So I dug out my replacement engine and had a quick look at it today. It looks to me like top hat liners were already installed - there is barely a 2-3 mm gap between liners. Am I right? I won't have to re-line the cylinders, will I? Apparently the guy who gave me the engine said it ran fine before it was pulled. I don't have a casting number yet. That, along with pictures will follow tomorrow.

 

When I see the pic of the block, I can give an opinion, but 2-3 mm is less than the width of the casting between the normal liners. Is it a 7L or 8L block and is it "slotted" between bores ?

 

Ok, here are a few pics of the block and the only numbers I could find. I didn't see anything that determined 7L or 8L unless that multi digit bit is a casting date which would make it a 7L I guess - 1977?

 

If you take the head gasket off the block and clean up a bit, I'll be able to see if you have top-hat liners. At the moment all I can see are the fire rings on the head gasket. I think it's an 8L block as you have the ribs on the side. If you're going to rebuild, knock out all the core plugs and flush the water jacket out thoroughly before taking out the head studs. You'll see these once you take out the core plugs. The back of the block is usually worst for crud.

It is clearly not a slotted block anyway, but the head gasket is for the later blocks as if you look between the pairs of head studs you'll see two holes for the water passage in the head that also allows coolant to pass up from the slot in the block. Only the two in the centre are used on your block because there is a cast water passage there.

 

It didn't occur to me until later that I should have pulled off the head gasket. I'll do that, and clean it up a bit tomorrow.

 

OK, I am more prepared now. As shown in the picture this IS an 8L block and it looks to be in pretty good shape.
So my next questions are -
1-Where do you get top hat liners?
2-Will my 7L head work on the 8L engine?

I do have 2 or 3 spare heads without valve train too.

Let me know what you guys think.

 

Hi Napoleon

Have you checked for cracks between the bores (1-2, 2-3, 4-5, & 5-6) ? You'll need to polish up the casting with a bit of fine emery paper to see them. The cracks are only found in the casting, not the liners. Earlier 4.2 heads fit, but may not have the larger inlet valves that came in with EFI around 1978/9.

Here's a UK supplier for liners. There may be one or two in the US making them.

http://www.westwoodcylinderliners.co...cc--6-cyl.html

 

Just an addendum.....

Here is an article that describes lipped liners in relation to the engine in the MG RV8 car. This used the Rover V8 all-alloy engine, originally designed and built by Buick.

Flanged liners

 

Napeleon:

Those liners look very decent and may well be useable as they are. That would save you a ton of bucks!

Run your finger nail up each liner and see if you feel a ridge at the top. Inconclusive as someone ay have used a reamer to cut it off.

Best is a snap guage to measure taper at four quadrants. I do not recall the values of acceptable taper.

But, others can expand. Or a Google search can develop some numbers. .015 seems familiar. Next to 0 is optimum.

Carl

 

Check for cracks or you'll get frequent head gasket failures !

 

I didn't upload any close up pics of the spaces between cylinders but after being walnut shell blasted at my shop, the deck is very clean. I didn't see any apparent cracks but I will polish the surfaces and get a magnifying glass to inspect.
Whether the liners or decent or not - should I upgrade to the lipped liners to make sure I don't have to do this again?
What mods will I have to make to the head?

Thanks guys

 

If there are no cracks, then you are very lucky, and if the bores are OK, then just rebuild the engine. I assume you have a standard size block, (the pistons will tell you if they are oversize). If, however, the bores are worn, and it needs a rebore, then think about putting in lipped, standard-size liners. You really need to find a good engine remanufacturer not too far away that has actually done this before. The old liners have to be machined out, then the block machined to take the new lipped liners. Final job is to face off the block lightly, with the aluminium timing cover attached, so the new liners are flush with the deck. Then it's just assembly as normal.

Have you ever rebuilt an XK engine ?

 

[QUOTE=Fraser Mitchell;864954

Have you ever rebuilt an XK engine ?[/QUOTE]


Nope....

 

I agree with Fraser. The it ain't broke, don't fix it theory.

If the bores measure within tolerances and there are no bad scratches in the liners and the block is uncracked, it is a sound basis for refreshment.

Same for the pistons. Collapsed? Meaure. Serious groove wear? Pins?

And the crank. Clean journals. Tolerable taper?

If all check out, rings and bearings and a good valve job will deliver a good engine.

I'd rather chance a loose bore over a poorly set liner.

A less than competent machinist can use sharp tools to raise havoc with a good core!
I;ve seen bores that are all different sizes!! And, the home is critical to ring seating.
Good equipment and skill needed to get a proper cross hatch. Just a glaze bust Ok in a used bore but bad in a new cut!!

Study and think. Lay out a budget on different alternatives!!

That used well running engine as is is tempting!!

Carl

 

Thanks Carl.

For the amount of driving the car will see when put back on the road I figure I won't bother removing the current liners if I don't need to. My budget will be based on getting the car operational and reliable while making improvements along the way.
I'm open to suggestions to establish a base line....

 

I think you might find it worthwhile converting the rear main oil seal to the split lip-type seal rather than the old (and pre-WW2 rope type).

Here's a US supplier of the split-lip type

Rear Main Oil Seal Conversion - 4.2 Engine - Terrys Jaguar Parts - TJP00542A

Note that you have to get a shop to machine, (grind), the crank to remove the scroll where the old rope seal sits

The old rope seals are awful and always leak a bit, and are very hard to get the sizing right. Too tight and the crank is heated up by friction so much it can melt the rear main bearing, too loose and oil floods out.

I have rebuilt one XK engine completely and done a top-end job on another, but this was years ago, so memory fades a bit. One thing, though if you have a decent workshop, is to get a heavy duty engine stand, so you can mount the engine at a good working height and be able to rotate it around. I took a 4.2, mounted it up, stripped it out totally, then took the block off, mounted an uncracked one back on and put the engine back together.

I do remember cleaning out the crankshaft oil ways and the sludge traps in the crank; mine were 2/3 blocked ! There is a main oil gallery in the block to clean out too. Apparently a 12 bore cleaning tool with paraffin is ideal, the access plug is right at the front of the engine. There is also a little hole to allow pressure into the lower cam chain tensioner, with a little gauze filter. This gets blocked up so must be cleaned up.

After I got that engine back in the car and running OK, I ran the car for severn years without trouble. Of course, I didn't go to work in it, the fuel consumption would have been enormous for a two mile journey, so took the bus !