3.4 litre engine upgrades?

XK
41

OK: these are my recommendations: these are what I’d consider minimums.

-desludge the crank.

-if the ring lands are out of spec, get new pistons. Don’t use chrome rings on ANYTHING but a brand new bore.

-At a minimum, soak the block in a barrel of some caustic, and brush all oil galleys.

-the wear on those mains looked like either bad maintenance, bad oil flow, or a possibly bent crank: get it done correctly.

-install stakedowns, exhaust side, seals, intake.

-make sure the block deck and cylinder head are flat, and repair any cooling passage corrosion.

-recondition rods and use new bolts and modern nuts.

-use a rope seal, just know they will leak. if you don’t want leaks, step up to the pump for real seals.

-Ditch the points and condenser, for at least a Crane, better a Pertronix.

-rebuild the dizzy so the shaft is snug, and check the curve/weights.

-New chains.

-possibly lighten flywheel, and use a diaphragm clutch.

-get it all balanced.

-replace all Welsh plugs.

-set valves (assuming tappets are all within spec) on the looser side, I.e., 0.006"/0.008"

-Make sure the valve seats are not recessed.

-Modern head gasket.

-Rebuild water pump (ceramic seals don’t do well, sitting that long).

-make sure throttle shafts are snug, otherwise it’ll never idle nicely.

-if possible, use new-style upper chain guides, and not any badly-made repops: I’d use decent old ones, before badly-made new ones.

3 Likes
42

If you pull the rear exhaust welch plug, which is easily accesible
imo, that will allow you to assess whether a block clean is needed
I think the XK engine is canted backwards by a few degrees, in at least some applications?

have seen them literally choked with silt up to that rear plug level

43

A boil out/hot tank is in order assuming those chemicals are still allowed in your state. Here in CA, machine shops cannot use that method, opting for baking instead. My machinist said align honing and rebore were required after the oven “cleaning” due to the high heat.

I stick with my view that changing valve guides and spring retainers ONLY to install seals is alot of cost and work for little gain. I needed to replace my guides so I DID buy new valves and associated hardware.

44

Thanks all for your insights and recommendations.

Preservation, upgrading or a combination of the two.

1 Like
45

Sorry to keep this a little OT, but only some Mustangs had that system from '67. My '68 was originally a 289 3spd manual which came with drums all round. I fitted '70 front discs and a servo, but kept the rear drums. It stops fine now in modern European traffic, which travels a lot faster and closer than US traffic! It’s survived the M25, the Paris Périphérique and central Palermo in the rush hour.

It does get about a bit…

1 Like
46

I’ve been wondering about this myself. For the last 40 years every engine I’ve rebuilt has been sent off for a chemi-clean before measuring and crack testing. My local shop has now stopped doing this, but offered a hot wash instead. Having given them the go-ahead, they then called to say the hot washer had broken. I had the rest of the work done and picked up the bare block ('67 Series IIA Land Rover, the famous two-and-a-quarter petrol).
I’ve had a really good scrape around inside it through every orifice and have now removed a good inch and a half’s depth of crud from the rear part (engine tilts back in the frame), and the water’s running clear. There are still bits of stuff in there, for which a magnet probe works well but takes ages. I’m fairly happy with it but there are bits I can’t see. My current plan is to try some Evaporust solution inside, left overnight (maybe longer?) to see what that does.
This will affect the plan for my XK engine, too. Nick’s thread has thrown up interesting comments on the effects of heat baking on the block, which makes me think I might just repeat my scraping, chipping and Evaporust routine so as not to risk any damage. It’s the original SE block and keeping it with this car is of prime importance to me.
It’s worth mentioning that I am not concerned about future corrosion, as this block will be cooled by Evans, just like all my other classics have been for 20 years now. It doesn’t boil until 180˚C, by which time boiling would be the least of my worries, but most importantly for me (and why I first chose it) there is zero corrosion (even after 20 years with just one coolant change at 12 years for the Mustang).

47

I second this. The DIY approach does not often include checking for a bent crankshaft, and the long, straight-six crank can easily be slightly tweeked. The wobble in bent crank is hard on the main bearings.

48

Speaking of which, I trust everyone on here knows to store a bare crankshaft vertically? Even for a short time!

1 Like
49

Yep!

When I was a kid, accompanying Dad on parts runs, I noticed that at the machine shop, they had hundreds of cranks…standing up.

Never was completely convinced it was because they’ll sag, but, hey…:yum:

50

I prefer storing the crank sitting in it’s upper main shells on the upside down block.

