£100 Mystery xk Engine Adventure

[politeperson]

I want a "temporary " engine for my car whilst I rebuild the original one over the winter.

This is what I got for £100 on Ebay+ £70 pallet delivery.

My expectations are not that high on the condition.



Who knows what it is like? I intend to take it to bits then put it back together again!

I poked my camera into the top. This is a cam. No mud or spiders!



I may need a set of 9:1/8:1 pistons. And loads of other bits. Maybe an XJ6 S3 head? Maybe a piper cam profile?

I want to experiment with it a bit, why not? Give ot some more torques



The engine number is 8439-8

7/12/67

Next instalment maybe this evening.

[JagWaugh]

Why bother with pistons and cams for a temporary engine?

My inclination would be to see if it turns over reasonably smoothly, and if it does rig a temporary stand to do a compression test, and if it isn't completely trashed, weld up a test stand, fit carbs etc and run it for long enough to verify that it is worth putting in the car.

Andrew

[politeperson]

I like your thinking. I have a spare Starter motor.

Maybe I should wizz it around with some clean oil and do a cold compression test.

On the other hand, if I refurbish it, I can get away from evening television and in all probability recoup all the expense if I sell it.

[JagWaugh]

The UK market may be different. You would be hard pushed to recover the parts costs if you were trying to sell it in fresh rebuilt and never used condition here.

In your place, if I could get it to run for say an hour I would consider a new waterpump if it was needed, and shimming the valves, but I wouldn't bother pulling the head or messing about with the front or rear seals, I wouldn't even putting new chains in. I would put the money in to the original motor.

I would probably even try to skip welding up a stand once I knew that it turned over and the cold compression values were ok.

Andrew

[politeperson]

Well,

So much for doing a compression test. The whole thing is seized solid.

That made taking the torque converter bolts off interesting, and the cam sprockets. Off they cam though.

It doesn't look like the weather got inside.

I took the head off, I shall post some pictures tomorrow. It lifted easily, the engine being of the short stud variety.

The head does not appear to have much corrosion, however a foreign body certainly left its print on number 6 (front crown) and the head.

The pistons and bores look suspiciously clean. 8:1 compression ration though so too boring for me.

9 to one pistons seem to vary from £42 each to £111 each!! For the same make, with rings and pins.

Then again, some firms are now charging £26k for a full XK rebuild. Cheaper than a Ferrari 330 I suppose but really.

[politeperson]

This is where I am with it.

If the pictures display.

Brain surgery by feel is the only thing in the world more difficult than taking a picture and posting it successfully on a forum.

Head Face Resized.jpg (20.01 KiB) Viewed 15860 times

Cam Resized.jpg (189.93 KiB) Viewed 15860 times

Piston Crown Resized.jpg (199.83 KiB) Viewed 15860 times

[Heuer]

Your photos are not displaying because you are uploading them as attachments. This used to work before we moved server but now no longer does for some reason I have yet to understand. Suggest you use Photobucket in the meantime and paste links into your posts.

[Mich7920]

I really don't understand what you want to do with this "engine"...
In this state, you are going to spend a lot of time and money to make it just acceptable.
Don't you think ?

[christopher storey]

I'm not quite sure why you are so against 8:1 CR. I have a fairly newly rebuilt 8:1 in my FHC and ( admittedly fully balanced ) it is smooth as silk and quite powerful. My 9:1 in my OTS is no faster but a good deal less smooth and more to the point it pinks in the 1800-2500 rpm range which they always did when new. I can virtually guarantee that you will never notice the difference between 8 and 9:1 in terms of performance , but a good deal in terms of usability with modern fuels. Also, be very careful messing about with camshafts - Jaguar retained the same cam timing throughout virtually the whole life of the XK, only retarding it by 4 degs at the end for emission control reasons . The torque spread of the XK engine particularly in standard form is what makes Es so sensational even by modern standards, particularly by comparison with eg 911 or 355/360 and in practice you will hardly ever be using more than 4500 rpm on the road

[288gto]

Quote Christopher Storey " in practice you'll hardly ever be using more than 4500rpm on the road..."

Christopher, you have clearly never been taken out in Alty Ian's car by his son . The needle rarely drops bellow that figure.

Simon

[Alty Ian]

Quote Christopher Storey " in practice you'll hardly ever be using more than 4500rpm on the road..."

Christopher, you have clearly never been taken out in Alty Ian's car by his son . The needle rarely drops bellow that figure.

Simon

Thanks for bringing that to my attention Simon,... but I was doing that myself the other day with you in it

With an engine like the XK when its working so beautifully its hard not to give it the beans

[politeperson]

Thanks chaps.

Thanks David, I shall try harder tomorrow with the photos.

Had a quick go this evening.

I managed to get a few more bits off. 4 out of the 6 pistons are out, 2 are stuck.

When I released numbers 4 and 2 end caps the crank spun 40 degrees for the first time in a long time.

The motor is upside down on the stand, I am soaking the last two pistons.

The crank needs a grind, one of the main journals is scored.

Crank pulley nut is stuck firm, might have to use our 1 inch zip gun in our big workshop next door to get it moving. a 4ft lever did nothing.

