it.
I have a feeling the water jacket is worse than just that hole. I did find this 1985 XJ block on ebay within a reasonable distance and am waiting for details from the seller. If still available, I also know of another '85 engine that supposedly ran when pulled for the same price (but would require renting a truck to retrieve it). Assuming all is good with it, would my crank, connecting rods (I definitely need new pistons!), head, timing covers, distributor, etc work on a S3 block? The slots between the cylinders were added by Jaguar to address crack problems, right?
The plan was to rebuild this while I looked for a Mk2, so originality isn’t important. I suppose motor mounts could be fabricated that would work.
So I got the idea from watching a USA show where various Transport operators bid against each other via an online system for your job
That could work for me I thought, and lo & behold such a service now exists in Australia (Truckit)
First time I used it and I was blown away with how cheap & great it was, cost me a fraction of what it would normally cost to get vehicle parts shipped hundreds of miles.
works best when the operator has a few jobs and wants to fill his truck to cream extra profit,
as long as you are flexible, the price and service was unbeatable (it cost me much less than it would have just for petrol to drive my own vehicle and retrieve it)
Yes it does and it’s good. I have used it, anyone capable can bid. An off side mudguard for our Outback (don’t ask) was delivered to me by Kev’s Country Campers, from Queensland for $75. Paul.
