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Spent some time looking at intake flow characteristics today.
What was interesting was the direction of flow into the cylinder was totally different than I had expected.
Looking at the head from underneath (head upside down) I was expecting air to flow anti-clockwise. What was unexpected that it was clockwise and flowing greatest from the bottom of the port, you can just see the thread. Very little air was exiting opposite the spark plug.
This was at all valve lifts and high and low flow.
This pic is for illustration only (at 4mm lift) it was too difficult to take a pic with the setup. When I tested it both valves were in place and the cylinder. What the pic does illustrate VERY clearly is the shrouding of the intake valve at mid lift. Maybe this is the issue with the HE head not the exhaust valve,,, food for thought............
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Yes, that is one problem, it is like they are not really open....
so full flow would be dia x 0.25 + the shroud depth... ugh!
statically speaking...
Last edited by Jonathan-W; 08-28-2016 at 11:06 AM.
Spent some time looking at intake flow characteristics today.
What was interesting was the direction of flow into the cylinder was totally different than I had expected.
Looking at the head from underneath (head upside down) I was expecting air to flow anti-clockwise. What was unexpected that it was clockwise and flowing greatest from the bottom of the port, you can just see the thread. Very little air was exiting opposite the spark plug.
This was at all valve lifts and high and low flow.
This pic is for illustration only (at 4mm lift) it was too difficult to take a pic with the setup. When I tested it both valves were in place and the cylinder. What the pic does illustrate VERY clearly is the shrouding of the intake valve at mid lift. Maybe this is the issue with the HE head not the exhaust valve,,, food for thought............
.
A thought
you could raise the intake to be even with the head solving the intake shrouding problem and then if you want to retain May head design elements cut these depressions into the head face trying to make the yellow and green line equal
and the surface area of the black and the welding in area of the intake the same
cc the heads before and after to maintain the CR
does not solve all problems but the intake VE will increase lots...
I was being stupid... I already see a problem I should fix in that....
Last edited by Jonathan-W; 08-28-2016 at 11:48 AM.
Reason: I was being stupid...
Thanks Ron, it's always good to get another opinion. Nothing is cast in stone yet.
My engine builder is Norman Lutz who has a world of V12 experience and has built an 800hp NA V12. He is using Chevy 305 KB pistons with very thick crowns the ability to machine some off the top to adjust clearance to 1.3mm. This will also reduce the crevice volume to advantage.
Laying the chamber walls back to open the path for exhaust. Funny you mention planing the head to the intake valve I was originally against this but might just re-consider it.
I have not seen inside a pre-HE exhaust port but the HE has a very sharp short side turn, seats on both intake and exhaust are better than most stock SBC I have seen.
I have a lot of experience in Flow measurement having worked in a Military Calibration laboratory, lets hope I can put some of this knowledge into improving the HE head somewhat.
I have some clear acrylic which I plan to make a transparent cylinder so I can see if there is any port induced swirl. I will be concentrating on low to mid flow on my homemade flowbench.
I think the biggest challenge in starting with a stock head is keeping CR up unless the capacity is increased. When you look at the HE heads, it seems Jaguar just took the flat head and machined a pocket. This has sharpened the short side radius on the exhaust. I am not sure if this is where the power is lost as my understanding most of the power comes from the Inlet port. If the exhaust port is restricted it will provide pumping losses and cost torque.
warrjon, sounds like you trying to find the low flow of the HE head!
for sure, the exhust short turn is not good for hi rpm flow(its well known in performance industry!)
if you look at some of the Pre-HE heads done by GRP44 castings(California), and the later ones done by TWR England, they raised the exhaust port at least a 1/2"(13MM), along with some careful porting, they also flattened out the short turn and widened port,(no longer round) flow was increased dramaticly.
course a straight down port would have been fantastic, but exhaust manifolds would be up high in the engine compartment!
on my V12 engine i used a 2MM oversize lightweight exhaust valve, 3 angle seat, and smoothly blended into the port and reduced short turn to best i could,
also, hoping to control some exhaust heat transfer into the cooling jackets, i THERMAL Coated the exhaust ports only not the inlet ports!
velocity of exhaust flow should be faster because less time spent in the port, flow to the ported and coated manifolds.
also coated complete cylinder head deck surface again to reduce transfer into cooling jacket !
