Engine strip tips?

(Roger King) #1

I’m planning to lift the head off my 140 engine. Any tips for engine strip-down in general? I shall be going through it completely, so presumably I won’t do any harm by just removing the timing gear rather than retaining the cam sprockets in their holders etc. I have a lot of experience with classic engines, but haven’t worked on a XK engine before - the only OHC motor I’ve stripped before was a Stag engine.

edit - should mention, it runs on 5 so I know it’s not seized.

(Paul Wigton) #2

Be careful to NOT rotate the cams or engine, once the chains are disconnected, and before setting it down, combustion chamber side down, to remove the cams.

Keep the cam bearing caps in their respected spots. It likely will need the cooling passages welded up, and that needs to be done by someone who understands these heads.

(Rob Reilly) #3

If you find the head won’t detach from the block due to corrosion on the studs, some people have used a hydraulic jack between the oil filter boss and the intake manifold to loosen it, though I have never done that myself.

I had the situation where one stud on the intake manifold was so corroded it could not be removed, so I suspended the head dangling from the manifold on my hoist and kept putting oil and heat on it, took about 2 weeks as I recall before it moved.

Note the very tiny part numbers stamped on the camshafts, and/or keep the tach drive attached, so you don’t get them mixed up. Measure and make a note of the clearances and shim thicknesses, and keep each valve and tappet in its place. You may get lucky and find none need changing.

If it lived in a warm climate where they don’t use anti-freeze, you may find the coolant passages in the head around the steel head gasket are corroded away. This has been discussed many times on this and the XK engine forums. Basically the procedure is to grind away the corrosion to expose good clean metal, then immediately like within a hour TIG weld it with low heat and skip around, letting each place cool so it doesn’t get warped, then file off the excess. If you do it right it should not be necessary to mill the whole surface. People do that too readily.

When you get to the crank, note the condition of the split pins (aka cotter pins) on the rods. I’ve seen some engines where they were all in excellent condition, and one Mark VII where they had been wrangled by pliers, obviously used at least twice, and there were broken ones in that sump. I make it a rule never to reuse an old split pin (i.e. penny wise and pound foolish).

(Paul Wigton) #4

Unless in an emergency, never.

Replacing the rod nuts with good quality ARP nuts is a good idea.

(Roger King) #5

Thanks chaps.
Bit of a result today - I managed to double-nut all 14 studs out, some easier than others but no breakages, and the head is now rocking around loose on top of the block. I’ll get my crane on it tomorrow to lift it off carefully, and report back on the condition of the aluminium waterways. The studs don’t look very corroded at all, which is good. Car was supplied new to Hofmann in NY, and spent its life in Sacramento CA from what I can tell. In storage since '83, and apart from the disgusting attempts at door hinge repairs all the surprises have been pretty good ones so far.

Wish I hadn’t typed that…

(Roger King) #6

Just a brief further update - the cam lobes look incredibly good, not a scuff on them and surprisingly ‘pointy’ for a fifties profile. I was going to strip the cams and valvegear and start again from scratch as I plan to go through this completely - all bearings, fasteners etc. and (unless I am unbelievably lucky) rebore and pistons, next grind on the crank, new valves and guides. My main concern is that I can keep the C-type head with the block as they are both original.

(Mike Spoelker) #7

(Raising hand) I have done this. You do not want to get carried away using this method.

My suggestion is to throw the split pin rod bolts in the trash and replace them with the later model modern bolt. I have found the remnants of far too many split pins in the bottom of sumps and wedged in the oil pump. Why risk reusing 60 year old rod bolts?

(Mike Spoelker) #8

A really good, economical alternative is to replace the rods and the bolts with those from a S3 XJ6, which also use the modern bolts.

(Lovell) #9

Greetings All,

Is “economical” the way to go when a good engine rebuild costs so much in labor and parts?

(Mike Spoelker) #10

Economical in that sets of good used XJ6 connecting rods are plentiful, and thus inexpensive, and provide a notable improvement on the original design. I don’t know if they can be purchased new these days. I’m sure lots of us have a set tucked away on a shelf, “just in case…”

(Paul Wigton) #11

I have a set, “tucked away” in the complete SII engine I got, years ago, for my never-to-be-finished hot rod!

(Rob Reilly) #12

Sorry friends, I did not intend to stir up that old topic we covered 10 years ago.

Not knowing the depth of the original poster’s pockets, I simply wanted to be sure he did not miss that point and use the old pins again. We have seen evidence that certainly many low budget repairers in the distant past did so.

(Mike Spoelker) #13

Oh yeah, me too. I eventually came to the conclusion that 2 complete spare engines, two cylinder heads and two crankshafts took up waaaaay too much room to justify. Someday, I may come to the same conclusion about spare rear axle housings, 4HA Thornton Powr Lok differentials and 2HA internals. But not yet. I just built a bigger garage on a remote site.

(Mike Spoelker) #14

Considering the average age of most of us, I’d say we live for old topics.

(Robin O'Connor) #15

And the rest of us probably cannot remember :slight_smile:

(Roger King) #16

Thanks for the tips and advice - very useful to a Jaguar novice. I’ve been rebuilding engines for over 40 years and feel I can say I know my way around a block, head and set of rods. Once the engine is stripped (which is probably a long way off - I am merely removing the head whilst it’s still in the car due to all the stories I’ve heard of what a struggle it could have been, but luckily wasn’t), the main components will be off to my usual machine shop for checking and measuring. Block, head, crank and rods will be chemically cleaned and crack-tested. Rods will be checked for twisting or other dimensional damage/wear and if OK will be re-used. Bore and crank journals will be treated as appropriate, possibly a line-bore but may not be needed, and the rotating assembly will be balanced once decisions are made regarding pistons, flywheel etc. I can’t believe Jag used split pins on the big end bolts - never seen that before. The whole lot will go together with ARP fasteners as far as these are available for a '55 XK engine.
As for assembly, my preference these days is for single-size piston installation sleeves (ring compressors), but I haven’t researched availability in Jag sizes yet. I hate the old spring-steel-and-screw things.
Spare engines kicking around - er… 6 5-bolt 289s, 6 6-bolt 289s, a 351W, 2 1275 Cooper Ss, 1 S54B32 BMW M3, 1 Land Rover 2.25 petrol, 2 602cc 2CVs… had to build a new shed as management reckoned the place was getting like a breaker’s yard.

(Phil.Dobson) #17

there area couple of XK engine ‘mini’ books that are very useful one I remember was published by practical classics. do you have a full factory workshop manual?
you need to be methodical

(Paul Wigton) #18

Ditto: They can be utilized, but I always hated them.

Used a nifty slide clamp design for Bugs, but never got one for other engines.

(David Langley) #19

A couple of XK engine rebuild tips that I don’t see mentioned here so far:

  1. Make sure you remove the staked plugs in the crankshaft and thoroughly clean it out.
  2. If you intend to use ARP rod bolts, then search the archives here for special steps that need to be taken with them. Unless something has changed recently, the ARP bolts that folks tend to select (which are not specifically for the XK engine) need to modified with a chamfer under the head, or they will not seat properly with potentially disasterous results.


(Paul Wigton) #20

I just used Jaguar mil-spec rod bolts that SNG sold: fit perfectly, and just used Chevy rod nuts.

Perfectly OK for all foreseeable street work.