1 Like
51

I would guess that you are referring to sodium hydroxide (oven cleaner) here. Would blocking the water escape routes and then filling the block with sodium hydroxide to let it soak for a week after removing everything that was not iron be a reasonably good alternative to hot tanking? No damage to cast iron?

52

About 5 years ago I was faced with building the engine for my 1952 FHC (679924), which had vanished in the 50 year hiatus the car had sat in a back yard in Worcester, MA. I searched for and found a 120 engine as closely numbered to my original as possible. I then found a good B head to fit up to it. I had the following done, along with all the typical good rebuild practices (inspection, cleaning, etc.) that many of you have mentioned above:

  1. 9:1 Mahle pistons with three piece oil control rings. I cannot stress enough the importance of modern three piece oil control rings, as they are the primary reason why modern engines now go 10,000 miles between oil changes. The Mahle website has a history of oil control ring development showing the oil consumption reduction achieved from the original one piece cast iron ring design (that consumed a quart of oil in 300 miles) to today’s design.

  2. Front and rear crankshaft seals. The front is fairly easy to handle and is a no-brainer, may require a bit of clearance machining for the metal cased lip seal to fit properly. The rear requires the scroll to be machined off the crankshaft, not difficult if you are having the crank turned undersize for new bearings. The replacement rear seal is a split lip type, similar to what is used on modern engines, and requires a new housing that bolts to the rear of the block, the same as what it replaces. My engine now has a thousand miles on it and does not leak oil. This is a huge improvement worth considering.

  3. Custom valve seat cutting. My rebuilder offers custom curved profiling of the valve seats with a programmable cutting machine. No longer are valve seats ground with stones, they are cut with a carbide cutter. He has flow tested heads with that profile and has data to verify the flow improvement. At minimum I would suggest you consider a three angle valve job, which is a vast improvement to the original flat faced design.

  4. High lift drilled back cams. These are standard Jaguar fare for B heads, although early ones were not drilled on the backside of the lobes. The hole in the back floods the tappets with oil and fully lubricates the tappet face and quiets them down.

  5. I used a new diaphragm clutch, which has a very positive engagement. I was able to find a 10" Borg and Beck version that did not require any redrilling of the flywheel as a 9 1/2" E Type diaphragm clutch requires.

  6. New bronze valve guides and lip seals on intake and exhaust. My rebuilder fits Harley Davidson valve stem seals on top of the new valve guides, which he has found to be superior to the rubber cups that Jaguar calls a stem seal. This requires a small groove to be machined on the top of the guides before installation.

  7. My rebuilder balanced the entire rotating assembly as a unit, from the front V belt sheave to the clutch cover. My rebuilder also weighed and matched the individual connecting rods.

I measured my original oil pump and found it to be within factory spec, and reused it. Oil pressure now is around 60 PSI on start-up and settles down a little lower when hot. I may adjust this down a bit. The oil suction strainer was disassembled and soda blasted to be perfectly clean, as was the pan, windage tray, head and intake manifold. I retained the original lower chain tensioner design, and replaced the blade and spring. Both timing chains were replaced and all sprockets inspected and replaced if showing pointed teeth.

I retained the original 1 3/4" H-6 carbs. I had to fiddle with the carb needle selection and used an air fuel ratio sensor to aid in carb adjustment. This process is still ongoing, winter has not allowed me back on the roadways for several weeks, but I am close to where I want to be, idle is good. More to follow as I refine this.

I have the straight through under frame dual exhaust on my car, as was originally offered as an option. It’s pretty loud but allows unrestricted exhaust flow. As Phil Dobson said, “it pulls like a train”.

3 Likes
53

No damage to anything ferrous.

54

Good to know. Will it clean back to bare metal without adding heat?

55

Some heat would be good: I recommend against building a bonfire under the barrel…:stuck_out_tongue_closed_eyes:

56

Geoff, when I rebuilt my 4.2 six years ago there was only one local machine shop still doing block boilouts but they were backed up 2-3 months. Not wanting to wait I pulled all the core plugs, wheeled the degreased block outside and shot in a couple of cans of heavy duty oven cleaner then let it sit it in the sun for several hours before pressure washing, followed by a generous application of WD40 (imagine that - actually using WD40 for the purpose it was formulated). The amount of crud that came out of that block was amazing, but it came out really clean. I plan to repeat the process with this one.

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57

Easily enough done DIY with the crank sitting upside down on the engine stand on its upper main bearing shells and using a dial gauge on each main journal to check for runnout as the crank is turned. Should be zero.

58

It was that hot Canadian sun that did the trick, Nick.

59

Here in the banana belt it can in summer get hot indeed. I won’t have that luxury this time, it being February and all, so I’ll be using a propane torch.

60

As usual: YooToobs, to the rescue!