Engine rebuild, various questions, and - hopefully - some good ideas.

[rfs1957]

Whilst meanderng my way through the re-build, I've come across a couple of dead-ends I could do with some guidance over, but also done some stuff that may be of interest to others.

Here's a mixture of both, in no particuar order.

1. Can anyone suggest a source for the very specific rectangular-section seals that are on the oil-fiter block, under the balance valve and the relief valve ? Shown as 8103 and 8107 respectively in publication J30. Not easily substituted by fibre-washers or o-rings.



2. Anyone not familiar with this stuff might find its use reassuring when checking clearances on mains and big-ends, helps to use a smear of silicone grease on the shell to stop it sticking, and orient the journal slightly off TDC to avoid the oil-hole.







3. Plasticene is useful for checking the fit and position of the oil pick-up pipe in relation to the sump screen, my pipe has a modified spigot going into the pump (perhaps due to a change of size on more recent pumps ?)



and as I'd also had to make a new tab-washer cum support, as the original options wouldn't reach,



I wasn't 100% confident of the accuracy, so doing this kind of test is reassuring.



4. Is there a reason why my old tensioner guide has a pressed reinforcing bump at the fold, see Left, which makes it much more rigid, and the new SNGB one (not a "budget" item) doesn't - see Right ; there are vague rumours about some guides not being up to scratch and I'd really like to find "original" parts, which are indeed available from SNGB for the upper tensioner blades, for example. Any informed observations most welcome



5. The "Engine Lock Tab Kit" EN1034 has predictably modern water-jet-cut tabs, unfortunately they're also predictably wrong in that the notch to produce the pair of ears isn't deep enough, see Right, as supplied, so that the bend is impossible to produce hard at 90° at the foot of the bolt-flat. If you use these suggest you take a square file and deepen them, as per the ones on the left.



See below, the notch is too shallow and it is impossible to bend the ears correctly.



Mind-boggling that the people making this stuff don't understand how it's meant to work ?

The eagle-eyed will see that I have used both the hardened steel washers AND the tabs, as mild-steel tabs often deform or twist when they are directly in contact with the underneath of a rotating bolt, whereas and the intermediate washer spreads this "rip". The tab requires more care to get the root of bend as close as possible to the bolt-flat but this is a reasonable compromise IMHO.



From this extract, XKs Unlimited seem to do the same, reading the text, tho' I suspect that their drawing is incorrect as the tab is shown over the washer, when it ought to be the other way round.



I'd be interested in informed and experienced comments about the pour et le contre regarding this.

6. I was struck how little anchorage the oil-delivery pipe has, and saw on XK-Unlimited



this exhortation to add something to provide an extra support - does anyone bother doing this, and its it a known issue ?



7. I have found that putting a tapped 3/8" UNF hole in the end of the crank-nose bolt is a boon when using a degree-disc for cam-timing checks or whatever.



8. The new engine stand is unspeakably brilliant, enabling endless orientations for better access, lighting, comfort - even better than I expected.







Available shortly from SNGB.

[Richardhealey]

All very interesting Rory - many thanks for posting!

[rfs1957]

It's not over yet, the pause was just to go and have a brew.

9. How does anyone else lock up the distributor/oil-pump driving shaft when undoing, and/or tightening the nut ? An 8.8 grade bolt of that diameter would normally take a 100 ft.lbs, probably excessive in the context, but nevertheless impossible to obtain with any kind of wedging of the bronze gears ? Nor with any big screw-driver ? Was there an original Churchill tool ? Or are we meant to have old distributor shaft that we've made our own tool from ?



This is not terribly elegant, and I took the picture so as to hide the fact that my SIF-brazing was a bit approximate, but it was a good way to use up a Mini front-subframe turret-bolt, and a shim out of some engine or another, and it worked perfectly.





10. Continuing with tab-washers, the SNGB EN1034 "set" doesn't include the tabs that are specific to the rear main bearing block, but assumes you'll use the same ones as on the other mains, whereas they don't really fit, and certainly don't give the same anchorage on the bolt head.



I made a new pair, similar in appearance but slightly offset to seat hard-up against the machined flats on the bearing cap seen here. I would go looking for an alternative source if I were to buy these parts again.

11. Graphogen engine-building compound, we used to use this on all valves/guides, cams, and shell-bearings, it's meant to be excellent for initial start-up, and it was the guy who built works Triumph motorcycle engines in the 60's - 70's who put me on to it.

http://www.graphogen.co.uk/index.asp?pageid=644920



The only downside is that it makes your oil worryingly black rather quickly.

12. Non-shrunk heat-shrink sleeving, with its generally oval section, makes good protective sleeves to fit over con-rod bolts when you're dropping pistons down the bores towards the crank, when it's quite easy to be a little careless with guiding the foot onto the bearing journal.



Yes, I did remove that Bengal cat-hair from the journal before closing up the con-rod.

13. And last of all, perhaps ominously the thirteenth item ............... has anyone any experience of sorting this out ?



The white-metal lining on the intermediate-sprocket has started to break up, and it is no longer available anywhere as far as I can tell - part C.2320 is the culprit.



