other than a thanks button I think we need a chuckle button...

not sure if you guys ever heard of Smokey Yunick, Daytona FL.USA. he was a GM/Ford factory R&D performance consultant.

well known in USA race person, many patents for auto stuff.

he had shop made flow bench, 1st time i saw it was around 1971/72 , seemed kooky to me, asked where he got the idea, he said he visited england and Jaguar shops, they where using a machine that measured cylinder head flow, he took pictures and came back and built one!

while i was at his place , seen head i recognized , BBC chevy, with a 1 1/2" hole bored right thru from the top down into the inlet valve bowl, it was an experiment and investigation.
studying flow and chamber flow patterns, just before GM released the famous open chamber head for BBC, it became most sought after release!
HP jumped 50HP and detonation control more managable , less timing for same power output!

warrjon i hope you do well with your endevors!

Smokey Yunick, thats a name that made me smile, Read and followed his book and ideas in the early '80's + 3 by Smith? Used their ideas and way of prep / doing things on MK2 Jags and my champ winning XJS later in the 80's. If you havent read these guys stuff and then worked out and understood what they are telling you you shouldn't be touching any decent engine, never mind a v12.
Bits I recall straight away ..... talking about how one chap had made mods to increase flow to his radiator, and where the guy had placed a frog mascot on the front of the car stated ' which sort of makes up for the airflow lost by the frog!'
another was a little 1.5v motor with a tiny prop, wired to put a tiny charge to the battery from the airflow thereby complying with the 'must have a working charging system fitted' bit (tried that one.)
lastly the having his car stripped and handed a list of oinfringements with all the part removed including the fuel tank, he started the car up and drove it away telling them to add another one to the list.
I used the 4" fuel pipe bit for years on group C cars with 100L tank limit until they finally changed the regs to include the fuel lines, LoL

Yeah, Smokey was a different kind of Cat!

unbelievable eccentric ideas, made a lot of money working R&D for the big car companies!

as i remember , that car they said cant race at Daytona track, because when it went out for qualifying, it was 10 MPH faster than the best of the field, in just 4 laps.

i had a good relation with him, i was teaching college level school,(DBCC Daytona), engines , he would come there for seminars, and speak some of his wizdom, to students!

when at his shop, he would talk about being at INDY RACES, 1960s, in the very back of pits/paddocks, was a chain link fence, he said the girls would line up trying to get to the race guys,(for your imagination), HA HA, LOL>.

I've nearly finished my flow bench, just waiting for some small brass pipe for the pitot tube for measuring flow.

http://i1259.photobucket.com/albums/...psak5yggke.jpg

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Once I have it up running a friend loaned my one of the heads off the race boat. It's a flat head with chambers machined into the head. One of the things I noticed first up was how small the intake ports are at 35mm, I have seen a lot of guys here on this forum with much larger ports with out the valve train for them to work.

This was a 5.3L engine with a big bore kit so 70mmx95mm.

Specs were
600hp at 7500rpm
6.0L

Ports
Intake 35mm
Exh 35.3mm

Valves
Intake 47.5mm
Exh 40mm

Lift 0.440"

http://i1259.photobucket.com/albums/...psuq6nalld.jpg

http://i1259.photobucket.com/albums/...psv0byc7si.jpg

Love the Pics,
I followed the whole series on photo bucket, I got confused as to what heads were the ones tested, seems to be a machined set of HE there too; very well done.
Could well be room for improvement as 35mm is small. I wonder on the logic of 35mm as the race diameter of the 5.3 TWR Group A cars was 36mm using std size valves. The valve size is very nearly full 7L TWR race size. and the 440 lift is about the max that you can do on a re profiled cam set up.
So I will take a guess that the port size is not selected on purpose but about the size a standard Pre He head cleans up to. Would also love to know how the figures where achieved and what the BHP would be from 5K upwards. I mention this as the 6L Group 44 race engines were maxing BHP below these revs. with 38mm ports and a ..450 cam. The bigger units were still increasing at 7500rpm but had 40 or even 42 ports and bigger cams.
The F1 boat engines I have have are 7L & 42mm inlets on sliders.

The HE heads on photobucket are mine and off a 1993 6.0L that I have modified by hand, my aim is to optimize them with the stock valve train. They haven't been flowed yet. I do not want to open the ports with out testing flow first.

I am not looking for peak HP as this is a street engine. I have read a lot of what Grumpy Jenkins and David Vizzard have written on modifying heads. So my plan is to flow them and optimise the port. I suspect this will require adding some material to the entry of the port, but testing will reveal what I need to do.

The heads in the pics here are pre-HE and off a racing boat (6.0L class hydroplane). The boat was dam near unbeatable.

35mm is the narrowest part of the port just before the guide, entry is about 37mm. The port size was optimised over the development cycle. The cam duration looks huge, but I don't know the spec. These heads won't be used again they are stuffed, lots of corrosion in the water jackets from raw water cooling.