,most of my work is hands on logic,, not just math and theory!( kinda old fashioned).
Before I dive in and take any material from the head, I'm going to talk to Norman when he gets back from the US about planing the head to remove the step around the intake. Yes low to mid flow, where the valve spends most of its time is terribly shrouded on the intake.
Funny enough the exhaust shrouding is way less than the intake at all but above 80% lift.
I need to increase the 6.0L chamber 9cc to keep CR at 11:1 with the capacity increase. if I remove the step ill need to take a lot from the exhaust side, or dish the pistons.
Another interesting thing I discovered - the thread down the exhaust port had a tendency to be sucked back into the chamber at low exhaust velocity.
At high velocity (I'm using a leaf blower on my bench) the turbulence from the exhaust port was extremely high, swirling as it exited the head. Ron any ideas on this?
Before I dive in and take any material from the head, I'm going to talk to Norman when he gets back from the US about planing the head to remove the step around the intake. Yes low to mid flow, where the valve spends most of its time is terribly shrouded on the intake.
Funny enough the exhaust shrouding is way less than the intake at all but above 80% lift.
I need to increase the 6.0L chamber 9cc to keep CR at 11:1 with the capacity increase. if I remove the step ill need to take a lot from the exhaust side, or dish the pistons.
Another interesting thing I discovered - the thread down the exhaust port had a tendency to be sucked back into the chamber at low exhaust velocity.
At high velocity (I'm using a leaf blower on my bench) the turbulence from the exhaust port was extremely high, swirling as it exited the head. Ron any ideas on this?
.
i donno might have to give it some time to sink in,thoughts!
i would think that hi velocity in exhaust would be good, but never know for sure without ,some measurements of CFM!
back when Jag was doing R&D on the flat chamber head , they tried reversing the swirl flow into the bore and moving the spark plug to different position in the chamber, but results were never released, saying something about emission problems!
also becarefull if you do cut/plane the heads, like mentioned , deck thickness, chain tensioner limits of travel.etc. but the original piston design before HE and before low comp. emission was the true Heron piston shape.
i donno might have to give it some time to sink in,thoughts!
i would think that hi velocity in exhaust would be good, but never know for sure without ,some measurements of CFM!
back when Jag was doing R&D on the flat chamber head , they tried reversing the swirl flow into the bore and moving the spark plug to different position in the chamber, but results were never released, saying something about emission problems!
also becarefull if you do cut/plane the heads, like mentioned , deck thickness, chain tensioner limits of travel.etc. but the original piston design before HE and before low comp. emission was the true Heron piston shape.
good luck ,its getting interesting, ron
The exhaust flow is not coming out of the exhaust port cleanly, it is swirling (or vortexing) in a circular motion. Have you seen this before. I would have expected a more laminar flow from the port exit, with some turbulence because I have no pipe on it.
You can see in the pic the thread is circling. In some cases I ended up with flow reversion and the tread being sucked back into the bore.
If you look at the pic below this is the direction of the swirl coming from the inlet port at ALL valve lifts and low as well as high flow rate. The area circled has most of the flow. This is the port floor side, it looks to me like the air is hitting the back of the valve and making this turn. I could not get the air to flow well from the plug side of the valve no matter what I did.
I bought some modeling clay today to experiment with port shapes and flow directors.
I will be using KB Chevy 305 pistons so they can be machined with valve reliefs if needed.
Engine building is not my area of expertise, YET, so lets see where we end up.
If we really have to talk about porting of the HE head and not about makeing 500hp. I want to let you know my opinion of porting the HE head.
I found this Picture on the web, this is how I would port the head if I had to.
But until then I stick With the Pre HE head.
This is not my work. but it look about right, and then use a flat top piston maybe With a Pocket under the intake.
maybe someone know who did this?
I'm in the process of building a 6.7L. A big bore kit in my spare 6.0L. I am not worried about peak HP it will be what it is. I'm looking to build a strong street engine.