I am guessing it was a pre-sized liner originally, not machined or honed once fitted.

I can find the C.2319 for the top (eccentric) tensioning sprocket as a bronze bush, not white-metal, and could indeed make a bronze bush to replace my C.2320 but once fitted it will require machining to size, which will probably require some tricky centering in a 4-jaw, and if there are other solutions or approaches then I'd be pleased to learn of them ?

I'm aware that the whole assembly is available, new, but the fewer remanufactured parts I use the easier I sleep.

[abowie]

1. We tend to reuse the old ones. They don't seem to leak.
2. Love plastigauge
3. Increasing the bore OD to get the 3.8 pickup pipe to fit the aftermarket oil pump is a necessity if you don't choose to just buy a 4.2 pipe. Whoever did yours hasn't fitted the sleeve accurately. Could you perhaps just cut the pipe length down a bit at the sleeved end?
4. You would think that the original was strengthened for a reason. Having said that we don't have problems with the aftermarket ones although to be fair the cars we rebuild rarely do enough mileage for a problem to become obvious quickly.
5. We don't use locktabs on the mains at all. We substitute ARP hardened steel washers.
6. Hard to know what's going on in the engine when its running but again we don't have problems.
7. Good idea. I will be copying this one!
8. I like this too.
9. We have brazed a piece of 1/2" square rod onto an oil pump drive collar, to make a T handle. This holds the shaft in place while tightening or loosening the nut. Ours probably has a more positive hold than your idea but either would work.
10. See 5.
11. Absolutely. Especially on the cams. I just use normal assembly lube for the crank.
12. We use 2" sections of vacuum hose.
13. I've not seen a bush wear that badly; we are almost always able to reuse the old ones after inspection. I have rebushed the idler sprocket on one occasion using C23191. This bush is undersized by about 10 thou and needs to be machined to fit once installed in the sprocket.
As I'm sure you know your sprocket is not usable. It might simply be cheaper to buy a new one (£66.00 aftermarket or £93.00 OEM) than getting someone to rebush your old one. I have no doubt that we would have useable 2nd hand ones in stock but we're in Australia so postage would probably make it uneconomic.

[rfs1957]

Many thanks for those insights Andrew, and for the offer of a sprocket

1. Re - washers, as you re-use them, were the originals maybe copper not plastic/rubber ? Easy enough to make them in copper or aluminium.

13. Yes the wear on that bush is very odd, almost looks as if it might have been damaged upon fitting. If those sprockets never wear out, maybe some kind soul out there on the Forum has one lying around in their Magic Box ?

[Heuer]

maybe some kind soul out there on the Forum has one lying around in their Magic Box ?

If not give Ken Jenkins a call: 01909 733209

[Bob.]

Item 4 - The Chain Tensioner
Just musing.
The tensioner will have a resonant frequency which without the dimple may have led to vibration and consequent fatigue failures during engine development. If so and given the constraints of the layout of the mounting points providing asymetric support, perhaps it was necessary to stiffen the structure to change that frequency. Or perhaps the designer was just good at their job and put the dimple in from square one to beef the bracket up, recognising the asymetric mounting points.
Or perhaps none of the above.
Bob

[Heuer]

Even the fuel filter bracket has a strengthening dimple. Good engineering practice?

[rfs1957]

The dimple is effectively a triangulation of the footing with a complete absence of stress-raisers, and concomitantly must make it's resonances a lot "softer" and more complex, so less susceptible to any kind of flutter.

But my reasoning was that if the dimple were indeed used by Jaguar, they must have thought it was necessary.

However, maybe they subsequently realised - or others have found ? - that it's not necessary, and makes no difference to the life of a part that seems always to be shortened by de-bonding of the pad rather than mechanical failure.

I'm still surprised nobody seems to sell an Original Jaguar Reference for this - or have I missed it ? - when other guides within the timing system ARE still available.

[288gto]

Hi Rory,

I got mine from Rob Beere along with tensioner, and oil pump and Guy fitted them.






Simon(e)

[abowie]

Many thanks for those insights Andrew, and for the offer of a sprocket

1. Re - washers, as you re-use them, were the originals maybe copper not plastic/rubber ? Easy enough to make them in copper or aluminium.

I've seen copper and aluminium. If you have a lathe I'd make new ones out of either.

[PeterCrespin]

One thing I always do to the pick-up pipe is cut a couple of vee notches in the lower end. I’ve measured some that come very close to the base of the sump and given the low pressure in that part of the circuit I am nervous about any restriction to flow.

By notching the end it is impossible to blank off the supply even after an impact on the sump or sloppy assembly.

Jag dropped the mild steel locktabs on the mains caps. I usually do too and use hard washers / Loctite.

[1954Etype]

Take any burrs off the oil pipes into the oil pump before sliding the o ring over. I also put a slight chamfer on the pipe so everything slides together easily.

[rfs1957]

Guide ordered off Rob Beere, and Sprocket off Ken Jenkins, many thanks for all the helpful suggestions.