Have you machined a channel into the top of the liner?

Greg thats the tool he is using in pic, with handles stiking up! it cuts a slot in the liner flange,actually works quite well!
my opinion in todays CNC world i would cut a groove up into the head surface at least an 1/8inch deep, and have a custom liner made that protrudes into the groove, maybe even use a seal ring gasket that would keep out of the slot away from heat and pressures!
i had the same tool yrs back , when i ran a performance engine business , in DAYTONA FL.
sealing gaskets lose ability when a hot spot in an area that may be weak, of course running close to wide open throttle for hours on end can find the weak hot spots!
any way OLE IS AWESOME machinist!! and a deep thinker!
i love what he does with the JAGUAR V12 engines and many other type engines, that takes serious thinking and out of the box of normal!

Thank you Ron, I wondered what that pic was!

Like this, make them real bullet proof, and I can use normal gaskets witch is smart if you have a mishap and need to to heads off work in a hurry
https://cimg9.ibsrv.net/gimg/www.jag...b9557313f3.jpg
https://cimg1.ibsrv.net/gimg/www.jag...571cccf02f.jpg
https://cimg0.ibsrv.net/gimg/www.jag...1814dd0c65.jpg

Brilliant!

OLE , i add back yrs ago i used copper wire , but talking with some Top fuel mechanics, they use a SOFT Stainless steel wire , saying it handles high temps better than copper,, but DAMIFINO???
never had a problem with either one??
ron

We may be saying much the same thing with different perspectives. You have done well with your Euro spec 9.0-1 pistons. And they would better than the 7.8-1 pistons common here in America. But with 7.8-1 pistons it’s possible to increase the boost without risk of detonation.
The stock Cast pistons will work and forged pistons ( which are heavier than stock cast pistons ) just aren’t needed unless all out racing is planned.
The real trick is to open up the ring gap.
I’m inclined to simply double the stock end gap. The slight additional loss of oil isn’t critical in racing applications.
Our V12 was conceived in the late 1950’s and first came into being in the 1960’s. Production started in 1971. That’s 50 years ago. There is absolutely no way a 50 year old engine will be competitive against new engines. But it will be fun when raced against similar aged engines in Vintage racing.

My budget limited by my retirement doesn’t allow me to spend to obtain the best. Instead I make do with OK. Vintage racing doesn’t put the same demands that professional racing does. Age and treachery will often provide me with the ability to race and even occasionally beat guys with massively bigger budgets.

I used the Gas filled O Rings Datsun used on their turbo’d Z cars. I don’t know if they are still available. But it was simple to chuck the cylinders in the lathe, cut a groove and set that O ring on top of the cylinder using a regular head gasket.

i use TOTAL seal GAPLESS piston rings,,
ron

given your progress with your tribute car I’m inclined to give you the respect I believe you’ve earned.
Given your goal, I understand your reluctance to embrace turbocharging. That’s reasonable. Frankly my goal is to save as many of these XJS’s as I can. If that means someone want 500 horsepower, that’s fine. I’ll discuss that possibility.
Few can achieve that with normal aspiration. Those than can probably don’t need my guidance.
A few more might be saved if the idea of 500 horsepower potential causes them to be saved. Used or not.

Ole

Have you considered this manifold?

https://rennsportfactory.co.uk/product/etype-itbs/

Xjeffs, I have seen it, thought about it, calculated, simulated and considered the whole package. And I have no plans of using it.
I cannot see what the intention of this design was regarding tuning. Sometimes when people have a strong urge to have something made they need help from someone, like a cad modeller, and sometimes this cad guy have never heard about pulsetuning, changing sparkplugs, mounting air filters and so on. But they can 3d modell pretty good.
I have no doubt there is resonance tuning in this manifold, its just not where and how I want it for my use, Its about the length and diameter. And when going to the length and cast and machine a manifold like this witch is a costly operation I would put more thought into it than make it look cool, sorry to say.. But this is just my opinion.
The resonance pulse tuning in a manifold is the most important job it has, we are after all talking about tuning of engines to get more tq-hp here, so this exactly question of length and diameter is not something I take lightly.
I have other plans... more adjustable, modular and service friendly.
I have no doubt it will produce 380 hp easily with a moderate setup, and probably 500 hp with another setup. The thing is that with sligtly other dimentions it could produce 420 and 550 with a more moderate setup and also accomodate filters and cold air easyer.