Flat heads are very hard to come by here in Australia, so I'll have to stick to the HE or these are my 6.0L heads.
If we really have to talk about porting of the HE head and not about makeing 500hp. I want to let you know my opinion of porting the HE head.
I found this Picture on the web, this is how I would port the head if I had to.
But until then I stick With the Pre HE head.
This is not my work. but it look about right, and then use a flat top piston maybe With a Pocket under the intake.
maybe someone know who did this?
Ole M
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that is a nice looking chamber, has a lot of USA wedge shape in it, plenty of laid back edges, and shroud relief around the valves!
for sure would requier a custom piston, that in its self would take a careful plan , but doable!
now, what do you think of some surface planing, like mentioned, maybe just .050 thou. )1.25mm), putting the valves deeper into the bore, and maybe a relief on the side of the cylinder liner bore,(ever so slight), right adjasent to the inlet valve, considering oversize valves, exhaust may not need it.
seems logical that valve shrouding would be reduced.
anyone have a spare air flow machine??? to actually measure CFM, etc?
Ron here are pics of the ports and runners on the 6.0L head. This engine was not a happy camper, there is 1mm of play in the exhaust valve guide on A6 and most of the exhaust guides are burnt away.
The more I look at it, the more I am inclined to think the Exhaust valve is NOT the issue with making power from the HE.
1. The short side radius in the Exhaust must have been sharpened when Jaguar sunk the valve. I think a slight increase on the port roof might help here, What do you think.
2. Shrouding on the Intake valve at low to mid lift is a major issue. See the second last pic, I have drawn the geometric shrouding envelopes around the valves.
3. Port induced swirl - See last pic, travels in the opposite direction to that shown. There is a vortex under the exhaust valve that wets the plug. Maybe lay the chamber back at the plug. The test I did was quick and dirty but adding fluid to the intake on the bench and watching from the bottom of the cylinder I could see fluid puddling in the EXH valve and around the plug - A MAJOR issue.
I have found Jaguar used Denso 12 hole 24lb injectors in the 3.0L X Type I am going to order 2 sets of these and run them at 60psi to get better atomisation.
I probably should have started a new thread for my engine build, but there are some knowledgeable folk subscribed to this thread, so I just kept it going.
My goal is not peak HP but a BIG wide power band from a 6.7L V12, with a total cost of $10-15K AUD including the purchase of the 6.0L. Bear in mind the 6.0L makes nearly 30% more power than the 5.3L under 4000rpm but peak power is only up about 12-13%.
So with the mods my engine will receive 400hp @ 5000-5500rpm should be doable. Hell TWR had 380hp from 6.1 HE @ 5250 with only CAI and exhaust, and this was tuned for 3% CO2 not max power.
My brother's Shelby Mustang engine cost $60k........
Not That I know but just an idea, You say that the port induced swirl travel in the oposite direction of what is shown. Yes I agree. But what is shown is Squish induced swirl, dont you think.
I think the "squish swirl" effect in the HE head because of the design of the squish areas and the different height of the valves and the shape under the inletvalve makes a swirl that really dont care of how the inlet port made swirl to fill the cylinder. Oh long sentence...
It will be so strong that is kills the swirl and tumble from the filling.
What do you think?
Ole M
Originally Posted by warrjon
Ron here are pics of the ports and runners on the 6.0L head. This engine was not a happy camper, there is 1mm of play in the exhaust valve guide on A6 and most of the exhaust guides are burnt away.
The more I look at it, the more I am inclined to think the Exhaust valve is NOT the issue with making power from the HE.
1. The short side radius in the Exhaust must have been sharpened when Jaguar sunk the valve. I think a slight increase on the port roof might help here, What do you think.
2. Shrouding on the Intake valve at low to mid lift is a major issue. See the second last pic, I have drawn the geometric shrouding envelopes around the valves.
3. Port induced swirl - See last pic, travels in the opposite direction to that shown. There is a vortex under the exhaust valve that wets the plug. Maybe lay the chamber back at the plug. The test I did was quick and dirty but adding fluid to the intake on the bench and watching from the bottom of the cylinder I could see fluid puddling in the EXH valve and around the plug - A MAJOR issue.
