Part 2 today .
What do you think of the bearings pistons and crank ? I would appreciate some feedback .
Can anyone recommend a reliable machine shop in the Midlands UK?
Part 2 today .
Con rod split pins - the ultimate DPO error, re-using old split pins and incorrect installation.
New pins of correct diameter and length and properly installed will not break off.
Crank damper bolt - On mine there were spacers to hold that locking ring out so it did indeed lock the main bolt.
Don’t take that little bolt out unless you plan on removing the dizzy drive shaft bushing. I’d like to see you set the engine right side up, then squirt water into the water passage which leads into the block…down and toward the left…observe results. That broken tensioner spring would have caused somewhat unstable cam timing and the obvious wear on the slipper pad. But overall, I’d say your engine is pretty darn nice compared to what it could have been. I’m a little curious about the extra hole in the rod bearings.
jim you can use chessman engineering in coventry. they do the machining for a lot of the bigger trade names in the jaguar world. mostly ex jaguar people . not the cheapest but…you get what you pa for.
i retained the spring blade tensioner in my 120 as i didn’t like the look of the kits that modify that arrangement to the later hydraulic version. however if i did it again i would make the change and probably go with the rob Beere version.
if you keep you existing rod blots i would change the nuts to the later type which does not require the split pins. some people change the bolts and nuts to new ARP manufacture but they are expensive its all a matter of personal preference.
additionally you can use the later type washers on the main bearing caps negating the need for the tab washers.
from what i can see in your video a simple refresh is the way to go, I’m not seeing anything that would require a machine shop, other than you should have the crankshaft bungs removed which is a pain in the bum to do.
others will comment.
Will the dizzy shaft come out with that little bolt left in ? I wil try the wster exoeriment and see what happens .
Thanks Phil i will give Chessmn a ring.
Jim, definitely worth getting a mic on the journals to check for ovality. Hopefully the workshop manual will give the spec figures you’ll need. I’d check bores as well with a bore mic, also rods for twist etc., but a decent machine shop can do all this as well as crack test block, crank, rods, head etc. The wear and muck on that engine are not commensurate with a 64-yr-old motor so work has clearly been done, but without knowing the history of that work I wouldn’t take any chances. Especially if you’ve asked about the value of useable C-type heads recently…
Unless the pistons are absolutely mint I would probably replace. I would also get the machine shop to do a full chemi clean for the water passages in block and head. I removed the three big hex socket plugs from the head valley too to aid cleaning, might need a little heat for that.
I do not intend to use castellated big end cap nuts - sounds like a recipe for trouble to me. I’m also not keen on reusing 60-yr-old big end bolts, either, but I haven’t yet investigated the new options on that.
Yes…that bolt only holds the bronze bushing in the block. Of course, if you were to have the block dipped, I would remove that bushing first…but it is an operation best avoided otherwise.
That reminds me, don’t use a big hammer to get that bronze bushing out, it will get distorted and you will have to ream it. Better to press it out gently with a big C-clamp or something like that.
I tried the water test , what am I looking for ?
Go ahead and squirt about a pint of water into the passage which leads from the water pump into the block, please…I don’t want to prejudice your observations.
Any deductions ?
Your block, and my somewhat later block do NOT have water pump-induced circulation throughout the block…the pump ONLY moves water into the top 2" of the exhaust side, then up into the cylinder head. The vast majority of coolant sits static, acting as merely a heat sink. If you reach or probe into the water passage, you should see and feel a pool of water sitting in a well or port to the left of the opening. I had assumed this “passage” would allow coolant to be circulated around the bores, but such is not the case…that passage is a dead end. I just wanted confirmation that my block was not an aberration, as had been suggested, so thanks for helping.
There is no conduction, at all, between the intake and exhaust side? I assume Jaguar addressed this in later years?
Had no idea!
Didn’t you find it strange that you could completely fill the intake-side water jackets WITHOUT water flowing out the water pump inlet…I did. That is what lead me to investigate further. There are several other design elements of the XK engine that one might miss unless one used a fine-toothed comb to explore the whole package.
I have not had anyone do a similar water flow test on later engines so I don’t know IF this design was changed…but I can tell you alot of assumptions, in general, have been made that turn out not to be true. So if any lister has a bare 3.8 or 4.2 block sitting around, I would like to see IF the cooling system WAS changed to a more “conventional” design.
This is not an error or oversite on the part of the factory, nor is it any cause for any concern.
Cooling is all about the alloy cylinder head, and the exhaust ports, which is exactly where the factory forces the coolant, are where the heat lives.
The intake side simply needs very little liquid cooling. It is cooled largely by the inrush of the intake charge. The intake charge temperature can run sub freezing, being cooled by both the temperature drop due to the reduction in manifold pressure, and by evaporative cooling from the liquid- vapor phase change from the fuel charge.
The minimal circulation in the block is more than adequate. By example, look at the alloy pistons. Only cooled by the intake charge (which quickly heats as it is compressed) and by oil spray from the crankshaft, they still survive.
It is not unheard of in some racing circles to fill the engine block jackets with concrete and only cool the cylinder head(s).
If you guys know me at all you know this kind of thing will pique my curiosity.
So I pulled all the stuff off of block G4686 so I could get a look inside.
The intake side water passage goes down to the lower end of the cylinders, and all six are connected.
The exhaust side has upper and lower chambers. The uppers are connected to each other, but do not go down to the core plugs.
The lowers connect to the core plugs.
There is a passage between the cylinders between the intake and exhaust sides. You can see it through the core plug holes.
Here I’m shining a flashlight into the deck on the intake side and viewing the light through a core hole on the exhaust side.
Its been a long time since I cleaned my 120 block, but I remember poking wire brushes through from the core plugs on one side to the other side because there was a lot of crud in there which I guess settles in the lower end around the cylinders.
So my advice is to get all 7 of those big core plugs out and clean in there.
There may be a smaller core plug above the starter motor. This is in an oil passage, not water, so usually does not have to be removed for cleaning.
Nope…the upper side of the exhaust side is the only area where water is forced into the engine…that is why filling the intake side with water does NOT cause water to come out the water pump passage. To Mike’s point, Jaguar was pretty advanced when it came to engine design; the long head stud design was to prevent bore distortion that the short studs could cause, and they also went with the “cool head/warm” block scenario race engine designers employ. This is sometimes known as “reverse cooling”, an idea Smokey Yunick tried to get GM to adopt. And “block fill” is very common in HiPo V-8 engines since, as Mike mentioned, the cylinders “like it hot”, while the head does not. So, I understood the Jag design when I saw it, I just don’t think many others every noticed/understood/cared.
Indeed. My Cobra’s '63-cast 5-bolt HiPo was treated many moons ago with Hardblok.
The chap who did the 289’s machining for me in Palo Alto has some interesting Smokey Yunick stories…