Finally finished my flow bench and got my head on there. I only had chance to flow 1 intake port. Maximum flow at 9.5mm lift was 215cfm at 28"h2o, ran this through the Wallace racing calculator and got 611hp, now I know I won't get to this level but it bodes well for a good 450hp.

Another interesting finding was port size. I am running the old stock valves ATM with no multi angle seats. My intake ports are 30.5mm ±0.1mm and as I lifted the valve past 9.5mm onto 10.5mm flow went up. What this means is my 30.5mm port is flowing enough air for the stock valve train and going bigger in the port WILL hurt power right across the rpm range unless changes to the valve train are made.


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http://i1259.photobucket.com/albums/...psnjcshy8m.jpg

Thought I would play with flow bench a bit more today and bolted the intake manifold to the head. The only mods to these manifolds are the flange near the head has been smoothed and the injector bump almost removed, they have not had any work done on the runners or plenum.

At full valve lift with the manifold bolted up the flow did not change, I didn't have the TB bolted on I'll do that next, and I only tested one port 3B.



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As it looks, the 6.0l intakes are a totally different cast, as the surfaces between manifold and heads are cast in one long section where as the standard 5.3l intakes have 6 feet (rather than one long one)...

These intakes were introduced when Jaguar did away with the barbed injectors in the 5.3L around 91/92. They are the same in the runners and plenum as the old manifolds.

The differences are smoother surface, removed fins on plenum and added frame for V12 badge, the flange as you noted and mounts for the O ringed injector rail and throttle pedestal is mounted to the manifold.

Warren,

Your manifolds look significantly different than my US market intake manifolds. I wonder if Jaguar produced different castings for different markets.

I see that, in addition to the difference in the mounting flanges, there are also differences in the mounting points on the runners, as well as the amount of webbing between the runners. Mine are AJ6 modified Plus Torque units, but, that shouldn't make any difference when it comes to the basic castings.

Attachment 146806

Scott, those manifolds are off a 5.3L with barbed injectors, the manifold in my pic is off a 6.0L. The different mounts are for the O ring injector rail and throttle pedestal.

The manifolds on my 89 5.3L look the same as yours except that mine have the fins on the top of the plenum.

Hi - can anyone tell me the current owner of the Bradley Smith twin supercharged XJS. Also does anyone know of any Lister Le Mans xjs mk 111 for sale in the USA or UK? chris

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you sure picked a couple of brutes, both VERY unusual cars!

my only contact was around 1997 or there abouts , when Lister came to USA for the Daytona/ Rolex 24hr race.

Lister brought a Lister Storm V12 Race car, and had a Lister XJS for running around the local resturants / hotels etc.

they did not give much info about the race car, but it had the largest plenum/manifold cover i have ever seen!

the car was competitive in race , untill some track debris put it out, at a chicane at end of the Daytona back strech , where speeds reach over 200mph.

i had some pix but they are lost in a moving situation,Darn :icon_photo:

I heard that Bradley Smith's XJS was up for sale again.

I had to refine my flow bench, the 100mm pipe between the bench and vacuum box was way too big, this caused the resolution of the readings to be too small. I had 0.3" water difference between maximum and minimum valve lift, now where near enough resolution to make readings repeatable. Replacing the 100mm pipe with a 50mm section fixed this, now I have a difference of about 14" water and repeatability of better than ±0.5" h2o.

One interesting finding was the difference between maximum lift and NO VALVE was the same, From this we can conclude the port is about as optimum as it could be for the stock valve train.

I also bolted the intake manifold back up to check my findings on this. There was NO drop in maximum flow with the IM installed. Hence the intake manifold has no restriction to flow in port 3A at least. I suspect 1 and 6 might be different, but I'll test these once I have the head finished.

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Really valuable and interesting data Warren. I am impressed and greatly admire your ingenuity and your scientific approach.

warron , if no difference in flow #'s ,measured at 3A,and like you say could be different at end ports.

like Chad Bolles used ,4 throttle bodies,2 on each side , none in the middle???. just may change things!

also noticed CFM flow was more at test 18 than 19, 18 using 9.5 lift, while 19 use 10.5 lift?

could there be some chamber shrouding at higher lift, would be nice to see flow patterns in the chamber?

so much to learn, so little time!

keep it up, some of us like this stuff!

Ron

If I used 4 TB's Norman would cut my nuts off. He was telling me he built one V12 with a Single stock TB on a single manifold and made 500hp. His suggestion to me was to cut the plenum off and weld on a 100mmx100mm square box section. I will increase the size of the plenum and flow match as best I can the runners.

That test was interesting I have no idea why the flow went down at 10.5mm lift, I repeated the test a number of times. I will re-test once I have the new valves and have had the valve seats multi-angle cut.