Thanks Warren. So what do you do about the guide, grind away the whole lot poking into the manifold, thick piece and thin piece I can see?
If so, doesn't that reduce the guide length and if it does, does it matter that there is more of the valve stem exposed, and less guide to support the stem?
Greg

 

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i been thinkin about this subject! LOL.

OK, is the inlet port on the pre HE the same as the HE head???

if so then the reason for the socalled venturi at the guide area for the pre-he was to try to induce some swirl of air flowing into the cylinder bore?

but does not contribute much for homogenus tumble and mixing of mixture.

if the HE uses it for same theory, that means that some swirl will allready be present at about 50% lift, then the May chamber shape will really have some serious swirl effect! but not for cylinder filling for swirl and tumble in the bore!

now on to what i did with my pre-he inlet ports and valve bowls, at the pinch point(venturi)! not sayin its perfect, but only used common sense port/flow ideas, 22yrs ago there was NO internet(worth ash$t). and getting any knowledge out of England was a joke!

realized that pre-he inlet and exhaust valves were recessed about .050 thou. deep into head surface, so i milled/planed the head surface down to the valve seat level, NOW that put both my valves at equal hite and NO shrouding!

so when valve starts opening air flows quickly, and fill is much greater window the full length of inlet phase/time!

i removed guides(standard operation), opened port and bowls/venturi about 1/16" all the way thru,tapered the guides, polished/shaped things like any common cutter marks, blending all the way thru.
thats standard procedure on hi-performance heads! been doin it since 1950s.

for the manifolds an plenums, i sent to company in NY , for what is called EXTRUDE HONING, thet took out all the internal humps,bumps and injector casting flash ,and opened plenum and runners about 1/8". a subject A.Scott says not needed!

port matching was a PITA getting it as close as i could.

anyway does any of this help,DONNO, but if i had it to do over i just stroke the son of a B$$tch to 84MM , balance it! and be done with it.

lest you may forget a piston moving down on inlet stroke,with 84MM sucks alot more AIR than the teeny/wheeny 2 3/4" stroke 5.3L at the SAME RPM!

also you are trying to fill the cylinder, the chamber only is to direct the air in! along with some semblence of combustion control! now thats a good one,LOL.

BUT YES, im getting anxious for WARRJON to show his build up and see what results he comes up with,, torque and HP, dynod! just his 6.0L stroke is a big torque producer!

 

hey guy, I was just trying to state that even in the new manifold design, seen in the picture, they still had to put baffles inside the plenum to equalize the air flow down each runner... and I must
apologize for restating what you wrote in post #4.

 

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hi greg, actually if you reduce the length of guide you let more air thru the pinch point along with necking down the stem area between guide and valve underhead,all is good!

some race engines put in all new guides with a smaller stem diameter, just to increase the volume of that port to valve bowl area, along with making the valves much lighter in weight!

of course using a hi quality material, titainium, super steels, and some steels i'v never heard of, another is Sodium filled are lighter and tougher!

i have never seen,in person, a Gp44 or TWR cylinder head but i know they are much bigger ports and valves.

but with big cubic inches you need more air flow!

did i mention my valves now are .050 thou. deeper into the cylinder bore, give thought how much more air can enter cylinder, only restriction is the bore side,in one area.

 

The thick bit is the guide boss and the thin bit the guide.

Remove all of the aluminium boss but do not remove the any of the valve guide. The port can be widened and the roof raised at the guide to increase the cross sectional area to 754mm˛. The valve guide diameter is 12.75mm and sticks into the port about 8.7mm giving an area of approx 111mm˛.

So port diameter should be ((110 + 754) / 3.14) sqrt x 2 = 33mm diameter

Any bigger than 33mm at the guide will IMO hurt power through the whole RPM range without valve train modifications, ie larger valve higher lift.

All of this also assumes a good 3 angle valve job first.

 

Build has stalled ATM until my broken wrist heals. 9 weeks in a cast then physio. So I'm still probably 4 weeks away from getting started again.

Norm has finished the bottom end but I'm the hold up with the heads.

I have bought new vacuum motors for my flowbench as I need to modify it from a leaf blower.

 

In my above post the 33mm diameter at the valve guide is a best guess based on some know ratios and a good place to start.

The port needs to be flow tested to verify my theory.

I am building a new flowbench and will flow test my heads before I remove ANY material from the valve guide area. I will be testing for flow at max lift and beyond (9.5mm to 10.5mm). The reason for this is if the valve continues to flow more air beyond maximum lift then the port is too big for the valve train. So either increase valve diameter/lift or reduce port size. If the port is too small then the flow will stagnate at some lift before maximum, it will then be gradually opening the port and testing until I get full flow at max lift.

I will fill the intake port entry with epoxy to bring it back to 33mm ID which is what the intake runners are.

I will document everything I do so anyone wanting to modify a set of HE heads has a good starting point.

As I am using the stock valve train for cost reasons, so lets see how it can be optimised for best power / torque.

 

Now days this sort of thing is made in China or Thailand for peanuts. Look at the price of aluminium radiators for example.

http://www.made-in-china.com/product...st_Header.html

 

we still waitin John, pix. talk is che$p

 

What are you waiting for?

 

This:
V12 ARCHIVES / AJ6 Engineering





And I agree, we should all ask Roger to restart production!
Greg

 

I would snap up a set if available. Now we are up to 4. Very interesting will be following closely.

 

I know this is an old thread but I thought I would add what Norm had done to my heads.

Exhaust valve guide was cut back to the guide boss, intake guide was left untouched, guide boss was cut back to aide flow.

 

Production in the UK would be very expensive and that’s the reason why Roger stopped making them if the posts above are correct.

Labour in the more modern factories in China is productive and 10% of the cost of Europe. All the tubes and bends required are easily and cheaply available. Look at the prices for Chevy extractors I sent in the link in my post above.

The jigs for these intake manifolds and extractors need to be sent to China.

 

cool i can do it i am in that makes what like 6 with me

 

what is the price for the setup

 

They are not on sale - yet! We are living in hope.