That's exactly how I did mine.

XJSV12 I started using a method similar to the pic you posted, the problem I had was repeatability, depending on how you put the rod on the rig the readings varied by upto 5 grams.

So I built a rig like the one in Gregs pics except I used bearings to hold the big and little ends on the chain and scales, this was so the rod would find its own centre.

I'll take a pic of it when I get home from work.

 

I'm waiting for the parcel with more precision scales. I'll recheck with this system of the scale. Thanks

 

It's not the scales that are the problem, it's the loading on the rod from how it's hung.

To get the repeatability in the measurement the rod needs to be centered on the big and little end axis, ANY loading in any direction will effect the measurement, the best scales in the world are useless if the measurement method is not good.

Even moving the post holding the non measurement end can add or subtract a couple of grams from the measurement.

 

Here are some pics of my set up

This did not work, I could not get repeatable measurements so I bought a better set of Laboratory scales to replace the kitchen scales, still didn't work.



Here is the setup that worked including the Laboratory scales. It is important that the distance from the centre of the 2 bearings is the same as the rod centre. The pipe is galvanised water pipe and fittings and the chain goes through holes in the pipe. It is important everything is level. Mine is mounted on my granite surface plate that is level with ±0.1°

 

Warren, why not just hang the rod on a rig from it's small end so that the entire load is transferred straight down onto the scale? If you're not interested in the relative weights between the big and small ends this would seem to be an easier way to go about it.

 

I think the relative weights are important. Because each end of the rod moves in an entirely different path from the other, this can set up unwanted stresses on the crank if the conrod ends along the crank are not the same weight. Imagine a rod with a heavy small end weighing the same as one with a heavy big end. They would not produce identical stresses and vibration patterns.

 

Warren
I expect you have seen post 814 on this thread:
https://www.jaguarforums.com/forum/x...1/#post1790497
The Bonner head photo look quite like your design.
Greg

 

Greg is correct each end needs to be balanced independently. The big end is rotating and the pin end reciprocating, if they are not balanced separately this could induce vibration.

Also the rod MUST be parallel on its centres to the scales. If you rest the rod on the scales and remove meal the rod centres will not be parallel, this will effect the measurement. Removing weight from one end will also effect the weight on the other end.

 

It looks like the intake valve is recessed further into the head and the chamber is bigger. My chambers are 31cc and with 6.7L this will give me 11:1 CR. My chambers on a stock 5.3 would drop CR to 9:1.

 

Are the pistons different between the 5.3 HE's? I'm thinking of the Euro cars with 12.5 compression(299 BHP) and the North American cars with 11.5 (262 BHP). I'm assuming Australia got the 12.5 version?

 

Yes, the piston is slightly different. But post about 1988 with the introduction of the Marelli system, ALL subsequent V12s were 11.5:1 CR.

 

My chambers are modified and enlarged 2cc over stock 6.0L chambers which are larger than the 5.3L chambers.

My marelli is 11.5:1 and 284hp, I suspect the power difference between this and the USA spec cars is to do with the air pump and cats in the down pipes, which we did not get.

There are also different part numbers for Marelli ECM which I suspect has different ignition maps depending on market and fuel available.

Maybe this is why USA cars burnt and ours didn't, just a thought........

 

I though the 6.0 cars were 11:1 compression? Or was that just USA? Typical best fuel available in North America is 91 AKI/95 RON, so the ignition maps may reflect that. Or it's emissions specific.

I've never heard of a Marelli car burning, I think it has been way over hyped relative to how prevalent actual occurrences are.

 

The 6.0L was listed as 11:1 here as well. Our best fuel is E85 @ 102-105RON although it's not available outside the big cities 98RON is available at almost every fuel outlet bar maybe very isolated remote areas.

The NA 5.3L was about 20hp down on the Aus spec car you can only assume that the NA model with the additional cats and air pump were more restricted than ours and needed retarded ignition timing as the NA Marelli ECM has a different part number to mine.

A friend of mine who is a Jag technician and very experienced building V12's told me the NA V12's ran hotter than ours here in Aus. My 6.0L came from NA and had under 100k miles and it was toast, chambers were black with carbon and all valve stems were out of tolerance most of them were worn oval. The bottom end however was perfect.

 

all well and good, but the HE combustion chamber temperature runs much hotter than the Pre HE chamber just by its design, because the heat is localized into the head ,while the pre has the chamber on top of the piston!! HE combustion surface area is larger so heat transfers into head cooling system!

HE was designed for MPG not HP. the only reason it made power was the unusually HIGH comp.ratios.

also the exhaust port has a tight turn, and that slows exhaust flow allowing more time for heat to transfer into the head!

seeing as i built my engine pre-HE 23yrs ago, and had NO experiance with the Famous Jag V12 overheat problems,(watching Daytona 24hr races ,most DNF because overheat,sad).

i had my cylinder flathead deck surface and exhaust ports CERAMIC coated ,to reduce heat transfer into head cooling jackets!

also piston tops, with a different type coating.

must work been 23 yrs and counting, lest remember FLA. and Texas have much higher temps , not uncommon in Texas 100F + in summer months.
i use an add on DIGITAL temp gage , sensor mounted where AAV used to be,never liked that thing anyway.
my engine temps have NEVER shown over 195F.

all my mods are done by logical dieciesons, i had nothing to go to!
NO computor at that time, probably would have messed things up anyway!

 

Had some time today so I made the first of 12 injector spacers. The first one took me a long time, the other 11 will be easier.

The X Type injectors are 9mm shorter than the V12. The green injector is a 12 hole Denso from an X Type these have a very fine spray pattern.

I have also reconfigured the Megasquirt ECU hardware for 2 low current ignition outputs to drive the Marelli ignition modules, I've decided to use the OEM distributor and forego the coil packs. This frees up a port on the MS2 so I can add knock sensor input. Unfortunately the knock sensor input and coil 5 use the same port on the MS, and as I have the knock sensor hardware already this won.

 

injectors were made for Ford by Denso?

Warrjon , do you think the very fine spray will win the race, or get better MPG, and by how much?

 

There are 2 reasons I used these injectors, they cost me less than LS1 injectors and reading up on them the finer spray gives much better fuel atomisation.

So in theory this should yield better mpg at light throttle and more power at WOT, due the better homogenized mixture. At worst they must be better than the stock V12 injectors. they are are also 14ohms so I don't need to configure PWM and flyback diodes for the Megasquirt.

BTW these injectors are for the Duratec V6 but were not used in the Mondeo they were used in the X type and S Type.

 

i'm using Nippondenso Honda injectors, 4 ohm and much higher fuel pressures, so atomizing is quite good!

some abstract theory, fuel/air mixture finely atomized has more chance of detonation than larger fuel dropplets, being as large drops absorb heat from the combustion slower
in process of atomization into vaporization.

heat is main cause of detonation.

BUT only time will tell when you up and running.

my opinion is you will make excellent power and torque from your swept volume/displacement,6.7L, than most anything else you are modifieing.

 

I'm not sure I get what you mean.

I understand heat (or hot spots) is one cause of detonation. Smaller fuel droplets have greater surface area absorbing more heat, so the incoming charge will be cooler with a finer spray.

The research I read on this was done by Toyota for their dual injected engine It has 2 fuel injectors per cylinder Port and Direct injectors. The findings were that the finer the port injection the cooler the intake charge was and this increased the engines detonation threshold. BMEP increased, so same power for less fuel.

For me this is more about the journey than the destination. I have never built an engine before so this for me is about getting as many small things optimised.

I should have the cams back after Xmas, it's a 600km round trip to pick them up.