Its a great piece, nice work, lots of parts and I understand why people like it. But its not for me.

Ole M

My issue with it is Individual stacks do not make as much power as a plenum chamber makes. 12 individual pulses of intake having to start and stop every two revolutions. ( intake, compression, power, and exhaust ) They look sexy but that’s it. In addition they are too short to have any low end boost.

I'm guessing the runner lengths are as long as the standard manifold so I don't think it has a lack of low end torque, just a plenum.

Well, the effect of stopping of pulses is exactly what you have to play with to make horsepower. This is what makes pulsetuning, and you have to be friends with it and not work against it. The thing is that air are springiest at a certain airspeed, and if the air is to slow you spoil this bouncing effect, and then the engine has to start up the airmovement over and over again by sucking, witch is not so smart. If you have a runner small enough to make the air springy and still large enough to flow enought you are on the right track of something. This diameter of runner is suprisingly small. Adding a plenum can contribute with a secondary pulse tuning effect if you have control of the volum of the plenum, and you are able to design the plenum in a way to smoothen out evetuall power dips. But the main and strongest pulse tuning is in the runners for shure.
But you cannot just make a manifold the look sexy as you say and hope the pulsetuning is correct to the use or engine setup. If you mismatch this you end up making less horsepower.

A typical thing is to increase the runner boresize to make it breathe better. But in reality it is the area 20mm before the valve that is the flow limiting place. And by increasing the runner bore you lower the air speed, and wery typical is to mount a hotter cam at the same time, with a longer dration witch increase the time air is sucked in and as an effect of that the airspeed goes decreases even more. So double slowing of air...

You have to play with these thing to get the right airspeed due to camshoice and rpm rage usage, then choose the correct length to get the tuning frequency where you want it. And you can trick the runner to think it is longer by makeing the runner conical. And also be absolutley shure your smallest section area is not in the runner but in the throat just before the valveseat. If you mnount 44mm valves and port it out to typical throatsize of 83% you get a throatsize of 36.5mm, and that is real silly of your manifold runner is 35mm at the face of the gasket against the head, and even vorse if you have an untouched std manifold witch is about 33mm. If you have sections that is smaller and then larger in the complete runner route you will change the airspeed several times on its route, and you loose huge amounts of pulse energy in the air.

And so on, could talk forever about this...

I think they may be even longer, but its the diameter that makes the torque loss problem of this manifold.

on my pre heads , i hand ported inlets and exhausts, and i looked carefully at the inlet port where the bowl connects and opened slightly and blended that area, hoping to increase the swirl effect as air enters the bowl pocket along with 3 MM oversize valves, to help direct swirl into piston chamber!
does it work DAMIFINO , never flowed them , engine been 26yrs and still runnind good!
valve lift is 400 thou, a slight releaf on top edge of bore diameter!
ron

My first set of V12 heads ( flatheads) I spent 200 hours opening them up and getting equal flow. Most of that was getting the flow equal. Only about 40 hours was spent improving flow.
With my vertical mill I cut that down to 10 hours. But I spent an additional 20 hours calculating the XY axis for each port.
The one thing I decided was the swirl would be as designed by the factory. I don’t feel capable of out thinking those factory engineers. I understand swirl is needed but achieving swirl comes at a cost of flow. I can’t afford to do proper back to back testing to determine which trade off to accept.

there is a computer program out there called engine analyzer pro. You can enter all that data and make your choices. Then run it and look at the numbers and curve. Make adjustments and run it again. Until you get the results you actually want.
It’s how I selected parts for the race cars. But I don’t don’t know anything about street driving.