The timing cover is still on.

Very interested in your 8:1 observations Christopher. I shall take my pistons for inspection along with the block. Not sure where I am yet with that little lot condition wise. At the end of the day, real world experience is everything on something like this.

Put a punch through the core plugs trying to distort them.

Anyway as to the costs of getting this old lump running like new, I shall let the forum know.

Anyway, no horrible cracks, corrosion or distortion noted so far.

Maybe a good clean, alloy polishing, new chrome domed nuts, crank grind, a set of bearings, studs, timing chain and tensioner, head skim, valves re seating, guides? some shims, rings, gaskets and off we go?

Lets see.

[JagWaugh]

I don't see the point. For what getting this engine running will cost you might as well just spend it on the original engine.

[Hugo]

[quote="politeperson"]I want a "temporary " engine for my car whilst I rebuild the original one over the winter.

You are rebuilding your new engine just so you can fit it as a temporary measure while you rebuild your engine? You must enjoy rebuilding engines - nothing wrong with that :) I wouldn't want to deprive you of your evening leisure activities, but how would you like to borrow my engine for the winter? I have just bought a series 2 ots imported from South Carolina. I was hoping to run it for a bit to see what the mechanics are like, but the clutch slips so much it's undriveable. So the engine is half way out at the moment. Trouble is I have no idea what state the engine is in, other than that it runs & has 2 core plugs rusted out. You could 'road test' the engine for me while keeping your car on the road. If you feel I am depriving you of another engine rebuild you could always do mine for me :)

[abowie]

We routinely use 8:1 pistons in our engine rebuilds. These blocks and heads have all been skimmed enough that if you use 9:1 pistons you will end up with compression too high and as mentioned above you will run into trouble with pinging.

A few years back, young and foolish, I rebuilt my first 4.2 engine with 9:1s. I ended up with 195psi on all cylinders and even on 98 I could not stop it pinging. After several years of messing about with everything I could think of, I had to put in a custom 2mm thick head gasket to get the pressures down to the point where it was driveable. I have CC'd a couple of engines and heads (including that one) and there is (from memory) between 10 and 15cc difference between the domes on the 8:1 and 9:1 pistons.

WRT the process you're looking at, personally I see no problem with stripping the engine down and seeing if you can get it running with no more than rings and bearings. However if after inspecting and measuring everything you need to machine bores, the crank etc it's not going to be a financially worthwhile exercise. It costs me AU$5000 for a quality machining job for an engine and head, plus AU$2500 or so for parts. We charge a customer around AU$11000 for a full rebuild including removing and replacing the engine. You're most unlikely to find someone who is going to pay you that kind of money for your rebuilt engine, given that someone else's rebuild is always an unknown quantity.

[politeperson]

Thanks Hugo, very generous offer, but I shall continue my mission.

Anyway, temporary could be a year or two!


https://dl.dropboxusercontent.com/u/936 ... esized.jpg

https://dl.dropboxusercontent.com/u/936 ... esized.jpg

https://dl.dropboxusercontent.com/u/936 ... 0Crank.jpg

[politeperson]

Well,

Not much to report, although I have now removed the crank pulley. Had to use the mega Zip gun from the farm workshops.

The only thing holding the crank in situ is the timing chain. I suspect I am going to have to cut through it as no split link is visible.

John the engine builder loves thick deck blocks, doesn't rate long stud blocks! I now have both.

He also rates 8:1 over 9:1 for low end torque. Certainly low end torque is what I want. I have an electric car for speed. Loads of torque from zero revs. 50,000 miles so far and clocking it up. I prefer the E type though. Who would not?

Oh, and a friend of a friend passed on the details of an engineering shop owner who was retiring today.

So I know own a reground (-20 mains -10 big ends) 4.2 crank with shells for £200 all in. I picked it up at lunch time.

I also bought the timing chains and tensioners for £80.

So in theory, I might be able to bolt the bottom end back together after the block is machined. I wonder if it will all fit together!

Not sure if I need a re-bore and pistons yet. Maybe tomorrow.

[PeterCrespin]

If you had to beat the pistons out I would be wary of reusing them. The crown can distort and spread. Measure very carefully, including for correct ovality.

Tell your engine guy to learn some physics because high compression delivers more torque - witness diesels. It also results in less wasted heat as more of the fuel's energy is extracted as work. What he may mean is the low comp engines are 'softer' and forgiving and as Chris said they pink less readily. But 'more' torque give they not.

It's similar with pimple cams - they can make an engine almost impossible to stall but whereas a softly tuned engine can be ultra tractable at low revs, in absolute terms it delivers less overall torque across most of the rev range. Remember torque is the only thing we can actually measure. Power is calculated and can't be measured directly on a dyno.

[Mich7920]

You don't need to cut the timing chain.
Just follow the technical book.
Mich

[Mark Gordon]

Mich is right; you don't need to cut the timing chain. Even if you did, you couldn't install the new one without releasing the sprockets from the end of the cam shafts. Just undo the bolts which are holding the sprockets to the cam shafts and the chain will come right off, but DO obtain and follow the service manual! The lower chain is a similar process, again described in the manual