I have found Jaguar used Denso 12 hole 24lb injectors in the 3.0L X Type I am going to order 2 sets of these and run them at 60psi to get better atomisation.
The major issue I see is the puddling of fluid and wetting of the spark plug. The induction swirl travels over the spark plug and then vortexes under the exhaust valve, puddling in the corners and the middle of the exh valve, this is really bad for complete burn.
I need to setup a better test method, ultimately using the Intake manifold, injector and some fuel is the best way. I'll have to blow through the manifold so I don't blow up.
Ron here are pics of the ports and runners on the 6.0L head. This engine was not a happy camper, there is 1mm of play in the exhaust valve guide on A6 and most of the exhaust guides are burnt away.
The more I look at it, the more I am inclined to think the Exhaust valve is NOT the issue with making power from the HE.
1. The short side radius in the Exhaust must have been sharpened when Jaguar sunk the valve. I think a slight increase on the port roof might help here, What do you think.
2. Shrouding on the Intake valve at low to mid lift is a major issue. See the second last pic, I have drawn the geometric shrouding envelopes around the valves.
3. Port induced swirl - See last pic, travels in the opposite direction to that shown. There is a vortex under the exhaust valve that wets the plug. Maybe lay the chamber back at the plug. The test I did was quick and dirty but adding fluid to the intake on the bench and watching from the bottom of the cylinder I could see fluid puddling in the EXH valve and around the plug - A MAJOR issue.
I have found Jaguar used Denso 12 hole 24lb injectors in the 3.0L X Type I am going to order 2 sets of these and run them at 60psi to get better atomisation.
.
warron , you say the exhaust guides are worn badly, that the same problem the early GM 6 inline engines had, they changed in late 1950s, and did away with that recessed exhaust combustion chamber! localized intense heat.
they had many problems and cracked cylinder heads , and with only 8-1 compression ratios.
i guess only time will tell!! do it, build it, and enjoy the ride!
the learning experience is 1/2 the fun anyway, you just may show the guys
what can be done!!
The guides on A head are not just worn some of them are worn away. This head has run very hot. I was talking to Norman about it and he said the US engines run much hotter than the Australian spec engines.
Yep Norman is back from his trip to the USA and will start with the build shortly. Rods will have the pin bush replaced for Chevy pins.
I'm doing the heads, I'm having Head Stud Developments do the machining, They have Daddy Cools Grp44 heads.
I agree with the learning and fun bit, lets see where we end up.............
There is a shop in town (about 30 miles away) that has a chassis dyno. Once the car is done I'll have it dynoed.
Question; like OP said has anyone ever had a durable/lasting race car with HE cylinder heads, that won a race?
like a long endurance race,at least 6 hours or 24 hours?
maybe even an endurance dyno pull , like 4 hours at full output/load!
i know some diesel manufactures, run there engines,in cells at full load, for 24 hours!
then they do the self destruct test,(like taking a direct shell hit into the radiator cooling), they drop all coolant within 30 seconds,at full load,YIKES.
guess what USA manufactured diesel engine lasted the longest, the old 2 stroke Detroit 8V71 turbo/supercharged, why, because they had close to 30% oil cooling.
some lasted up to 20minutes, long enough to get out of harms way,military tanks!
none of the 4 stroke engines lasted more than 3 to 7 minutes(like Cummins, Caterpillar,).
these were tank engines circa, Korea, Vietnam.
we could count in the German Duetz Air cooled engines but if a shell took out the fan drive, they dont last long either!
The answer to the best of my knowledge is no. The way forward with HE heads would be to have the combustion chambers machined out like an LS engine; why do the work and experimentation when a Multi National has done the hard stuff for you already!
As for the larger capacity V12s producing more torque lower down; well yes of course they would but you are using the very same road car inlets designed for 'usable power on the original 5.3L engines, even the 6L needs larger inlets to work as efficiently as the 5.3L engines. Thats inlet manifolds not throttle bodies BTW.
08-28-2016, 10:13 AM
